Industrial high-efficiency conductive noise reduction filter

Abstract

The present invention relates to an industrial high-efficiency conductive noise reduction filter, comprising: a filter body having an input terminal connected to an AC power source and an output terminal connected to a load; at least one inductor arranged in series in a power line between the input terminal and the output terminal inside the filter body; at least one first capacitor connected between the power lines; at least one second capacitor connected between the power line and a ground line; a discharge resistor connected in parallel to the first capacitor to discharge a charge remaining in the first capacitor; and a power connection unit electrically connected to the input terminal and the output terminal to conduct power under conditions of a rated voltage of 250V to 500V, a rated frequency of 50Hz or 60Hz, and a rated current of 5A to 700A; wherein the inductor comprises at least one of a nanocrystalline core and a ferrite core, and the filter body is configured to be installed in a built-in manner in a single-phase power line or a three-phase power line to reduce conductive noise generated from at least one of an industrial inverter, a power converter, or an uninterruptible power supply.

Description

Technology Field

[0001] The present invention relates to an industrial high-efficiency conductive noise reduction filter. Background Technology

[0002] In equipment that receives, converts, or controls AC power inputs, such as industrial inverters, power converters, and uninterruptible power supplies, conducted noise can occur due to switching operations, rectification operations, load fluctuations, and internal wiring structures. Since this conducted noise can be transmitted along single-phase or three-phase power lines to the upper power system or lower load side and affect the operational stability of other circuits within the same equipment or adjacent equipment, technology to reduce conducted noise by interposing noise reduction filters on power lines is widely used. Generally, such filters can employ a passive filter structure in which inductors and capacitors are placed between the input and output sides; however, because industrial equipment varies widely in terms of applied voltage, current, installation space, and operating environment, relying solely on a simple general-purpose filter structure presents a problem in that it is difficult to simultaneously satisfy sufficient noise reduction performance and stable operating conditions.

[0003] In particular, conventional conducted noise reduction filters are often formed with a simple LC structure consisting of a single inductor and a single capacitor, or with a structure that primarily considers only one type of noise transmission. Consequently, there was a limitation in that it was difficult to sufficiently suppress both symmetric mode noise formed between power lines and asymmetric mode noise formed between the power line and the ground line simultaneously. Furthermore, if only a single attenuation section is formed along the path from the input terminal to the output terminal, noise reduction may be effective in a specific frequency band, but the amount of attenuation may be insufficient in other frequency bands. This presented a problem in securing consistent attenuation characteristics for the wide frequency band conducted noise components required for industrial equipment. Moreover, if the inter-phase capacitor and the ground-side capacitor were not considered together, or if a separate discharge path for discharging residual charge was insufficient, there were limitations in terms of safety during maintenance and the reliability of repeated filter use.

[0004] In addition, conventional technology often relies on a single magnetic material to form inductors, which has resulted in a problem where it is difficult to simultaneously address conducted noise components across low and high frequency bands. For example, a core made of a specific material may provide sufficient inductive characteristics in a certain frequency range, but may not form the expected attenuation characteristics in other frequency ranges; consequently, there were limitations in broadly processing complex conducted noise components actually generated in industrial equipment. In particular, industrial filters installed as built-in components in single-phase or three-phase power lines must be operated for a long time under relatively high voltage and current conditions. Although the core material, winding structure, and multi-stage LC network of the inductor are directly related to conducted noise reduction performance, conventional technology has a problem in that it does not sufficiently reflect these factors. The problem to be solved

[0005] The present invention aims to resolve the aforementioned problems by configuring a filter body having an input terminal connected to an AC power source and an output terminal connected to a load side to include an inductor arranged in series with a power line, a first capacitor connected between power lines, a second capacitor connected between a power line and a ground line, and a discharge resistor connected in parallel with the first capacitor. This configuration allows for the simultaneous processing of noise components between power lines and noise components that need to be dispersed toward the ground side, while also securing a discharge path for residual charge. Furthermore, by forming a first LC circuit section and a second LC circuit section along a current path extending from the input terminal side to the output terminal side, a single-stage or two-stage multi-stage LC circuit network is configured to attenuate symmetric mode noise and asymmetric mode noise through different current paths. Consequently, conducted noise, which is difficult to sufficiently suppress with only a single attenuation section, can be reduced over a wider frequency band.

[0006] Furthermore, by forming the inductor into a structure including a first reactor wound on a nanocrystalline core and a second reactor wound on a ferrite core, and configuring the coil with a 180°C grade winding, an inductance path corresponding to conducted noise components of different frequency bands from low frequency bands to high frequency bands can be formed, and stable noise reduction performance and durability can be secured even when applied in a built-in manner to equipment such as industrial inverters, power conversion devices, or uninterruptible power supplies. means of solving the problem

[0007] According to one embodiment of the present invention, an industrial high-efficiency conductive noise reduction filter comprises: a filter body having an input terminal connected to an AC power source and an output terminal connected to a load; at least one inductor arranged in series with a power line between the input terminal and the output terminal inside the filter body; at least one first capacitor connected between the power lines; at least one second capacitor connected between the power line and a ground line; and a discharge resistor connected in parallel to the first capacitor to discharge a charge remaining in the first capacitor. and a power connection unit electrically connected to the input terminal and output terminal to conduct power under conditions of a rated voltage of 250V to 500V, a rated frequency of 50Hz or 60Hz, and a rated current of 5A to 700A; wherein the inductor comprises at least one of a nanocrystalline core and a ferrite core, and the filter body is configured to be installed in a built-in manner on a single-phase power line or a three-phase power line to reduce conducted noise generated in at least one of an industrial inverter, a power converter, or an uninterruptible power supply.

[0008] The filter body comprises a first LC circuit and a second LC circuit sequentially arranged along a current path extending from the input terminal side to the output terminal side, wherein at least one of the first LC circuit and the second LC circuit comprises an inductor connected in series to each power line, an inter-phase capacitor connected between each power line, and a ground-side capacitor connected between each power line and a ground line, and wherein the first LC circuit and the second LC circuit form a multi-stage LC circuit network of one or two stages so that symmetric mode noise and asymmetric mode noise are attenuated through different current paths.

[0009] The above inductor comprises a first reactor wound on a nanocrystalline core and a second reactor wound on a ferrite core, wherein the nanocrystalline core is selected from an annular core with a diameter in the range of 25 mm to 140 mm and the ferrite core is selected from an annular core with a diameter in the range of 31 mm to 140 mm, and the coils of the first reactor and the second reactor are formed with windings of 180°C grade to form an inductance path corresponding to a conduction noise component of different frequency bands from a low frequency band to a high frequency band.

[0010] The above power connection unit comprises a terminal block and a copper bar connected to the terminal block to transmit current to the input terminal or output terminal, wherein the copper bar is formed as a plate-shaped conductor and is formed to have cross-sectional dimensions of 5 mm × 25 mm or 8 mm × 45 mm, and the connecting stud or screw shaft of the terminal block has a nominal diameter of 6 mm or 10 mm, and the terminal block and the copper bar are arranged such that, inside the metal case of the filter body, the distance between the live line part and the metal case is 10.7 mm or more, and the distance between live line parts having different polarities or phases is 20.0 mm or more.

[0011] The filter body further comprises a metal case, an insulating sheet, an insulating tube, and a substrate disposed inside the metal case, and the discharge resistor is formed to have a resistance value of 2 MΩ, and the inductor, the first capacitor, the second capacitor, the discharge resistor, and the power connection are fixed to each other inside the metal case, so as not to cause cracking, deformation, insulation breakdown, or detachment of fastening in a temperature environment of -25℃ to 85℃, a humid heat environment of 21 days, an overcurrent application environment of 135% of the rated current, and a vibration environment in which an excitation of 20 m / s² is applied in the range of 10Hz to 150Hz.

[0012] Inside the metal case, a shielding partition is further provided with a baffle structure applied to separate the internal space into multiple compartments to suppress resonance of the acoustic device, and the shielding partition includes a first partition plate and a second partition plate made of a non-conductive material, wherein the first partition plate is arranged to separate a first compartment space in which the input terminal-side inductor is placed and a second compartment space in which the first capacitor and discharge resistor are placed, and the second partition plate is arranged to separate the second compartment space from a third compartment space in which the output terminal-side inductor or ground-side capacitor is placed, and through holes through which each power line or ground line passes are formed in the first partition plate and the second partition plate, respectively, wherein the center axis of the through hole of the first partition plate and the center axis of the through hole of the second partition plate are spaced apart from each other so as not to coincide in a straight line, and the first compartment space, the second compartment space, and the third compartment space are formed on the power line for the input terminal, the inductor, the first capacitor, and the The discharge resistor, the second capacitor, and the output terminal are formed to be arranged sequentially, and the shielding partition is configured to block leakage flux or electric field components generated from the inductor on the input terminal side from directly coupling along a straight path to the power line on the output terminal side, and to cause the leakage flux or electric field components to follow a bypass path deflected by the first partition plate and the second partition plate, thereby suppressing conducted noise from being recoupled to the output side without passing through the first capacitor and the second capacitor. Effects of the invention

[0013] By configuring the filter body, which has an input terminal connected to the AC power side and an output terminal connected to the load side, to include an inductor arranged in series with the power line, a first capacitor connected between the power lines, a second capacitor connected between the power line and the ground line, and a discharge resistor connected in parallel with the first capacitor, it is possible to process noise components between the power lines and noise components that need to be dispersed toward the ground side together, and also secure a discharge path for residual charge. Furthermore, by forming a first LC circuit section and a second LC circuit section along the current path from the input terminal side to the output terminal side, a single-stage or two-stage multi-stage LC circuit network is configured to attenuate symmetric mode noise and asymmetric mode noise through different current paths, thereby allowing conducted noise, which is difficult to sufficiently suppress with only a single attenuation section, to be reduced over a wider frequency band.

[0014] Furthermore, by forming the inductor into a structure including a first reactor wound on a nanocrystalline core and a second reactor wound on a ferrite core, and configuring the coil with a 180°C grade winding, it is possible to form an inductance path corresponding to conducted noise components of different frequency bands from low frequency bands to high frequency bands, and to provide an industrial high-efficiency conducted noise reduction filter that ensures stable noise reduction performance and durability even when applied in a built-in manner to equipment such as industrial inverters, power conversion devices, or uninterruptible power supplies. Brief explanation of the drawing

[0015] FIG. 1 is a schematic diagram illustrating the overall application configuration in which an industrial high-efficiency conductive noise reduction filter according to one embodiment of the present invention is positioned between an AC power source side and an industrial load side. FIG. 2 is a plan view showing the internal configuration of an industrial high-efficiency conductive noise reduction filter according to one embodiment of the present invention in an open state. FIG. 3 is a circuit diagram illustrating an electrical circuit configuration including a first LC circuit section and a second LC circuit section sequentially arranged from the input terminal side to the output terminal side in an industrial high-efficiency conductive noise reduction filter according to one embodiment of the present invention. FIG. 4 is a schematic diagram illustrating a structure in which an inductor according to one embodiment of the present invention includes a nanocrystalline core and a ferrite core, and a reactor configuration wound thereon. Specific details for implementing the invention

[0016] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the drawings, identical reference numbers or symbols refer to components that perform substantially the same function, and the size of each component in the drawings may be exaggerated for clarity and convenience of explanation. However, the technical concept of the present invention and its core components and operations are not limited only to the components or operations described in the following embodiments. In describing the present invention, if it is determined that a detailed description of known technologies or components related to the present invention may unnecessarily obscure the essence of the invention, such detailed description will be omitted.

[0017] In embodiments of the present invention, terms including ordinal numbers, such as first, second, etc., are used solely for the purpose of distinguishing one component from another, and singular expressions include plural expressions unless the context clearly indicates otherwise. Furthermore, in embodiments of the present invention, terms such as 'composed of,' 'include,' 'have,' etc., should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Additionally, in embodiments of the present invention, 'module' or 'part' performs at least one function or operation and may be implemented in hardware or software, or as a combination of hardware and software, or may be integrated into at least one module and implemented as at least one processor. Furthermore, in embodiments of the present invention, 'at least one' among a plurality of elements refers not only to all of the plurality of elements but also to each individual element excluding the remainder or all combinations thereof. Additionally, "configured to" may be used interchangeably with, depending on the context, for example, "suitable for," "having the capacity to," "designed to," "adapted to," "made to," or "capable of." "Configured to" does not necessarily mean that it is "specifically designed to" in hardware. Instead, in some situations, the expression "device configured to" may mean that the device is "capable of" doing so in conjunction with other devices or components.For example, the phrase “a processor configured (or set) to perform A, B, and C” may mean a dedicated processor for performing said operations (e.g., an embedded processor), or a generic-purpose processor (e.g., a CPU or an application processor) capable of performing said operations by executing one or more software programs stored in a memory device.

[0018] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. This description is intended to be detailed enough for a person skilled in the art to easily practice the invention, and it should be noted that the technical scope and concept of the present invention are not limited thereby.

[0019] FIG. 1 is a schematic diagram illustrating the overall application configuration in which an industrial high-efficiency conductive noise reduction filter according to one embodiment of the present invention is positioned between an AC power source side and an industrial load side; FIG. 2 is a plan view illustrating the internal configuration of an industrial high-efficiency conductive noise reduction filter according to one embodiment of the present invention in an open state; FIG. 3 is a circuit diagram illustrating an electrical circuit configuration including a first LC circuit section and a second LC circuit section sequentially positioned from the input terminal side to the output terminal side in an industrial high-efficiency conductive noise reduction filter according to one embodiment of the present invention; FIG. 4 is a schematic diagram illustrating a structure in which an inductor according to one embodiment of the present invention includes a nanocrystalline core and a ferrite core, and a reactor configuration wound thereon.

[0020] With reference to FIGS. 1 to 4, the term "industrial" according to one embodiment of the present invention is a concept contrasted with "household" or "personal portable," and may refer to a range of applications designed to be used in or applicable to facilities such as workplaces, factories, logistics centers, research facilities, power generation areas, communication facilities, server rooms, building machine rooms, charging facilities, plants, semiconductor manufacturing lines, automation lines, air conditioning rooms, and equivalent facilities, such as production facilities, processing facilities, inspection facilities, transportation facilities, storage facilities, conversion facilities, supply facilities, control facilities, or monitoring facilities. Here, "industrial" is not understood to refer only to a specific industry or a specific installation location, but rather as a concept referring to an area of ​​use that comprehensively considers the scale of power processed by the device, continuous operation time, installation method, surrounding environmental conditions, safety requirements, and maintenance requirements.

[0021] The aforementioned term "industrial" may also be understood based on the nature of the object to which the device is connected. For example, devices or components that are connected to loads sensitive to disturbances or that process power continuously or repeatedly—such as motor drivers, inverters, converters, rectifiers, uninterruptible power supplies, switchboards, distribution boards, automatic control panels, servo drive units, machine tools, refrigerators, compressors, pumps, blowers, welding machines, robot drive units, process equipment, measuring equipment, charging devices, energy storage devices, elevator control units, and power supply units for railway or port facilities—may be classified as industrial. In this case, the determination of industrial status is not made uniformly by the specific designation itself, but rather may be determined based on the voltage, current, heat, insulation, durability, electromagnetic compatibility, and mechanical strength conditions required for the device to withstand actual usage conditions.

[0022] Furthermore, the industrial category can be defined in terms of rated conditions and operating conditions. That is, a device may be included in the industrial category if it is designed to accommodate relatively small currents ranging from the level of a few amperes to large currents exceeding several hundred amperes, voltages ranging from low voltages to voltages exceeding several hundred volts, single-phase or three-phase power systems, 50 Hz or 60 Hz commercial frequency systems, intermittent or long-term continuous operation, repetitive starting and stopping, operating modes with large load fluctuations, or operating modes where multiple devices are connected in parallel to the same power system. Here, rated conditions may refer to the electrical allowable range pre-set to ensure the device continues normal operation, and operating conditions may be understood as a concept encompassing load factors, heat generation levels, power fluctuations, inrush current, potential for disturbance intrusion, and maintenance cycles occurring in the actual installation environment.

[0023] The term "industrial" may also be used to reflect the characteristics of the installation environment. For example, if a device may be installed in a built-in, panel-mounted, chassis-mounted, or independent modular manner inside a control panel, power distribution cabinet, metal housing, rack, machine frame, on top of an equipment base plate, wall mounting point, rail connection point, or terminal connection point, and even after installation may be exposed to vibration, shock, dust, oil, moisture, temperature rise, temperature change, ventilation constraints, confined space placement, wiring density, differences in grounding structure, and electromagnetic interference from surrounding devices, such usage may be understood as a typical example of industrial use. Here, the built-in method may refer to an installation method assembled inside a finished product or a higher-level system that is not directly separated and used externally, and the panel-mounted method may refer to a method of being connected to the fixed surface of a control panel or enclosure via screws, bolts, brackets, or rails.

[0024] Furthermore, the industrial category can be described as a concept encompassing usage situations where reliability and safety requirements are relatively high. That is, when a device is used in an environment where temporary malfunction could lead to production stoppages, quality degradation, data loss, equipment shutdowns, component degradation, worker safety issues, or abnormal operation of the entire system, the device may be considered to meet industrial requirements. Accordingly, for industrial devices, factors such as insulation performance, withstand voltage performance, leakage current management, grounding continuity, temperature rise management, overcurrent tolerance, residual charge discharge performance, vibration resistance, moisture resistance, connection stability, and long-term operation reliability may be considered together. Here, insulation performance may refer to the ability to maintain electrical isolation between different potential points or between a live line and an enclosure, and grounding continuity may refer to a state in which the grounding path is continuously maintained without becoming disconnected or unstable.

[0025] Furthermore, the term "industrial" is not limited by the user or sales channel, but can be broadly interpreted based on the functional role of the system to which the device is applied. For example, even if a component has the same structure, it may be understood as industrial if it is assembled into production line control devices, power converters, automation equipment, or infrastructure devices—rather than being used inside general electronic devices—for purposes such as maintaining power quality, reducing interference, performing protection functions, supporting stable operation, or ensuring system reliability. Therefore, the expression "industrial" is not limited to a specific specification number, product family, corporate facility, or site, but can be interpreted to encompass a wide range of practical application areas requiring power processing scale, operational continuity, environmental resistance, safety design, ease of maintenance, and system connectivity.

[0026] Meanwhile, the scope of industrial applications may include not only currently widely used equipment but also future-developed automation devices, energy management devices, power quality improvement devices, mobile industrial equipment, stationary industrial equipment, modular power supply units, control units for smart factories, autonomous transport equipment, robot cells, data center power supply units, renewable energy integration facilities, and equipment where multiple devices are interconnected via networks or power lines. In other words, the term "industrial" is not bound to the representative device names of a specific era but can be used as a general technical term referring to the entire range of applications requiring relatively high power processing capabilities, high operational reliability, high environmental resistance, and equipment-level safety requirements.

[0027] Conducted noise according to one embodiment of the present invention may refer to unwanted electrical fluctuation components that travel along or superimpose along a conductive path for transmitting electrical energy. Here, a conductive path refers to any continuous electrical path through which current can flow, and may include power lines, ground lines, neutral lines, signal lines, wiring patterns, cable conductors, terminals, busbars, connectors, shielding layers, metal frames, or common ground paths between multiple devices. Furthermore, unwanted electrical fluctuation components may be understood as a concept that includes voltage fluctuations, current fluctuations, pulse components, harmonic components, transient components generated by switching, components amplified by resonance, or components added by external inflow that appear superimposed on the power components, reference signal components, or control information components originally intended to be transmitted.

[0028] The aforementioned conducted noise can be formed in various ways depending on the cause of generation. For example, conducted noise may be formed by the on / off operation of semiconductor switching devices, rectification operation, inverting operation, high-speed pulse control, PWM control, relay contact opening / closing, motor driving, sudden load changes, changes in cable impedance, ground potential differences, coupling due to parasitic inductance or parasitic capacitance, and the ingress of electromagnetic interference from peripheral devices. Here, parasitic inductance may refer to an inductance component formed incidentally by the length of the conductor, loop area, arrangement structure, or spacing between components, rather than an inductance intentionally imparted by the circuit designer; and parasitic capacitance may refer to an unintended capacitance component formed between spaced-apart conductors or metal members with a dielectric material in between.

[0029] Furthermore, conducted noise may include differential and common components depending on the mode of transmission. The differential component may refer to noise that appears as a potential difference between two conductors and flows along those two conductors in mutually opposite directions, while the common component may refer to noise transmitted relative to ground or the enclosure in a superimposed state across multiple conductors with the same direction or polarity tendency. However, conducted noise is not strictly separated into only these two categories; in actual circuit or wiring environments, differential and common components may appear in a mixed state, or one component may appear relatively dominant in specific frequency ranges or under specific load conditions.

[0030] The above-mentioned conducted noise can also be broadly understood in terms of frequency characteristics. That is, ripple components appearing in a relatively low-frequency region adjacent to commercial frequency, periodic components prominent near the switching frequency, harmonic and multiple frequency components, high-frequency transient components caused by rapid voltage rise and fall, narrowband components amplified in a specific band by resonance or reflection, and broadband components distributed across a wide frequency range can all be included in the category of conducted noise. Here, a ripple component may refer to periodic voltage or current fluctuations superimposed on a DC or quasi-DC component after rectification or switching, and a transient component may refer to a sudden change component occurring for a short period before converging to a steady state.

[0031] Conducted noise does not exist at a single point within the circuit but can travel along the input side, internal power paths, output side, ground paths, protective conductor paths, or mutual interface paths connected to adjacent devices. For example, noise generated within a device can return to the power input line and be transmitted to the upstream power system, travel to output or signal lines to affect the operation of load devices, or be recoupled to adjacent devices via ground lines or metal enclosures. In this context, recoupleting refers to the phenomenon where noise components that were separated in one path re-enter the measurement target or sensitive circuit through other wiring paths, ground paths, or metal structures.

[0032] The magnitude or impact of the aforementioned conducted noise may not be determined solely by voltage amplitude or current amplitude. Even for noise of the same amplitude, the actual degree of impact may vary depending on frequency, repetition rate, rise time, duration, impedance matching status, circuit resonance characteristics, measurement location, reference ground point, wiring length, distance from surrounding components, shielding status, or load sensitivity. For example, pulse noise with a short rise time contains many high-frequency components and can cause interference across a relatively wide frequency band; furthermore, repetitively occurring noise can act as a cause of control malfunctions, communication errors, sensor errors, or protection device malfunctions, rather than just average power loss.

[0033] Furthermore, the measurement or assessment of conducted noise can be performed in various ways. For example, noise voltage can be identified by measuring the voltage difference between specific conductors, and noise current can be identified by measuring the current flowing through the conductors. Additionally, the noise level can be determined through spectral distribution by frequency band, insertion loss at a specific reference frequency, attenuation, conducted emission level, transient response waveforms, or peak and average values ​​in the time domain. Here, insertion loss can be understood as a value indicating how much the noise component transmitted along a desired path has been reduced by comparing the state before and after a specific circuit or component is inserted, and the conducted emission level can refer to the relative magnitude of the noise component transmitted from the device to the external wiring.

[0034] Conducted noise itself does not necessarily cause the same problems in all cases and can lead to different issues depending on the connected device or the operating environment. For example, in control circuits, it can result in reference potential fluctuations, false detections, computational errors, or communication errors; in power circuits, it can cause increased heat generation, component degradation, increased switching losses, increased insulation stress, or abnormal operation of protection devices; and in instrumentation circuits, it can cause measurement drift, noise superposition, reduced resolution, or reduced repeatability. As such, conducted noise can be understood as an electrical disturbance component that can affect the overall functional reliability, electrical stability, lifespan, and electromagnetic compatibility of a device.

[0035] Furthermore, the term "conducted noise" is not limited to referring only to components measured within a restricted measurement band or by specific test equipment in specific standards. In other words, it can be understood to encompass not only noise in frequency ranges subject to regulation or test standards, but also all unwanted components based on the conduction path that affect circuit performance, peripheral connectivity, communication stability, sensor accuracy, power quality, or system protection functions during actual device operation. Therefore, conducted noise is not limited to specific test conditions, installation types, wiring structures, or systems of specific power capacities, but can be used as a general technical term encompassing a wide range of electrical interference components that may occur or be transmitted in devices with electrical connections in general.

[0036] A noise reduction filter according to one embodiment of the present invention may refer to a circuit, combination of components, or module that intentionally forms an electrical impedance to reduce unwanted electrical components transmitted along power lines, signal lines, ground lines, or equivalent electrical connection paths, or to allow components of a specific frequency band to pass through while attenuating other components. Here, a filter may refer to a means for imparting frequency-dependent transmission characteristics between electrical components entering the input side and electrical components transmitted to the output side, and reduction may refer to an action of reducing the voltage, current, energy, spectral level, peak magnitude, or repetitive disturbance effects of noise components. Furthermore, the noise reduction filter may be formed as a single component, or it may be implemented in the form of a circuit network composed of multiple components, a board assembly, a cable assembly, an enclosure-embedded module, a panel-mounted device, or a sub-unit embedded in a higher-level system.

[0037] The above noise reduction filter may be classified into power filters, signal filters, communication filters, control filters, sensor filters, or composite path filters depending on the application target. For example, a power filter is intended to reduce unwanted components of voltage and current in an AC or DC power path, a signal filter is intended to reduce interference components that overlap with detection signals, control signals, measurement signals, or communication signals, and a composite path filter may be intended to simultaneously provide different attenuation characteristics to the power path and the signal path within a single device. In this case, the type of application target is not a factor that limits the scope of the filter's rights, but rather should be understood as a representative example in which the noise reduction filter can be used.

[0038] In addition, noise reduction filters can be implemented as passive filters, active filters, or hybrid filters depending on their operating principle. A passive filter may refer to a structure that reduces noise based on impedance characteristics without an external power supply by utilizing inductors, capacitors, resistors, ferrite components, common-mode chokes, transformers, attenuation elements, surge suppression elements, or combinations thereof. An active filter may refer to a structure that cancels out specific components or performs feedback correction using operational amplifiers, amplifier elements, switching elements, detection circuits, or control circuits. A hybrid filter may refer to a structure that includes both a passive network and an active compensation circuit, performing passive attenuation in a specific frequency band and active control in other bands or during transient conditions.

[0039] Each term constituting the above noise reduction filter can be understood as follows. An inductor may refer to a component that forms inductive reactance in response to changes in current to suppress high-frequency components or sudden changes in current, and a capacitor may refer to a component that forms capacitive reactance in response to changes in voltage to bypass components above a certain frequency or disperse them to the ground side. A resistor may refer to a component that dissipates energy within the circuit in the form of heat or stabilizes the transient response by mitigating peaks caused by resonance. A ferrite component may refer to a component that weakens the transmission of high-frequency components by utilizing the loss characteristics of magnetic materials, and a common mode choke may refer to a magnetic element configured by winding multiple conductors simultaneously to provide high impedance to the common component and have a relatively low effect on the normal operating current.

[0040] Noise reduction filters may include series and parallel elements depending on the circuit connection configuration. A series element refers to a component placed along the main path between the input and output terminals to directly suppress noise currents or sudden current changes passing through that path, while a parallel element refers to a component connected between power lines, signal lines, or between a line and ground to bypass or disperse noise components. For example, a series inductor can hinder the transmission of high-frequency components along the current path, while a parallel capacitor can induce high-frequency components to flow through a different path before reaching the load. When series and parallel elements are arranged together in this manner, both blocking and bypass paths are simultaneously formed within a single filter, allowing for the reduction of noise across a wider range of frequency bands.

[0041] The above noise reduction filter can be classified into low-pass, high-pass, band-pass, band-stop, or composite response types depending on the filter characteristics. A low-pass type may refer to a structure that relatively passes components below a reference frequency while attenuating components above the reference frequency, while a high-pass type may refer to a structure having the opposite transmission characteristics. A band-pass type may refer to a structure that selectively passes only frequency components within a specific range, and a band-stop type may refer to a structure that selectively suppresses only components within a specific range. A composite response type may refer to a structure that combines multiple circuit stages or multiple attenuation mechanisms to form different attenuation curves in different frequency bands. Here, the reference frequency may refer to a frequency value or frequency range determined by the designer to set the transmission characteristics, and it may be a single numerical value or a range.

[0042] Furthermore, the noise reduction filter may include a differential mode filter and a common mode filter corresponding to the noise transmission mode. A differential mode filter may refer to a structure designed to reduce noise appearing as a potential difference between two conductors, while a common mode filter may refer to a structure designed to reduce the phenomenon where components commonly superimposed across multiple conductors are transmitted relative to ground or the enclosure. In an actual filter structure, a single circuit network can simultaneously attenuate both differential and common components, and specific components may contribute more significantly to the attenuation of differential components, while other components may contribute more significantly to the attenuation of common components. Therefore, the noise reduction filter is not limited to a specific noise type but can be designed to respond to actual usage environments where multiple transmission modes are mixed.

[0043] Noise reduction filters can be broadly understood in terms of their physical implementation structure. Specifically, they may be small circuits with winding and chip components mounted on a substrate, modular devices housing magnetic elements and capacitors within a metal enclosure, inline structures inserted in the middle of cables, connector-integrated structures, panel-through structures, rail-mounted structures, externally attached structures, or structures fixed to the internal frame of a higher-level device. Here, the metal enclosure can serve to shield the internal circuit from external interference or reduce the external radiation of internal components, while insulating members can maintain electrical isolation between live sections or between the live sections and the enclosure. Furthermore, wiring paths, spacing between components, ground connection locations, terminal placement, and internal space partitioning structures can also be understood as components that affect the electrical performance and mechanical reliability of the filter.

[0044] The performance of the above noise reduction filter can be described through various indicators. For example, insertion loss may be an indicator representing how much a specific frequency component is reduced before and after the filter, and attenuation may refer to the relative degree of reduction in output compared to input. Additionally, cutoff frequency, resonance frequency, quality factor, DC resistance, allowable current, insulation resistance, withstand voltage, temperature rise, leakage current, ground continuity, or transient response stability may also serve as technical elements describing the characteristics of the filter. Here, cutoff frequency may refer to the reference point at which transfer characteristics begin to change significantly, and DC resistance may refer to the conductor resistance component that affects voltage drop and heat generation during normal power transfer. These numerical values ​​or characteristics are presented not as limiting factors of the filter, but as representative evaluation criteria for a person skilled in the art to understand the structure and operation of the noise reduction filter.

[0045] In addition, noise reduction filters may be auxiliary components additionally mounted on specific devices, or they may be essential basic components included for the normal operation of a system. For example, they may be used for purposes such as maintaining power quality, ensuring electromagnetic compatibility, protecting sensitive circuits, reducing communication errors, stabilizing sensor detection, preventing malfunctions, suppressing component degradation, mitigating switching transients, or blocking external interference. In this case, the filter can be understood not merely as a function to reduce noise, but as a functional component that contributes to ensuring the reliability, lifespan, stability, and compliance of the entire device.

[0046] Meanwhile, the term "noise reduction filter" should not be interpreted as being limited to a specific circuit type, specific component combination, specific installation location, specific frequency range, or specific industrial field. That is, a simple structure consisting of a single inductor and a single capacitor can be included in a noise reduction filter, as can a structure in which multiple stages of magnetic elements, multiple types of capacitors, resistance networks, shielding structures, grounding structures, and compensation circuits are complexly combined. Therefore, the term "noise reduction filter" can be used as a general technical concept encompassing all forms of circuit, structural, and functional means to reduce unwanted components transmitted along electrical connection paths.

[0047] An industrial high-efficiency conductive noise reduction filter according to one embodiment of the present invention comprises: a filter body having an input terminal connected to an AC power source and an output terminal connected to a load; at least one inductor arranged in series with a power line between the input terminal and the output terminal inside the filter body; at least one first capacitor connected between the power lines; at least one second capacitor connected between the power line and a ground line; a discharge resistor connected in parallel to the first capacitor to discharge a charge remaining in the first capacitor; and a power connection part electrically connected to the input terminal and the output terminal to conduct power under conditions of a rated voltage of 250V to 500V, a rated frequency of 50Hz or 60Hz, and a rated current of 5A to 700A.

[0048] A filter body having an input terminal connected to an AC power source and an output terminal connected to a load side according to one embodiment of the present invention may refer to a structure configured to form a path for current to flow in and out between two sides while electrically separating the side receiving AC power supplied from the outside and the side of the equipment or device to which the AC power is transmitted. Here, the filter body may refer to a reference body to which the input terminal and the output terminal are mechanically fixed and electrically connected, and may be formed as a case, housing, base plate, cover assembly, frame, molded body, or a combined structure thereof made of metal or insulating material. The filter body may be formed to have sufficient mechanical strength to form a space for accommodating an electrical connection part inside, maintain a constant terminal position to which external wiring is connected, and prevent the relative position of the terminal from changing when fastened to a device to be installed.

[0049] The above-mentioned AC power side may refer to a power supply side that provides power upstream of the filter body, such as commercial AC power, industrial distribution power, AC power supplied from power generation facilities, transformer secondary power, inverter front-end power, output power from an uninterruptible power supply, or AC power branched from a distribution board. The above-mentioned AC power side may be single-phase or three-phase power, and the line voltage, phase voltage, rated frequency, presence or absence of a neutral line, presence or absence of protective grounding, and wiring specifications may vary depending on the system to which it is applied. A person of ordinary skill in the art can determine the phases, rated voltage, rated frequency, and number of wires of the AC power side by checking the nameplate, circuit diagram, power specification, or field wiring diagram of the device to be installed, and accordingly determine the number of input terminals, spacing, and connection order. For example, when applied to a single-phase AC power source, two power conductor terminals and a grounding terminal may be provided to connect the live wire and the neutral wire, and when applied to a three-phase AC power source, three power conductor terminals to connect the R phase, S phase, T phase or the corresponding U phase, V phase, and W phase may be provided, and if necessary, a neutral wire terminal and a grounding terminal may be additionally provided.

[0050] The above-mentioned input terminal may refer to a conductive connection part to which the wiring of the AC power source is first connected. The above-mentioned input terminal may be implemented in the form of a bolt-fastened terminal, a screw-fastened terminal, a crimp-lug-fastened terminal, a spring-clamp-type terminal, an insert-type connector terminal, a terminal block-type terminal, or a copper-bar-coupled terminal. The above-mentioned input terminal may be formed from copper, brass, tin-plated copper, nickel-plated conductor, or a low-resistance conductive material equivalent thereto, and the contact surface may be formed flat or a plating layer may be formed so that contact resistance does not increase rapidly upon repeated fastening. Furthermore, the above-mentioned input terminal may be formed in a straight, bent, or right-angle configuration so that the direction in which the external wiring is connected and the direction of current flow inside the filter body are naturally connected, and the spacing between terminals may be set considering the applied voltage, contamination level, insulation material, and installation environment. A person of ordinary skill in the art can manufacture the input terminal by specifically determining the width, thickness, fastening hole diameter, and spacing between terminals after verifying the creepage distance and clearance distance required by the applicable standard, the cross-sectional area of ​​the wire used, the external dimensions of the crimp terminal, the fastening torque range, and the expected current flow.

[0051] The aforementioned load side may refer to the device side to which the power passing through the filter body is actually supplied. Here, the term "load" does not refer merely to a simple resistive element, but may also include a motor, actuator, power converter, automation equipment, control device, measuring device, communication device, lighting device, battery charging device, server power supply, refrigerator, compressor, pump, blower, robot drive unit, or an entire system combining multiple circuits. Since the load side refers to the side located downstream of the filter body that actually consumes, converts, or distributes the power transmitted from the AC power source, the wiring method and terminal structure may vary depending on the specific type of device. For example, it may be an independent device to which a cable is directly connected, or it may be a structure connected to a busbar inside a distribution panel or a terminal block of another device; the filter body may be formed with different arrangement directions of output terminals or connection structures to accommodate these different load connection types.

[0052] The above-mentioned output terminal may refer to a conductive connection portion provided to transmit power passing through the filter body to the load side. The above-mentioned output terminal may be formed structurally in the same form as the above-mentioned input terminal, or it may be formed in a different form from the input terminal depending on the installation space or the wiring direction of the load device. For example, the above-mentioned input terminal may be formed as a lug-fastening structure to receive an external power cable, and the above-mentioned output terminal may be formed as a bar-type connection structure or a direct connection terminal structure to be directly connected to a terminal block inside the load device. The above-mentioned output terminal may be identified by letters, symbols, colors, engravings, protruding shapes, or placement positions to distinguish it from the input terminal, and may be marked as LINE IN and LOAD OUT in a single-phase system, and R-IN, S-IN, T-IN and R-OUT, S-OUT, T-OUT in a three-phase system, so as not to confuse the power inlet side and the outlet side. A person of ordinary skill in the art can verify through circuit continuity testing or wiring verification procedures whether each output terminal is accurately connected to the corresponding load-side conductor, and can determine the terminal arrangement to prevent incorrect phase sequence or mutual cross-connection.

[0053] The specific method of forming input and output terminals on the filter body described above can be implemented as follows. First, the length, width, and height of the body are determined by checking the outer dimensions of the device to be installed, the direction of wiring entry, maintenance space, and fastening location. Then, the area where AC power supply wiring approaches one side or the top surface of the body can be set as the input terminal placement surface, and the area where load-side wiring approaches the other side or the opposite side of the body can be set as the output terminal placement surface. Next, fastening holes for inserting or fixing conductive terminals, insulation bushing receiving holes, terminal support ribs, or terminal block fixing surfaces are formed on each placement surface, and a clearance space can be provided around the terminals to secure a tool insertion space and a wire bending radius. In particular, in the case of three-phase wiring, the terminals are arranged in a single line or parallel to prevent the phase conductors from becoming entangled with each other, and the order of the input terminals and the order of the output terminals are maintained identically so that field workers can easily visually check the wiring direction.

[0054] In addition, the filter body may have an internal fixing structure so that an electrical path between the input terminal and the output terminal is formed in an intended direction. For example, the power inlet side wall where the input terminal is installed and the power outlet side wall where the output terminal is installed may be formed to face each other so that the direction of current flow follows the length of the body, or the input terminal and the output terminal may be arranged vertically to enable installation even within a narrow panel. In this case, a person skilled in the art may determine the relative arrangement structure of the input terminal and the output terminal after reviewing the location of the wiring duct of the device to be installed, the location of the cable entry point, and whether there is interference with adjacent components. After wiring work, with the AC power side cable connected to the input terminal, unintentional conduction between the input side and the exposed metal part of the body can be checked using a multimeter or an insulation resistance meter, and with the load side cable connected to the output terminal, a continuity test can be performed to verify whether each phase or each line is connected only to the corresponding load side terminal.

[0055] The filter body having the above-mentioned input and output terminals may be implemented with consideration for ease of maintenance and assembly. For example, when the body cover is removed, the input terminal connection part and the output terminal connection part may be formed to be simultaneously exposed, and a wiring guidance space may be partitioned inside the body so that wiring work on the input terminal side and wiring work on the output terminal side do not interfere with each other. In addition, an opening, inspection window, or inspection cover may be provided around the terminals to allow visual inspection of the terminal connection status, and torque markings or loosening indicator lines may be applied to check whether the tightening torque is secured above a certain level. As such, the filter body is not merely a structure that forms an external appearance, but can be understood as a mechanical and electrical reference structure that clearly distinguishes and maintains the connection starting point of power flowing in from the AC power source and the connection ending point of power transmitted to the load side, and ensures that a safe and repeatable electrical connection state is maintained between them.

[0056] According to one embodiment of the present invention, at least one inductor arranged in series with a power line between an input terminal and an output terminal inside the filter body may refer to a conductive and magnetic coupling structure inserted in the middle of the power line such that the alternating current flowing into the input terminal does not conduct directly to the output terminal but must pass through a winding portion having a magnetic induction component. Here, being arranged in series may refer to a connection state in which one end of the inductor is electrically connected to the power line on the input terminal side and the other end of the inductor is electrically connected to the power line on the output terminal side, so that both the normal current and the noise current moving from the input terminal to the output terminal pass through the inductor on the same current path. Therefore, the inductor may not be a structure that is bypassed in parallel with the power line, but may be implemented as a line element that constitutes the main current path itself.

[0057] When the above power line is single-phase, the at least one inductor may be implemented in a structure in which it is inserted in series only on the live line, in a structure in which it is inserted in series on the live line and the neutral line respectively, or in a structure in which multiple windings are formed on a single magnetic body and each winding is inserted in series on each line. Additionally, when the above power line is three-phase, the at least one inductor may be implemented in a structure in which an independent inductor is provided for each phase power line, in a structure in which multiple windings corresponding to the first, second, and third phases are formed on a single common magnetic core, or in a structure in which some phases use independent inductors and other phases use multi-winding type inductors. At this time, a person skilled in the art may determine whether to have a single winding path for each power line or to integrate multiple windings on a single magnetic body after verifying the number of phases of the device to be installed, the rated current for each phase, the allowable voltage drop, the wiring path, and the internal space of the main body. An important point is that, regardless of the implementation form, at least a portion of the conduction path between the input terminal and the output terminal in each power line is connected to necessarily pass through the winding section.

[0058] The above inductor may be composed of a core portion around which a winding is wound, a conductor wound around the core portion, and lead portions for connecting the start and end ends of the conductor to the power line. The core portion may be formed in a ring shape, E-shape, U-shape, rod shape, laminated shape, or air-core structure, and as a magnetic material, nanocrystalline material, ferrite material, powder iron material, silicon steel material, or a magnetically inductive material equivalent thereto may be used, and an air-core structure may be used depending on the impedance characteristics required in a specific frequency range. The conductor may be formed as an enameled copper wire, flat wire, stranded wire, multi-strand parallel wire, insulated wire, copper foil laminated conductor, or copper bar connection structure. When implemented for high current, a multi-strand parallel winding or flat wire winding may be applied rather than a single circular wire, and when low current or high inductance is required, a structure in which a relatively small diameter insulated copper wire is wound multiple times may be applied. The above-mentioned lead end may be formed as a conductor end extending from the winding start and end points, and may be directly connected to a lug fastening part, a screw fastening part, a terminal block coupling part, or a copper bar connection part.

[0059] To actually implement the above inductor, the rated current, maximum continuous current, operating voltage, power frequency, and allowable internal space of the main body of the power line used in the device to be installed can first be specified. Next, the series reactance required in the noise frequency band to be reduced can be determined, and a target inductance value corresponding to that reactance can be set. For example, if the series reactance required at a specific frequency f_n is set as X_Lreq, the target inductance L_target can be calculated as L_target = X_Lreq / (2pif_n). Here, f_n may be a frequency point where a relatively large noise component is detected, and it may be determined based on the most stringent value among a representative frequency or multiple frequencies, rather than a single value. X_Lreq can be determined by reviewing the allowable voltage drop range that can be inserted into the power line together with the noise attenuation requirement, and the voltage drop at the commercial frequency can also be calculated and verified to ensure that the reactance at a commercial frequency of 50Hz or 60Hz does not become excessively large and hinder normal power transmission.

[0060] The number of turns corresponding to the above target inductance can be determined using actual measured values ​​of the core specimen. For example, a test winding can be formed by setting the reference number of turns N_ref to 10 turns on a selected core, and the reference inductance L_ref can be measured using an LCR meter under conditions of 1 kHz and 1 V. Then, the effective inductance coefficient AL of the core is calculated as AL = L_ref / (N_ref^2), and the calculated number of turns N_calc corresponding to the target inductance can be obtained as N_calc = sqrt(L_target / AL). Subsequently, during actual production, three types of prototypes with N_calc-1 turns, N_calc turns, and N_calc+1 turns are manufactured, and the inductance of each is measured again, and the prototype that falls within the target range can be selected. In this way, instead of simply using the figures from the core manufacturer's catalog, if the AL value is directly calculated by forming a test winding on the core specimen to be used for actual production, the influence of core material variations, winding tension differences, insulation thickness, and the actual winding window occupancy rate can be reflected, allowing a skilled technician to reproduce the same level of inductance through repeated production.

[0061] In addition, the conductor cross-sectional area and winding structure of the above-mentioned inductor can be determined based on the current flow and heat generation. For example, when the rated current is small, a single enameled copper wire can be used to wind the required number of turns, and when the rated current increases, multiple strands of parallel wire or flat conductors can be used to lower the conductor resistance. In actual implementation, two or three specimens are fabricated with the same core and number of turns conditions, differing only in the total conductor cross-sectional area, and the winding surface temperature and core surface temperature at 30, 60, and 120 minutes while the rated current is continuously applied to each specimen can be measured using a thermocouple or an infrared thermometer. At this time, a conductor cross-sectional area can be adopted that maintains low line resistance while remaining within a temperature range sufficiently lower than the winding insulation class and the core allowable temperature. The line resistance of an inductor can be measured with a four-terminal resistance meter to determine the DC resistance value between the input terminal and the output terminal. Since a larger value increases voltage drop and heat generation during normal current transmission, a skilled technician can determine the winding structure by checking the inductance value and the line resistance value together.

[0062] The above-mentioned inductor can be implemented to be mechanically and stably fixed inside the filter body. For example, when using an annular core, the core center hole can be fixed by using an insulating support rod or an insulating bracket; when using an E-shaped or U-shaped core, it can be fixed to the bottom surface of the body using a core clamp or an insulating base. Additionally, insulating sleeves, heat shrink tubing, cable ties, or fixing members may be placed near the lead-out section to prevent the winding start and end sections from shaking due to body vibration or wiring tension. The conductor lengths extending from the input terminal to the inductor and from the inductor to the output terminal can be arranged so that they do not become unnecessarily long, and insulating members may be inserted to prevent the winding lead-out section from coming into contact with sharp metal edges. By implementing it in this way, the inductor can ensure not only electrical functionality but also assembly stability within the body, reliability of repeated current flow, and durability in a vibrating environment.

[0063] Whether the above-mentioned inductor has been implemented according to the design values ​​can be verified through a prototype verification procedure. For example, after winding is completed, the inductance of each inductor can be measured in a no-load state, and then the DC line resistance can be measured with the inductor actually inserted in series into the internal power line of the main body. Next, after continuously energizing with a rated current for more than 2 hours, the winding temperature, core temperature, and lead-out temperature can be recorded, and the winding insulation damage, core cracks, winding unraveling, and lead-out loosening can be visually inspected. According to the attached test report, in the actual prototype, the three-phase 700 A class inductor showed an inductance of 1.0 mH and a DC line resistance of 0.2 mΩ for each phase, the three-phase 300 A class inductor showed 1.1 mH and 1.0 mΩ for each phase, and the three-phase 30 A class inductor showed 12.2 mH and 4.0 mΩ for each phase, and the inductor temperatures were measured at 100.2℃, 79.2℃, and 60.5℃, respectively, when the rated current was applied. By following this measurement procedure, it is possible to numerically verify whether the number of turns, core specifications, conductor cross-sectional area, and series insertion structure of the inductor are reproducible under actual current conditions.

[0064] Accordingly, at least one inductor arranged in series in the power line between the input terminal and the output terminal inside the filter body is a magnetic induction type line element formed to be directly inserted into the main current path connecting the input terminal and the output terminal so that the current necessarily passes through the winding section, and the type of core, winding shape, number of windings, conductor cross-sectional area, phase arrangement method, and fixing structure can be varied in various ways depending on the current capacity of the device to be applied, allowable voltage drop, internal space of the body, and verification test results.

[0065] According to one embodiment of the present invention, at least one first capacitor connected between the power lines may refer to a capacitive element that is electrically connected between two different power lines among a plurality of power lines passing through the filter body, thereby providing an alternating current path corresponding to a potential difference component formed between the two power lines. Here, being connected between the power lines means a connection state in which one electrode of the first capacitor is connected to one power line and the other electrode is connected to another power line, and may refer to an inter-phase connection structure in which neither electrode of the first capacitor is intentionally connected to a ground line. Accordingly, the first capacitor may be understood as a configuration that forms an electrical path to allow a high-frequency component or a transient component corresponding to the difference voltage to bypass the two power lines when a difference voltage exists between the two power lines.

[0066] When the power line is single-phase, the first capacitor may be connected between the live line and the neutral line, or between two different live lines. Additionally, when the power line is three-phase, the first capacitor may be connected to at least one pair among between the first phase and the second phase, between the second phase and the third phase, and between the first phase and the third phase. For example, in a three-phase three-wire structure, it may be implemented with a plurality of first capacitors, each connected one between the U-phase and the V-phase, between the V-phase and the W-phase, and between the U-phase and the W-phase, respectively. In a three-phase four-wire structure, it may also be implemented with a structure connected only between mutually different pairs of live lines, separate from the neutral line. In this case, the expression "at least one" may include not only a form in which one capacitor is placed in only one pair of power lines, but also a form in which one capacitor is placed in each of a plurality of pairs of power lines, or a form in which a plurality of capacitive elements are integrated within a single module.

[0067] The first capacitor may structurally include a first electrode, a second electrode, and a dielectric interposed between the first electrode and the second electrode. The dielectric may be formed from a metallized film, ceramic, a laminated insulator, or an insulating material capable of withstanding a continuous AC application state, and the first electrode and the second electrode may be formed from a metal film, a metal foil, a lead terminal connection part, or a conductive terminal capable of connecting to an external power line. In an embodiment where industrial AC power lines are connected for a long time, a safety standard capacitor for inter-phase connection may be used, and in an actual prototype, X1 capacitors with an AC rating of 440 V and 1 μF, and X2 capacitors with an AC rating of 275 V and 2.2 μF were used. Such examples demonstrate that the first capacitor can be implemented as a continuous-use capacitor capable of withstanding both the AC voltage repeatedly applied and high-frequency noise components in an inter-phase connection state.

[0068] In order to actually design the first capacitor, the type of power line and the line-to-line voltage can first be determined. In a single phase, the effective voltage between the live line and the neutral line or the effective voltage between two live lines can be determined, and in a three-phase, the line-to-line voltage between each phase can be determined. Next, based on the maximum value of the commercial frequency voltage that can be continuously applied to the first capacitor, a capacitor with a rated voltage capable of withstanding that voltage can be selected. Subsequently, the capacitance of the first capacitor can be determined by examining together the capacitive current that can flow at the commercial frequency and the capacitive reactance at the noise frequency to be reduced. Since the capacitive current I_c flowing through the first capacitor when the commercial frequency f_line, the phase-to-phase voltage V_ll, and the capacitance C can be calculated as I_c = 2pif_lineCV_ll, if the allowable commercial frequency current is determined first, the allowable maximum capacitance range can be derived through the relationship C_max = I_allow / (2pif_line*V_ll). For example, if the line voltage is set to 440 V, the frequency to 60 Hz, and the allowable capacitive current to 0.4 A, C_max becomes approximately 2.41 μF, so a 2.2 μF inter-phase capacitor can be selected as a candidate value. In this way, the capacitance of the first capacitor is not determined arbitrarily, but can be determined after first calculating the upper limit range based on the actual applied voltage, frequency, and allowable current conditions.

[0069] In addition, the capacitance of the first capacitor can also be specified based on the capacitive reactance formed at the noise reduction target frequency. Since the reactance X_c formed by the first capacitor at a specific noise frequency f_n can be calculated as X_c = 1 / (2pif_n*C), for example, in the case of bypassing interphase noise components in a band of 150 kHz or higher, X_c at the corresponding frequency can be calculated for each of the candidate capacitances of 0.22 μF, 1.0 μF, and 2.2 μF. At this time, at 150 kHz, X_c of 0.22 μF is approximately 4.82 Ω, X_c of 1.0 μF is approximately 1.06 Ω, and X_c of 2.2 μF is approximately 0.48 Ω, so the larger the capacitance, the lower the bypass path impedance formed for the interphase high-frequency components. A person of ordinary skill in the art can determine the actual capacitance candidate group by comparing the allowable current range at commercial frequency and the degree of reactance reduction in the noise band based on these calculation results.

[0070] The first capacitor described above may be positioned to form a direct path between two power lines as short as possible when physically implemented. For example, in a single-phase structure, it may be positioned to cross between the live terminal and the neutral terminal, and in a three-phase structure, it may be positioned to connect the U-phase conductor and the V-phase conductor, the V-phase conductor and the W-phase conductor, and the U-phase conductor and the W-phase conductor, respectively. In this case, if the lead wire becomes excessively long, the inductance of the lead wire itself increases, which may reduce the bypass function of the first capacitor in the high-frequency band; therefore, a person skilled in the art can verify the difference in the actual connection state by fabricating prototypes with different lead lengths, lead bending shapes, and connection point positions, even when using a capacitor of the same capacitance. In actual implementation, the capacitor body may be placed directly between two adjacent power lines, the leads or terminals extending from each electrode are connected to the corresponding power line at the shortest possible distance, and the capacitor body may be supported by an insulating bracket, adhesive, clamp, or board fixing part to prevent the soldered or fastened parts from shaking due to repetitive vibration or wiring tension.

[0071] The capacitance and placement suitability of the first capacitor mentioned above can be verified through prototype fabrication and measurement. For example, under the same filter body and the same power line placement conditions, multiple prototypes can be fabricated by replacing the inter-phase connection capacitors with 0.22 μF, 1.0 μF, and 2.2 μF, respectively. Then, the commercial frequency current is measured while the rated AC voltage is applied to each prototype, and the capacitor surface temperature, lead terminal temperature, and connection temperature can be recorded at regular time intervals. Subsequently, an LCR meter is connected to the inter-phase measurement point to verify the capacitance in the actual assembled state. In the actual test report, the capacitance between U1-V1, U1-W1, and V1-W1 in the three-phase filter prototype was repeatedly measured as 2.2 μF, and the components used are listed as X1 0.22 μF, X1 1 μF, X2 1 μF, and X2 2.2 μF. In this way, by directly measuring the capacitance after installation, it is possible to immediately verify whether the capacitance formed between power lines in the actual assembly state falls within the design range, rather than the capacitance specified in the drawing.

[0072] In addition, whether the first capacitor is properly connected to the power lines can be verified through a wiring verification procedure. For example, a continuity test can be performed based on the two electrodes of the capacitor to verify whether one electrode is connected only to the first power line and the other electrode is connected only to the second power line, and an insulation resistance meter can be used to measure whether any electrode is unintentionally conducting to the ground conductor or metal case. Furthermore, to verify whether the actual connection location of each inter-phase connected capacitor has changed, in a three-phase structure, the capacitance of each line pair can be measured again after assembly according to the wiring diagram marked for each pair of UV, VW, and UW. In this process, for example, if capacitance is measured only in UV and not detected in VW or UW, it can be determined that some inter-phase connections are missing, and if the same capacitance is detected in only two pairs, it can be determined that it is a partial implementation with only two capacitors installed.

[0073] Accordingly, at least one first capacitor connected between the above power lines is configured to be directly connected between two different power lines to form a capacitive bypass path corresponding to the inter-phase potential difference, and may be implemented as a single capacitor for one pair of power lines or as multiple capacitors placed for each of the multiple pairs of power lines, and its rated voltage, capacitance, placement location, and mounting type can be specifically determined based on the actual applied voltage, allowable capacitive current, target noise band, lead length, and measurements after assembly.

[0074] According to one embodiment of the present invention, at least one second capacitor connected between the power line and the ground line may refer to a component configured to form a capacitive path through which a high-frequency component or a transient component existing superimposed on the power line can bypass toward the ground line. Here, the power line may refer to a live line, neutral line, phase line, or a corresponding conductive path that transmits power between the input terminal and the output terminal, and the ground line may refer to a reference conductive path connected to a protective ground terminal, a ground busbar, a ground conductor, a protective conductor electrically continuous with a metal case, or an equipment grounding point. Furthermore, being connected between the power line and the ground line means a state in which one electrode of the second capacitor is connected to one of the power lines and the other electrode is connected to the ground line, and may refer to a structure in which the second capacitor is placed between the line and the ground rather than between the two power lines.

[0075] In a single-phase structure, the above-mentioned at least one second capacitor may be placed between the live line and the ground line, or implemented as a structure with two capacitors placed between the live line and the ground line and between the neutral line and the ground line, respectively. In a three-phase structure, one capacitor may be placed between the first phase and the ground line, between the second phase and the ground line, and between the third phase and the ground line, respectively. When multiple second capacitors are used, the capacitance of each capacitor may be the same, or may be determined differently depending on the wiring length per phase, the leakage current allowance per phase, or the mounting space. However, regardless of the implementation form, the above-mentioned second capacitor is common in that it is directly connected between the power line and the ground line to form a current path corresponding to the voltage difference between the line and the ground.

[0076] The second capacitor may structurally include a first electrode, a second electrode, and a dielectric interposed between the first electrode and the second electrode. The dielectric may be formed from a metallized film, ceramic, a laminated insulator, or an insulating material capable of withstanding repeated applied voltage between an AC power source and ground, and the first electrode and the second electrode may be formed as lead terminals, flat terminals, solder pads, or connecting terminals. Since the second capacitor is intended to be placed between a line and ground, a person skilled in the art may apply a safety-standard capacitor suitable for ground connection rather than a general signal capacitor, and for example, Y2 capacitors of 4700 pF and 0.047 μF of 250 V class and 0.01 μF of 300 V class have been used in actual prototypes.

[0077] The capacitance of the second capacitor can first be determined based on the allowable ground leakage current at commercial frequency. If the commercial frequency is f_line, the effective voltage between the power line and the ground line is V_lg, and the capacitance of the second capacitor is C_y, the capacitive current I_leak flowing through a single second capacitor can be calculated as I_leak = 2pif_lineC_yV_lg. In cases where multiple second capacitors are connected to multiple power lines, the total ground leakage current I_total can be calculated as I_total = sum(2pif_lineC_iV_lg,i). Therefore, the designer can first determine the total allowable leakage current in the facility and calculate the upper limit of the capacitance of each second capacitor so as not to exceed that value. For example, if a second capacitor of 10 nF is used under conditions of 220 V and 60 Hz, I_leak becomes approximately 0.83 mA, and if 47 nF is used, it becomes approximately 3.9 mA, so it is possible to immediately verify how the ground-side current increases with increasing capacitance even under the same voltage and frequency conditions. By performing such calculations first, the capacitance of the second capacitor can be determined numerically based on the actual applied voltage and allowable leakage current, rather than being arbitrarily determined.

[0078] In addition, the capacitance of the second capacitor can also be determined based on the capacitive reactance formed in the noise frequency band to be reduced. When a specific noise frequency is denoted as f_n, the reactance X_c of the second capacitor can be calculated as X_c = 1 / (2pif_n*C_y). For example, in the 150 kHz band, a second capacitor of 10 nF forms a reactance of approximately 106 Ω, 47 nF forms a reactance of approximately 22.6 Ω, and 150 nF forms a reactance of approximately 7.07 Ω; thus, it can be confirmed that as the capacitance increases, the high-frequency bypass path impedance between the line and ground becomes lower. Therefore, a person skilled in the art can determine a prototype candidate from among single devices or parallel-coupled devices with capacities such as, for example, 4700 pF, 0.01 μF, 0.047 μF, 0.1 μF, or equivalent capacities, after performing the calculation of the allowable leakage current at commercial frequency and the reactance in the noise band together.

[0079] The second capacitor can be positioned so that the path from the power line to the ground line is not unnecessarily long when physically implemented. For example, in a three-phase structure, each second capacitor can be symmetrically positioned by phase so that the distance from each phase conductor to the common ground busbar is as short and similar as possible; in a single-phase structure, the second capacitor can be placed in close proximity to the conductor path through which the live or neutral line passes, and the other electrode can be directly connected to the ground busbar or ground terminal block. Additionally, the leads or terminals of the second capacitor can be prevented from coming into direct contact with the sharp edges of the metal case through insulating sleeves, heat shrink tubing, or insulating supports, and the part connected to the ground line can be formed by bolt fastening, soldering, riveting, or a ground busbar crimping structure. In this case, the second capacitor must be connected only after first verifying that the ground line conducts continuously with the actual protective ground; simply connecting it to an electrically floating metal plate or a non-connected metal case cannot be considered a ground line connection structure.

[0080] The actual implementation value of the second capacitor can be determined through prototype fabrication and measurement. For example, while maintaining the same filter body and the same series inductor conditions, multiple prototypes can be fabricated by changing only the second capacitor to 4700 pF, 0.01 μF, 0.047 μF, and parallel combinations thereof. Then, for each prototype, the capacitance between the power line and ground can be measured using an LCR meter under conditions of 1 kHz and 1 V, the leakage current can be measured using a ground ammeter under the application of rated AC voltage and rated frequency, and the insulation status between the line and ground can be verified using an insulation resistance meter and a withstand voltage tester. Since the capacitance between each phase and ground was repeatedly measured as 150 nF in the actual prototype, this can be understood as an implementation example in which the equivalent capacitance between the power line and ground is formed to 150 nF by arranging multiple Y capacitors in parallel or distributed, rather than using a single high-capacity single component.

[0081] In addition, the connection status of the second capacitor can be verified through a wiring verification procedure after assembly is completed. For example, the continuity between one electrode of each second capacitor and the corresponding power line, and the continuity between the other electrode and the ground busbar, can be measured respectively, and it can be verified that no electrode of the second capacitor conducts directly to any other unintended phase conductor or other line. Subsequently, when measuring capacitance, the equivalent capacitance deviation by phase can be verified by measuring individually for each line, such as U-phase to ground, V-phase to ground, and W-phase to ground. If the deviation exceeds the allowable range, the component error, missing soldering, faulty connection of the ground busbar, or open lead of the parallel-connected second capacitor can be re-inspected. Through such a procedure, a person skilled in the art can directly and reproducibly verify whether the second capacitor properly implements the capacitive path that should actually be formed between the power line and the ground line.

[0082] Accordingly, at least one second capacitor connected between the power line and the ground line can be configured to provide a line-to-ground capacitive bypass path formed between each power line and the protective ground path, and can be implemented in various ways such as a single element, multiple elements, a phase-independent arrangement structure, a parallel combination structure, or a distributed mounting structure, and its capacitance, rated voltage, mounting location, and connection method can be specifically determined based on the actual applied voltage, allowable leakage current, target noise band, ground wiring length, and measured values ​​after assembly.

[0083] A discharge resistor connected in parallel to the first capacitor according to one embodiment of the present invention to discharge the charge remaining in the first capacitor may refer to a device that forms a resistive discharge path so that the charging voltage of the first capacitor is not maintained for a long time even after the power is cut off, by being connected between two connection points identical to two power lines to which the two electrodes of the first capacitor are respectively connected. Here, being connected in parallel means a state in which one terminal of the discharge resistor is connected to a power line connection point identical to one electrode of the first capacitor, and the other terminal of the discharge resistor is connected to another power line connection point identical to the other electrode of the first capacitor. Accordingly, the discharge resistor can be understood as being connected between two nodes identical to the first capacitor, so that the charge accumulated in the first capacitor is attenuated by passing through the discharge resistor.

[0084] The reason the above discharge resistor is required is that if the first capacitor is structured to be connected between power lines, voltage may remain across the first capacitor even after the power is removed. Although the first capacitor repeatedly charges and discharges while a commercial frequency voltage is applied, the voltage across the first capacitor may not drop to zero immediately depending on the phase at the time the external power is cut off, the capacitance of the first capacitor, the presence or absence of an external load connected to the power line, and the open circuit state immediately after the cutoff. In this case, without the discharge resistor, the voltage remaining in the first capacitor may be applied to a worker during terminal inspection, maintenance, or rewiring, and the repeated residual charge may also place a burden on the insulation design of the connection part; therefore, a continuous resistance path may be placed between the two nodes identical to the first capacitor to allow the residual charge to decrease over time.

[0085] The resistance value of the discharge resistor can be determined based on the capacitance of the first capacitor and the time to reach the allowable residual voltage after power cutoff. If the capacitance of the first capacitor is C_x, the initial voltage across the first capacitor immediately after power cutoff is V_0, the target residual voltage is V_s, the allowable discharge time is t_d, and the discharge resistance value is R_d, then the voltage decay of the first capacitor can be explained by the relationship V(t) = V_0 * exp(-t / (R_d * C_x)). Therefore, the allowable upper limit of the discharge resistor can be determined as R_d <= -t_d / (C_x * ln(V_s / V_0)). For example, if the first capacitor is 2.2 μF and the line-to-line RMS voltage is 440 V, the initial voltage is set to V_0 = sqrt(2) * 440, and the residual voltage is set to drop to 60 V or less within 15 seconds after power cutoff, the calculated upper limit of the allowable resistance is approximately 1.42 MΩ. In this case, a resistor of 1.0 MΩ or 1.2 MΩ can be selected as a priority candidate. Conversely, if the allowable discharge time is set to 25 seconds, up to approximately 2.37 MΩ is allowed, so a resistor of 2.0 MΩ can also be adopted. As such, the discharge resistance value is not determined by a simple conventional value, but can be calculated numerically based on the actual capacitance of the first capacitor, the expected initial voltage immediately after cutoff, the target residual voltage, and the allowable time.

[0086] In addition, since the discharge resistor is continuously connected in parallel to the same two nodes as the first capacitor even in a normal state where power is applied, the power consumption under a continuous voltage application state must also be considered. If the RMS voltage applied across the first capacitor is V_rms and the discharge resistor value is R_d, the average power consumption P_r of the discharge resistor can be calculated as P_r = V_rms^2 / R_d. For example, when V_rms is 440 V and R_d is 2.0 MΩ, P_r is approximately 0.0968 W, so a 0.25 W, 0.5 W, or 1 W resistor can be selected considering the margin for continuous use. In the actual prototype, a discharge resistor with 1 W, 2 MΩ, and a tolerance of ±5% was used. Therefore, a person of ordinary skill can first determine the resistance value range based on the discharge time, and then calculate the power consumption for the continuous applied voltage to select a resistance component that satisfies the rated power and insulation strength.

[0087] The physical implementation of the discharge resistor may be formed as a metal film resistor, a metal oxide resistor, a high-voltage fixed resistor, or a structure of multiple resistors connected in series. When the discharge resistor is implemented as a single element, a lead-type resistor may be placed directly between two connection points identical to the first capacitor. If the distance between leads is short and insulation margin is insufficient, multiple resistors may be connected in series to reduce the voltage distributed to each resistor. For example, by connecting two 1 MΩ resistors in series to form a total 2 MΩ discharge path, the voltage applied to each resistor can be distributed to half the level, and the spacing between resistor bodies can also be secured. Additionally, the discharge resistor may be placed as close as possible to the leads or terminals of the first capacitor to be directly connected in parallel between the same two nodes. Furthermore, an insulating sleeve or heat shrink tube may be added to prevent the lead length from becoming excessively long, thereby preventing interference with other conductors or insufficient spacing from the internal metal part of the main body.

[0088] Whether the discharge resistor is actually connected in parallel with the first capacitor can be verified by measuring continuity and voltage attenuation after assembly. First, the equivalent resistance value of the discharge resistor can be measured by connecting a resistance meter based on the nodes across the first capacitor. At this time, if the measured value is within the design value and the allowable tolerance range, it can be determined that the discharge resistor is connected between the two nodes. Next, after sufficient commercial AC voltage is applied to the first capacitor and the power is cut off, the residual voltage can be recorded at 1-second or 2-second intervals with a high-input impedance voltmeter or differential probe connected across the first capacitor. For example, by recording the voltage at 0, 5, 10, 15, and 20 seconds, the point at which it reaches below the V_s set during design can be identified, and by comparing a specimen without a discharge resistor with a specimen with a discharge resistor under the same conditions, the difference in the residual voltage attenuation rate can be immediately verified numerically. By undergoing such a verification procedure, a person skilled in the art can confirm through repeated measurements whether the discharge resistor actually discharges the residual charge of the first capacitor.

[0089] The reliability of the above discharge resistor can be reconfirmed under voltage application, humid heat conditions, and long-term use conditions. The actual test report states that a 1 W resistor with 2 MΩ ±5% was used as the discharge resistor, and that there was no external damage after the discharge resistor test under 2150 V DC conditions corresponding to 4.3 times the rated voltage. It also states that there was no visible damage or insulation breakdown after the humid heat test, and that the change in resistance value remained within 20% of the initial value. Furthermore, in the temperature rise test under rated current application, the discharge resistor temperature was measured at 73.6°C for the 700 A class prototype, 41.6°C for the 300 A class prototype, and 47.7°C for the 30 A class prototype. Therefore, the above discharge resistor can be implemented as a component that not only satisfies the calculated value but also maintains its resistance value and operates without insulation damage under actual applied voltage and temperature environments.

[0090] If there are multiple first capacitors, the configuration can be implemented by connecting a discharge resistor in parallel to each first capacitor. For example, in a three-phase structure, if first capacitors are placed between the first and second phases, between the second and third phases, and between the first and third phases, an independent discharge resistor can be connected to each terminal of each first capacitor to allow the residual voltage of the inter-phase capacitors to be attenuated individually. Alternatively, if multiple first capacitors are connected in parallel between the same two nodes to form a single equivalent capacitance, a single discharge resistor calculated based on the total equivalent capacitance can be connected between those two nodes. In either implementation form, the discharge resistor is identical in that it is connected to the same two connection points as the first capacitors and performs the function of dissipating residual charge through a resistive path.

[0091] Accordingly, the discharge resistor connected in parallel to the first capacitor to discharge the charge remaining in the first capacitor is a constant resistive path formed between two identical nodes at both ends of the first capacitor, and the resistance value, rated power, number of components, and mounting type can be specifically determined according to the capacitance of the first capacitor, the initial voltage immediately after cutoff, the target residual voltage, the allowable discharge time, the power consumption at the continuous applied voltage, the insulation margin after mounting, and the actual discharge test results.

[0092] A power connection portion electrically connected to the input terminal and output terminal according to one embodiment of the present invention, which conducts power under conditions of a rated voltage of 250V to 500V, a rated frequency of 50Hz or 60Hz, and a rated current of 5A to 700A, may refer to a conductive connection structure formed so that alternating current flowing into the input terminal is transmitted along a continuous conductive path to the output terminal. Here, the power connection portion may be understood not merely as a single metal member, but as a concept including a terminal fastening portion coupled to the input terminal and output terminal, a conductor path electrically connecting the terminal fastening portions, a fastening member mechanically fixing the conductor path, and an insulating member separating the live portion so that it does not unintentionally come into contact with a metal case or an adjacent conductor. In the actual prototype data, terminal blocks and copper wiring structures are presented as power connection structures, and the product is formed as a built-in wiring type and is specified as a noise filter used under conditions of 250V, 450V, or 500V and 50Hz or 60Hz. In addition, the model system is classified to have a rated current system of 5A to 700A for the three-phase structure and 5A to 300A for the single-phase structure.

[0093] In order to actually implement the above power connection, the rated voltage required by the device to be applied is first specified as one of 250V, 450V, or 500V, the rated frequency of the power supply used is specified as 50Hz or 60Hz, and the rated current to be continuously conducted is specified in the range of 5A to 700A. Then, a person skilled in the art can select terminal components and conductor components capable of withstanding a target rated current or higher. For example, since the actual component group listed in the test report includes terminal blocks of 30A, 60A, 100A, 150A, 200A, 400A, and 600A grades, the terminal block of the nearest grade capable of withstanding a rated current or higher can be selected, such as a 30A grade in the 5A to 30A range, a 60A grade in the 30A to 60A range, and a 100A grade in the 60A to 100A range. In addition, in the 700A class implementation example, a terminal block and an 8T×45 mm copper bar are used, and since the technical data of the copper bar is listed as 770A, it can be configured so that the conductor allowable current is greater than the rated current even under the condition of a rated current of 700A. Similarly, if a 355A class conduction path is required, a 5×25 mm copper bar can be used. In this way, each component of the power connection section can be specifically selected by first determining the target current value, then excluding components with a rating smaller than that value, and adopting terminals and conductors with a rating greater than or equal to that value.

[0094] The conductor path electrically connected to the input and output terminals in the above power connection section may be formed as a wire-type conductor, a flat-plate conductor, or a bar-type conductor; however, in the high-current section, a copper bar structure may be applied to reduce conduction resistance and heat generation. A person skilled in the art may determine the conductor cross-section by first applying a 5×25 mm copper bar when the required rated current is 355A or less, and applying an 8×45 mm copper bar when it exceeds 355A. In addition, the connection between the terminal block and the copper bar may be implemented by a bolt or screw fastening method, and the nominal diameter of the screw shaft and the fastening torque may be specified together to ensure the fastening reliability of the connection section. In actual tests, it was confirmed that the nominal diameter of the fastening screw for the 700A and 300A class models was 10 mm and the fastening torque was 4.0 Nm, and the nominal diameter of the fastening screw for the 30A class model was 6 mm and the fastening torque was 2.5 Nm. Therefore, a person of ordinary skill in the art can first determine the terminal size based on the applicable current rating, and then implement the input terminal side fastening part and the output terminal side fastening part by applying the same screw diameter and tightening torque corresponding to that terminal. In this way, the power connection part can be implemented not merely as a structure that conducts, but as a structure in which contact pressure is maintained even during repeated connection and current flow.

[0095] The above power connection unit may be positioned so that an insulation distance between the live line and other conductors is maintained under conditions of a rated voltage of 250V to 500V. In this case, a person skilled in the art may design the unit by ensuring a separation distance greater than the actual measured value between the live line on the input terminal side and the live line on the output terminal side, or between the live line and the metal case. An embodiment is described in which the distance between live lines of different polarities or phases was measured as 20.0 mm, 35.0 mm, and 38.0 mm, and the distance between the live line and the metal enclosure was measured as 10.7 mm, 11.6 mm, and 19.2 mm. In addition, an insulating tube may be used in the power connection, and since extruded insulating tubes of specifications of 30.0 / 15.0 mm, 25.0 / 12.5 mm, 20.0 / 10.0 mm, 18.0 / 9.0 mm, 15.0 / 7.5 mm, 12.0 / 6.0 mm, 10.0 / 5.0 mm, 8.0 / 4.0 mm, 6.0 / 3.0 mm, 4.0 / 2.0 mm, and 2.0 / 1.0 mm are included in the actual parts list, a person skilled in the art can select the inner and outer diameters of the insulating tube to match the external dimensions of the conductor or copper bar, and can secure insulation margin by covering the part where the conductor is close to the case corner or adjacent terminal with the corresponding insulating tube. Therefore, the power connection may be embodied not only as a conductor cross-section and a connection part, but also as an embodiment that includes a separation distance corresponding to the voltage rating and an insulating sheath structure.

[0096] Whether the above power connection actually conducts power under conditions of 250V to 500V, 50Hz or 60Hz, and 5A to 700A can be confirmed through a verification procedure after assembly. First, the continuity between the input terminal and the output terminal can be checked using a multimeter or a 4-terminal resistance meter to verify whether a conductive path is formed for each phase or each line. Subsequently, the DC line resistance can be measured to check whether the resistance of the connection has increased excessively, and in the actual prototype, the 700A class model showed a DC line resistance of 0.2 mΩ, the 300A class model showed 1.0 mΩ, and the 30A class model showed 4.0 mΩ. Next, the temperature rise of the terminals can be measured with the rated current actually applied, and the test report indicates that the temperature of the bare terminals was measured at 81.0°C at the 700A class, 69.4°C at the 300A class, and 47.6°C at the 30A class. By following this procedure, it is possible to verify through measurements whether the power connection section possesses the rating on paper, or whether it continuously conducts power between the input and output terminals in the actual assembly state.

[0097] In addition, the mechanical reliability of the aforementioned power connection can be verified through fastening strength tests and vibration tests. The actual test report states that there was no visible damage to the terminals after a 20 N tensile test and no damage after a torque test on the fastening screws. Furthermore, in a separate vibration test, no cracks or deformation occurred even after excitation in the X, Y, and Z directions under conditions of 20 m / s² within the range of 10 Hz to 150 Hz. Therefore, when implementing the power connection, a person skilled in the art can determine the terminal block fixing position, copper bar support position, number of fastening screws, arrangement of insulation supports, and fixing state of the wiring bends to a level capable of withstanding the above test conditions. Specifically, this can be implemented by directly screw-fixing the terminal block to the main body or double-fixing it via a bracket, placing intermediate support points to prevent bending vibrations from increasing due to an excessively long free end length of the copper bar, and shrink-fixing both ends of the insulation tube to prevent it from detaching during vibration. In this way, the above-mentioned power connection unit can be specifically implemented to include not only electrical conduction performance under rated voltage, frequency, and current conditions, but also maintenance of the assembled state and fastening stability.

[0098] Accordingly, the power connection unit, which is electrically connected to the input and output terminals and conducts power under conditions of a rated voltage of 250V to 500V, a rated frequency of 50Hz or 60Hz, and a rated current of 5A to 700A, can be implemented as a conductive connection structure in which the target rated voltage and rated current are first determined, then terminal blocks and conductors with ratings greater than or equal to them are selected, the diameter of the fastening screw and the fastening torque are assigned according to the component grade, the separation distance between the live parts and between the live parts and the enclosure is secured to be greater than the actual measured value, and after assembly, line resistance, terminal temperature, fastening damage, and vibration damage are measured and determined.

[0099] According to one embodiment of the present invention, the inductor comprises at least one of a nanocrystalline core and a ferrite core. In the inductor, the term “core” may refer to a magnetic material portion that provides a magnetic flux path formed by a winding, thereby causing the magnetic induction of the winding to appear greater than in an air-core structure. Here, the inductor comprising a nanocrystalline core may mean that it comprises a core made of a nanocrystalline material as a magnetic material that is wound, placed inside the winding, or coupled with the winding, and the inductor comprising a ferrite core may mean that it comprises a core made of a ferrite material in the same manner. Furthermore, “at least one of” may encompass cases where the inductor comprises only a nanocrystalline core, only a ferrite core, a single inductor comprising both a nanocrystalline core and a ferrite core, or a plurality of inductors where some of the inductors comprise a nanocrystalline core and the remainder comprise a ferrite core. The proposal presents a configuration that forms inductance characteristics from the low to high frequency range by combining a nanocrystalline core and a ferrite core.

[0100] The above-mentioned nanocrystalline core can be implemented as a structure formed by winding or laminating a ribbon or thin sheet material formed by rapidly cooling and heat-treating a metallic soft magnetic material, and the above-mentioned ferrite core can be implemented as an annular, split, rod-shaped, or equivalent structure formed by sintering an oxide-based magnetic material. A person skilled in the art can first determine the required inductance, rated current, winding accommodation space, and installable external dimensions, and then form test windings on each of the nanocrystalline core specimen and the ferrite core specimen under the same number of windings conditions, and measure the inductance using an LCR meter under conditions of 1 kHz and 1 V. Next, by measuring the winding temperature and the core surface temperature at regular time intervals while continuously applying the rated current, a core type that satisfies the target inductance without causing an excessive temperature rise can be determined. At this time, the selection of the core is not determined simply by the name of the material, but can be concretized by fabricating actual specimens under the same number of windings, the same conductor cross-sectional area, and the same measurement frequency conditions and performing comparative measurements.

[0101] In an embodiment in which the above-described inductor includes a nanocrystalline core, the nanocrystalline core may be formed as a ring-shaped core and an insulated wire may be wound along its outer circumference. A person skilled in the art may consider that as the rated current increases, the thickness of the winding conductor and the winding window area increase together, first determine the inner and outer diameters of the core corresponding to the required outer diameter of the conductor and the number of windings, and then select a core specification that falls within that range. For example, when forming the same target inductance but the conductor becomes thicker, a specification with a larger core window area may be selected, and under relatively low current conditions, a core with a smaller outer diameter may be selected to reduce the overall volume.

[0102] In an embodiment in which the above-described inductor includes a ferrite core, the ferrite core may be formed as an annular or split-coupled core, and an insulating conductor may be wound around or placed through the ferrite core. A person skilled in the art can select the ferrite core specifications based on the required winding space, installation area, and target inductance. For example, if the goal is to obtain the target inductance by increasing the number of windings at the same rated current, the height protruding outward as the windings are stacked can be calculated first, and a core diameter capable of accommodating that height can be selected. Conversely, if the goal is to suppress the rise in resistance by reducing the winding length within the same external shape, a specimen with a larger ferrite core specification can be fabricated instead of increasing the number of windings, and the inductance and heat generation can be measured again.

[0103] When the above-mentioned inductor includes both a nanocrystalline core and a ferrite core, the two types of cores may be arranged within a single inductor to form a series or parallel magnetic flux path, or the first winding portion of the inductor may be coupled with the nanocrystalline core and the second winding portion may be coupled with the ferrite core. Furthermore, the term “included together” does not refer only to a form in which the two material cores are physically placed simultaneously within a single assembly, but may also include a form in which a portion containing a nanocrystalline core and a portion containing a ferrite core are used together within an assembly that performs the same inductor function. In this case, a person skilled in the art can first fabricate specimens using only a nanocrystalline core, using only a ferrite core, and using both material cores together, respectively, and determine which combination meets the requirements by comparing and measuring the inductance and temperature rise under the same winding conditions. This method of comparison ensures that the selection of core materials is not arbitrary but is based on the results of actual specimen tests.

[0104] The specific selection procedure for the above core can be implemented as follows. First, the required target inductance is set as L_target, and a test coil can be fabricated for each candidate core by fixing the number of test turns N_ref constant, for example, to 10 or 20 turns. Next, the reference inductance L_ref for each test core is measured under conditions of 1 kHz and 1 V, and the effective inductance coefficient for each core can be calculated using AL = L_ref / (N_ref^2). Subsequently, the number of calculated turns N_calc required for the target inductance can be obtained using N_calc = sqrt(L_target / AL), and a specimen can be fabricated with the integer number of turns closest to N_calc, after which the actual inductance can be measured again. Next, the rated current is applied, and the winding temperature and core surface temperature at 30, 60, and 120 minutes are recorded, and it can be verified whether the corresponding temperature values ​​fall within the insulation class and the core allowable temperature range. If this procedure is performed for the nanocrystalline core group and the ferrite core group, respectively, a person skilled in the art can reproducibly verify which core specification and material simultaneously satisfy the required inductance and thermal conditions.

[0105] In one example of the test, the inductance of a three-phase 700A class prototype was measured to be 1.0 mH per phase, the inductance of a three-phase 300A class prototype was 1.1 mH per phase, and the inductance of a three-phase 30A class prototype was 12.2 mH per phase, and the inductor temperatures were measured to be 100.2°C, 79.2°C, and 60.5°C, respectively, under the condition of applying rated current. Therefore, the core included in the above inductor is not merely a conceptual material selection, but can be a subject of material selection implemented and measured in actual product specimens in response to target inductance and rated current conditions. However, the above figures are merely examples for specific prototypes, and different inductance and temperature values ​​may be formed depending on the combination of core material, diameter, number of turns, conductor cross-sectional area, and rated current.

[0106] Therefore, in the context of this invention, the fact that the inductor includes at least one of a nanocrystalline core and a ferrite core means that a magnetic core made of a nanocrystalline material or a ferrite material can actually be employed as the magnetic flux forming part of the inductor, and the form of such adoption may include the use of a single material alone, the combined use of two materials, the distribution of materials among multiple inductors, or the combination of multiple cores within the same inductor assembly, and each core specification can be specifically determined through the measurement of inductance for a test winding and the measurement of temperature under the condition of applying rated current.

[0107] According to one embodiment of the present invention, the filter body is installed in a built-in manner on a single-phase power line or a three-phase power line and is configured to reduce conducted noise generated from at least one of an industrial inverter, a power converter, or an uninterruptible power supply.

[0108] The filter body according to one embodiment of the present invention is configured to be installed in a built-in manner on a single-phase power line or a three-phase power line to reduce conducted noise generated in at least one of an industrial inverter, a power converter, or an uninterruptible power supply. This means that the filter body is not a test component that is temporarily connected externally, but is mounted in a state of being permanently coupled within a wiring system that constitutes the power inlet path of the device, thereby being arranged to reduce the magnitude of the conducted noise component transmitted along the power line while power is applied. Here, a single-phase power line may refer to a two-wire power path including a live line and a neutral line, or a two-wire power path between live lines, and a three-phase power line may refer to a power path composed of three live lines, such as the R-phase, S-phase, T-phase, or U-phase, V-phase, and W-phase, and may include a neutral line and a protective ground as needed. A person of ordinary skill in the field can first determine whether the power line is single-phase or three-phase by checking the nameplate, circuit diagram, or wiring diagram of the device to be installed, and then select a filter body corresponding to the corresponding number and insert and install it between the power input side and the device side.

[0109] The term "installed in a built-in manner" may refer to an installation configuration in which the filter body is mounted within a control panel, switchboard, device enclosure, metal cabinet, power module, or equipment frame using bolt fastening, bracket fixing, baseplate fastening, or panel fixing, and an external power supply line is wired to pass through the filter body first before being connected to the power input terminal of an industrial inverter, power converter, or uninterruptible power supply. For example, when applied to an industrial inverter, a single-phase or three-phase power line drawn from commercial AC power or a switchboard can be connected to the power inlet side of the filter body, and the power outlet side of the filter body can be connected to the power input terminal of the inverter, thereby ensuring that the filter body is included in the entire power inlet path of the inverter. When applied to a power converter, the filter body can be fixedly installed upstream of the AC input terminal of a rectifier, converter, charger, servo drive, or similar power conversion module; and when applied to an uninterruptible power supply, the filter body can be inserted between the commercial power and the UPS input terminal or in a path requiring conducted noise blocking within the UPS bypass input path. In this way, the filter body is not structured to be loosely placed outside the device, but can be installed as an embedded component that forms the device's power path during actual operation.

[0110] The above-mentioned industrial inverter may refer to a device that rectifies or converts AC power and provides power of variable frequency or variable voltage to the load side; the power conversion device may refer to a device that performs at least one of AC-DC conversion, DC-AC conversion, AC-AC conversion, or DC-DC conversion; and the uninterruptible power supply may refer to a device including a battery and a power conversion unit to continuously supply power to the load even in the event of a commercial power failure. Since the main causes of conducted noise in the above-mentioned devices are high-speed on / off operation of switching elements, rectification operation, PWM driving, sudden load changes, parasitic components of internal wiring, and fluctuations in ground potential, a person skilled in the art can confirm the necessity of installing the filter by placing the filter body in the AC input path of these devices and measuring the noise components returning to the power line or entering the device during operation. Here, conducted noise reduction may mean that the magnitude of the noise voltage or noise current transmitted along the power line when the device is operating is reduced compared to the case without the filter body, and this determination may be made through insertion loss at a specific frequency point, symmetric mode attenuation, asymmetric mode attenuation, conducted emission level, or similar indicators. In actual test data, this product is also specified as a passive LC filter for suppressing conducted electromagnetic interference occurring in industrial inverters, power converters, and UPS systems.

[0111] Whether the above filter body is actually applicable to a single-phase power line or a three-phase power line can be determined by first specifying the applicable voltage, frequency, and current ranges. A person skilled in the art can check the power specifications of the device to be installed to determine which category the rated voltage belongs to among the 250V, 450V, or 500V series, whether the rated frequency is 50Hz or 60Hz, and what range the continuous current is. Then, in the case of a single-phase device, a single-phase model corresponding to the corresponding current can be selected, and in the case of a three-phase device, a three-phase model corresponding to the corresponding current can be selected. For example, since single-phase models are classified into ranges of 250V, 450V, 500V, and 5A to 300A, and three-phase models are classified into ranges of 250V, 450V, 500V, and 5A to 700A, for example, a single-phase 450V 80A model can be installed correspondingly to a single-phase device of 60Hz, 450V, and 80A, and a three-phase 500V 300A model can be installed correspondingly to a three-phase device of 50Hz, 500V, and 300A. In this way, the fact that the filter body is applied to a single-phase or three-phase power line can be understood not as an abstract description of use, but as a concrete embodiment in which the power constant and rated voltage, frequency, and current are first specified, and then a model corresponding thereto is selected and inserted and mounted into the power input wiring.

[0112] Whether the filter body is configured to reduce conducted noise can be verified through a prototype verification procedure. First, a test jig corresponding to a single-phase or three-phase power line can be prepared, and a reference wiring state without the filter body and a wiring state with the filter body inserted can be configured, respectively. Then, an insertion loss measurement under a 6 dBm condition in a 50Ω system can be performed, or the amount of attenuation can be measured at 50 kHz, 1 MHz, 10 MHz, and 100 MHz for each of the symmetric mode and the asymmetric mode. In actual three-phase prototype tests, the 700A class model showed insertion loss of 36.30 dB to 36.31 dB at 50 kHz, 41.50 dB to 41.52 dB at 1 MHz, 29.00 dB to 29.03 dB at 10 MHz, and 9.45 dB to 9.46 dB at 100 MHz in symmetrical mode, the 300A class model showed approximately 40.20 dB at 50 kHz, approximately 56.38 dB at 1 MHz, approximately 39.16 dB at 10 MHz, and approximately 11.19 dB at 100 MHz in symmetrical mode, and the 30A class model showed insertion loss of approximately 76.40 dB at 1 MHz and approximately 61.20 dB at 10 MHz in symmetrical mode. In addition, attenuation of 10 dB or more to 77 dB or more was confirmed for each current class model even in asymmetric mode. By measuring the frequency-dependent attenuation while the filter is inserted into a single-phase or three-phase power line, a person of ordinary skill can directly verify whether the filter body is structured to actually reduce conducted noise generated by industrial inverters, power converters, or uninterruptible power supplies.

[0113] In addition, the filter body can be implemented to maintain its installed state even in a long-term operating environment after built-in installation. Actual test data states that the product showed no cracks, deformation, insulation breakdown, or fastening damage even after undergoing a low-temperature test at -25°C, a high-temperature test at 85°C, a 21-day moist heat test, an overcurrent test corresponding to 135% of the rated current, and a vibration test at 10 Hz to 150 Hz and 20 m / s². Therefore, when a person skilled in the art installs the filter body in a built-in manner inside an industrial inverter, power converter, or uninterruptible power supply, they can determine the fixing position and fastening method of the body so as to withstand the temperature, humidity, vibration, and overcurrent conditions expected in the actual operating environment of the device, rather than simply connecting it electrically. In this regard, the expression “configured” of the filter body above is not merely a functional declaration, but may refer to a structure that is actually assembled into a single-phase or three-phase power line, is always included in the power input path of an industrial power device, and whose conducted noise attenuation and environmental durability are confirmed by test data.

[0114] The filter body according to one embodiment of the present invention includes a first LC circuit section and a second LC circuit section sequentially arranged along a current path from the input terminal side toward the output terminal side.

[0115] The filter body according to one embodiment of the present invention is configured to be installed in a built-in manner on a single-phase power line or a three-phase power line to reduce conducted noise generated from at least one of an industrial inverter, a power converter, or an uninterruptible power supply. This means that the filter body is not used as a separate external adapter or a temporary test component, but is permanently fixed and included within the wiring system that constitutes the power inlet path of the device. Here, a single-phase power line may refer to an AC power path consisting of a live wire and a neutral wire, or an AC power path consisting of two different live wires, and a three-phase power line may refer to three live wire paths consisting of a first phase, a second phase, and a third phase, and may additionally include a neutral wire and a protective ground wire as needed. A person skilled in the art can first determine whether the device is for single-phase or three-phase use through the power specification table, wiring diagram, nameplate, or terminal marking of the device to be installed, and then select a filter body corresponding to the phase and insert and install it between the power inlet side of the device and the device input terminal. For example, product types are classified into single-phase and three-phase types, and each type may be subdivided according to voltage groups of 250V, 450V, and 500V and current grades.

[0116] The term "installed in a built-in manner" may refer to an installation type in which the filter body is fixed via a fastening member in a pre-secured installation space inside a control panel, device enclosure, metal cabinet, power module frame, or power distribution structure, and AC power flowing in from the outside passes through the filter body first before being transmitted to the input terminal of an industrial inverter, power converter, or uninterruptible power supply. In this case, the fastening member may be a bolt, nut, bracket, support plate, rail coupling part, or a mechanical fixing part equivalent thereto, and after installation, the filter body may be securely fixed to a metal base or insulating support plate so that it does not shake or detach during operation. Since the product's installation and usage classification in actual test data is specified as "Built-in" and the power connection method as "Wiring type," the filter body may be implemented as an embedded device directly connected via internal wiring rather than a separate plug-in structure.

[0117] The above-mentioned industrial inverter may refer to a device that rectifies or converts AC power and then provides variable voltage or variable frequency power to a load; the power conversion device may refer to a device that performs at least one of AC-DC conversion, DC-AC conversion, AC-AC conversion, or DC-DC conversion; and the uninterruptible power supply may refer to a device that includes a battery unit and a power conversion unit to continuously supply power to a load even in the event of a commercial power failure. The fact that the filter body is applied to such a device can be understood to mean that the filter body is placed on the power input path of the device to suppress the transmission of conducted noise superimposed on the power line to an upstream power system or adjacent device due to the device's internal switching operation, rectification operation, PWM driving, sudden load changes, or parasitic components of the internal wiring. The proposal and test data also describe the product as a passive filter for suppressing conducted EMI generated in industrial inverters, power conversion devices, and UPS systems.

[0118] The statement that the above-mentioned conducted noise is configured to be reduced means that the filter body has a structure that lowers the voltage or current level of noise components transmitted along the power line during device operation compared to the case where the filter body is not present. In this case, whether "reduction" has occurred is not determined solely by abstract descriptions of effects, but can be verified by configuring a reference wiring state without the filter body inserted and a state with the filter body inserted, respectively, and then measuring the insertion loss or attenuation amount under specified measurement conditions. In actual test data, the product was tested with a structure that measures insertion loss according to CISPR 17 conditions, and attenuation amounts were measured at 50 kHz, 1 MHz, 10 MHz, and 100 MHz for symmetrical and asymmetrical modes. For example, the three-phase 700A prototype exhibited attenuation of approximately 36.30 dB at 50 kHz and approximately 41.52 dB at 1 MHz in symmetrical mode, the three-phase 300A prototype exhibited attenuation of approximately 40.20 dB at 50 kHz and approximately 56.38 dB at 1 MHz in symmetrical mode, and the three-phase 30A prototype exhibited attenuation of approximately 76.40 dB at 1 MHz in symmetrical mode. In addition, in asymmetrical mode, the same prototypes exhibited attenuation levels ranging from 10 dB to 77 dB in each frequency band. Therefore, when the filter body is built-in into the power line of an industrial inverter, power converter, or UPS, the effect of reducing conducted noise can be numerically verified through an actual measurement procedure.

[0119] Whether the above filter body is actually applicable to a single-phase or three-phase power line can be specifically implemented according to the power specifications. First, it can be determined which voltage group the device to be installed belongs to—250V, 450V, or 500V—and whether the frequency is 50Hz or 60Hz, and what the rated current is. Then, a single-phase type filter body is selected for a single-phase device, and a three-phase type filter body is selected for a three-phase device, and the corresponding model can be determined according to the respective current rating. For example, a single-phase 20A rated filter body can be applied to a single-phase power converter with 250V, 60Hz, and 20A, and a three-phase 300A rated filter body can be applied to a three-phase industrial inverter with 500V, 50Hz, and 300A. This application process can be implemented not merely by abstractly listing the types of devices, but by first specifying the phase, voltage, frequency, and current, and then connecting the corresponding filter body into the built-in wiring structure.

[0120] In addition, since the filter body must be able to be continuously used in an industrial environment even after built-in installation, it can be implemented with a structure capable of withstanding environmental conditions expected inside the actual device. Actual test data indicates that the filter body passed low-temperature conditions of -25°C, high-temperature conditions of 85°C, 21 days of humid heat conditions, 135% of the rated current overcurrent conditions, and vibration conditions of 10 Hz to 150 Hz and 20 m / s². Therefore, when a person skilled in the art installs the filter body in a built-in manner inside an industrial inverter, power converter, or uninterruptible power supply, they can determine the connection location and fixing method by considering the internal temperature rise, vibration, humidity, long-term continuous operation, and the possibility of overcurrent occurrence of the device, rather than simply connecting it in the middle of the power line. In this way, the filter body can be specifically implemented with a structure that is embedded in a single-phase or three-phase power line, forms the power path of the industrial device, confirms conducted noise attenuation in prescribed measurement procedures, and maintains its installed state even after environmental testing.

[0121] At least one of the first LC circuit and the second LC circuit according to one embodiment of the present invention includes an inductor connected in series to each power line, an inter-phase capacitor connected between each power line, and a ground-side capacitor connected between each power line and a ground line.

[0122] According to one embodiment of the present invention, the fact that at least one of the first LC circuit section and the second LC circuit section includes an inductor connected in series to each power line, an inter-phase capacitor connected between each power line, and a ground-side capacitor connected between each power line and a ground line may mean a circuit unit having a series path forming an inductive component on a current path flowing along the power line, an inter-phase capacitive path bypassing a differential voltage component formed between the power lines, and a ground-side capacitive path bypassing a common component directed from each power line to the ground line. Here, the phrase "at least one of the first LC circuit section and the second LC circuit section" may mean that only the first LC circuit section may have such a configuration, only the second LC circuit section may have such a configuration, or both the first LC circuit section and the second LC circuit section may each include the same type of inductor, inter-phase capacitor, and ground-side capacitor. Therefore, the above wording does not necessarily mean that both circuit sections must be composed of the same configuration and the same numerical values, but can be understood to mean that at least one circuit section is formed as an LC circuit network combining the three types of passive components mentioned above.

[0123] The inductor connected in series to each of the above power lines may refer to an inductor inserted into at least one of the conduction paths of the live line or the live line and neutral line in a single-phase structure, and may refer to an inductor inserted into each of the conduction paths of the first phase, second phase, and third phase in a three-phase structure. At this time, being “connected in series to each power line” means that the inductor is placed on the main current path so that the normal current and noise current passing through the LC circuit must pass through it, and does not mean that it is placed on an auxiliary path branched in parallel with the power line. For example, in an embodiment of a three-phase structure, one winding path may be formed in each of the first phase path, the second phase path, and the third phase path, and the three-phase filter circuit diagram of the actual test data also illustrates a 1-stage and 2-stage structure in which a series inductor is placed in each phase line.

[0124] The interphase capacitor connected between each of the above power lines may refer to a capacitor in which both electrodes are respectively connected between two different power lines. In a single-phase structure, it may be placed between a live line and a neutral line, or between two live lines, and in a three-phase structure, it may be placed between the first phase and the second phase, between the second phase and the third phase, and between the first phase and the third phase. The interphase capacitor can form a capacitive path that allows high-frequency components corresponding to the voltage difference between two power lines to flow along a bypass path between the lines rather than being transmitted directly to the load side. The actual parts list lists capacitors of class X1 0.22 μF, X1 1 μF, X2 1 μF, and X2 2.2 μF that can be used as interphase capacitors, and the interphase capacitance of the actual three-phase prototype was measured to be 2.2 μF between U1-V1, U1-W1, and V1-W1, respectively.

[0125] The ground-side capacitor connected between each of the above power lines and ground lines may refer to a capacitor in which one electrode is connected to a power line and the other electrode is connected to a ground line. In a single-phase structure, one or more may be placed between the live line and ground or between the neutral line and ground, and in a three-phase structure, one may be placed between the first phase and ground, the second phase and ground, and the third phase and ground, respectively. The ground-side capacitor can form a capacitive path through which high-frequency components commonly superimposed on the power lines can bypass the ground line. The actual parts list lists Y2 4700 pF, Y2 0.01 μF, and Y2 0.047 μF components that can be used as ground-side capacitors, and in an actual three-phase prototype, the equivalent capacitance between each phase and ground was measured to be 150 nF. Therefore, the ground-side capacitor may be a single high-capacity component, or it may be a structure in which multiple components are arranged in parallel or distributed to form an equivalent capacitance.

[0126] In order to actually implement the above LC circuit, it is first necessary to determine whether the power line to be applied is single-phase or three-phase, and then determine the number of series inductors, inter-phase capacitor connection pairs, and ground-side capacitor connection pairs corresponding to the number of power lines. For example, when implementing a single LC circuit in a three-phase structure, inductors connected in series can be placed on each of the first, second, and third phases, inter-phase capacitors can be placed between the first and second phases, between the second and third phases, and between the first and third phases, and ground-side capacitors can be placed between the first and ground, between the second and ground, and between the third and ground. In addition, in a single-phase structure, a series inductor may be placed on only one live line, or series inductors may be placed on both the live line and the neutral line; an inter-phase capacitor may be placed between the live line and the neutral line, and ground-side capacitors may be placed between the live line and the ground and between the neutral line and the ground. In this way, the placement of each component can be specifically implemented to correspond to the number of power lines.

[0127] The numerical values ​​of the above inductor, inter-phase capacitor, and ground-side capacitor can be selected based on the noise reduction target frequency and the allowable electrical characteristics at commercial frequency. For example, if the series reactance X_Lreq required for each power line at a specific noise frequency f_n is determined, the target inductance of the inductor can be determined as L_target = X_Lreq / (2pif_n), and if the capacitive reactance X_Creq that the inter-phase capacitor or ground-side capacitor must form is determined, the target capacitance can be determined as C_target = 1 / (2pif_nX_Creq). However, since capacitive current flows together through the inter-phase capacitor and the ground-side capacitor at commercial frequency, an upper limit can be considered to ensure that the allowable current at commercial frequency is not exceeded by utilizing the relationship, for example, I_x = 2pif_lineC_xV_ll for the inter-phase capacitor and I_y = 2pif_lineC_y*V_lg for the ground-side capacitor. The inter-phase capacitance of 2.2 μF and ground-side capacitance of 150 nF confirmed in the actual prototype data, along with the series inductance of each phase of the 700A class 3-phase prototype (1.0 mH), the series inductance of each phase of the 300A class 3-phase prototype (1.1 mH), and the series inductance of each phase of the 30A class 3-phase prototype (12.2 mH), demonstrate that even the same LC circuit can have different values ​​depending on the rated current class and structural differences.

[0128] The actual wiring structure of the first or second LC circuit section can be implemented based on the prototype circuit diagram. In the actual test data, circuit diagrams for a 3-phase EMI filter, specifically for 250 / 450V and 500V, are shown, and in each diagram, a structure is confirmed in which series inductors for each phase, capacitors between power lines, and capacitors between line and ground are repeatedly arranged. A person skilled in the art can, based on these circuit diagrams, place the first LC circuit section as a primary component group close to the input side and the second LC circuit section as a secondary component group at the next position; a single-stage structure can be implemented when only one of the circuit sections is adopted, and a two-stage structure can be implemented when both are adopted. In this case, while maintaining the same circuit format, the capacitor rating and wiring spacing may be varied depending on whether the voltage rating is 250 / 450V or 500V.

[0129] Whether the above-mentioned LC circuit section has been actually constructed can be verified through a measurement procedure after assembly. First, the inductance can be measured for the series inductor of each phase or each line using an LCR meter, and the results indicate that the inductance for each phase in the actual three-phase prototype was repeatedly measured to the same value. Next, the inter-phase capacitor and the ground-side capacitor can be verified as designed by measuring the inter-phase capacitance between each power line and the capacitance between each power line and ground. In the actual prototype, the inter-phase capacitance was measured as 2.2 μF for each line pair, and the line-ground capacitance was measured as 150 nF for each phase. Subsequently, the insertion loss is measured at 50 kHz, 1 MHz, 10 MHz, and 100 MHz to verify whether the structure including the above-mentioned LC circuit section actually forms attenuation in symmetric and asymmetric modes. By following this measurement procedure, a person of ordinary skill can numerically verify whether the configuration includes an inductor, an inter-phase capacitor, and a ground-side capacitor in the first LC circuit or the second LC circuit.

[0130] Accordingly, in the context of this invention, the fact that at least one of the first LC circuit section and the second LC circuit section includes an inductor connected in series to each power line, an inter-phase capacitor connected between each power line, and a ground-side capacitor connected between each power line and a ground line means that one circuit section is formed as a passive LC circuit unit having a series inductive path, an inter-line capacitive path, and a line-ground capacitive path together, and the specific implementation thereof can be specifically determined according to the number of single-phase or three-phase power lines, voltage rating, target noise band, allowable current, and the inductance, capacitance, and insertion loss measurements of the prototype.

[0131] According to one embodiment of the present invention, the first LC circuit and the second LC circuit are configured to form a multi-stage LC circuit network of one or two stages so that symmetric mode noise and asymmetric mode noise are attenuated through different current paths. This means that if only one LC circuit unit is provided inside the filter body, it can be implemented as a single-stage circuit network, and if two LC circuit units are arranged consecutively from the input side to the output side, it can be implemented as a two-stage circuit network.

[0132] Here, the first LC circuit unit may refer to a first-stage LC circuit unit closer to the input terminal side, and the second LC circuit unit may refer to a second-stage LC circuit unit positioned closer to the output terminal side at the rear end of the first LC circuit unit. Accordingly, a 1-stage circuit network can be formed using only one of the first LC circuit unit or the second LC circuit unit, and a 2-stage circuit network can be formed by arranging both the first LC circuit unit and the second LC circuit unit in a serial order. In actual data, circuit diagrams for 1-stage and 2-stage 3-phase EMI filters are presented respectively, and since the d item of the model code is distinguished as 1S or 2S, the multi-stage LC circuit network can be realized as a 1-stage type and a 2-stage type at the actual product level.

[0133] In order to actually implement the above-mentioned multi-stage LC circuit network, the attenuation level required in the power line to be applied and the allowable installation space can first be verified. Then, under the same rated voltage and rated current conditions, a single-stage prototype containing only the first LC circuit section and a two-stage prototype having a second LC circuit section added after the first LC circuit section can be manufactured, respectively. At this time, the first LC circuit section and the second LC circuit section may be formed with completely identical component values, or they may be formed by setting different component values ​​for the circuit section closer to the input side and the circuit section closer to the output side. However, in either case, since the first LC circuit section and the second LC circuit section must be sequentially arranged along the main path where current moves from the input terminal side to the output terminal side, when implementing the two-stage, a wiring path can be formed so that the current passing through the first LC circuit section first subsequently passes through the second LC circuit section again. In the actual test data, 1-stage and 2-stage circuit diagrams are listed for 3-phase filters for 250 / 450V and 500V, respectively, confirming that implementation is possible with a difference in the number of stages within the same product family.

[0134] The above-mentioned symmetric mode noise may refer to noise primarily transmitted by the differential voltage component formed between two different power lines, and the above-mentioned asymmetric mode noise may refer to noise formed asymmetrically between each power line and a reference potential or ground reference. Here, “attenuation through different current paths” means that the symmetric mode noise component is attenuated by flowing mainly along the closed-loop path formed between the power lines and passing through some components of the LC network, while the asymmetric mode noise component is attenuated in a different way by flowing along a different path from the power line toward the ground reference. In other words, even in a multi-stage LC network formed within the same filter body, not all noise components are attenuated equally along the same loop; rather, the symmetric mode component may be attenuated by flowing along the inter-phase path, and the asymmetric mode component may be attenuated by flowing along the line-to-reference path, respectively. The above expression is not limited to a specific theoretical classification but can be understood as explaining the phenomenon where the insertion loss of the symmetric mode and the asymmetric mode appears as different numerical values ​​during actual measurements.

[0135] To actually verify the aforementioned different current paths, a symmetric mode measurement configuration and an asymmetric mode measurement configuration can be formed separately for the same prototype. For example, a test jig can be configured to measure symmetric mode insertion loss by applying a differential voltage component between power lines, and then a separate test jig can be configured to measure asymmetric mode insertion loss by applying an asymmetric component between a power line and a reference point. Then, by recording the attenuation amounts at different frequency points, such as 50 kHz, 1 MHz, 10 MHz, and 100 MHz, in each measurement configuration, it is possible to directly verify whether different attenuation values ​​appear in symmetric mode and asymmetric mode, even for the same product. In actual three-phase prototype testing, the attenuation amounts for symmetric mode and asymmetric mode were recorded separately for each model, and even for the same model, the values ​​for the two modes were measured differently. For example, in the case of KCT-T5700-2SH, the symmetric mode attenuation was measured to be 36.30 dB to 36.31 dB at 50 kHz and 41.50 dB to 41.52 dB at 1 MHz, and the asymmetric mode attenuation was measured to be 10.10 dB to 10.12 dB at 50 kHz and 39.59 dB to 39.61 dB at 1 MHz. Also, in the case of KCT-T5300-2SH, the symmetric mode attenuation was measured to be 40.20 dB to 40.22 dB at 50 kHz and 56.37 dB to 56.40 dB at 1 MHz, and the asymmetric mode attenuation was measured to be 13.79 dB to 13.82 dB at 50 kHz and 67.94 dB to 67.96 dB at 1 MHz. For the KCT-T5030-2SH, the symmetric mode attenuation was measured to be 37.74 dB to 37.75 dB at 50 kHz and 76.39 dB to 76.41 dB at 1 MHz, and the asymmetric mode attenuation was measured to be 39.54 dB to 39.56 dB at 50 kHz and 77.65 dB to 77.67 dB at 1 MHz.These measurement results directly show that symmetric mode noise and asymmetric mode noise have different transmission paths and are attenuated to different levels by the multistage LC network.

[0136] How to select the above-mentioned single-stage or two-stage multi-stage LC network can be determined based on the target attenuation amount and installation constraints. A person skilled in the art can first manufacture a single-stage prototype to measure the insertion loss in the symmetrical and asymmetrical modes and verify whether there are any frequency ranges where the measured value falls short of the required criteria. Then, a two-stage prototype with a second LC circuit added while maintaining the same voltage and current ratings can be manufactured and measured again under the same frequency conditions. Subsequently, by comparing the difference in frequency-specific attenuation between the single-stage and two-stage prototypes, for example, if the target attenuation amount is satisfied with only the single-stage structure, the single-stage structure can be adopted, and if the attenuation amount is insufficient in a specific frequency range, the two-stage structure with the second LC circuit added can be adopted. In this process, the criteria for selecting the number of stages can be determined not by abstract expressions, but by performing insertion loss measurements on prototypes under the same conditions and comparing whether the required attenuation amount is satisfied in the necessary frequency ranges.

[0137] In addition, the arrangement order of the first LC circuit and the second LC circuit can be determined based on the actual direction of current flow. First, the wiring length from the input terminal side to the first LC circuit can be minimized so that attenuation in the first stage occurs immediately after the external power is supplied, and then the second LC circuit can be arranged to perform attenuation again after passing through the first LC circuit. In this case, the connection length between the first LC circuit and the second LC circuit can also be kept from becoming excessively long so that unnecessary parasitic components between the two circuits do not increase excessively. When implementing based on the actual circuit diagram, only one LC bundle can be placed in a single-stage structure, and two LC bundles connected in the same direction can be sequentially placed in a two-stage structure so that the power line continuously passes through two attenuation sections. Therefore, the distinction between the first and second stages mentioned above does not simply mean an increase in the number of components, but can be understood as a concept that specifically determines whether an LC attenuation section is formed once or twice along the current path leading from the input side to the output side.

[0138] Therefore, in the context of this document, the first LC circuit and the second LC circuit are configured to form a multi-stage LC circuit network of one or two stages so that symmetric mode noise and asymmetric mode noise are attenuated through different current paths. This means that one or two LC circuit units can be sequentially arranged along the direction of current flow, and the symmetric mode component and the asymmetric mode component flow along unequal current loops, thereby forming insertion losses separately for each, and the selection of the stage and the attenuation characteristics can be specifically determined through the measurement of symmetric mode and asymmetric mode insertion losses for actual one-stage and two-stage prototypes.

[0139] The inductor according to one embodiment of the present invention includes a first reactor wound on a nanocrystalline core and a second reactor wound on a ferrite core.

[0140] This may mean that two types of reactors using different magnetic materials are provided together within an assembly that performs the function of a single inductor. Here, the first reactor may refer to a wound-type reactor utilizing a nanocrystalline core as a magnetic flux path, and the second reactor may refer to a wound-type reactor utilizing a ferrite core as a magnetic flux path. Furthermore, the term “includes” may encompass cases where the first reactor and the second reactor are connected to form a single continuous current path for the same power line, cases where the same structure is repeatedly arranged for each of multiple power lines, or cases where the first reactor section and the second reactor section are accommodated together within a single inductor module while spaced apart from each other. Therefore, the above-mentioned inductor is distinguished from a structure using only a single-material core and can be understood as a composite reactor structure that simultaneously possesses a first reactor and a second reactor having different magnetic characteristics.

[0141] The nanocrystalline core constituting the first reactor may be an annular or similar closed-loop structure formed by winding or laminating a metal-based soft magnetic ribbon, and the ferrite core constituting the second reactor may be an annular, split annular, or similar magnetic structure formed by sintering an oxide-based soft magnetic material. The windings of the first reactor and the second reactor may each be formed as independent conductors, and may use insulated wires of the same thickness, or may use insulated wires of different thicknesses depending on the rated current. For example, the nanocrystalline core may be implemented as an annular core with a diameter in the range of 25 mm to 140 mm, and the ferrite core may be implemented as an annular core with a diameter in the range of 31 mm to 140 mm, and the winding conductor may use a wire in the range of 1.3 mm to 2.0 mm of Class H insulation grade. In this way, the first reactor and the second reactor each have separate cores and winding sections, but can be implemented together within a single inductor assembly.

[0142] In order to actually implement the above inductor, the target total inductance value can first be determined. For example, after setting the total inductance required for a single power line as L_total, the total inductance can be distributed into a first inductance L1 handled by the first reactor and a second inductance L2 handled by the second reactor. At this time, it can be determined to satisfy the relationship L_total = L1 + L2, and the distribution ratio of L1 and L2 can be determined through prototype testing rather than being determined arbitrarily. For example, multiple candidate combinations can be prepared with L1:L2 varying to 20:80, 40:60, 50:50, 60:40, and 80:20, and for each candidate combination, the inductance, DC resistance, temperature rise, and insertion loss under the same current conditions can be measured. Subsequently, by adopting a combination that satisfies both the required damping band and temperature range, the division of roles between the first and second reactors can be numerically specified. By following this procedure, the description that the first and second reactors are included together is not limited to a simple parallel arrangement, and a person skilled in the art can reproducibly understand the actual ratio in which they are configured.

[0143] The number of turns for each of the first and second reactors can be specifically calculated using test windings. First, a test coil is fabricated by winding the reference number of turns N_ref1 identically, for example, 10 turns, on a nanocrystalline core for the first reactor candidate, and the inductance L_ref1 can be measured under conditions of 1 kHz and 1 V. Then, the effective inductance coefficient AL1 for the first reactor can be calculated as AL1 = L_ref1 / (N_ref1^2). In the same way, the reference number of turns N_ref2 identically is wound on a ferrite core for the second reactor candidate, and after obtaining the measured inductance L_ref2, the effective inductance coefficient AL2 for the second reactor can be calculated as AL2 = L_ref2 / (N_ref2^2). Subsequently, for the previously determined first inductance L1 and second inductance L2, the calculated number of turns N1 for the first reactor can be calculated as N1 = sqrt(L1 / AL1), and the calculated number of turns N2 for the second reactor can be calculated as N2 = sqrt(L2 / AL2), respectively. Then, the first reactor and the second reactor are each manufactured with an integer number of turns closest to the calculated value, and the actual inductance is measured again to verify whether it is within the error range. With this method, even if the core material changes, the number of turns is derived according to the actual magnetic characteristics of each core, so the first reactor and the second reactor can be specifically reproduced.

[0144] The physical arrangement of the first and second reactors may be a series arrangement along the same power line, where the first reactor is placed first and the second reactor is placed after it, or conversely, a series arrangement where the second reactor is placed first and the first reactor is placed after it. Additionally, if multiple power lines exist, the same combination of the first and second reactors can be repeatedly arranged for each power line. In this case, the length of the connecting conductor between the first and second reactors can be kept from becoming excessively long to prevent unnecessary parasitic inductance and parasitic resistance from increasing, and the cores and windings of each reactor can be spaced apart and fixed so as not to come into contact with each other through insulating support members or core fixing members. Furthermore, the lead ends of the first and second reactors may be aligned in the same direction so that the direction of the power line can be visually identified, or markings may be assigned to the start and end ends of each reactor to reduce wiring errors.

[0145] The thickness of the winding conductors used in the first and second reactors can also be determined based on the rated current and heat generation measurements. For example, specimens can be fabricated using 1.3 mm, 1.6 mm, 1.8 mm, and 2.0 mm insulated wires for the same core specifications, and the DC resistance can be measured using a 4-terminal ohmmeter under the same number of turns condition. Then, the winding surface temperature and the core surface temperature can be recorded at 30, 60, and 120 minutes while continuously applying the rated current. Subsequently, cases where the winding resistance is too high, causing voltage drop and increased heat generation, can be excluded, and conversely, cases where the conductor is excessively thick, resulting in insufficient windings or not being accommodated in the core window, can be excluded, thereby selecting a conductor thickness suitable for each of the first and second reactors. At this time, since the core material and magnetic flux distribution are different even when the same current flows through the first reactor and the second reactor, the rising pattern may differ even after applying wires of the same thickness, and therefore, the conductor thickness can be examined individually for each of the first reactor and the second reactor.

[0146] Whether an inductor including both the first and second reactors is actually implemented can be confirmed through a verification procedure after assembly. First, the inductance can be measured for the first reactor alone, the second reactor alone, and the assembly in which the first and second reactors are connected in series. At this time, if the measurement value of the first reactor alone is close to L1, the measurement value of the second reactor alone is close to L2, and the measurement value of the assembly is close to L_total, it can be determined that both reactors are included as designed. Subsequently, the winding temperature of the first reactor, the core surface temperature of the first reactor, the winding temperature of the second reactor, and the core surface temperature of the second reactor can be measured separately while applying the same rated current. Afterward, if only one of the reactors generates excessive heat, the number of windings, conductor thickness, or core specifications can be readjusted. Furthermore, by measuring the frequency-dependent insertion loss of the filter assembly including the above-mentioned inductor, it is possible to directly verify how the damping characteristics change depending on the combination of the first reactor and the second reactor. Through this procedure, it can be seen that the configuration in which the first reactor and the second reactor are included together is not merely a conceptual description, but a concrete structure confirmed through measurement and correction.

[0147] Therefore, in this context, the fact that the inductor includes a first reactor wound on a nanocrystalline core and a second reactor wound on a ferrite core means that two reactors using different magnetic materials are provided together in one inductor assembly, and the core specifications, number of turns, conductor thickness, arrangement order, and inductance share of each reactor can be specifically determined through the measurement of inductance of the test winding, the measurement of temperature under the rated current application state, the measurement of DC resistance, and the measurement of insertion loss.

[0148] According to one embodiment of the present invention, the nanocrystalline core is selected from an annular core with a diameter in the range of 25 mm to 140 mm, and the ferrite core is selected from an annular core with a diameter in the range of 31 mm to 140 mm.

[0149] This may mean that the nanocrystalline core and the ferrite core are both provided with a ring-shaped annular structure having a central hole, and that a specification satisfying the required electrical characteristics and winding conditions is selected from among a plurality of standard core groups prepared in advance. Here, an annular core may refer to a closed-loop structure in which a through hole is formed in the center and a conductor can repeatedly pass through and be wound along the circumference. In addition, the diameter may refer to a circular dimension identified in the core manufacturing specifications and may be specified as a representative diameter value based on the outer circular part. For example, the candidate group of nanocrystalline cores may be provided as annular cores with diameters of 25 mm, 30 mm, 50 mm, 65 mm, 80 mm, 90 mm, 110 mm, and 140 mm, and the candidate group of ferrite cores may be provided as annular cores with diameters of 31 mm, 48 mm, 51 mm, 68 mm, 87 mm, 107 mm, and 140 mm.

[0150] The reason for limiting the diameter range as described above is that the core size in which the winding can actually be accommodated and the resulting inductance value must be considered together. For example, even assuming the same insulated wire and the same number of turns, an annular core with an excessively small diameter may cause the bending radius of the wire passing through the center hole to decrease sharply and the windings to overlap too densely, which may increase the possibility of damage to the insulation sheath. Conversely, an excessively large core may increase the winding length at the same number of turns, thereby increasing conductor resistance and increasing the installation volume. Therefore, a person skilled in the art can first specify the outer diameter of the winding conductor to be applied, the required number of turns, and the allowable core shape, then select multiple annular core diameters that allow for actual winding under those conditions, and among them, select a specification that satisfies both the inductance and temperature rise conditions.

[0151] The selection of the diameters for the nanocrystalline core and the ferrite core can be specified through the same procedure. First, a core of each candidate diameter is prepared, and the center hole size, core height, and outer diameter of each core can be verified using a vernier caliper or an equivalent measuring instrument. Next, a test winding can be formed by applying the same insulating wire and the same reference number of turns. For example, after forming a test winding of 10 or 20 turns under the same conditions for each candidate core, the inductance can be measured using an LCR meter under conditions of 1 kHz and 1 V. Subsequently, by comparing the effective inductance coefficients for each core, the core specification that is closer to the target inductance at the same number of turns can be designated as a priority candidate. Next, the number of calculated turns required for the target inductance can be calculated using the relationship N = sqrt(L_target / AL), and the final diameter can be determined by fabricating a specimen with the integer number of turns closest to the calculated number of turns and remeasuring it.

[0152] In addition, the selection within the above diameter range is not determined solely by the simple inductance value, but can be determined by examining winding capacity and heat generation conditions together. For example, if there is almost no margin left in the center hole when actual winding is performed with the calculated number of turns, or if the winding overlaps beyond the core height, causing the winding shape to become unstable, that diameter may be excluded, and the next larger diameter core may be selected. Conversely, if there is sufficient winding margin but the conductor resistance and temperature rise increase significantly due to the increase in winding length under rated current application, the next smaller diameter core may be re-examined. To this end, the winding surface temperature and the core surface temperature are measured at 30, 60, and 120 minutes after the rated current is applied to each candidate diameter specimen, and the specifications capable of long-term use can be adopted by comparing them with the insulation class of the winding conductor. Through this procedure, the range of 25 mm to 140 mm or 31 mm to 140 mm can be specified not as an arbitrary numerical range, but as a range of core candidates that examines whether actual winding is possible, whether inductance is formed, and whether temperature rises.

[0153] The fact that both the nanocrystalline core and the ferrite core are selected as annular cores also has specific implementation significance. Since the winding conductors in an annular core are arranged continuously along the circumference of the core, the magnetic flux path can form a closed loop without interruption, and the coupling length between the winding conductors and the core can be maintained relatively constant. Therefore, it is easy to compare specimens under the same number of turns, and changes in winding length and inductance due to changes in diameter can be directly measured and reflected. Furthermore, if both the nanocrystalline core and the ferrite core are prepared as annular structures, even when comparing different materials, the evaluation can focus on changes due to differences in material and diameter rather than variables due to differences in shape, so a person skilled in the art can more clearly select the core for the first reactor and the core for the second reactor.

[0154] Therefore, in the context of this invention, the fact that the nanocrystalline core is selected from an annular core with a diameter in the range of 25 mm to 140 mm and the ferrite core is selected from an annular core with a diameter in the range of 31 mm to 140 mm means that there are multiple groups of annular diameter specifications prepared in advance for each different magnetic material, and a person skilled in the art can perform test winding under the same conditions, inductance measurement, application of actual number of turns, verification of winding feasibility, and temperature measurement under rated current application for each specification group, and then select and implement a diameter specification that satisfies the required electrical characteristics and physical acceptance conditions.

[0155] According to one embodiment of the present invention, the coils of the first reactor and the second reactor are formed with a winding of 180°C grade, thereby forming an inductance path corresponding to conduction noise components of different frequency bands from a low frequency band to a high frequency band.

[0156] This may mean that the winding conductors forming the conduction paths of the first and second reactors, respectively, are made of an insulating coating winding material having a heat resistance rating of 180°C. Here, a coil may refer to a winding section in which a conductor is wound multiple times to form a magnetic field, and a winding of 180°C rating may refer to a winding material with an insulation rating of 180°C determined so that the electrical insulation of the insulating coating is maintained even under conditions of continuous current flow and repeated temperature rise. The first and second reactors may each have independent coils, and each coil may be implemented as a structure in which a single conductor is continuously wound, a structure in which multiple conductors are arranged in parallel and wound together, or a structure formed by winding flat conductors in a stacking direction. At this time, a person skilled in the art may first determine the rated current and the required number of windings, and then select a 180°C rating winding material so that insulation breakdown does not occur even if the temperature of the winding section rises repeatedly under those conditions. In the attached materials as well, a winding material rated at 180°C is presented as a candidate for the winding of the first reactor and the second reactor.

[0157] A specific method for forming the above coil into a 180°C grade winding can be implemented as follows. First, the conductor diameters of the winding material used for the first reactor and the winding material used for the second reactor can be determined according to the rated current and the winding window occupancy rate. For example, under the same current conditions, multiple 180°C grade winding specimens with conductor diameters of 1.3 mm, 1.6 mm, 1.8 mm, and 2.0 mm can be prepared, and the first reactor and the second reactor can be manufactured with the same number of turns. Next, the DC resistance is measured for each specimen, and the winding surface temperature and core surface temperature are recorded at 30, 60, and 120 minutes after the rated current is continuously applied. Subsequently, a conductor diameter can be adopted that satisfies the required inductance while maintaining a sufficient margin for the winding temperature relative to the insulation grade of the winding material. Through this procedure, a 180°C rated winding can be realized not merely as a simple material substrate, but as a winding structure capable of being sustained under continuous current conditions and temperature rise conditions.

[0158] Furthermore, the fact that the coils of the first and second reactors form inductance paths corresponding to conducted noise components in different frequency bands, ranging from low to high frequency bands, may mean that the coils of the first reactor and the second reactor each form different inductive impedances depending on the frequency, so that noise currents in different frequency ranges do not flow only along the same path but are attenuated by being influenced by two coil paths having different reactance distributions according to frequency characteristics. Here, an inductance path may refer to a conductive path in which current passes through a winding section to form magnetic energy and, accordingly, exhibits frequency-dependent inductive reactance. The coil of the first reactor may form a first inductive path according to the core material and number of turns of the first reactor, and the coil of the second reactor may form a second inductive path according to the core material and number of turns of the second reactor. At this time, the first inductive path and the second inductive path may be arranged in series on the same power line, or they may be repeatedly arranged in the same structure on each of multiple power lines.

[0159] In order to specifically determine the inductance paths corresponding to the different frequency bands mentioned above, the frequency range of the noise to be reduced can first be determined by measurement. For example, in the absence of a filter assembly, multiple measurement points such as 50 kHz, 100 kHz, 150 kHz, 300 kHz, 1 MHz, 10 MHz, and 100 MHz can be set for the power line, and the noise level at each frequency can be recorded. Next, the frequency range requiring attenuation can be divided into a low-frequency section and a high-frequency section, and the target inductance value L1 to be handled by the first reactor and the target inductance value L2 to be handled by the second reactor can be determined, respectively. Subsequently, the reactance formed by the first reactor at each frequency f is calculated as X_L1 = 2pifL1, and the reactance formed by the second reactor is calculated as X_L2 = 2pifL2, so that the inductive influence of which reactor appears more significantly in which frequency range can be compared. For example, if L1 is formed to be relatively large and L2 is relatively small, the influence of X_L1 may be greater on the low-frequency side, while conversely, on the high-frequency side, the influence of the second reactor path may be greater due to the loss characteristics according to the core material and differences in winding structure. In this way, the coils of the first and second reactors, respectively, do not simply exist in series but can be specified as paths corresponding to different frequency bands based on the calculation and measurement results of the reactance for each frequency.

[0160] Whether the coils of the first and second reactors actually correspond to conducted noise components in different frequency bands can be verified through a prototype comparison test. First, specimens containing only the first reactor, specimens containing only the second reactor, and specimens containing both the first and second reactors can be fabricated, respectively. Then, under the same voltage and current conditions, the insertion loss of each specimen can be measured at 50 kHz, 1 MHz, 10 MHz, and 100 MHz for both the symmetric mode and the asymmetric mode. Subsequently, the frequency range attenuated more significantly in the specimen containing only the first reactor and the frequency range attenuated more significantly in the specimen containing only the second reactor can be compared, and it can be verified whether the two ranges are continuously attenuated in the specimen containing both the first and second reactors. Through such a procedure, a person skilled in the art can determine, based on actual measurements, whether the coil of the first reactor corresponds to a relatively low-frequency conducted noise component and the coil of the second reactor corresponds to a relatively high-frequency conducted noise component, or vice versa.

[0161] In addition, the reason for adopting a 180°C rated winding is that the heating characteristics of the winding section may differ during the process of the first reactor and the second reactor responding to noise in different frequency bands. That is, even under the same rated current conditions, the heating characteristics of the coil of the first reactor may differ depending on the number of turns, core magnetic flux density, and conductor length, and the coil of the second reactor may exhibit different temperature rises due to the skin effect, proximity effect, and core loss caused by high-frequency components. Therefore, a person skilled in the art can apply the same 180°C rated winding material to each of the first reactor and the second reactor, and then individually measure the temperature of each winding under the condition of applying the rated current to verify whether only one winding is excessively heated. Since the attached data also lists the 180°C rated winding material as the component used and presents the inductor temperature measurement value under the condition of applying the rated current, the above winding structure can be realized based on actual thermal conditions.

[0162] Therefore, in this context, the coils of the first and second reactors are formed with windings of 180°C grade to form inductance paths corresponding to conducted noise components of different frequency bands from low frequency bands to high frequency bands. This means that each coil of the first and second reactors is made of winding material of 180°C insulation grade, and the number of turns, conductor diameter, and reactance characteristics of each coil are specifically determined according to the noise measurement values ​​by frequency and the temperature measurement values ​​under the rated current application state, and as a result, the two coils can be implemented to provide different inductive paths for conducted noise components of different frequency ranges.

[0163] According to one embodiment of the present invention, the power connection unit comprises a terminal block and a copper bar connected to the terminal block to transmit current to the input terminal or output terminal, wherein the copper bar is formed as a plate-shaped conductor and is formed to have cross-sectional dimensions of 5 mm × 25 mm or 8 mm × 45 mm, and the connecting stud or screw shaft of the terminal block has a nominal diameter of 6 mm or 10 mm.

[0164] It may refer to a structure in which a terminal portion to which an external power line is connected, and a plate-shaped conductor that actually transmits current from the terminal portion to the input terminal or the output terminal, form an integrated conduction path. Here, the terminal block may refer to an insulated support type terminal module to which the end of an external or internal wiring is connected, and the copper bar may refer to a current-transmitting conductor formed by cutting or processing copper or a low-resistance conductive material equivalent thereto into a plate shape. Furthermore, transmitting current to the input terminal or output terminal may mean that the current flowing into the terminal block from the external wiring continuously moves through the copper bar to the conduction path on the input terminal side or the conduction path on the output terminal side. Therefore, the power connection portion can be understood as a structure that simultaneously possesses a terminal connection function and a high-current conduction function.

[0165] The above terminal blocks may be selected according to different specifications depending on the rated current. For example, among 30 A, 60 A, 100 A, 150 A, 200 A, 400 A, 600 A, or 700 A terminal blocks, a specification with a rated current greater than or equal to the continuous current can be selected. For example, if the continuous current is 20 A, a 30 A terminal block can be applied; if it is 80 A, a 100 A terminal block can be applied; and if it is 180 A, a 200 A terminal block can be applied. Additionally, a 400 A terminal block can be applied in the 350 A to 400 A range, a 600 A terminal block can be applied in the 600 A range, and a 700 A terminal block can be applied in the 700 A range. As such, since the rating of a terminal block can be determined by first specifying the target current and then selecting a rating that is not smaller than it, an ordinary technician can repeatedly select the appropriate terminal block specification simply by checking the rated current of the device to be installed.

[0166] Since the above copper bar is formed as a plate-shaped conductor, it can be implemented as a conductor having a rectangular cross-section with distinct thickness and width. The above 5 mm × 25 mm copper bar refers to a plate-shaped conductor with a thickness of 5 mm and a width of 25 mm, and the above 8 mm × 45 mm copper bar refers to a plate-shaped conductor with a thickness of 8 mm and a width of 45 mm. In this case, the cross-sectional areas of the copper bars are 125 mm² and 360 mm², respectively, and each copper bar can be selected to correspond to different current grades. In one example, since a 5 mm × 25 mm copper bar can be used for transmitting a 355 A class current and an 8 mm × 45 mm copper bar can be used for transmitting a 770 A class current, a person of ordinary skill in the art can determine the copper bar specifications by first specifying the current I_target to be continuously conducted, and then applying the 5 mm × 25 mm copper bar first if I_target is 355 A or less, and applying the 8 mm × 45 mm copper bar if I_target exceeds 355 A and is 700 A or less. This selection method is not based on simple rules of thumb, but is based on the allowable current class for each copper bar specification. For example, when constructing a 300 A class product, continuous conduction is possible with a 5 mm × 25 mm copper bar, and when constructing a 700 A class product, the allowable current of the conductor can be made greater than the target current by applying an 8 mm × 45 mm copper bar.

[0167] When actually manufacturing the above copper bar, a plate-shaped copper material is first prepared, cut to the required length, and fastening holes can be machined at both ends or at the intermediate connection points. The length of the above copper bar can be determined by the distance between the terminal block and the input terminal or the output terminal. If a straight arrangement is possible, it can be formed in a straight shape, and if there are space constraints, it can be formed into a Z-shape, L-shape, or stepped path through bending. However, since the cross-sectional dimensions are maintained at 5 mm × 25 mm or 8 mm × 45 mm, even if the length and bending shape are deformed, the minimum cross-section for transmitting current can be maintained. Additionally, since the above fastening holes can be positioned to correspond to the fastening studs or screw shafts of the terminal block, a person skilled in the art can first measure the spacing between the holes of the terminal block and then determine the position of the fastening holes of the copper bar according to that spacing.

[0168] The fact that the fastening stud or screw shaft of the terminal block has a nominal diameter of 6 mm or 10 mm may mean that the external dimensions of the shaft portion forming the mechanical connection and electrical contact between the terminal block and the copper bar are set to a 6 mm or 10 mm grade. For example, a fastening stud or screw shaft with a nominal diameter of 6 mm may be used for a power connection portion of a relatively low current grade, and a fastening stud or screw shaft with a nominal diameter of 10 mm may be used for a power connection portion of a relatively high current grade. In the verification example, a 30 A grade product has a nominal diameter of 6 mm, and a 300 A grade and 700 A grade products have a nominal diameter of 10 mm; therefore, a person skilled in the art can determine the fastening shaft specifications by applying a 6 mm grade in the low current range, such as the 30 A grade, and applying a 10 mm grade in the medium-to-high current range, such as the 300 A grade or higher, based on the rated current grade of the terminal block selected first. In addition, for the intermediate current section, either the 6 mm class or the 10 mm class can be determined by matching the fastening specifications of the selected terminal block itself with the specifications of the copper hole machining.

[0169] The specific procedure for combining the copper bar and the terminal block can be implemented as follows. First, a terminal block suitable for the rated current is selected, and it is determined whether the connecting shaft is 6 mm or 10 mm. Next, a connecting hole in the copper bar is machined to match the specifications of the selected connecting shaft, and one end of the copper bar can be inserted into the connecting shaft of the terminal block and secured with a nut or a connecting member. Subsequently, the other end of the copper bar can be connected to the conductive part on the input terminal side or the conductive part on the output terminal side in the same manner. At this time, the copper bar is pressed flatly so that it does not twist or become eccentric between the connecting parts, and after connection, it can be visually checked whether there is any gap between the surface of the copper bar and the contact surface of the terminal block. In addition, when using a 10 mm connecting shaft, since the width and thickness of the copper bar increase, assembly can be performed after first securing an assembly space around the connecting part where a tool can be inserted.

[0170] Whether the above-mentioned power connection actually conducts the target current can be verified using a verification specimen. First, a first specimen using a 5 mm × 25 mm copper bar and a second specimen using an 8 mm × 45 mm copper bar are fabricated, and for each specimen, after assembling them with the same fastening specifications as the selected terminal block, the DC resistance between the input terminal side and the output terminal side can be measured. Next, a current of 355 A or less is continuously applied to the first specimen, and a current exceeding 355 A and up to 700 A is continuously applied to the second specimen, and after a certain period of time, the surface temperature of the copper bar and the temperature of the terminal block fastening part can be measured. Subsequently, by checking for loosening of the fastening part, deformation of the copper bar, traces of overheating, or insulation damage, it can be specifically determined whether the selected copper bar cross-section and fastening shaft specifications are reusable at the corresponding current rating. In the verification example, different fastening shaft specifications and copper bar specifications were applied to the 700 A-class product, 300 A-class product, and 30 A-class product, and since the temperature rise and fastening stability were confirmed, the power connection part can be reproducibly implemented based on the cross-sectional dimensions and fastening shaft specifications.

[0171] Accordingly, in the context of this invention, the power connection unit comprises a terminal block and a copper bar connected to the terminal block to transmit current to the input terminal or output terminal, wherein the copper bar has cross-sectional dimensions of 5 mm × 25 mm or 8 mm × 45 mm and the connecting stud or screw shaft of the terminal block has a nominal diameter of 6 mm or 10 mm, which means that the structure can be specifically implemented to form a continuous high-current conduction path to the input terminal or output terminal by first specifying a target rated current, selecting a terminal block capable of withstanding a current greater than that current, selecting one of a 5 mm × 25 mm copper bar with an allowable current rating of 355 A or an 8 mm × 45 mm copper bar with an allowable current rating of 770 A, and applying a 6 mm or 10 mm connecting structure in accordance with the connecting shaft specifications of the selected terminal block.

[0172] In the metal case of the filter body according to one embodiment of the present invention, the terminal block and copper bar are arranged such that the distance between the live wire part and the metal case is 10.7 mm or more, and the distance between the live wire parts having different polarities or phases is 20.0 mm or more.

[0173] This may mean that the positions of the conductive parts exposed or electrically chargeable inside the filter body are mechanically arranged to be separated from each other by a predetermined standard distance or more. Here, the inside of the metal case may refer to the inner space of the metal casing forming the filter body, and the live section may be understood as a concept including the conductive fastening part of the terminal block, the conductive body of the copper bar, and the exposed conductive surface to which power can be applied as the terminal block and the copper bar are fastened. Additionally, the separation distance from the metal case may refer to the shortest straight-line distance between the outer surface of the live section and the inner metal surface of the metal case, and the separation distance between live sections having different polarities or phases may refer to the shortest straight-line distance between the outer surfaces of two live sections having different potentials.

[0174] The condition that the separation distance between the live wire section and the metal case is 10.7 mm or more means that when the terminal block or the copper bar is mounted inside the metal case, either live wire section is positioned so as not to be excessively close to the inner surface of the metal case. To implement this, the inner bottom surface, side wall surface, and top cover surface of the metal case are first set as reference planes, and the fixed position of the terminal block and the extension direction of the copper bar can be determined. Next, the maximum outer shape range of each live wire section is set based on the outer edge of the conductive fastening part of the terminal block and the outer contour of the copper bar, and the fastening position can be adjusted so that the shortest distance between the maximum outer shape range and the inner surface of the metal case is 10.7 mm or more. For example, when the terminal block is fixed to the bottom surface, the distance from the top cover is first calculated by considering the height of the conductive part of the terminal block and the height of the upper surface of the copper bar, and then the center position of the terminal block can be moved in the left and right directions by considering the distance from the side wall. In addition, when the above-mentioned bar is bent, the outer corner of the bent portion can be the point closest to the inner surface of the metal case, so the placement position can be determined based on the shortest distance including not only the flat portion but also the outer point of the bent portion.

[0175] The condition that the separation distance between live sections having different polarities or phases is 20.0 mm or more may mean that two conductive sections having different potentials are not placed too close to each other inside the metal case. In a single-phase structure, this may mean the distance between two live sections connected to a live line and a neutral line, or between live sections connected to two different live lines; in a three-phase structure, this may mean the distance between the first phase live section and the second phase live section, between the second phase live section and the third phase live section, and between the first phase live section and the third phase live section. To implement this, the conductive connection positions of the terminal blocks corresponding to each phase or each polarity are first arranged in a line or in parallel, and the center spacing may be determined such that the shortest distance between the outer surfaces of adjacent live sections is 20.0 mm or more. For example, when rectangular supports are arranged parallel to each other, the distance between the opposing sides of the two supports can be used directly as a design value; and when the conductive fastening portion of the terminal block protrudes in a circular or hexagonal shape, the shortest distance can be calculated based on the maximum circumscribing shape including the outer contour of the protrusion. Furthermore, when supports are not straight but are bent or arranged with a height difference, the mutual separation can be verified based on the shortest straight-line distance in space, rather than just the distance in a simple plane.

[0176] The specific placement procedure for the terminal blocks and copper bars described above can be formed as follows. First, a connection reference line for the terminal blocks can be marked on the inner bottom surface of the metal case, and the center coordinates of the terminal blocks for each phase or each polarity can be set. Next, the extension direction of the copper bars to be connected to each terminal block can be determined as the input terminal side or the output terminal side, and an outer contour line considering the width and thickness of the copper bars can be set on the drawing. Subsequently, the shortest distance d1 between the outer contour of the first live line section and the inner surface of the metal case, the shortest distance d2 between the outer contour of the second live line section and the inner surface of the metal case, the shortest distance d12 between two adjacent live line sections, and the shortest distance d23 between another adjacent live line section can be calculated, respectively. At this time, since each distance value must be calculated as the actual distance between outer surfaces rather than a simple center interval, for example, d1 can be obtained in the manner of d1 = case reference plane position - first live line outer surface position, and d12 can be obtained in the manner of d12 = second live line outer surface start position - first live line outer surface end position. Subsequently, the final arrangement can be determined by modifying the fixed position of the terminal block or the bending position of the bar so that d1 and d2 are both 10.7 mm or more, and d12, d23, etc. are all 20.0 mm or more.

[0177] In addition, the above separation distance can be reconfirmed in the actual product state after assembly. To this end, with the terminal block and copper bar fastened inside the metal case, each shortest distance can be measured using a depth gauge, vernier caliper, thickness gauge, or equivalent length measuring means. When measuring, the point closest to the live line on the inner surface of the metal case is first located, and the vertical or shortest straight-line distance between that point and the outer edge of the live line can be measured. The distance between live lines can also be measured by the distance between the two outer points or outer lines closest to each other. If any part among the protruding screw head, fastening nut, bent corner of the copper bar, or outer edge of the terminal block's conductive part within the same live line is identified as the closest point, the separation distance can be determined based on that point. By setting the measurement reference point as the "most protruding part of the conductive outer surface" in this way, a person of ordinary skill can perform repeated measurements for each product using the same standard.

[0178] The above separation distance condition can be formed to be satisfied based not only on the no-load stopped state but also on the completed connection state. That is, after the copper bar is connected to the terminal block and an actual conductive path is formed, the distance between the live section and the metal case, as well as the distance between the live sections, can be verified based on the final state where the position is determined by the connection. In this case, since the measurement is taken based on the state where the copper bar is pressed and aligned by the connection studs or screw shafts, rather than a simple component layout diagram before connection, the insulation margin of the final structure, including assembly errors, can be evaluated. Furthermore, since the smallest separation distance can be formed at any part of the copper bar—such as the longitudinal end, the outer surface of the bend, the side of the terminal block's conductive section, or the conductive protrusion around the connection section—the entire section can be visually inspected after assembly, and the distance at each candidate point can be sequentially measured to record the minimum value. By making a judgment based on the minimum value in this manner, it is possible to prevent a situation where a wide distance is secured only at a specific location while a distance shortage occurs at other locations.

[0179] Accordingly, in the context of this invention, the arrangement of the terminal block and the copper bar within the metal case of the filter body such that the distance between the live wire and the metal case is 10.7 mm or more, and the distance between live wires having different polarities or phases is 20.0 mm or more means an arrangement structure in which the shortest straight-line distance between the inner surface of the metal case and the adjacent live wire is calculated based on the conductive fastening part of the terminal block and the outer contour of the copper bar, respectively, and the fixed position of the terminal block and the extension direction and bending shape of the copper bar are specifically determined so that the minimum values ​​in the completed assembly state are 10.7 mm and 20.0 mm or more, respectively.

[0180] According to one embodiment of the present invention, the filter body further comprises a metal case, an insulating sheet, an insulating tube, and a substrate disposed inside the metal case.

[0181] The metal case described above may be formed to form the outer structure of the filter body, mechanically protect the electrical assembly housed inside, and suppress external impact, dust, moisture ingress, and positional displacement of internal components. The metal case may be a combined structure of a lower case and an upper cover formed by bending a conductive metal plate, or it may be an integrally molded box-shaped housing structure, and may form an internal housing space including an inner bottom surface, a side wall surface, and an upper cover surface. The material of the metal case may be a steel plate, a galvanized steel plate, an aluminum plate, or a metal material equivalent thereto, and may provide a fixed reference surface including fastening holes, fixing ribs, or bracket fastening parts to prevent internal components from shaking. The size of the metal case can be determined based on the outer dimensions of the substrate placed inside, the interposed area of ​​the insulating sheet, the outer shape of the conductive part covered by the insulating tube, and the access space for assembly tools. In one example, it may have outer dimensions such as 250 mm × 105 mm × 100 mm, 350 mm × 155 mm × 130 mm, or 500 mm × 240 mm × 210 mm, but is not limited thereto. A person skilled in the art can first calculate the length and width of the substrate to be placed inside, the coverage area of ​​the insulating sheet, the increase in the outer diameter formed by the insulating tube, and the minimum clearance distance from the inner surface of the case, and then determine the length, width, and height of the metal case so that an inner space greater than the sum thereof is secured.

[0182] The insulating sheet may be a plate-shaped insulating member interposed between the inner surface of a metal case and a substrate or a conductive part to block unintentional contact. The insulating sheet may be formed from PET, PI, PPS, or an insulating film or insulating plate material equivalent thereto, and in one example, it may be implemented as a PET insulating sheet with a thickness of 0.25 mm. The insulating sheet may be placed in close contact with the bottom surface of the metal case to block direct contact between the bottom surface of the substrate and the metal case, or it may be attached to the inner side of the side wall or the top cover surface to locally insulate the portion where the protruding section of the conductive part approaches the metal case. The shape of the insulating sheet may be cut into a rectangular, L-shape, C-shape, or a partially open shape including a through hole, and assembly interference can be prevented by first marking the location of the fastening hole for fixing the substrate, the location of the case rib, and the location of the wiring passage, and then cutting it while avoiding those locations. The area of ​​the insulating sheet can be formed to be larger in each direction than the outline of the protected area, and in one example, it can be cut to extend 3 mm to 15 mm further from the edge of the outline of the protected area so that the conductive part does not directly face the metal case even if there is a fastening error. When actually applying the insulating sheet, the inner surface of the metal case is cleaned and then attached tightly using an adhesive layer or a fixing member, and after assembly, by checking for lifting, curling, tearing, and damage around the fastening hole of the insulating sheet, it can be confirmed whether the insulating state is maintained even during repeated assembly.

[0183] The insulating tube is a tubular insulating member that surrounds the outer circumference of a conductive part through which current can flow, and may be provided to form an additional insulating layer in the section where the exposed conductive surface is close to a metal case or substrate pattern. The insulating tube may be formed from an extruded insulating tube, a shrink insulating tube, or a tubular insulating material equivalent thereto, and in one example, insulating tubes of multiple specifications with different outer and inner diameters may be used. For example, one of insulating tubes of specifications of 30.0 / 15.0 mm, 25.0 / 12.5 mm, 20.0 / 10.0 mm, 18.0 / 9.0 mm, 15.0 / 7.5 mm, 12.0 / 6.0 mm, 10.0 / 5.0 mm, 8.0 / 4.0 mm, 6.0 / 3.0 mm, 4.0 / 2.0 mm, and 2.0 / 1.0 mm may be selected. The selection of the specifications for the insulation tube above can be made by first measuring the outer diameter or diagonal dimension of the conductive part to be coated, and then selecting an insulation tube having an inner diameter larger than that dimension. For example, if the outer diameter of the conductive part is D_c and the inner diameter of the insulation tube is D_t, D_t can be selected to be greater than or equal to D_c and within the range of 1.05 to 1.30 times D_c in order to simultaneously ensure assembly and adhesion. The length of the insulation tube can be cut longer than the length of the exposed conductive section so that both ends overlap with the uncoated section, and in one example, it can be cut to extend 3 mm to 20 mm further from each end of the exposed section. After assembly, both ends can be retracted or supported with fixing members to prevent the insulation tube from slipping and detaching, and the shortest distance between the outer circumference of the insulation tube and the inner surface of the metal case can be measured again in the assembled case state to verify whether an additional insulation layer is actually secured.

[0184] The above substrate may be a plate-shaped insulating substrate that supports electrical components and forms a conductive path inside a metal case. The above substrate may be formed from a glass fiber reinforced epoxy resin substrate, a ceramic substrate, or an insulating substrate equivalent thereto, and in one example, it may be implemented as a substrate of FR-4 material, 1 layer, thickness 2T, and flame retardant grade V-0. The outer shape of the above substrate may be formed as a rectangular or irregular cut shape to correspond to the bottom surface or support frame of the metal case, and may include fastening holes, slots, through holes, and pattern forming portions. The length and width of the above substrate may be formed to be smaller than the internal receiving space of the metal case, but may be determined by considering the space where an insulating sheet can be interposed between the outer edge of the substrate and the inner surface of the metal case and the assembly tolerance. For example, if the outer length of the substrate is L_b and the inner length of the metal case is L_c, and the sum of the assembly tolerance on both sides and the insulating interposed space is M, the length and width may be determined to satisfy the relationship L_b <= L_c - M, and the width direction may be calculated in the same way. In addition, the thickness of the substrate can be determined based on the spacing of the fastening parts, the loading load, and vibration conditions, and in one example, a substrate with a thickness of 2 mm can be used to suppress bending deformation. The substrate can be placed on top of an insulating sheet or fixed with a gap using an insulating spacer so as not to come into direct contact with the bottom surface of the metal case, and after assembly, durability can be verified by checking for substrate bending, cracking, pattern peeling, or damage to the fastening holes.

[0185] The combination of the metal case, insulating sheet, insulating tube, and substrate described above can be specifically implemented according to the assembly sequence. First, a fastening reference point is marked on the bottom surface of the metal case, and the insulating sheet is cut to the required position and shape and then fixed to the inner surface of the metal case. Subsequently, the substrate can be positioned on the insulating sheet or on an insulating spacer and fixed through fastening holes. Next, an insulating tube is placed over the conductive section requiring insulation, and then any interference between the substrate and the metal case, or between the outer circumference of the insulating tube and the metal case, can be checked. After assembly is complete, with the metal case closed, a withstand voltage test, an insulation resistance test, a temperature rise test, and a vibration test are performed to verify whether there is any damage to the insulating sheet, detachment of the insulating tube, displacement of the substrate, or unintentional conductivity between the metal case and the internal assembly. Through this procedure, the metal case, insulating sheet, insulating tube, and substrate can be specifically implemented not as a simple arrangement of independent components, but as an assembly structure that performs both insulation and support within the metal case.

[0186] According to one embodiment of the present invention, the discharge resistor is formed to have a resistance value of 2 MΩ, and the inductor, the first capacitor, the second capacitor, the discharge resistor, and the power connection part are fixed to each other inside the metal case so as not to cause cracking, deformation, insulation breakdown, or detachment of connection in a temperature environment of -25℃ to 85℃, a humid heat environment of 21 days, an overcurrent application environment of 135% of the rated current, and a vibration environment in which an excitation of 20 m / s² is applied in the range of 10Hz to 150Hz.

[0187] According to one embodiment of the present invention, the discharge resistor is formed to have a resistance value of 2 MΩ. Here, being formed to have a resistance value of 2 MΩ includes not only the case where a single resistor element has a rated resistance value of 2 MΩ, but also the case where a plurality of resistor elements are connected in series to form a combined resistance value of 2 MΩ. Since the discharge resistor is connected in parallel between two connection points identical to both ends of the first capacitor, the charge charged in the first capacitor can be formed to attenuate through the discharge resistor after the power is cut off. The resistance value of the discharge resistor is not set arbitrarily, but can be determined by considering together the capacitance of the first capacitor, the voltage that can be formed across the first capacitor, the time to reach the allowable residual voltage after the power is cut off, and the power consumption in the continuous applied voltage state of the discharge resistor. For example, if the capacitance of the first capacitor is C_x, the initial voltage across the first capacitor immediately after power cut is V_0, the target residual voltage is V_s, the allowable discharge time is t_d, and the discharge resistance value is R_d, the voltage decay of the first capacitor can be expressed by the relationship V(t) = V_0exp(-t / (R_dC_x)), and accordingly, R_d can be calculated based on -t_d / (C_x*ln(V_s / V_0)). If the first capacitor is 2.2 μF and the voltage that can be formed across the first capacitor corresponds to a line voltage of 440 V, the initial voltage can be set to sqrt(2)*440 and the allowable discharge time can be set in the range of 20 to 25 seconds, and a discharge resistance of 2 MΩ can be adopted according to the calculated result. In addition, when a commercial frequency voltage is continuously applied to the discharge resistor, the power consumption is calculated according to the relationship P=V_rms^2 / R, so the power consumption corresponding to a resistance value of 2 MΩ is calculated first, and then a resistor element with a rated power greater than that can be selected.For example, a 1 W 2 MΩ resistor can be used, and when multiple resistors are connected in series, the voltage and heat generated by each resistor can be checked to ensure that the total combined value is 2 MΩ. As the discharge resistor component, a resistor element with 1 W, 2 MΩ, and a tolerance of ±5% can be applied.

[0188] The statement that the inductor, the first capacitor, the second capacitor, the discharge resistor, and the power connection part are fixed to each other within the metal case may mean that each component is not in a state where it can freely shake or move within the metal case, but rather is in a state where it is mechanically supported and coupled so that its relative position is maintained even during operation. The inductor may be fixed to a reference plane inside the metal case by a fastening structure using the outer edge of the core or a central hole, the first capacitor and the second capacitor may be arranged in a fixed state so that their lead portions or terminal portions maintain a certain direction, and the discharge resistor may be supported so that its body does not shake due to vibration while connected to two connection points identical to both ends of the first capacitor. Additionally, the power connection part may be maintained through a fastening shaft and a contact surface so that the fixed position of the terminal block and the fastening position of the copper bar do not change within the metal case. In this case, "fixed to each other" does not mean that all components are directly in contact with each other and become an integral, but may mean a structure in which the position and connection state of each component within the metal case are maintained even after repeated current flow, temperature changes, and vibration application. Therefore, a person of ordinary skill in the art can achieve a mutually fixed state by first determining the placement coordinates of each part inside a metal case, then determining the fastening points, support points, and connection points of each part, and checking whether there is any movement of each part after assembly.

[0189] The above temperature environment of -25°C to 85°C may be a condition for verifying whether the external appearance, insulation state, and connection state of each component are maintained under low and high temperature conditions. To this end, the assembled filter body may be placed in a low-temperature chamber and maintained at -25°C to check its external appearance and conductivity, and then placed in a high-temperature chamber and maintained at 85°C to check its external appearance and conductivity again. At this time, the subjects of verification may include whether there is a crack in the core of the inductor, whether the outer resin of the first capacitor and the second capacitor is deformed, whether there is a crack in the body of the discharge resistor, whether there is a change in the fastening state of the power connection part, and whether there is insulation breakdown. After the temperature environment test, inductance, capacitance, and insulation resistance measurements may be performed to verify whether each value is within the acceptable range by comparing it with the value before assembly or with the reference measurement value. The above product family may be set to a climate category that includes -25°C low temperature and 85°C high temperature conditions.

[0190] The above 21-day humid and hot environment may be a condition for verifying whether the insulation performance and connection status of each component are maintained under conditions where high humidity is sustained for a long period of time. To this end, a specimen in which the inductor, the first capacitor, the second capacitor, the discharge resistor, and the power connection part are assembled inside the metal case may be placed in a humid and hot tester, and after maintaining the humid and hot condition for 21 days, it may be removed to remeasure the appearance, insulation resistance, inductance, and capacitance. During this process, it may be verified whether there are any signs of swelling, cracks, or leakage on the outer materials of the first capacitor and the second capacitor, whether the change in the resistance value of the discharge resistor is within an acceptable range, and whether there is any oxidation, loosening, or increase in contact resistance at the connection part of the power connection part. In addition, after the humid and hot test, additional withstand voltage tests and insulation resistance tests may be performed to verify whether insulation breakdown occurs between the metal case and the live part, or between conductive parts of different phases or polarities. The above product family can be configured to pass a 21-day moist heat steady-state condition.

[0191] The environment of applying an overcurrent of 135% of the rated current may be a condition to verify whether each of the above components is not damaged even if a current greater than that in normal operating conditions is applied temporarily or for a certain period of time. To this end, when the rated current of each model is denoted as I_rated, the test applied current I_over can be set as I_over = 1.35 * I_rated. For example, 945 A can be applied for the 700 A class, 405 A for the 300 A class, and 40.5 A for the 30 A class. During the application of overcurrent, the winding temperature and core temperature of the inductor, the outer temperatures of the first capacitor and the second capacitor, the discharge resistor temperature, and the terminal block and copper bar temperatures can be measured, respectively. After the application is terminated, an external inspection and insulation resistance measurement can be performed to verify whether there are any traces of ignition, cracks, damage, resin leakage, loosening of fasteners, or insulation breakdown. In one example, the inductor temperature may be confirmed to be at a level of 100.2°C, 79.2°C, or 60.5°C, the discharge resistance temperature at a level of 73.6°C, 41.6°C, or 47.7°C, and the case temperature at a level of 72.2°C, 55.9°C, or 44.9°C, and even after an overcurrent test, the insulation resistance may be maintained above the standard, and it may be determined that there is no ignition, cracking, or damage.

[0192] The vibration environment in which an excitation of 20 m / s² is applied in the range of 10 Hz to 150 Hz may be a condition for verifying whether the fixed state of each component is maintained against repetitive vibrations that may occur during transportation or operation at the installation site. To this end, a specimen assembled inside the metal case may be fixed to a vibration tester, and a sinusoidal excitation in the range of 10 Hz to 150 Hz under a condition of 20 m / s² may be applied in each of the X-axis, Y-axis, and Z-axis directions. Before the vibration test, the initial positions of the inductor connection part, the first capacitor and the second capacitor fixing part, the discharge resistor connection part, the terminal block connection part, and the copper bar connection part may be recorded, and after the vibration test, the position change at the same point, loosening of the connection, traces of metal fatigue, lead wire damage, or core cracking may be checked. In addition, after the vibration test, the inductance, capacitance, insulation resistance, and continuous conduction status may be measured again to verify whether there is a change in electrical performance. The above vibration conditions can be set to sinusoidal conditions of 10 Hz to 150 Hz and 20 m / s², and there should be no cracks or deformation even after these conditions.

[0193] The configuration that prevents the occurrence of cracks, deformation, insulation breakdown, or detachment of the connection may mean that, even after applying each of the above environmental conditions independently or sequentially, there are no cracks in the core or winding structure of the inductor, no expansion, deformation, or detachment of the terminals in the external shape of the first capacitor and the second capacitor, no cracks or sudden changes in resistance value in the body of the discharge resistor, the connection state between the terminal block and copper bar of the power connection part does not loosen, and no insulation breakdown occurs between the metal case and the live part or between different potential parts. To verify this, external photography, verification of connection torque, measurement of continuity, measurement of insulation resistance, measurement of inductance, and measurement of capacitance may be performed sequentially before and after each test, and if the measured value after the test is within the allowable range relative to the reference value before the test, it can be determined that environmental reliability has been secured. The above discharge resistor can be formed to maintain a resistance value of 2 MΩ while ensuring that the change in resistance value after the above environmental conditions does not exceed an allowable range, and each of the above components can be assembled to maintain a state where their relative positions do not change inside a metal case. In environmental and safety tests of the above product family, conditions can be confirmed in which there is no external damage or insulation breakdown even after low temperature, high temperature, humid heat, overcurrent, and vibration conditions, and resistance, inductance, and capacitance are maintained within an allowable range.

[0194] In the interior of the metal case according to one embodiment of the present invention, a shielding partition is further provided, wherein a baffle structure is substituted to separate the internal space into a plurality of compartments to suppress resonance of the acoustic device.

[0195] According to one embodiment of the present invention, the shielding partition may refer to a plate-shaped or plate-like partition member that divides a single continuous empty space formed inside the metal case into two or more. Here, the inside of the metal case may refer to a closed or semi-closed space enclosed by the bottom surface, side wall surface, and top cover surface of the metal case to accommodate components. The additional provision of the shielding partition may mean that the metal case does not merely perform the function of an outer housing, but is formed such that a separate partition-forming member is additionally mounted or integrally molded inside it to interrupt the continuity of the internal space. The shielding partition may be formed as a single plate, or may have a structure in which a plurality of plates are spaced apart from each other or arranged continuously. It may be formed to protrude upward from the bottom surface of the metal case, protrude inward from the side wall surface, or protrude downward from the top cover surface. Furthermore, the shielding partition may be fixed inside the metal case by at least one of screw fastening, rivet fastening, bending joint, groove fitting joint, adhesive joint, or injection molding.

[0196] The fact that a baffle structure is applied to separate the internal space into multiple compartments to suppress resonance in the above-mentioned acoustic device implies that the design principle of dividing a large cavity into multiple spaces to cut off direct internal transmission paths in the acoustic field is applied to an electrical noise shielding structure. That is, if one side of a space and another side of a space inside a metal case are directly connected as a single empty space, electrical coupling components generated from a conductive or magnetic part placed between them can be transmitted directly to the opposite side of the space along a path that is close to a straight line. Therefore, by placing the shielding partition in the middle to divide the internal space into two or more sections, the direct transmission path can be cut off, and the transmission path can be formed to bend or bypass. Here, "multiple compartments" may mean including at least two compartmentalized spaces; thus, two compartmentalized spaces may be formed with one shielding partition, or three or more compartmentalized spaces may be formed using two or more shielding partitions. A person skilled in the art can first measure the length, width, and height inside the metal case, determine the two locations inside where electrical influence must be separated from each other, and determine the location and height of the shielding bulkhead so that the shortest straight path connecting those two locations must pass through the shielding bulkhead. For example, if the length inside the metal case is L and the installation location of the shielding bulkhead is the input-side reference distance x, x can be set to a value greater than 0 and less than L, and can be placed in an intermediate section so that the input-side space and the output-side space do not directly lead to the same open space. In addition, the height of the shielding bulkhead can be set to be smaller than the inner height H of the metal case, but to occupy a significant portion of H so that the upper opening gap is not excessively large and the actual space separation effect is not weakened, and the specific height can be determined by considering assembly tolerances and whether there is interference with upper components.

[0197] The specific shape of the shielding bulkhead may be a flat plate, a folded plate, a U-shaped frame, or a plate structure reinforced with ribs. If the shielding bulkhead is formed from an insulating plate, it may provide both electrical insulation and space separation functions, and if an insulating layer is further formed on a metallic plate, it may provide both mechanical rigidity and shielding functions. However, regardless of which material is adopted, the shielding bulkhead may be formed to perform the function of separating the internal space into multiple compartments. When designing the shielding bulkhead, a non-bulkhead specimen, a two-compartment specimen, and a three-compartment specimen are each fabricated for a metal case of the same external shape, and identical conductive model bodies are placed at equal intervals at corresponding positions inside each specimen. Then, a frequency-variable signal is applied to one model body, and the transmission component induced in the other model body is measured to compare the degree of transmission reduction according to the number of compartments. At this time, the measurement frequency can be set to include 50 kHz, 1 MHz, 10 MHz, and 100 MHz to match the band targeted for conducted noise reduction, and after recording the transmission level at each frequency, the number and location of the shielding bulkheads can be determined by comparing whether the transmission component decreases as the number of compartments increases. Subsequently, low temperature, high temperature, humid heat, and vibration conditions are sequentially applied to an assembly to which the selected shielding bulkhead arrangement is applied, and by checking for cracks, bending, detachment, or loosening of the connection with the metal case of the shielding bulkheads, it can be confirmed whether the shielding bulkheads satisfy both electrical space separation and mechanical maintenance functions. Therefore, the shielding bulkheads can be specifically implemented not as simple internal reinforcing plates, but as compartmental members formed to divide a single continuous space inside the metal case into two or more to interrupt the internal transmission path.

[0198] According to one embodiment of the present invention, the shielding partition includes a first partition plate and a second partition plate made of a non-conductive material, wherein the first partition plate is arranged to separate a first partition space in which the input terminal-side inductor is arranged and a second partition space in which the first capacitor and discharge resistor are arranged, and the second partition plate is arranged to separate the second partition space from a third partition space in which the output terminal-side inductor or ground-side capacitor is arranged.

[0199] According to one embodiment of the present invention, the shielding partition includes a first partition plate and a second partition plate made of a non-conductive material, wherein the term "non-conductive material" may refer to a material having a sufficiently large volume resistance so that current does not flow even when in contact with or near an internal component to which power is applied. The non-conductive material may be formed from an insulating resin plate, a glass fiber reinforced epoxy plate, a polycarbonate plate, a PPS-based insulating plate, a PET-based insulating plate, or a plate-shaped insulating material equivalent thereto. Since the first partition plate and the second partition plate are not merely display members but plate-shaped members that actually divide the internal space of a metal case into two or more, they may be formed in a flat plate shape or a folded plate shape so as to be fixed to at least one of the bottom surface, side wall surface, or top cover surface of the metal case. A person skilled in the art can first measure the inner length, width, and height of the metal case, determine the thickness at which the first and second bulkhead plates can stand without bending at the position where they are to be erected, and form a fastening part or a fitting part at the bottom or side end of each bulkhead plate so that no shaking occurs after assembly.

[0200] The first partition plate is positioned to separate the first partition space in which the input terminal-side inductor is placed and the second partition space in which the first capacitor and discharge resistor are placed, so it can be understood as a first separator plate erected at a position closer to the input terminal side inside the metal case. Here, the first partition space may refer to the space in which the input terminal-side inductor is accommodated, and the second partition space may refer to the space in which the first capacitor and discharge resistor are accommodated. The position of the first partition plate can be determined to be located between the outer end of the input terminal-side inductor and the outer end of the first capacitor or discharge resistor, where Lc is the internal length of the metal case. For example, if the length section occupied by the input terminal-side inductor is 0 to Li and the length section occupied by the first capacitor and discharge resistor is Lm1 to Lm2, the center position x1 of the first partition plate can be determined as a value greater than Li and smaller than Lm1. In this way, the first partition plate can be interposed between the area where the input terminal-side inductor is placed and the area where the first capacitor and discharge resistor are placed, so that the two spaces are not directly connected as a single continuous space. The width of the first partition plate can be formed to span the entire or most of the internal width direction of the metal case, and the height can be formed to extend to a range excluding the upper cover assembly tolerance from the internal height of the metal case. For example, when the internal height of the metal case is Hc and the upper assembly tolerance is Hg, the height H1 of the first partition plate can be set to Hc-Hg or less, and Hg can be set as the minimum clearance height where assembly interference does not occur. Subsequently, with the first partition plate in an upright position, corresponding component models are placed in the first partition space and the second partition space, respectively, and when a frequency-variable signal is applied from the first partition space side, the organic component detected from the second partition space side is measured, and the placement position where the transmission component is reduced compared to the case without the first partition plate can be determined as the position of the first partition plate.

[0201] Since the second partition plate is positioned to separate the second partition space from the third partition space where the output terminal-side inductor or ground-side capacitor is placed, it can be understood as a second separator plate erected at a location closer to the output terminal side than the first partition plate. Here, the third partition space may refer to a space where the output terminal-side inductor is accommodated, where the ground-side capacitor is accommodated, or where both the output terminal-side inductor and the ground-side capacitor are accommodated together. The position of the second partition plate can be determined to be formed between the end of the second partition space where the first capacitor and discharge resistor are placed and the beginning of the section where the output terminal-side inductor or ground-side capacitor is placed. For example, when the length section of the second partition space is Lm1 to Lm2 and the starting position of the third partition space is Lo1, the center position x2 of the second partition plate can be determined as a value that is not greater than Lm2 and is smaller than Lo1. In addition, x2 can be set to a value that is necessarily greater than x1 so that a second partition space is actually formed between the first partition plate and the second partition plate. In this case, the effective length L2c of the second partition space can be expressed as x2-x1-((t1+t2) / 2), where t1 and t2 are the thicknesses of the first partition plate and the second partition plate, respectively. Since the effective length L2c must be set to be greater than the sum of the outer dimensions of the first capacitor and the discharge resistor and the sum of the assembly clearance space, a person skilled in the art can first measure the outer length of the first capacitor, the outer length of the discharge resistor, the lead or terminal connection clearance, and the assembly tool access clearance, respectively, and then determine x1 and x2 so that L2c is formed to be greater than the sum thereof.

[0202] The formation of the above-mentioned first, second, and third compartment spaces is not merely a separation in name, but signifies the establishment of actual component placement standards. The first compartment space must be provided with length, width, and height capable of accommodating the outer shape and assembly clearance of the input terminal-side inductor; the second compartment space must be provided with length, width, and height such that the first capacitor and discharge resistor can be placed without mutual interference; and the third compartment space must be provided with length, width, and height such that the output terminal-side inductor or ground-side capacitor can be placed. To this end, the outer rectangular dimensions of the component to be placed in each compartment are first calculated, and then the minimum size of the compartment space can be determined by adding the assembly clearance and the spacing distance for each direction. For example, the minimum length L1min of the first compartment space can be determined by adding the left and right assembly allowances a1 and a2 to the outer length Li of the inductor on the input terminal side, and the minimum length L2min of the second compartment space can be determined by adding the left and right assembly allowances a4 and a5 to the sum of the outer length C1 of the first capacitor, the outer length R1 of the discharge resistor, and the spacing allowance a3 between them. The minimum size of the third compartment space can also be determined by adding the outer length Lo of the inductor on the output terminal side or the outer length Cy of the capacitor on the ground side and the assembly allowance. In this way, after first calculating the minimum size of each compartment space, if the positions of the first and second partition plates are determined so that L1min, L2min, and L3min are all secured within the internal length Lc of the metal case, the first, second, and third compartment spaces can be formed as spaces where actual assembly is possible.

[0203] Furthermore, the fact that the first and second partition plates are formed from a non-conductive material can serve to prevent metallic plates from forming new conductive paths between each partition space. That is, if the first or second partition plate is formed from a metallic material, it acts as a floating conductor or a ground-coupled conductor, which can form unintended coupling paths in specific frequency bands; therefore, by applying a non-conductive material, it is possible to maintain the partitioning function while preventing the formation of separate current paths. A person skilled in the art can prepare metallic plate specimens and non-conductive plate specimens of the same shape, respectively, and install them alternately at the same location to compare and measure how much of the component induced from the first partition space is transmitted to the second or third partition space. Based on the results, it can be verified whether the non-conductive plate reduces unnecessary conductive coupling while maintaining the partitioning function. Subsequently, the materials for the first and second partition plates can be determined by measuring insulation resistance, conducting heat resistance tests, and checking for damage after vibration regarding the selected non-conductive material.

[0204] Whether the actual arrangement of the first and second partition plates is appropriate can be verified through a verification procedure after assembly. First, a reference specimen without the first and second partition plates, a specimen with only the first partition plate installed, a specimen with only the second partition plate installed, and a specimen with both the first and second partition plates installed can be prepared, respectively. Next, with a model of an inductor on the input terminal side placed at a position corresponding to the first partition space, a model of a first capacitor and discharge resistor placed at a position corresponding to the second partition space, and a model of an inductor on the output terminal side or a capacitor on the ground side placed at a position corresponding to the third partition space, a frequency-variable current or voltage can be applied from the first partition space side to measure the induced voltage or current on the second and third partition space sides, respectively. Subsequently, by comparing the measured values ​​when there are no partition plates and when both partition plates are present, it can be verified whether the transfer component from the first partition space to the second partition space and the transfer component from the second partition space to the third partition space are both reduced. In this way, by separately observing the separation effects of the first partition plate and the second partition plate, and finally confirming the reduction amount when both partition plates are present, a person skilled in the art can repeatedly verify whether a structure dividing into a first compartment space, a second compartment space, and a third compartment space is actually feasible.

[0205] Accordingly, in the context of this invention, the shielding partition includes a first partition plate and a second partition plate made of a non-conductive material, wherein the first partition plate is arranged to separate a first partition space in which the input terminal-side inductor is placed and a second partition space in which the first capacitor and discharge resistor are placed, and wherein the second partition plate is arranged to separate the second partition space from a third partition space in which the output terminal-side inductor or ground-side capacitor is placed, means a space separation structure in which at least two non-conductive plates are spaced apart from each other to form three partition spaces inside a metal case, the minimum dimensions of each partition space are calculated based on the outer dimensions of the components to be placed therein and the assembly allowance, and the positions of the first partition plate and the second partition plate are specifically determined based on the measurement results of the transfer components between each partition space.

[0206] According to one embodiment of the present invention, the first partition plate and the second partition plate each have a through hole formed therein through which a power line or a ground line passes, and are spaced apart from each other so that the center axis of the through hole of the first partition plate and the center axis of the through hole of the second partition plate do not coincide in a straight line with each other.

[0207] This may mean that the first and second partition plates are not merely formed as partition plates, but that a passage is formed in each partition plate to allow a power line or ground line to actually pass between each compartment space, and that the passage is formed offset so as not to penetrate in a straight line. Here, a penetration hole may refer to an opening formed to be continuously open from one side of the partition plate to the other so that a linear conductor can pass through, and a central axis may refer to a virtual axis in the normal direction passing through the center of the circle when the penetration hole is circular, or a representative passage axis passing through the center point of the opening when the penetration hole is elongated or polygonal. In addition, since the fact that they do not coincide in a straight line may mean that a virtual straight line extending the center axis of the through hole of the first bulkhead plate is formed so as not to pass through the center of the through hole of the second bulkhead plate, a power line or ground line passing between the first bulkhead plate and the second bulkhead plate cannot pass through the second through hole by only going straight after passing through the first through hole, and may be arranged so as to pass through the second through hole after changing direction or position at least once in an intermediate section.

[0208] The shape of the above-mentioned through hole may be formed as at least one of a circular, elliptical, elongated, or porous structure that allows multiple lines to pass through separately. When a single power line or a single ground line passes through individually, one through hole may be formed for each line, and when multiple lines must pass through simultaneously while spaced apart from each other, an independent through hole may be formed for each line. In this case, the size of the through hole may be determined based on the outer diameter or outer dimension of the line to be passed through. For example, if the outer diameter of the power line or ground line is denoted as D_line and the minimum clearance to be maintained between the bulkhead plate and the line is denoted as C_gap, the inner diameter D_hole of a circular through hole may be determined as D_hole = D_line + 2C_gap. In the case of an elongated through hole, the short axial dimension may be set to D_line + 2C_gap or greater, and the long axial dimension may be set to a value with additional clearance added to account for assembly tolerances and wiring deviations. Here, C_gap can be determined by summing the track sheath thickness variation, assembly error, displacement during vibration, and thermal expansion margin. A person of ordinary skill in the field can determine C_gap by preparing multiple specimens of the same track, measuring the maximum outer diameter, and adding the assembly tolerance to that maximum value. By numerically determining the through-hole size based on the track outer diameter and the clearance gap in this way, it is possible to prevent the track from contacting the bulkhead plate and damaging the sheath, or conversely, to prevent the through-hole from becoming excessively large and weakening the spatial separation effect.

[0209] A specific method of arranging the center axis of the through hole of the first bulkhead plate and the center axis of the through hole of the second bulkhead plate so as to be offset from each other can be formed using at least one of a length direction offset, a height direction offset, or a width direction offset. For example, if the length direction of the metal case is the x-axis, the width direction is the y-axis, and the height direction is the z-axis, the center coordinates of the first through hole of the first bulkhead plate can be set as (x1, y1, z1), and the center coordinates of the second through hole of the second bulkhead plate can be set as (x2, y2, z2). In this case, to ensure that the center axis of the first through hole and the center axis of the second through hole do not coincide on a straight line, they can be formed such that at least the relationship y1 ≠ y2 or z1 ≠ z2 holds. That is, even if the first through hole and the second through hole are separated from each other in the direction of travel of the bulkhead plate, an additional offset in the width direction or height direction can be applied so that the two center axes do not lie on the same virtual straight line. For example, the first through hole may be formed at a position offset to the left of the center of the first bulkhead plate, and the second through hole may be formed at a position offset to the right of the center of the second bulkhead plate; as another example, the first through hole may be formed on the lower side and the second through hole on the upper side. As yet another example, they may be formed offset simultaneously in both the width direction and the height direction so that the track changes position in both the horizontal and vertical directions after passing through the first through hole and before reaching the second bulkhead plate.

[0210] The degree of separation of the center axis of the above-mentioned through hole can be set to a level that can substantially block the straight transmission path. To this end, if the gap between the first bulkhead plate and the second bulkhead plate is denoted as S_p and the lateral offset between the center of the first through hole and the center of the second through hole is denoted as O_s, the deflection angle θ formed for the line to reach the second through hole after passing through the first through hole can be expressed by the relationship tan(theta) = O_s / S_p. A person skilled in the art can first determine the gap between the bulkhead plates S_p according to the internal length of the metal case and the required size of each compartment space, and then set O_s to a non-zero value so that θ does not become zero. Then, multiple specimens with O_s values ​​varying in steps, for example, specimens with O_s of 0 mm, 5 mm, 10 mm, and 15 mm, can be fabricated to measure the coupling component between the first compartment space side and the third compartment space side under the same frequency conditions. Subsequently, as O_s increases, it is determined from what point the transmission component significantly decreases, and the minimum offset at which that decrease is maintained can be set as the minimum offset standard of the through-hole center axis. In this case, rather than simply stating that it “is appropriately offset,” the relationship between the distance between the bulkhead plates and the center offset is determined first, and the final arrangement is confirmed through comparative measurements of specimens, so that a person skilled in the art can implement it reproducibly through the same procedure.

[0211] When the above-mentioned through-holes are formed in a structure through which each power line or ground line passes, in an embodiment where multiple power lines and ground lines exist, a separate set of through-holes may be provided for each line. For example, when a three-phase power line and a ground line pass together, a first through-hole for the first phase, a first through-hole for the second phase, a first through-hole for the third phase, and a first through-hole for grounding may be formed in the first partition plate, and corresponding second through-holes may be formed in the second partition plate. In this case, the first through-hole and the second through-hole corresponding to the same phase line may have a corresponding relationship with each other, but may be offset so that their center axes do not coincide. Additionally, the spacing between each through-hole may be set separately to prevent the phase lines and ground lines from coming close to each other. For example, the minimum spacing between the through-holes in the first partition plate may be set as G1 and the minimum spacing between the through-holes in the second partition plate as G2, and G1 and G2 may be set to be greater than or equal to the minimum value considering the outer diameter of the corresponding line and the amount of wiring bending. Afterward, the spacing between holes can be determined by checking whether adjacent track sheaths do not come into contact with each other and whether there is friction with the edges of the through holes while the tracks are actually passed through.

[0212] The effect of the structure in which the center axes of the through holes are offset is to block the straight-line open path. To verify this, through holes are formed in the first and second partition plates, wherein the center axes of the two through holes in the first specimen are arranged so that they lie on the same straight line, and the center axes of the two through holes in the second specimen are arranged so that they are offset from each other. Then, the same power line or a simulated conductor is passed through each of the two specimens, and the component induced in the third partition space can be measured while a frequency-variable current is applied to the first partition space. The measurement frequency can be set to include 50 kHz, 1 MHz, 10 MHz, and 100 MHz, reflecting the frequency range related to conduction noise. Subsequently, by comparing the transmission components of the specimen arranged in the same straight line and the specimen arranged offset, it can be confirmed whether the transmission component to the third partition space is reduced when the center axes of the through holes are offset compared to when they coincide in a straight line. In addition, it is possible to verify whether the track passing through the through hole does not rub against the edge of the bulkhead plate and cause coating damage even after vibration testing, and to simultaneously verify whether deformation or cracks occur at the edge of the through hole even after temperature and humid heat tests. Through these procedures, it can be seen that the offset arrangement of the through hole center axis is not a simple shape design, but a structure determined through measurement and environmental testing.

[0213] Accordingly, in this context, the statement that each of the first and second bulkhead plates has a through hole through which a power line or ground line passes, and that the center axis of the through hole of the first bulkhead plate and the center axis of the through hole of the second bulkhead plate are spaced apart from each other so as not to coincide in a straight line, means a structure in which an opening for passing a line is formed in each bulkhead plate, the size of the opening is calculated based on the outer diameter of the line and the assembly clearance, and the center position of each corresponding through hole is determined to have an offset in at least one of the width direction or the height direction, so that the line passing through the first and second through holes forms a path that includes bending or positional shifting rather than a straight line.

[0214] According to one embodiment of the present invention, the first partition space, the second partition space, and the third partition space are formed such that an input terminal, an inductor, the first capacitor, the discharge resistor, the second capacitor, and an output terminal are sequentially arranged on the power line.

[0215] This may mean that the components are not scattered at random locations within the metal case, but rather that the arrangement order of each component is determined based on the electrical progression from the input terminal, which serves as the starting point for current inflow, to the output terminal, which serves as the end point for current outflow. Here, the phrase “on the aforementioned power line” does not mean that all components must be placed on a single straight line, but rather that the electrical sequence encountered along the conduction path from the input terminal to the output terminal is determined in the order of the input terminal, inductor, first capacitor, discharge resistor, second capacitor, and output terminal. Therefore, components may be arranged left and right on a plane, or arranged with a difference in vertical height, and some wiring may be bent or bypassed, but they can be formed to maintain the functional arrangement order based on the direction of progression of the power line.

[0216] The first partition space described above may be formed as a space where the input terminal and the inductor are placed first. Since the input terminal is the initial connection point where external power is introduced, it may be placed on the power inlet side wall of the metal case or at a location adjacent thereto, and the inductor may be placed at a rear location electrically connected to the input terminal so that the current flowing into the input terminal passes through the inductor first. The length, width, and height of the first partition space may be determined by first measuring the outer dimensions of the input terminal and the inductor, and then adding the wiring bending allowance and assembly tool access allowance between the two components. For example, if the length of the input terminal is L_in, the length of the inductor is L_ind, and the wiring and assembly allowance between the input terminal and the inductor is M_1, the minimum length G_1 of the first partition space may be determined to satisfy the relationship G_1 >= L_in + L_ind + M_1. Here, M_1 is not a simple margin, but can be calculated by measuring the actual bending radius of the wiring conductor, the insertion width of the fastening tool, and the separation distance from adjacent parts.

[0217] The second partition space described above may be formed as a space in which the first capacitor and the discharge resistor are placed. Here, since the first capacitor is a component connected between power lines, it may be placed at a position corresponding to the node after the inductor, and since the discharge resistor is a component connected in parallel to the same node pair as the first capacitor, it may be placed within the same partition electrically corresponding to the first capacitor. However, since the discharge resistor is not a series component through which the main current continuously passes, the phrase "sequentially placed" can be understood to mean that the discharge resistor is formed to be located together with the section functionally corresponding to the inductor and the second capacitor, that is, the area after the first capacitor where it is placed. The size of the second partition space described above may be determined based on the outer length L_c1 of the first capacitor, the outer length L_r of the discharge resistor, the separation distance M_2 between the first capacitor and the discharge resistor, and the wiring connection margin M_3 on both sides. For example, the minimum length G_2 of the second compartment space can be determined to satisfy the relationship G_2 >= L_c1 + L_r + M_2 + M_3, and the width and height can also be determined by summing the outer dimensions of the two elements and the insulation margin. In this way, even if the first capacitor and the discharge resistor are placed within the same compartment, they do not interfere with each other and can be stably placed at a position corresponding to the rear end of the inductor based on the progression of the power line.

[0218] The third compartment space described above may be formed as a space where the second capacitor and the output terminal are placed. Here, the second capacitor may be placed at a position corresponding to the power line section at the rear end of the second compartment space, and since the output terminal is the final connection point where the power line is transmitted back to the external load side, it may be placed adjacent to the end side of the third compartment space or the wall on the power outflow side of the metal case. The minimum length G_3 of the third compartment space may be determined to satisfy the relationship G_3 >= L_c2 + L_out + M_4 + M_5 by considering the outer length L_c2 of the second capacitor, the outer length L_out of the output terminal, the wiring clearance M_4 between them, and the assembly clearance M_5. If the structure is such that the output terminal is directly fixed to the case wall, the position of the second capacitor may be determined adjacent to the output terminal so that the conductor from the second capacitor to the output terminal does not become excessively long; conversely, if additional insulation separation is required between the output terminal and the second capacitor, the length of the third compartment space may be recalculated after adding that separation length.

[0219] The criteria for determining the above sequential arrangement may be based on the order of the actual connection nodes formed along the power line, rather than the order of the center points of each component. To this end, the input terminal reference position on the bottom surface of the metal case or on the internal reference surface may be set as x_0, and the direction of the power line may be set as the x-axis. Next, the power line connection center position of the inductor may be set as x_1, the power line corresponding connection position of the first capacitor as x_2, the parallel connection corresponding position of the discharge resistor as x_3, the power line corresponding connection position of the second capacitor as x_4, and the output terminal connection center position as x_5. In this case, the above sequential arrangement structure may be determined to satisfy the relationship x_0 < x_1 < x_2 <= x_3 < x_4 < x_5. Here, since the first capacitor and the discharge resistor correspond to the same node pair, x_2 and x_3 may be set as the same position or as slightly separated values. By assigning coordinate standards in this way, it is possible to objectively determine whether the sequential arrangement is maintained according to the power line progression standards, even if the parts are slightly misaligned vertically or connected with bent wiring.

[0220] Whether the first, second, and third compartments are actually formed to satisfy the above sequence can be verified through the specimen assembly and measurement procedure. First, multiple specimens are fabricated for metal cases of the same external shape with different positions for the first and second partition plates, and an input terminal, inductor, first capacitor, discharge resistor, second capacitor, and output terminal can be assembled for each specimen. Next, the outer starting point, outer ending point, and power line connection location of each component can be recorded by photographing the internal reference plane of each specimen or measuring it with a dimensional measuring instrument. Subsequently, the sequence of the power lines of each component is verified from the recorded values, and specimens in which the sequence is reversed or a component that should belong to the second compartment encroaches upon the first or third compartment can be excluded. Next, for specimens in which sequential arrangement is maintained, if DC line resistance measurement, verification of the parallel node between the first capacitor and the discharge resistor, and verification of continuity between the second capacitor's output terminal and the output terminal are performed, a person of ordinary skill can repeatedly verify whether each component forms the exact order as written in the power line progression criteria.

[0221] In addition, since the above sequential arrangement must be maintained even after environmental testing, temperature, humid heat, overcurrent application, and vibration environments can be applied to the assembled specimen, respectively, and then the position reference of each component can be measured again. The positional differences before and after the test are recorded as Δx_in, Δx_ind, Δx_c1, Δx_r, Δx_c2, and Δx_out. If these displacements remain within the assembly tolerance range while maintaining the relationship x_0 < x_1 < x_2 <= x_3 < x_4 < x_5, it can be determined that the first, second, and third compartments maintain a sequential arrangement structure not only in a simple assembly state but also after environmental loading. Through this verification procedure, it can be seen that the formation of the compartments is not an arbitrary arrangement, but a fixed structure that reflects the outer dimensions of each component, wiring length, assembly allowance, and even the amount of positional change after testing.

[0222] Therefore, in this context, the first compartment space, the second compartment space, and the third compartment space are formed such that an input terminal, an inductor, the first capacitor, the discharge resistor, the second capacitor, and an output terminal are sequentially arranged on the power line. This means a structure in which the minimum size of each compartment space is calculated based on the outer dimensions and assembly allowance of the components to be arranged within the compartment, and the connection position coordinates of each component are sequentially set based on the direction of travel of the power line, so that the positions of the first partition plate and the second partition plate are specifically determined so that the order of the input terminal, inductor, first capacitor, discharge resistor, second capacitor, and output terminal is maintained as one moves from the input terminal side to the output terminal side.

[0223] According to one embodiment of the present invention, the shielding partition is configured to block leakage flux or electric field components generated in the input terminal-side inductor from being directly coupled to the output terminal-side power line along a linear path, and to cause the leakage flux or electric field components to follow a bypass path deflected by the first partition plate and the second partition plate, thereby suppressing conducted noise from being recoupled to the output side without passing through the first capacitor and the second capacitor.

[0224] This may mean that the magnetic or electric field component formed in the section where the input terminal-side inductor is placed interrupts the internal transmission path that leads directly to the output terminal-side power line along the empty space inside the metal case, and is formed so that the transmission direction proceeds to the next space only after being bent at least once by two or more partition plates. Here, the input terminal-side inductor may refer to an inductor placed along the power line at a location closer to the power inflow side, and the output terminal-side power line may refer to the conductive path that is finally connected to the output terminal. Additionally, leakage flux may refer to a magnetic field component leaking out into the core of the inductor or outside the intended magnetic flux path, and the electric field component may refer to an electric field component formed in the space inside the metal case due to the potential difference between the inductor terminal section, the winding section, or an adjacent conductive section. The above-mentioned straight path may refer to the shortest or equivalent direct transmission path formed between the inductor on the input terminal side and the power line on the output terminal side without intermediate interruption, and the above-mentioned curved detour path may refer to a transmission path in which the direct transmission direction is blocked by the first and second partition plates, and the path proceeds to the next space only after the direction is changed at least once while passing through the side, top surface, bottom gap, or through hole of the partition plate.

[0225] To implement a structure that blocks the aforementioned direct coupling, the center position of the inductor on the input terminal side and the representative position of the power line on the output terminal side can first be determined inside the metal case. Next, a virtual straight line L_dir connecting the two positions can be established, and the positions and heights of the two partition plates can be determined such that the virtual straight line necessarily passes through at least one of the first partition plate and the second partition plate. For example, if the center of the inductor on the input terminal side is set as P_in and the center of the power line on the output terminal side is set as P_out, L_dir can be defined as the line segment connecting P_in and P_out, and the first and second partition plates can be arranged so that the line segment L_dir penetrates the physical parts of the partition plates. Subsequently, the relationship between the height H_b of the partition plate and the inner height H_c of the metal case can be set such that H_b < H_c, and an upper limit of G_top can be set so that the upper opening gap G_top = H_c - H_b is excessively large, thereby preventing the formation of a straight path similar to L_dir. Additionally, a distance S_12 between the first partition plate and the second partition plate can be set, and the distance S_1 between the input terminal side inductor and the first partition plate and the distance S_2 between the second partition plate and the output terminal side power line can be set. Then, S_1, S_12, and S_2 can all be set to values ​​greater than 0, thereby ensuring that the input side space, the intermediate space, and the output side space are substantially separated. By doing so, the structure in which magnetic flux or electric field components generated from the input terminal side inductor are directly coupled to the output terminal side power line along a path close to a straight line can be fundamentally reduced.

[0226] A specific method for following a detour path deflected by the first and second partition plates can be implemented by setting the positions of the open passages formed between the first partition space and the second partition space, or between the second partition space and the third partition space, to be offset from each other. For example, if the path moving to the next space after passing through the first partition plate and the path moving to the next space after passing through the second partition plate are not placed on the same centerline, the magnetic flux or electric field component generated from the inductor on the input terminal side cannot go directly to the power line on the output terminal side after passing through the first partition plate; instead, the position must first move in the lateral or vertical direction and then pass near the second partition plate again, causing the transmission path to bend. At this time, the degree of deflection of the detour path can be determined by the offset O_s between the passing center on the first partition plate side and the passing center on the second partition plate side, and the distance S_p between the two partition plates, and the degree of bending in the transmission direction can be expressed by the relationship tan(theta) = O_s / S_p. A person of ordinary skill in the art can prepare multiple specimens with progressively different O_s values ​​under the same metal case and inductor placement conditions, and for each specimen, apply a frequency-variable signal at the inductor position on the input terminal side and measure the component induced at the power line position on the output terminal side to determine at what offset the linear coupling component noticeably decreases. Subsequently, if the minimum offset at which the decrease persists is adopted as a design standard, the degree of deflection of the bypass path can be objectively determined.

[0227] Suppressing the conduction noise from recombining to the output side without passing through the first and second capacitors may mean reducing the phenomenon in which noise components, which should originally be dispersed or bypassed through the first or second capacitor after the inductor, are induced back into the power line on the output terminal side by internal spatial coupling without passing through that bypass path. Here, recombination may refer to a phenomenon in which magnetic flux or electric field components generated in the inductor are induced back into the conductive path on the output terminal side through the internal space of the metal case, and consequently, noise components that have not been attenuated through the capacitor path are superimposed again on the conductive path on the output side. Therefore, the shielding partition does not perform the electrical function of the capacitors, but rather serves to organize the spatial structure so that the first and second capacitors process the noise components at their intended locations by reducing the occurrence of bypass coupling through the internal space before the capacitors intervene. A person skilled in the art can prepare a specimen without a shielding partition and a specimen with a shielding partition for the same filter assembly including a first capacitor and a second capacitor, and compare and measure the residual noise level appearing on the power line on the output terminal side under the same frequency conditions. Then, if the output-side residual noise is measured to be lower in the specimen with the shielding partition, it can be determined that the path for the noise component to recombine to the output side without sufficiently passing through the capacitor has been reduced.

[0228] As a procedure to verify whether the above structure is actually implemented, first, for a metal case of the same external shape, a reference specimen without a shielding partition, a specimen with only a first partition plate, a specimen with only a second partition plate, and a specimen with both a first partition plate and a second partition plate can be fabricated, respectively. Next, after aligning the position of the inductor on the input terminal side and the position of the power line on the output terminal side in each specimen, a frequency-variable current is applied to the position corresponding to the inductor on the input terminal side, and the voltage or current component induced in the power line on the output terminal side can be measured at 50 kHz, 1 MHz, 10 MHz, and 100 MHz. Next, the same specimen is assembled with the first capacitor and the second capacitor included, and the residual noise on the output terminal side can be measured again at the same frequency point. Subsequently, by comparing whether the output terminal-side organic components and residual noise are reduced together in the double-walled specimen compared to the non-walled specimen, it is possible to verify stepwise whether the shielding partition blocks the linear coupling of leakage flux or electric field components generated in the input terminal-side inductor and suppresses recombination paths that do not pass through the first and second capacitors. In addition, by sequentially applying low temperature, high temperature, humid heat, and vibration conditions to the same specimens and performing the same measurements again, it is possible to verify whether the same suppression effect is maintained without positional changes or damage to the first and second partition plates. By following this procedure, the function of the shielding partition can be concretized not as a mere estimation or declaration, but as a structure supported by the results of stepwise comparative measurements of internal space coupling within the metal case.

[0229] Therefore, in this context, the statement that the shielding partition is configured to block leakage flux or electric field components generated in the input terminal side inductor from being directly coupled along a straight path to the output terminal side power line, and to cause the leakage flux or electric field components to follow a bypass path deflected by the first partition plate and the second partition plate, thereby suppressing conducted noise from being recoupled to the output side without passing through the first capacitor and the second capacitor, means a space blocking structure designed such that the partition plate body is positioned to block the direct transmission line between the input terminal side inductor and the output terminal side power line, and the centers of the open passages of each partition plate are offset from each other so that the internal transmission direction is formed to bend at least once, and as a result, the output side recoupled component bypassing the capacitor path is reduced compared to the comparative specimen.

[0230] When the industrial high-efficiency conductive noise reduction filter according to one embodiment of the present invention is applied to a three-phase power line, the metal case is further provided with a wiring guide section in which a flow path design is substituted to compensate for the length and number of bends of each flow path in order to equalize the residence time of the fluid passing through multiple flow paths in the microfluidic chip.

[0231] This may mean that an internal wiring alignment structure is added to intentionally match the wiring paths of each phase to similar conditions, in order to prevent the length, number of bends, and arrangement shape of the conductive paths for each phase from being formed unevenly as multiple power lines corresponding to the first, second, and third phases pass through the inside of the metal case. Here, the wiring guide section may refer to a non-conductive or insulating support structure that defines the passage position, bend position, and extension direction of the power lines so that the power lines do not bend in arbitrary directions, cross each other, or are positioned skewed to one side inside the metal case. Furthermore, the substitution of the microfluidic chip's flow path design may mean that the principle of adjusting the flow path length and number of bends to reduce the variation in residence time while the fluid passes through each flow path is applied by corresponding it to the principle of adjusting the length and number of bends of the conductive paths formed while the power lines of each phase pass through the inside of the metal case.

[0232] To actually implement the wiring guide unit described above, it is first possible to determine where the first, second, and third phase conductive paths corresponding to the three-phase power lines are formed within the metal case. For example, after first determining the input and output connection points for each phase, a wiring reference line can be established on the bottom surface or inner reference surface of the metal case so that each phase conductive path is formed by connecting these two points. In this case, if the three lines are simply connected in a straight line over the shortest distance, one phase may pass almost in a straight line while another phase may have more bends or detours, resulting in variations in the path length and number of bends for each phase. Therefore, a person skilled in the art can first measure the shortest straight distances L1_raw, L2_raw, and L3_raw for each phase, and then set the longest value among them as the reference length L_ref. Subsequently, for the shortest phase or the phase of intermediate length, detour sections or gentle bend sections can be added by the wiring guide unit, so that after correction, the actual path lengths L1, L2, and L3 for each phase all approximate L_ref. For example, if the length deviation standard is set to ΔL_allow, the shape of the wiring guide can be determined to satisfy the relationships |L1-L2|<=ΔL_allow, |L2-L3|<=ΔL_allow, and |L1-L3|<=ΔL_allow. Here, ΔL_allow can be determined by considering the internal clearance of the metal case, the bending radius of the wiring, the rigidity of the copper bar or conductor, and the assembly error, and a person skilled in the art can produce multiple batch specimens and adopt the structure with the smallest length deviation among them.

[0233] In addition, the wiring guide section described above can be formed to correct not only the total length but also the number of bends in each phase's conductive path. Here, the number of bends refers to the number of times a power line changes direction while proceeding in a straight line, and the bend angle can be defined as the amount of change in the direction of travel between two consecutive straight sections or two curved sections. For example, if the first phase conductive path has one bend, the second phase conductive path has three bends, and the third phase conductive path has five bends, the distribution constant characteristics for each phase may differ even if the same length condition is satisfied; therefore, the wiring guide section can be used to adjust the number of bends for each phase to be equal or to ensure that the difference is within one. To this end, the number of bends for each phase can be set as N1, N2, and N3, and the rib position, passage groove position, and bypass section length of the wiring guide section can be determined to satisfy the relationships |N1-N2|<=1, |N2-N3|<=1, and |N1-N3|<=1. Furthermore, the radius of curvature of each bend can also be ensured so that there is no excessive difference. For example, when the bending radii for each phase are set as R1_i, R2_i, and R3_i, if the difference between bends of the same sequence is formed to be within a predetermined allowable radius deviation, it is possible to reduce the increase in local parasitic components caused by only a specific phase bending abruptly. A person skilled in the art can determine which arrangement reduces phase deviation more by fabricating specimens of the same length but different number of bends, and specimens with both length and number of bends matched, and comparing and measuring the transmission characteristics by frequency.

[0234] The structure of the wiring guide section described above may be formed by an insulating guide frame, a plurality of passage grooves or guide ribs formed in the guide frame, and a spacing maintenance section between the passage grooves. The guide frame may be fixed to the bottom surface of a metal case or coupled to a side wall, and may include a plurality of grooves or channels that define the position through which each phase's conductive path passes. In this case, since the centerline of each groove itself can serve as the wiring path for each phase, the lengths of the first, second, and third phase grooves can be calculated in advance, matched to be similar to each other, and then the wiring guide section can be manufactured according to that shape. For example, if the path of one phase is too short, the groove can be extended by adding a gentle S-shaped or U-shaped detour instead of leaving it as a simple straight line. Conversely, if the path of a phase is excessively long, the total length can be reduced by removing unnecessary detours or decreasing the number of bends. In this way, the wiring guide section can be understood not as a simple fixing device, but as a design component that defines the shape of the conductive path of each phase itself.

[0235] When applying the flow path correction principle of the above-mentioned microfluidic chip to an electrical wiring structure, it can be implemented by comparing the electrical distribution characteristics formed by the conductive paths of each phase power line, instead of directly calculating the fluid residence time. First, the actual length, number of bends, bending angle, radius of curvature, distance from adjacent metal surfaces, and distance from adjacent phase conductive paths of each phase conductive path can be measured and organized into placement parameters. Next, the DC resistance of each phase conductive path is measured using a four-terminal ohmmeter, and the insertion loss or transmission deviation by frequency can be measured at multiple frequency points such as 50 kHz, 1 MHz, 10 MHz, and 100 MHz. Subsequently, by comparing the DC resistance deviation by phase, the insertion loss deviation by phase, and the temperature rise deviation by phase, it can be verified whether the deviation in electrical characteristics by phase decreases as the length and number of bends are formed more uniformly in the specimen. For example, the first specimen can be formed with only the phase length deviation matched and a different number of bends, the second specimen can be formed with both the phase length and the number of bends matched, and the third specimen can be formed with the phase length, the number of bends, and the radius of curvature matched together. Subsequently, by comparing the frequency-dependent transmission characteristics of the three specimens, a person of ordinary skill in the art can directly determine to what extent the wiring guide section must be formed precisely to ensure uniformity for the three-phase power line.

[0236] The above-mentioned wiring guide is not only meaningful within the metal case but can also be configured to maintain the phase wiring shape even in environments with vibration and temperature changes after assembly. To this end, the groove depth and width of the wiring guide can be formed to be larger than the outer dimensions of the conductor or copper bar to be accommodated, while ensuring that the conductor does not deviate from the groove during vibration. For example, if the outer diameter of the conductor or the width of the copper bar is denoted as W_cond and the effective width of the groove as W_slot, W_slot can be defined as being larger than W_cond but within the value obtained by adding assembly tolerances and thermal expansion allowances to W_cond. Additionally, the height of the side wall of the groove or the height of the cover rib can be determined within a range that prevents the conductor from floating vertically, and if necessary, point-coupled clips or insulating fixing parts can be added to ensure that the position of each phase wiring does not change before and after testing. Afterward, vibration tests in the range of 10 Hz to 150 Hz and temperature environment tests are performed on the assembly including the wiring guide, and the centerline position of each phase conduction path is measured again to verify whether the design for length and number of bends is maintained. Through this procedure, the wiring guide can be realized not merely as a design concept, but as a physical structure capable of maintaining its shape even under environmental loads after assembly.

[0237] Therefore, in the context of this invention, when the above-mentioned industrial high-efficiency conductive noise reduction filter is applied to a three-phase power line, the fact that a wiring guide section is further provided within the metal case with a flow path design applied to compensate for the length and number of bends of each flow path in order to equalize the residence time of the fluid passing through multiple flow paths in the microfluidic chip means that an insulating guide structure defining the passage path for each phase is added within the metal case to match the conductive path length and number of bends of each power line corresponding to the first, second, and third phases similarly, and the shape of the guide structure is a placement correction structure specifically determined based on the results of comparing and measuring the phase-specific path length deviation, the number of bend deviation, the frequency-specific transmission characteristic deviation, and whether the position is maintained after environmental load.

[0238] According to one embodiment of the present invention, the wiring guide section comprises a support frame made of an insulating material and a first wiring path, a second wiring path, and a third wiring path formed on the support frame, wherein the first wiring path, the second wiring path, and the third wiring path are each formed to guide power lines of different phases, and the difference in the total path length of each power line extending from an input terminal through an inductor to an output terminal is formed to be within 5% of a reference length, and a bypass groove or a bending groove is additionally formed in the wiring path with the shortest straight distance among the first wiring path, the second wiring path, and the third wiring path so as to extend the actual conduction path of the corresponding power line.

[0239] According to one embodiment of the present invention, the wiring guide portion may be a structure comprising a support frame made of an insulating material and a first wiring path, a second wiring path, and a third wiring path formed on the support frame. Here, the support frame made of an insulating material may refer to a support member formed to be disposed inside a metal case without allowing current to flow, and may be implemented as a structure in which a plurality of grooves, ribs, or through holes are integrally formed on a plate-shaped base, or as a structure in which a plurality of insulating blocks are connected to form a single frame. The material of the support frame may be FR-4, polycarbonate, PPS, PBT, epoxy-based insulating resin, or a non-conductive material equivalent thereto, and may be fixed to the bottom surface or side wall surface of the metal case by screw fastening, rivet fastening, snap-fitting, or adhesive bonding. The support frame may perform the function of providing a reference path so that three independent conductive paths corresponding to three-phase power lines do not come into contact with or intersect each other.

[0240] Since the first wiring path, the second wiring path, and the third wiring path are each formed to guide power lines of different phases, for example, the first phase power line may be placed along the first wiring path, the second phase power line may be placed along the second wiring path, and the third phase power line may be placed along the third wiring path. Here, "formed to guide" may mean that each wiring path is not merely a marking line, but is formed as a groove, channel, space between ribs, or insulating support surface so that an actual power line passes through it or between them. The width or effective accommodating dimension of each wiring path may be determined based on the outer dimension of the power line to be passed through. For example, if the outer diameter of the insulated wire is D_line, the effective width W_i of the circular or semicircular groove may be determined to be larger than D_line and satisfy the relationship W_i = D_line + 2*C_i. Here, C_i may be the sum of the assembly tolerance, thermal expansion allowance, vibration displacement allowance, and insertion work allowance. When plate-type supports are installed, let B_bar be the width of the supports and T_bar be the thickness. The effective width of the groove may be greater than B_bar, and the effective depth of the groove may be formed to be T_bar or greater than a value capable of accommodating T_bar. A person skilled in the art can determine the specific dimensions of each wiring path by first measuring the outer diameter or outer width and thickness of the power line to be applied, and then forming different path widths on multiple specimen frames and comparing the insertability, degree of wobble, and position retention after environmental testing.

[0241] The statement that the difference in the total path length of each power line extending from the input terminal through the inductor to the output terminal is formed to be within 5% of the reference length may mean that the centerline lengths of the actual conductive paths formed by the power lines of each phase inside the metal case are determined so that they do not differ excessively from one another. Here, the total path length may refer to the total centerline length extending from the input terminal connection point for each phase, through the section passing through the inductor of that phase, to the output terminal connection point. The total path length can be calculated by summing the length of the straight section and the length of the curved section, and the arc length of the curved section can be calculated as rtheta when the radius of curvature is r and the center angle is theta. For example, the first phase path length can be set as L1, the second phase path length as L2, and the third phase path length as L3, and the longest value among them can be set as the reference length L_ref. Subsequently, the length deviation rates E1, E2, and E3 of each path can be calculated according to the relationships E1 = |L_ref-L1| / L_ref100, E2 = |L_ref-L2| / L_ref100, and E3 = |L_ref-L3| / L_ref100, respectively, and the support frame can form each wiring path such that E1, E2, and E3 are all 5 or less. The 5% standard is not an arbitrary value, but can be determined by fabricating multiple specimens with path length deviations ranging from 0 to 3%, 5%, 8%, and 12% for a metal case of the same external shape and a three-phase filter assembly of the same rating, and then comparing and measuring the phase-specific DC line resistance, phase-specific insertion loss, and phase-specific temperature rise deviation when rated current is applied in each specimen, and determining the standard based on the section where the phase-specific electrical characteristic deviation increases when the path length deviation exceeds 5%. In this way, the reference length and allowable deviation can be specifically determined based on the results of measuring the path length, conduction resistance, and frequency characteristics together, rather than as arbitrary values ​​on the drawing.

[0242] The configuration in which a bypass groove or a bending groove is additionally formed in the wiring path with the shortest straight distance among the first, second, and third wiring paths to extend the actual conduction path of the corresponding power line may mean that for the phase in which the length is formed shortest when the input terminal, inductor, and output terminal are connected by the shortest straight line or the shortest centerline in the basic arrangement state of the phase, a bypass section for length correction is additionally formed in the support frame itself. Here, the wiring path with the shortest straight distance may refer to a path in which the total extension length is minimized when the reference point on the input terminal side, the reference point corresponding to the inductor, and the reference point on the output terminal side are connected by the simplest connecting line. The bypass groove may be a groove formed to deviate to one side from the section where it can originally proceed in a straight line and return to the original direction, and the bending groove may be a groove formed so that the direction of wiring proceeds bends as it passes through one or more bending points. A person skilled in the art can first calculate the basic path lengths L1_base, L2_base, and L3_base for each of the three phases and select the path corresponding to the minimum value L_min among them as the shortest path. Then, for the path, calculate the minimum correction length required to satisfy the additional length ΔL = L_ref - L_min or 5% criteria, and determine the shape such that the increase in the centerline length of the bypass groove or bend groove is greater than or equal to ΔL. For example, if the bypass groove is formed in a U-shape, the increase length can be calculated as the sum of the additional portions of the reciprocating side length and the bottom surface length, and if the bend groove consists of multiple straight sections, it can be calculated as the sum of each additional straight section length and the bend arc length. Subsequently, the final shape can be determined by recalculating whether the relationship |L_ref - L_short_adj| / L_ref * 100 <= 5 is satisfied for the corrected length L_short_adj.

[0243] The specific shape of the aforementioned bypass groove or bending groove can be determined within a range that allows the power line to pass without excessive bending while still achieving a length correction effect. For example, when an insulated wire passes through, the allowable minimum bending radius can be first set to R_min, and the bypass groove or bending groove can be formed so that all inner bending radii are greater than or equal to R_min. When a copper bar passes through, the bending angle and bending radius of the copper bar can be determined first, and then the bending groove can be formed to have a length and width capable of accommodating the bending shape. Furthermore, to ensure that the separation from the wiring paths of the other two phases is maintained even when a bypass groove or bending groove is added, the minimum separation distance G_sep between the outer edge of the bypass section and the adjacent wiring path can be measured, and G_sep can be made to be greater than or equal to a predetermined insulation margin. A person of ordinary skill can determine which bypass length satisfies the 5% standard while ensuring both assembly and durability by fabricating multiple specimens with different bypass groove lengths on the same support frame shape and checking for path length, phase conduction resistance, phase temperature after applying rated current, and whether path deviation occurs after vibration testing for each specimen.

[0244] Whether the formation of the wiring guide section described above is actually appropriate can be confirmed through a verification procedure after assembly is completed. First, a comparison specimen without a support frame, a specimen with a support frame but without a bypass groove or bending groove, and a specimen with both a support frame and a bypass groove or bending groove formed can be prepared. Next, for each specimen, three-phase power lines are assembled while maintaining the positions of the input terminal, inductor, and output terminal identically, and the length deviation rate can be calculated by measuring the actual centerline length for each phase. Subsequently, for each specimen, the DC resistance, insertion loss, temperature rise upon application of rated current, and position change after vibration are measured. By comparing the results, it can be confirmed whether the length deviation rate is maintained within 5% and the deviation in electrical characteristics for each phase is reduced only when the support frame and the bypass groove or bending groove are present. Through this procedure, a person of ordinary skill can repeatedly demonstrate that the wiring guide section is not merely an internal organization component, but a structure that corrects the conduction path of the three-phase power line to meet length standards.

[0245] Accordingly, in the context of this invention, the wiring guide section comprises a support frame made of insulating material and a first wiring path, a second wiring path, and a third wiring path formed in the support frame, wherein each wiring path is formed to guide power lines of different phases, and the difference in the total path length of each power line extending from the input terminal through the inductor to the output terminal is formed to be within 5% of the reference length, and a bypass groove or a bending groove is additionally formed in the wiring path with the shortest straight distance to extend the actual conduction path, means a wiring correction structure in which the shape of the support frame is specifically determined such that the length deviation rate of all paths is 5% or less by calculating the centerline lengths of the three-phase power lines, setting the longest path as the reference length, and providing a bypass structure for length correction to the shortest path.

[0246] According to one embodiment of the present invention, the first wiring path, the second wiring path, and the third wiring path are formed such that the number of bends in each power line is the same or differs by only one or less, and the radius of curvature of each bend is also formed such that it is the same or within the allowable tolerance range.

[0247] This may mean that each conductive path corresponding to the three-phase power line is formed not merely to have a similar overall length, but also to have a similar number of direction changes constituting the path and the bending shape of each direction change section. Here, the number of bends may refer to the number of sections where the straight-line direction changes by more than a certain standard when proceeding along the centerline of each wiring path from a reference point on the input terminal side through an inductor to a reference point on the output terminal side. Additionally, the radius of curvature may refer to the radius of the arc when the centerline bends in an arc shape at each bend section, and in the case of a polygonal bend, it may be defined as the radius of a virtual circle inscribed or circumscribed within the bend section.

[0248] The number of bends mentioned above is not determined arbitrarily, but can be calculated by extracting the centerline of each wiring path based on the drawing or prototype and applying the same rule. For example, the centerline of each wiring path can be decomposed into straight sections and curved sections, and if the difference in the tangent direction between two adjacent straight sections is 10 degrees or more, or if a curved section of a certain length or more is included, this can be counted as one bend. More specifically, when the number of bends of the first wiring path is N1, the number of bends of the second wiring path is N2, and the number of bends of the third wiring path is N3, the case where the number of bends is the same may be a case satisfying the relationship N1=N2=N3, and the case where there is only a difference of one or less may be a case satisfying the relationship max(N1,N2,N3)-min(N1,N2,N3)<=1. A person of ordinary skill in the art can first establish a temporary ce...

Claims

Claim 1 An industrial high-efficiency conductive noise reduction filter comprises: a filter body having an input terminal connected to an AC power source and an output terminal connected to a load; at least one inductor arranged in series with a power line between the input terminal and the output terminal inside the filter body; at least one first capacitor connected between the power lines; at least one second capacitor connected between the power line and a ground line; and a discharge resistor connected in parallel to the first capacitor to discharge a charge remaining in the first capacitor. and a power connection unit electrically connected to the input terminal and output terminal to conduct power under conditions of a rated voltage of 250V to 500V, a rated frequency of 50Hz or 60Hz, and a rated current of 5A to 700A; wherein the filter body is configured to be installed in a built-in manner on a three-phase power line to reduce conducted noise generated from at least one of an industrial inverter, a power converter, or an uninterruptible power supply; wherein the filter body includes a first LC circuit unit and a second LC circuit unit sequentially arranged along a current path extending from the input terminal side to the output terminal side; wherein at least one of the first LC circuit unit and the second LC circuit unit includes an inductor connected in series to each power line, an inter-phase capacitor connected between each power line, and a ground-side capacitor connected between each power line and a ground line; and wherein the first LC circuit unit and the second LC circuit unit form a single-stage or two-stage multi-stage LC circuit network so that symmetric mode noise and asymmetric mode noise pass through different current paths The inductor is configured to be damped, and the inductor comprises a first reactor wound on a nanocrystalline core and a second reactor wound on a ferrite core, wherein the nanocrystalline core is selected from an annular core with a diameter in the range of 25 mm to 140 mm, and the ferrite core is selected from an annular core with a diameter in the range of 31 mm to 140 mm.The coils of the first and second reactors are formed with 180°C rated windings to form inductance paths corresponding to conducted noise components of different frequency bands, ranging from low to high frequency bands; the power connection includes a terminal block and a copper bar connected to the terminal block to transmit current to the input or output terminal; the copper bar is formed as a plate-shaped conductor and is formed to have cross-sectional dimensions of 5 mm × 25 mm or 8 mm × 45 mm; the connecting stud or screw shaft of the terminal block has a nominal diameter of 6 mm or 10 mm; the terminal block and the copper bar are arranged inside the metal case of the filter body such that the separation distance between the live wire part and the metal case is 10.7 mm or more, and the separation distance between live wire parts having different polarities or phases is 20.0 mm or more; the filter body further includes a metal case and an insulating sheet, an insulating tube, and a substrate disposed inside the metal case; and the discharge resistor has a resistance value of 2 MΩ. The inductor, the first capacitor, the second capacitor, the discharge resistor, and the power connection are fixed to each other inside the metal case and configured so as not to cause cracking, deformation, insulation breakdown, or detachment of fastening in a temperature environment of -25℃ to 85℃, a humid heat environment of 21 days, an overcurrent application environment of 135% of the rated current, and a vibration environment in which an excitation of 20 m / s² is applied in the range of 10Hz to 150Hz; further provided inside the metal case is a shielding partition with a baffle structure applied to separate the internal space into a plurality of compartments to suppress resonance of the acoustic device, and the shielding partition includes a first partition plate and a second partition plate made of a non-conductive material, and the first partition plate is arranged to separate a first compartment space where the input terminal side inductor is placed and a second compartment space where the first capacitor and the discharge resistor are placed.The second partition plate is arranged to separate the second partition space from the third partition space where the output terminal-side inductor or ground-side capacitor is placed, and through holes through which each power line or ground line passes are formed in the first partition plate and the second partition plate, respectively, and are spaced apart from each other so that the center axis of the through hole of the first partition plate and the center axis of the through hole of the second partition plate do not coincide in a straight line with each other, and the first partition space, the second partition space, and the third partition space are formed so that the input terminal, the inductor, the first capacitor, the discharge resistor, the second capacitor, and the output terminal are sequentially arranged on the power line, and the shielding partition part blocks the leakage flux or electric field component generated from the input terminal-side inductor from directly coupling to the output terminal-side power line along a straight path, and causes the leakage flux or electric field component to follow a bypass path refracted by the first partition plate and the second partition plate, so that conducted noise to the first capacitor and the second capacitor It is configured to suppress reconnection to the output side without passing through, and a wiring guide part is further provided inside the metal case, and the wiring guide part includes a support frame made of an insulating material and a first wiring path, a second wiring path, and a third wiring path formed on the support frame, and the first wiring path, the second wiring path, and the third wiring path are each formed to guide power lines of different phases, and are formed such that the difference in the total path length of each power line extending from the input terminal through the inductor to the output terminal is within 5% of the reference length, and the total path length of the first wiring path, the second wiring path, and the third wiring path is calculated as the total centerline extension length from the input terminal side reference point through the inductor corresponding reference point to the output terminal side reference point, and the reference length is determined as the longest value among the total path lengths of the first wiring path, the second wiring path, and the third wiring path, and the first wiring path,An industrial high-efficiency conductive noise reduction filter characterized by the fact that a bypass groove or a bending groove is additionally formed in the wiring path with the shortest straight distance among the second and third wiring paths to extend the actual conduction path of the corresponding power line, wherein the bypass groove or the bending groove is formed such that the increase in the centerline length of the wiring path with the shortest straight distance corresponds to the difference between the reference length and the basic path length of the wiring path with the shortest straight distance, and wherein the difference in the total path length of the first, second, and third wiring paths after the bypass groove or the bending groove is formed is within 5% of the reference length. 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