Leakage electromagnetic field collection device using isolated LC filter and operating method thereof

Abstract

The present invention relates to a leakage electromagnetic field collection device using an isolated LC filter and, more specifically, to a leakage electromagnetic field collection device using an isolated LC filter, and an operating method thereof, in which harmonic components included in an output voltage generated by inverter switching are recovered by means of an LC filter and a bridge diode and reused.

Description

Leakage electromagnetic field collection device using an insulated LC filter and its operating method

[0001] The present invention relates to a leakage electromagnetic field collecting device using an insulated LC filter, and more specifically, to a leakage electromagnetic field collecting device using an insulated LC filter that regenerates and reuses harmonic components and leakage electromagnetic fields contained in an output voltage generated by inverter switching using an insulated LC filter and a bridge diode, and an operating method thereof.

[0002] Inverters are devices that convert DC energy into AC energy, and they are widely used in the power electronics industry. These inverters are used in numerous applications, including motor control inverters, solar inverters, induction heating and wireless power transfer (WPT) high-frequency inverters, and vehicle-to-grid (V2G) or vehicle-to-light (V2L) inverters.

[0003] However, the output voltage generated by the switching of the various inverters above contains harmonic components as well as the fundamental wave, which causes problems. The harmonic components included in the output voltage generate heat in the system or circuit or reduce efficiency, and in severe cases, cause component damage, malfunction, electrical pulsation, or flicker, and also cause side effects such as EMI (Electromagnetic Interface, hereinafter EMI) due to increased leakage electromagnetic fields and induced interference (hereinafter induced interference) and malfunction of peripheral devices due to EMF (Electromagnetic Field, hereinafter EMF).

[0004] In addition, energy harvesting technology, which converts waste or unused energy into usable electrical energy, has recently been attracting attention as a new and renewable energy source. Since energy harvesting can directly obtain electrical energy from nature, it can maintain the stability, security, and sustainability of energy supply, and is attracting attention as an eco-friendly energy utilization technology that can reduce environmental pollution. It also has the advantage of high energy conversion efficiency and can be applied in various fields.

[0005] In particular, in the technology sector where energy efficiency is important for long-distance driving, such as electric vehicles, the use of energy harvesting technology is important. Energy harvesting technology that converts the kinetic energy of electric vehicles into electrical energy, such as regenerative braking devices, is widely used, but there is little technology to utilize the electromagnetic energy leakage generated on electric power lines, or it is at a basic level, so it is not possible to achieve energy harvesting efficiency that can be utilized in the industry.

[0006] Although various technologies have been developed to remove harmonic components from existing output voltages, few have been effective in eliminating them. Furthermore, energy harvesting technologies that not only remove harmonic components from the output voltage but also regenerate and reuse the removed harmonic components as an energy source have been rare. Furthermore, there has been no technology utilizing cores in energy harvesting technologies that capture and regenerate harmonic components contained in the output voltage generated by inverter switching and reuse them as an energy source.

[0007] Accordingly, the technical problem of the present invention is conceived from this point, and the purpose of the present invention is to provide a leakage electromagnetic field collection device utilizing an insulated LC filter that removes harmonic components included in an output voltage generated by switching of an inverter by utilizing a core, and regenerates the removed harmonic components to utilize them again as an energy source, and an operating method thereof.

[0008] In addition, by removing the harmonic components included in the output voltage generated by the switching of the inverter, the present invention provides a leakage electromagnetic field collection device utilizing an insulated LC filter that prevents side effects such as system or circuit heat generation, efficiency reduction, component damage, malfunction, electrical pulsation or flicker phenomenon, EMI due to increased leakage electromagnetic fields, and peripheral device induced interference and malfunction due to EMF, which may be caused by the harmonic components.

[0009] In addition, in removing harmonic components included in the output voltage generated by switching of an inverter, a leakage electromagnetic field collecting device utilizing an insulated LC filter capable of selecting the frequency of the harmonic components to be removed and an operating method thereof are provided.

[0010] In addition, the present invention provides a leakage electromagnetic field collecting device utilizing an insulated LC filter and an operating method thereof, which can implement an insulated leakage electromagnetic field collecting device by using an LC filter utilizing a core to remove harmonic components included in an output voltage generated by switching of an inverter.

[0011] In addition, the bridge diode provides a leakage electromagnetic field collection device and an operating method thereof using an insulated LC filter that can lower the barrier voltage using a Schottky diode and quickly perform recovery switching for high-order harmonics.

[0012] In order to achieve the above object of the present invention, a leakage electromagnetic field collecting device utilizing an insulated LC filter is implemented as a circuit including a core into which an output current generated by inverter switching flows as an input current of an input portion; a capacitor connected to an input / output terminal line of an output portion of the core to implement an LC filter; and a bridge diode configured by sequentially connecting four single-phase bridge rectifier diodes to each other through a line to form a closed circuit, wherein a line connecting an output terminal of an output portion of the core and an input terminal of the capacitor is connected to an input terminal line of the bridge diode, and an operating method thereof are provided.

[0013] According to the present invention, harmonic components included in the pole voltage (hereinafter, output voltage) generated by switching of the inverter can be removed.

[0014] In addition, by removing the harmonic components included in the output voltage generated by the switching of the inverter, adverse effects such as system or circuit heat generation, efficiency reduction, component damage, malfunction, electrical pulsation or flicker phenomenon, EMI due to increased leakage electromagnetic field, and peripheral device induced interference and malfunction due to EMF can be prevented that may be caused by the harmonic components.

[0015] Additionally, the harmonic components removed from the output voltage generated by the switching of the inverter can be recovered and reused as an energy source.

[0016] In addition, in removing harmonic components included in the output voltage generated by switching of the inverter, the frequency of the harmonic components to be removed can be selected.

[0017] Additionally, the cut-off frequency can be set by tuning the L and C values ​​by setting it as a low-pass filter (LPF) made up of a combination of LCs.

[0018] In addition, an insulated leakage electromagnetic field collection device can be implemented using an LC filter utilizing a core to remove harmonic components included in the output voltage generated by switching of the inverter.

[0019] Additionally, the bridge diode can lower the barrier voltage by using a Schottky diode and can quickly perform recovery switching transitions even for high-order harmonics.

[0020] However, the effects of the present invention are not limited to the above effects, and can be expanded in various ways without departing from the spirit and scope of the present invention.

[0021] FIG. 1 is a diagram showing a pole voltage and a pole current generated by inverter switching according to one embodiment of the present invention.

[0022] FIG. 2 is a diagram showing a histogram of fundamental and harmonic components included in an output voltage generated by inverter switching according to one embodiment of the present invention.

[0023] FIG. 3 is a diagram showing a process of eliminating harmonics included in an output voltage generated by inverter switching according to one embodiment of the present invention through an LPF (low pass filter).

[0024] FIG. 4 is a diagram showing a circuit diagram of an insulated LC filter that captures an inverter leakage electromagnetic field according to one embodiment of the present invention.

[0025] FIG. 5 is a drawing showing an enlarged portion (LC filter and bridge diode portion) of a circuit diagram of an insulated LC filter that captures an inverter leakage electromagnetic field according to one embodiment of the present invention.

[0026] FIG. 6 is a drawing showing the operation of an insulated LC filter that captures an inverter leakage electromagnetic field according to one embodiment of the present invention.

[0027] FIG. 7 is a diagram showing a circuit diagram of an insulated LC filter that captures an inverter leakage electromagnetic field in a three-phase motor system according to one embodiment of the present invention.

[0028] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

[0029] The present invention is susceptible to various modifications and takes various forms. Specific embodiments are illustrated in the drawings and described in detail herein. However, this is not intended to limit the present invention to specific disclosed forms, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0030] FIG. 1 is a diagram showing a pole voltage and a pole current generated by inverter switching according to an embodiment of the present invention, and FIG. 2 is a diagram showing a histogram of fundamental and harmonic components included in an output voltage generated by inverter switching according to an embodiment of the present invention.

[0031] Referring to Figure 1, an inverter is a device that converts DC energy into AC energy and is widely used in the power electronics industry. These inverters are used in numerous applications, including motor control inverters, solar inverters, induction heating and wireless power transfer (WPT) high-frequency inverters, and vehicle-to-grid (V2G) or vehicle-to-light (V2L) inverters.

[0032] The pole voltage and pole current generated by the switching of the various inverters above have a sine wave form. In addition, the period of the fundamental wave constituting the sine wave of the pole voltage and pole current is T, and the frequency F is 1 / T. Meanwhile, the switching period of the square wave that implements the sine wave is t, and the switching frequency (f) of the square wave that implements the sine wave is generally included in the range of 5 kHz to 20 kHz.

[0033] Referring to Figure 2, the output voltage generated by inverter switching can be seen to contain even and odd nth-order harmonics centered around the fundamental wave. These harmonic components can generate heat or reduce efficiency in systems or circuits, and in severe cases, can cause component damage, malfunction, electrical pulsation, or flicker. Furthermore, they can cause adverse side effects, such as EMI (Electromagnetic Interference) due to increased leakage electromagnetic fields, and EMF (Electromagnetic Field Mobility), which can lead to induced interference and malfunctions in peripheral devices.

[0034] FIG. 3 is a diagram showing a process of eliminating harmonics included in an output voltage generated by inverter switching according to one embodiment of the present invention through a low pass filter (LPF).

[0035] Referring to FIG. 3, as shown in FIG. (a), the LPF generally passes a waveform with a frequency lower than the cutoff frequency (fc) and attenuates a waveform with a frequency higher than the cutoff frequency (fc).

[0036] As shown in Figure (b), the frequency of the harmonic included in the output voltage generated by inverter switching is higher than the frequency of the fundamental wave, and as the order of the harmonic increases, the frequency of the harmonic also increases.

[0037] That is, by setting the cutoff frequency (fc) of the LPF, the fundamental wave contained in the output voltage generated by inverter switching can be passed, while harmonic waves can be attenuated. Furthermore, the order (or frequency) of harmonic waves to be attenuated can also be determined by setting the cutoff frequency (fc).

[0038] FIG. 4 is a diagram showing a circuit diagram of an insulated LC filter for capturing an inverter leakage electromagnetic field according to an embodiment of the present invention, and FIG. 5 is a diagram showing an enlarged portion (LC filter and bridge diode portion) of a circuit diagram of an insulated LC filter for capturing an inverter leakage electromagnetic field according to an embodiment of the present invention.

[0039] Referring to FIGS. 4 and 5, both ends of the core (10) for the filter are connected to both ends of the capacitor (20) for the filter (first line (L1) and second line (L2)).

[0040] In addition, the third line (L3) branches off from the first line (L1) and is connected to a contact point formed by two adjacent single-phase bridge rectifier diodes among the four single-phase bridge rectifier diodes constituting the bridge diode (30). In addition, another contact point formed symmetrically with respect to the contact point and the center point of the bridge diode (30) and by the contact point of two adjacent single-phase bridge rectifier diodes is connected to a fifth line (L5) branched off from the second line (L2).

[0041] At this time, the four single-phase bridge rectifier diodes constituting the bridge diode (30) are sequentially connected to each other to form a closed circuit, and the four single-phase bridge rectifier diodes are arranged symmetrically with respect to the internal center point of the bridge diode (30).

[0042] In addition, the remaining two contact points formed by the two adjacent single-phase bridge rectifier diodes of the bridge diode (30) that are not connected to the third line (L3) and the fifth line (L5) are connected to the converter (40) and the input terminal, respectively (the fourth line (L4) and the sixth line (L6)).

[0043] Additionally, the seventh line (L7) connected to the output terminal of the converter (40) is connected to the battery (50).

[0044] The above core (10) refers to a device that allows leakage electromagnetic energy generated by the current of the line (LN) to be utilized as induction and harvesting energy on the secondary side. Ferrite, silicon steel plate, nanocrystal, permalloy, etc. can be applied to the core (10) according to the characteristics of the motor system of the primary side (motor (MT) and motor drive unit (MT DR). Leakage electromagnetic energy generated by the current flowing on the primary side of the core (10) is induced on the secondary side to generate induced power.

[0045] For example, the core (10) may have a toroidal shape formed of ferrite, silicon steel plate, nanocrystal, etc., and a shape in which a secondary winding is wound to capture the magnetic field flux before leakage on the primary side and convert it into electric energy (harvesting energy) by applying it as an induced voltage. The line (LN) connecting the motor (MT) and the motor drive unit (MT DR) may be arranged to pass through the core (10). The electromagnetic energy generated by the line (LN; primary side) is output to the winding (secondary side) of the core (10), thereby producing induced power.

[0046] That is, the core (10) includes a diamagnetic material having a high permeability in a toroidal shape connected to a high-frequency alternating current-flowing line, and has a function of converting a large amount of leakage electromagnetic field energy (hereinafter, leakage flux) generated by the flow of alternating current in the high-frequency line into useful electrical energy. The core (10) has an output characteristic map in which the size and output of the induced voltage are determined by the primary parameters (frequency, current size) and the secondary parameters (shape, number of turns, material properties, dimensions, and series / parallel quantity) within a range that is not electrically saturated.

[0047] The induced voltage characteristic (secondary side) of the above core (10) is generally proportional to the amount of magnetic flux that interlinks with the current flowing in the primary side (line; LN), but is limited by the shape and material properties of the core (10) to related factors (permeability and magnetic hysteresis characteristics, magnetic flux density, magnetic resistance), and has a characteristic in which the induced voltage decreases when a magnetic saturation state due to the above parameters is reached.

[0048] FIG. 6 is a drawing showing the operation of an insulated LC filter that captures an inverter leakage electromagnetic field according to one embodiment of the present invention.

[0049] Referring to Fig. 6, the harmonic components of the primary current output to the output line of the inverter are captured due to the LC impedance (L: inductance, C: capacitance) of the core (10) and capacitor (20) constituting the LC filter (at this time, the fundamental component is not captured and is bypassed).

[0050] At this time, the harmonic [leakage electromagnetic field] component (h1) that is refluxed / cancelled by the LC impedance circulates through L1 (first line) and L2 (second line) of the LC filter, and the harmonic [leakage electromagnetic field] component (h1) that is refluxed / cancelled by the circulating LC impedance is picked up by the rectifier line including the bridge diode (30) and moves to L3 (third line) to be recovered. If the harmonic [leakage electromagnetic field] component (h1) that is refluxed / cancelled by the LC impedance is not picked up by the bridge diode (30), it disappears while circulating through the LC filter, but is picked up by the bridge diode (30) and recovered, and is changed into the recovered harmonic component.

[0051] The recovered harmonic components are recharged to the battery through the converter (40), and the converter (40) picks up the harmonic components through the above process and regenerates them into energy.

[0052] At this time, the cutoff frequency (fc) is determined by the following formula.

[0053] Mathematical formula 1

[0054]

[0055] (Here, L is the inductance of the core, and C is the capacitance of the capacitor)

[0056] In addition, the bridge diode (30) may use a Schottky diode with the lowest barrier voltage and excellent recovery switching for high-order harmonics, and a PFC (Power Factor Correction), Buck, or Boost converter may be used as the converter (40).

[0057] Meanwhile, the capacity of the capacitance (C) of the capacitor is determined through the following process. For example, if the current and voltage energy output by the inverter is used in a motor drive that drives a motor, the inductance (L) value of the core (10) is determined according to the rotational frequency (rpm) of the motor, and then the cutoff frequency (fc) of the harmonic wave is determined. Thereafter, the capacitance (C) value of the capacitor (20) is determined according to the determined inductance (L) value of the core (10) and the cutoff frequency (fc) of the harmonic wave.

[0058] FIG. 7 is a diagram showing a circuit diagram of an insulated LC filter that captures an inverter leakage electromagnetic field in a three-phase motor system according to one embodiment of the present invention.

[0059] Referring to Fig. 7, the leakage electromagnetic field collection device utilizing the insulated LC filter in Figs. 4 to 6 was described in the case where the current source, which is the energy source (primary side), is a motor system, but can also be applied to other application systems such as single-phase and three-phase high-frequency inverters.

[0060] The circuit diagram of an isolated LC filter for capturing inverter leakage electromagnetic fields in a three-phase motor system includes lines (LN1, LN2, LN3), cores (10a, 10b, 10c), capacitors (C1, C2, C3), and bridge diodes (DB1, DB2, DB3).

[0061] The above routes (LN1, LN2, LN3) are electrically connected to the motor (MT) and the motor drive unit (MT DR), and may include a first primary route (LN1), a second primary route (LN2), and a third primary route (LN3).

[0062] The above cores (10a, 10b, 10c) may include a first core (10a), a second core (10b), and a third core (10c) each having the first primary side route (LN1), the second primary side route (LN2), and the third primary side route (LN3) as their primary sides.

[0063] Additionally, the secondary sides of the cores (10a, 10b, 10c) can be connected to capacitors (C1, C2, C3). That is, the first core (10a), the second core (10b), and the third core (10c) can be connected to the first capacitor, the second capacitor, and the third capacitor, respectively.

[0064] In addition, the lines connecting the output terminals of the respective core output units and the input terminals of the respective first capacitor, second capacitor, and third capacitors of the first core (10a), second core (10b), and third core (10c) are connected to the lines of the input terminals of the first bridge diode, second bridge diode, and third bridge diode, respectively.

[0065] The process in which the harmonic components captured by each LC filter are picked up and recovered by each bridge diode is the same as the process described in FIGS. 4 to 6, and is therefore omitted.

[0066] According to this embodiment, the motor (MT) of the three-phase motor system is described as a three-phase motor (ACIM, PMSM, BLAC, BLDC, etc.) having three conductors, but is not limited thereto, and the number and types of conductors connected to the motor may vary.

[0067] Although the present invention has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

[0068] [Explanation of symbols]

[0069] 1: Insulated LC filter to capture inverter leakage electromagnetic fields

[0070] 10: Core

[0071] 20: Capacitor

[0072] 30: Bridge diode

[0073] 40: Converter

[0074] 50: Battery

[0075] L1: Route 1

[0076] L2: Second Line

[0077] L3: Third route

[0078] L4: Route 4

[0079] L5: Route 5

[0080] L6: Route 6

[0081] L7: Route 7

[0082] h1: Harmonic [leakage electromagnetic field] component that is refluxed / cancelled by LC impedance

[0083] C1: First capacitor

[0084] C2: Second capacitor

[0085] C3: Third capacitor

[0086] 10a: 1st core

[0087] 10b: Second core

[0088] 10c: Third Core

[0089] DB1: first bridge diode

[0090] DB2: Second bridge diode

[0091] DB3: Third bridge diode

[0092] LN1: First primary line

[0093] LN2: Second primary line

[0094] LN3: Third primary line

[0095] MT: Motor

[0096] MT DR: Motor Drive Unit

Claims

1. A core in which the current output by inverter switching flows into the input current of the input section; In a leakage electromagnetic field collecting device utilizing an insulated LC filter, the leakage electromagnetic field collecting device is implemented as a circuit including a capacitor that is connected to the input / output terminal line of the output section of the core and implements an LC filter; and a bridge diode in which four single-phase bridge rectifier diodes are sequentially connected to each other through the line to form a closed circuit. A leakage electromagnetic field collection device utilizing an insulated LC filter, the line connecting the output terminal of the output section of the above core and the input terminal of the above capacitor being connected to the input terminal line of the above bridge diode.

2. In paragraph 1, The above LC filter is a leakage electromagnetic field collection device that utilizes an insulated LC filter that bypasses the fundamental wave component of the input current.

3. In paragraph 1, The above LC filter is a leakage electromagnetic field capturing device utilizing an insulated LC filter that captures harmonic components among the output current.

4. In paragraph 3, A leakage electromagnetic field collection device utilizing an insulated LC filter that picks up and recovers the harmonic components collected above the bridge diode.

5. In paragraph 4, A leakage electromagnetic field collection device utilizing an insulated LC filter to which a converter is additionally connected to the output terminal of the above bridge diode.

6. In paragraph 5, The above converter is a leakage electromagnetic field collection device utilizing an isolated LC filter selected from among PFC, Buck or Boost converters.

7. In paragraph 1, The diodes that make up the above bridge diode are leakage electromagnetic field collecting devices that utilize an insulated LC filter that is a Schottky diode.

8. A method for capturing a leakage electromagnetic field using an insulated LC filter, comprising: a step of bypassing a fundamental component and capturing a harmonic component of a current output by inverter switching that is input to an input part of the core by an LC filter composed of a core and a capacitor; and a step of picking up and recovering the captured harmonic component by a bridge diode composed of four single-phase bridge rectifier diodes sequentially connected to each other through a line to form a closed circuit.

9. In paragraph 8, A method for capturing a leakage electromagnetic field using an insulated LC filter, further comprising a step of outputting harmonic components recovered through the bridge diode to a converter.

10. In paragraph 8, A method of capturing leakage electromagnetic fields using an insulated LC filter in which the diode constituting the above bridge diode is a Schottky diode.

11. In paragraph 9, The above converter is a leakage electromagnetic field capture method utilizing an isolated LC filter selected from among PFC, Buck or Boost converters.

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