Three-phase L-type intelligent protector

Abstract

This invention discloses a three-phase L-type intelligent protector, comprising a three-phase input DC relay group, a three-phase three-channel electronic switch group, a filter output control module, a three-phase multi-level detection module, a three-phase output DC relay group, and a central processing module. The input terminals of the three-phase input DC relay group are connected to three-phase AC power. The three-phase input DC relay group is electrically connected to the three-phase three-channel electronic switch group. The three-phase three-channel electronic switch group is electrically connected to the filter output control module. The filter output control module is electrically connected to the three-phase multi-level detection module. The three-phase output DC relay group is also electrically connected to the three-phase multi-level detection module. This invention utilizes the high voltage withstand capability and high speed of silicon carbide MOS transistors, and employs a common-drain design to achieve bidirectional AC / DC electronic movement. It replaces the traditional mechanical three-phase circuit breaker or air switch that relies on electromagnetic tripping, thereby effectively suppressing the hazards of electrical fires caused by sparks generated during load overload or branch circuit failure.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit breakers, and in particular to a three-phase L-type intelligent protector. Background Technology

[0002] Most electronic circuit breakers or smart protectors on the market are based on the I-type structure, with almost no L-type structures, and most are single-phase, with three-phase being extremely rare. Therefore, the research and development of three-phase smart protectors is particularly important. As the pre-stage of a single-phase smart protector, it can provide the original protection for three-phase four-wire systems while also performing voltage vector regulation. As the secondary protection stage of a single-phase smart protector, it can provide secondary protection for lines or loads, achieving dual protection. It is applicable to any three-level protection electrical application. Connected to the output of a three-level switch, it is suitable for homes, shopping malls, office buildings, schools, hospitals, shops, banks, government agencies, units, scenic spots, and many other areas requiring protection. It is especially useful in hospitals, particularly psychiatric hospitals, where patients, lacking basic awareness, may inadvertently touch electrical outlets with metal objects, posing a risk of electric shock. It is particularly important for protecting heavy loads such as three-phase motors, scenic area water pumps, and industrial applications in water conservancy and energy sectors. At the same time, it can be widely used in environments with dust, flammable gases, flammable liquids, mines, smelting, and production plants. These environments are extremely sensitive to sparks generated by electrical circuits or equipment, and even a tiny spark can lead to catastrophic consequences.

[0003] Traditional Type I electronic circuit breakers composed of MOS and IGBT types can only be used in single-phase environments and cannot achieve three-phase functionality because the phase angle of three-phase electricity differs by 120 degrees, making vector adjustment of the output voltage impossible. Furthermore, silicon MOS cannot achieve high voltage, and IGBTs cannot achieve high frequency; therefore, these two types of devices can only perform simple single-phase electronic switching functions. In terms of circuit breaking and arc extinguishing, the lack of a freewheeling path prevents the discharge of residual current in the line, which can still cause significant sparking during short circuits or load problems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a three-phase L-type intelligent protector.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A three-phase L-type intelligent protector includes: a three-phase input DC relay group, a three-phase three-channel electronic switch group, a filter output control module, a three-phase multi-stage detection module, a three-phase output DC relay group, and a central processing module.

[0007] The input terminals of the three-phase input DC relay group are respectively connected to the three-phase AC power. The output terminals of the three-phase input DC relay group are electrically connected to the three-phase three-channel electronic switch group. The output terminals of the three-phase three-channel electronic switch group are electrically connected to the filter output control module. The output terminals of the filter output control module are electrically connected to the three-phase multi-level detection module. The input terminals of the three-phase output DC relay group are electrically connected to the three-phase multi-level detection module. The output terminals of the three-phase output DC relay group are used to output voltage. The central processing module is electrically connected to the three-phase input DC relay group, the three-phase three-channel electronic switch group, the filter output control module, the three-phase multi-level detection module, and the three-phase output DC relay group.

[0008] The advantages and beneficial effects of this invention compared to the prior art are as follows:

[0009] This invention is a three-phase L-type intelligent protector. By utilizing the advantages of high voltage withstand and high speed of silicon carbide MOS and employing a common-drain method, it achieves bidirectional AC / DC electronic movement. It replaces the traditional mechanical three-phase circuit breaker or air switch that relies on electromagnetic tripping, thereby effectively suppressing the hazards of electrical fires caused by sparks generated during overload or circuit breaking. Attached Figure Description

[0010] Figure 1 This is a functional principle diagram of a three-phase L-type intelligent protector according to an embodiment of the present invention;

[0011] Figure 2 This is a functional schematic diagram of a traditional circuit breaker.

[0012] Figure 3 This is a functional schematic diagram of a traditional circuit breaker.

[0013] Figure 4 This is a schematic diagram of the main frame of a three-phase L-type intelligent protector according to an embodiment of the present invention;

[0014] Figure 5 This is a circuit diagram of a three-phase L-type intelligent protector according to another embodiment of the present invention;

[0015] Figure 6 This is a circuit diagram of a three-phase L-type intelligent protector according to an embodiment of the present invention;

[0016] Figure 7 The circuit diagram (1) shows the working principle of the power bridge of the present invention;

[0017] Figure 8 The circuit diagram (2) shows the working principle of the power bridge of the present invention;

[0018] Figure 9The circuit diagram (3) shows the working principle of the power bridge of the present invention;

[0019] Figure 10 This is a circuit diagram of the power bridge DC operating mode of the present invention;

[0020] Figure 11 This is a circuit diagram of the present invention when performing short-circuit arc extinguishing function on the output short circuit;

[0021] Figure 12 This is a waveform diagram of the present invention when performing short-circuit arc extinguishing function on the output short circuit;

[0022] Figure 13 This is a circuit diagram of the present invention when waveform correction is in progress;

[0023] Figure 14 The waveforms of the decomposition current and the synthesis current of the present invention are shown.

[0024] Figure 15 This is a driving waveform diagram of a three-phase L-type intelligent protector according to an embodiment of the present invention;

[0025] Figure 16 This is a driving waveform diagram of a three-phase L-type intelligent protector according to another embodiment of the present invention;

[0026] Figure 17 The circuit diagram (1) shows the auxiliary power supply for the three-phase L-type intelligent protector of the present invention;

[0027] Figure 18 The circuit diagram (2) shows the auxiliary power supply for the three-phase L-type intelligent protector of the present invention;

[0028] Figure 19 The circuit diagram (3) shows the auxiliary power supply for the three-phase L-type intelligent protector of the present invention;

[0029] Figure 20 The circuit diagram (4) shows the auxiliary power supply for the three-phase L-type intelligent protector of the present invention.

[0030] Figure 21 The circuit diagram (5) shows the auxiliary power supply for the three-phase L-type intelligent protector of the present invention.

[0031] Figure 22 The circuit diagram (6) shows the auxiliary power supply for the three-phase L-type intelligent protector of the present invention;

[0032] Figure 23 The circuit diagram is for the secondary isolation power supply drive circuit of the auxiliary power supply of the present invention.

[0033] Figure 24 The circuit diagram shows the control output of a three-phase L-type intelligent protector according to one embodiment of the present invention.

[0034] Figure 25 The circuit diagram of the MCU processor of a three-phase L-type intelligent protector according to one embodiment of the present invention is shown. Detailed Implementation

[0035] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0036] This is a three-phase L-type high-speed electronic circuit breaker intelligent protector developed from a single-phase L-type high-speed electronic circuit breaker intelligent protector. It uses silicon carbide (SiC) devices as the main switching devices, leveraging the low internal resistance of SiC devices to reduce switching losses. This results in a contactless, high-voltage, high-current, AC / DC universal protector with no short-circuit sparks. It employs a single nine-unit BUCK-BOOST assembly made with SiC devices, capable of individually adjusting the vector of each phase. Under the premise of no phase difference, it can independently adjust the voltage of each phase during three-phase AC operation to achieve dynamic balance. It also uses a silicon carbide (SIC) common drain connection method, combining single-phase electronic switches into bidirectional electronic switches, and adding a bidirectional BUCK-BOOST method to achieve vector boost and buck, while also being able to work with both AC and DC power supplies. Nine sets of bidirectional electronic switches and three inductors are combined into three pairs of bidirectional back-to-back L-type connections, and then output after passing through three sets of LC low-pass filters to form three-phase AC or DC power.

[0037] The three-phase L-type high-speed electronic current-cutting intelligent protector is designed to eliminate the catastrophic consequences of short circuits caused by faults or damage during the use or transmission of three-phase four-wire power supplies, which could result in large sparks and endanger personal safety and property. It is a two-pole protector connected to a main circuit breaker or air switch, utilizing the high-speed power-cutting and high-speed current-discharging principle of nine sets of bidirectional electronic switches to suppress short-circuit sparks to a very small range. It employs nine sets of four-phase limited PWM modulation pulses to split the three-phase four-wire power supply into three single-phase groups for individual modulation, allowing for separate control of the A / B / C phases. The vector voltage of each phase can be individually controlled, transforming the original method of requiring three transformers for separate voltage regulation into a method that only requires three sets of bidirectional electronic switches, significantly saving costs while improving efficiency and reducing heat generation. When the input is DC, three sets of bidirectional electronic switches are combined into one electronic switch to independently boost and buck the DC voltage. Simultaneously, the high voltage withstand capability of silicon carbide (SiC) allows for wide application in high-voltage DC charging piles and industrial and commercial energy storage. Because DC voltage lacks a zero-crossing point, DC air switches or circuit breakers require special customization and are very expensive. With the gradual establishment of 1500V high-voltage platforms, conventional circuit breakers will arc the moment they disconnect under load in such high-voltage environments, and the arc length increases with the voltage level. Therefore, the bidirectional electronic switch with an absorption circuit can effectively suppress this; at the moment of disconnection, the bleedering channel opens, suppressing the remaining charge within the LC resonant cavity.

[0038] The three-phase L-type high-speed electronic circuit breaker intelligent protector combines power metering, information communication, fault arc detection, combustible gas smoke collection, AC / DC step-up / step-down control, leakage and residual current collection, and overload, overcurrent, overvoltage, and undervoltage control. It changes the working principle of traditional mechanical air switches or circuit breakers, transforming from a mechanical structure to an electronic architecture. This shortens the MS (millisecond) level response time to the NS (nanosecond) level, fundamentally reducing and suppressing the sparks generated during short circuits. Because the energy of a short-circuit spark is directly proportional to the current multiplied by time, a short circuit in the output line of a mechanical circuit breaker will produce a very large spark, which can easily ignite flammable materials and gases. The faster the short-circuit action, the less energy is generated.

[0039] The three-phase L-type high-speed electronic circuit breaker intelligent protector adopts the advantages of high voltage resistance and high speed of silicon carbide MOS and uses a common drain to realize bidirectional AC and DC electronic movement. It replaces the traditional mechanical three-phase circuit breaker or air switch and relies on electromagnetic tripping to effectively suppress the hazards of electrical fires caused by sparks generated during load overload or circuit breaking. It employs three sets of LC low-pass filters to filter out high-frequency current. Simultaneously, utilizing the principle that inductor current cannot change abruptly, the three-phase L-type high-speed electronic current-breaking intelligent protector can automatically distinguish between starting current and short-circuit current. It separates starting current and short-circuit current using a tracking comparison method. The BUCK-BOOST-PWM modulation method provides stepless adjustment of the line voltage. The rail-to-rail leakage current following technology can rapidly dissipate residual current in the line, whether there is leakage or not. When a person accidentally touches a live conductor, the three-phase three-pole bidirectional electronic switch discharges the current in the line at a speed of NS (nanoseconds). The electric shock sensation is extremely slight, like the voltage released by a lighter, thus achieving personal safety. This achieves the purpose of suppressing sparks generated during short circuits or faults when the three-phase L-type high-speed electronic current-breaking intelligent protector is used for live-to-live, live-to-neutral, and live-to-ground connections.

[0040] This is a new type of intelligent protector that iterates and updates upon the traditional MOS-type and IGBT-type electronic circuit breaker type I architecture intelligent protector. Traditional MOS-type and IGBT-type type I electronic circuit breakers can only be used in single-phase environments and cannot achieve three-phase functionality because the phase angle of three-phase electricity differs by 120 degrees, making vector adjustment of the output voltage impossible. Furthermore, silicon MOS cannot achieve high voltage, and IGBTs cannot achieve high frequency; therefore, these two devices can only perform simple single-phase electronic switching functions. In terms of circuit breaking and arc extinguishing, the lack of a freewheeling path prevents the discharge of residual current in the line, which can still cause significant sparking during short circuits or load problems.

[0041] The three-phase L-type high-speed electronic circuit breaker intelligent protector uses a silicon carbide MOS bidirectional back-to-back L-type switch. Under normal operating conditions, the three freewheeling channels are closed. The freewheeling channels only open under abnormal conditions, especially when the load is a three-phase asynchronous motor or generator. Due to inertia, the motor or generator can become a generator. In this case, due to inertia, the circuit will experience very high voltage and current due to backflow from the motor or generator. At this time, the freewheeling channel of the three-phase L-type high-speed electronic circuit breaker intelligent protector can become a discharge channel similar to that of a frequency converter, dissipating excess energy in the resonant cavity.

[0042] The three-phase L-type high-speed electronic current-cutting intelligent protector changes the original bidirectional electronic switch composed of silicon MOS. Silicon MOS bidirectional electronic switches cannot achieve high voltages; their highest voltage is only 800V, which is insufficient for the ultimate requirements of new energy and industrial / commercial energy storage. It changes the original bidirectional electronic switch composed of IGBTs. Because in an IGBT-based bidirectional electronic switch, when any half-cycle passes through an IGBT, the current must flow through the body diode of the other IGBT. Since the internal structure of the IGBT is a PN junction, electrons cannot flow bidirectionally, resulting in very high losses. Under high current conditions, its heat loss can reach hundreds of watts or even higher.

[0043] The three-phase L-type high-speed electronic current interruption intelligent protector uses a bidirectional electronic switch composed of silicon carbide MOS combined with BUCK-BOOST-PWM modulation to achieve stepless vector regulation of three-phase voltage, reduce neutral point voltage deviation, reduce neutral line load current, and utilize the principle of electronic arc extinguishing composed of high-speed switch and freewheeling channel to suppress short-circuit sparks in any of the A / B / C / N lines, thereby minimizing or even eliminating the energy of the short circuit.

[0044] Please see Figure 2 In the traditional method, the power supply enters the inductors L1 / L2 / L3 after passing through K1 / K2 / K3, and the bidirectional switches K4 / K5 / K6 serve as freewheeling channels. Although this method can only achieve voltage reduction and short-circuit arc suppression, it cannot achieve the BOOST function due to the single-level architecture and can only be used as the BUCK function.

[0045] Please see Figure 3 In another traditional method, power flows through circuit breaker Q1 to bidirectional electronic switch K1. When voltage regulation is not required, K1 / K2 operates, while K3 remains closed. Current flows through K1 / K2 into the relay output channel. After high-frequency noise is filtered out by L2 and C1, the current flows through the current acquisition channel and then through the fault arc detection channel for output. When BUCK-BOOST mode is required, K1 / K2 enters PWM modulation mode, with the two bidirectional switch groups providing complementary outputs, regulated by a duty cycle of 10%-90%. After high-frequency filtering by L2 and C1, the required voltage is restored for output. This method is only suitable for single-phase AC and DC power; it cannot be implemented for three-phase AC and DC power combined.

[0046] The three-phase L-type high-speed electronic circuit breaker intelligent protector of this invention is a new type of electronic circuit breaker intelligent protector derived from the single-phase L-type high-speed electronic circuit breaker intelligent protector. The difference is that the single-phase L-type high-speed electronic circuit breaker intelligent protector can only modulate a single phase, while the three-phase four-wire modulation requires three sets of phases staggered by 120 degrees, and synchronous modulation is also required. Therefore, the technology and application fields have been greatly improved and upgraded. Most electronic circuit breakers or intelligent protectors on the market are mainly of the I-type structure, with almost no L-type architecture, and most are single-phase, with three-phase being almost nonexistent. Therefore, the research and development of three-phase intelligent protectors is particularly important. As a pre-amplifier for single-phase intelligent protectors, it provides the original protection for three-phase four-wire systems while also performing vector voltage regulation. As a secondary protection stage for single-phase intelligent protectors, it provides secondary protection for lines or loads, achieving dual protection. It is applicable to any tertiary protection electrical application. Connected to the output of a tertiary switch, it is suitable for homes, shopping malls, office buildings, schools, hospitals, shops, banks, government agencies, institutions, scenic spots, and many other areas requiring protection. It is particularly useful in hospitals, especially psychiatric hospitals where patients, lacking basic awareness, may inadvertently touch electrical outlets with metal objects, posing a risk of electric shock. It is particularly effective for protecting heavy loads such as three-phase motors, water pumps in scenic areas, and industrial environments involving water conservancy and energy. Furthermore, it finds high application potential in environments with dust, flammable gases, flammable liquids, mines, smelting plants, and manufacturing facilities, where sparks from electrical circuits or equipment are extremely sensitive; even a small spark can have catastrophic consequences.

[0047] In the new energy field, the three-phase L-type high-speed electronic circuit breaker can act as a contactless electronic switch. In photovoltaic, energy storage, and charging applications, the lack of a zero point in direct current (DC) causes arcing when the energy storage battery cuts off its output while carrying current. The intensity of this arcing varies with voltage and current; higher voltage and current result in a longer and more intense arc. Traditional DC circuit breakers and vacuum switches are bulky, expensive, and have short lifespans. The three-phase L-type high-speed electronic circuit breaker uses a 1600V silicon carbide MOSFET. Instead of mechanical contacts, it uses an electric field channel, enabling it to operate in a 1600V voltage environment and achieve its protective function.

[0048] Specifically, please refer to Figure 1A three-phase L-type intelligent protector includes: a three-phase input DC relay group, a three-phase three-channel electronic switch group, a filter output control module, a three-phase multi-level detection module, a three-phase output DC relay group, and a central processing module. It should be noted that the three-phase input DC relay group plays an initial connection and isolation role in the power system. When the system is operating normally, the central processing module sends a control signal to close the three-phase input DC relay group, introducing three-phase AC power into the subsequent circuits. When a system fault occurs, requiring maintenance or repair, the central processing module can quickly control the three-phase input DC relay group to open, isolating the input power supply from the subsequent circuits, preventing fault escalation and the risk of electric shock. The three-phase three-channel electronic switch group can achieve millisecond-level current response, effectively suppressing current surges and impacts, protecting power equipment from damage caused by current overload and voltage fluctuations. Through precise current control, the efficiency and stability of the power system are improved, reducing energy waste. Furthermore, its multi-channel design allows the protector to adapt to the needs of different loads, resulting in a wider range of applications. The filter output control module filters and regulates the current processed by the three-phase three-channel electronic switch group. It utilizes a filter circuit composed of inductors, capacitors, and other components to filter out high-frequency noise and interference signals in the current, making the output current smoother and more stable. Simultaneously, an internal voltage regulation control circuit adjusts the output voltage in real time, ensuring its stability and accuracy. The filtered and regulated current is then sent to the three-phase multi-level detection module, providing a high-quality signal source for subsequent detection and analysis. The three-phase multi-level detection module, through its multi-level detection design, improves detection sensitivity and reliability, enabling timely detection of various potential faults and anomalies. High-precision detection data provides strong support for the central processing module's decision-making, allowing the protector to take fast and accurate protective actions. The three-phase output DC relay group features rapid disconnection and reliable isolation. It can respond to fault signals within milliseconds, disconnecting the output circuit and effectively protecting the load equipment from short circuits, overloads, leakage current, and other faults. Its reliable isolation function prevents the spread of fault current, protecting the safety of other equipment and personnel. Furthermore, the on / off status of the relay group can intuitively reflect the system's operating status, facilitating troubleshooting and maintenance. The central processing module is the core control component of the entire three-phase L-type intelligent protector. It receives real-time detection data from the three-phase multi-level detection module, analyzes, processes, and judges this data, and makes corresponding control decisions based on preset protection strategies and algorithms. Then, the central processing module sends control signals to the three-phase input DC relay group, the three-phase three-channel electronic switch group, and the three-phase output DC relay group to achieve intelligent control of the entire protector. Simultaneously, it can also communicate with external devices to achieve functions such as remote monitoring, parameter setting, and fault alarm.

[0049] The input terminals of the three-phase input DC relay group are respectively connected to the three-phase AC power. The output terminals of the three-phase input DC relay group are electrically connected to the three-phase three-channel electronic switch group. The output terminals of the three-phase three-channel electronic switch group are electrically connected to the filter output control module. The output terminals of the filter output control module are electrically connected to the three-phase multi-level detection module. The input terminals of the three-phase output DC relay group are electrically connected to the three-phase multi-level detection module. The output terminals of the three-phase output DC relay group are used to output voltage. The central processing module is electrically connected to the three-phase input DC relay group, the three-phase three-channel electronic switch group, the filter output control module, the three-phase multi-level detection module, and the three-phase output DC relay group.

[0050] Furthermore, the three-phase input DC relay group includes a relay KM1 that is connected across phase A and phase B, and a relay KM2 that is connected across phase B and phase C. The relay KM1 is used to control the on / off state between phase A and phase B, and the relay KM2 is used to control the on / off state between phase B and phase C.

[0051] It should be noted that relays KM1 and KM2 do not operate in isolation in a three-phase DC input system, but rather cooperate and work together. From a control logic perspective, they are usually driven by the same control signal or interconnected control logic. For example, when the system needs to achieve a specific three-phase power switching or control function, the control circuit will send control signals to the coils of KM1 and KM2 simultaneously or in a specific timing sequence according to a preset program or external instructions.

[0052] When the KM1 coil receives a valid control signal, its internal electromagnetic system activates, generating a strong electromagnetic force that attracts the armature, causing the contacts to close and establishing electrical continuity between phases A and B, allowing current to flow normally between them. Conversely, when the control signal disappears or changes, the electromagnetic force weakens, the armature returns to its original position under the action of the return spring, the contacts open, and the electrical connection between phases A and B is severed.

[0053] Similarly, the operation of KM2 is similar to that of KM1. When the coil of KM2 receives a suitable control signal, the contacts close, and conduction occurs between phase B and phase C; after the control signal is removed, the contacts open, and the current path between phase B and phase C is blocked.

[0054] This interaction mechanism enables KM1 and KM2 to work together, achieving precise control of different phase-to-phase circuits of the three-phase power supply. For example, in applications where the three-phase power supply connection method needs to be changed to adapt to different load requirements, by reasonably controlling the on / off states of KM1 and KM2, the phase sequence or connection combination of the three-phase power supply can be flexibly switched, thereby meeting the power supply characteristics requirements of different loads.

[0055] It should also be noted that, please refer to Figure 5 The three-phase three-channel electronic switch group includes T-type electronic switch groups connected to phases A, B, and C respectively. In one of the T-type electronic switch groups, the T-type electronic switch group includes a first dual silicon carbide MOSFET group K1, a second dual silicon carbide MOSFET group K2, a third dual silicon carbide MOSFET group K3, and a connecting inductor L. The input terminal of the first dual silicon carbide MOSFET group K1 is electrically connected to the input AC power supply. The output terminal of the first dual silicon carbide MOSFET group K1 is connected to the input terminal of the second dual silicon carbide MOSFET group K2 and one end of the connecting inductor L. The other end of the connecting inductor L is electrically connected to the input terminal of the third dual silicon carbide MOSFET group K3. The output terminal of the second dual silicon carbide MOSFET group K2 is electrically connected to the input terminal of the filter output control module. The output terminal of the third dual silicon carbide MOSFET group K3 is grounded.

[0056] The first dual silicon carbide MOSFET group K1 serves as the interface between the entire T-type electronic switch group and the input AC power supply. When the AC power supply provides power, K1 is turned on according to the control signal, allowing current to flow in from the input terminal. At this time, the current forms a path inside K1 and flows in two directions simultaneously: part of the current flows directly to the input terminal of the second dual silicon carbide MOSFET group K2; the other part of the current enters the end connected to the inductor L.

[0057] The inductor L acts as an energy storage and buffer in the circuit. When current flows into inductor L, it generates a self-induced electromotive force, which impedes sudden current changes. This characteristic allows the current to gradually accumulate energy in inductor L and flow smoothly to the input of the third dual silicon carbide MOSFET group K3. The presence of inductor L effectively smooths current fluctuations, reduces current spikes and ripples, and provides a more stable current for subsequent circuits.

[0058] The second dual silicon carbide MOSFET group K2 is located between K1 and the filter output control module. It determines whether to pass the current from K1 to the filter output control module according to the control signal. When K2 is turned on, the current can smoothly pass through K2 into the filter output control module to provide power to the load; when K2 is turned off, the current path is cut off, preventing the current from flowing to the load.

[0059] The third dual silicon carbide MOSFET group K3 has one end connected to inductor L and the other end grounded. The main function of K3 is to work in conjunction with K1 and K2 to achieve bidirectional current control and energy feedback. Under a specific control strategy, when energy regulation or feedback in the circuit is required, K3 can be turned on according to the control signal, allowing the energy stored in inductor L to be released to ground through K3, thereby achieving energy balance control in the circuit.

[0060] The design employing a dual silicon carbide MOSFET group (K1 / K2 / K3) results in low on-resistance, high switching speed, and good voltage withstand performance. Low on-resistance reduces energy loss as current flows through the K1 / K2 / K3 group, improving circuit efficiency. High switching speed enables rapid response to changes in control signals, achieving precise current control and reducing energy loss and electromagnetic interference during switching. Furthermore, the energy storage function of the inductor L provides additional energy support during transient changes or sudden load shifts, ensuring stable circuit operation and reducing damage to the load from voltage fluctuations and current surges.

[0061] Furthermore, please refer to Figure 4 and Figure 5 Taking the first dual silicon carbide MOSFET group K1 as an example, the first dual silicon carbide MOSFET group K1 includes silicon carbide MOSFET Q11, silicon carbide MOSFET Q12, bridging resistor KR1 and bridging capacitor KC1. The input terminal of silicon carbide MOSFET Q11 is electrically connected to the AC power input terminal, and the output terminal of silicon carbide MOSFET Q11 is electrically connected to the input terminal of silicon carbide MOSFET Q12. The output terminal of silicon carbide MOSFET Q12 is connected to the input terminal of the second dual silicon carbide MOSFET group K2 and one end of the connecting inductor L. The bridging resistor KR1 and the bridging capacitor KC1 are connected in series. The input terminal of the bridging resistor KR1 is also electrically connected to the input terminal of silicon carbide MOSFET Q11, and the output terminal of the bridging capacitor KC1 is also electrically connected to the output terminal of silicon carbide MOSFET Q12. The structural connections of the second dual silicon carbide MOS transistor group K2 and the third dual silicon carbide MOS transistor group K3 are the same as those of the first dual silicon carbide MOS transistor group K1, and will not be described again here.

[0062] The silicon carbide MOSFET Q11, as a key switching element on the input side, has its input terminal directly connected to the AC power input terminal. When the AC power supply provides electrical energy, Q11 turns on or off according to an external control signal, controlling whether current can flow from the power supply terminal into the entire MOSFET group. When Q11 is on, current flows smoothly from its input terminal to the output terminal, and then to the input terminal of Q12.

[0063] The silicon carbide MOSFETs Q12 and Q11 are connected in series, with Q12 receiving current from Q11. Q12 is also regulated by a control signal, determining whether to continue current flow to the subsequent circuitry, specifically the input of the second dual silicon carbide MOSFET group K2 and one end connected to the inductor L. Through this series connection, Q11 and Q12 collaboratively control the on / off state and direction of current flow, forming the basic current control path of K1.

[0064] A bridging resistor KR1 and a bridging capacitor KC1 are connected in series between the input of Q11 and the output of Q12. This bridging method allows KR1 and KC1 to participate in the dynamic process of the entire circuit. When the switching states of Q11 and Q12 change, the voltage and current in the circuit will experience transient changes. At this time, the series circuit composed of bridging KR1 and KC1 will respond to these transient changes. Capacitor KC1 has charging and discharging characteristics, and can absorb or release charge when the voltage changes, while resistor KR1 plays the role of limiting current and regulating the charging and discharging rate. They work together to affect the transient characteristics of the circuit. The bridging resistor KR1 can effectively limit current spikes, reduce electromagnetic interference, and improve the electromagnetic compatibility of the circuit. At the same time, the presence of the bridging resistor KR1 can also improve the stability of the circuit, prevent unstable phenomena such as oscillation during switching, and ensure that the circuit can operate stably under various operating conditions. The bridging capacitor KC1 can effectively reduce voltage ripple and current harmonics in the circuit, and reduce interference and damage to the load. Meanwhile, KC1's energy buffer function can improve the circuit's dynamic response capability, and can quickly provide or absorb energy during load changes or power fluctuations to ensure stable circuit operation.

[0065] The high electron mobility of silicon carbide (SiC) results in extremely low on-resistance for Q11, meaning minimal energy loss when current flows through it, thus improving overall circuit efficiency. Simultaneously, the high switching speed of the SiC MOSFET allows for rapid response to changes in control signals, reducing switching delays and enabling more precise and timely current control. Furthermore, the high-temperature stability and radiation resistance of SiC allow Q11 to operate stably in harsh environments with high temperatures and high radiation, significantly improving circuit reliability and stability and extending equipment lifespan.

[0066] Compared to traditional MOSFET designs, the K1 circuit, employing a combination of silicon carbide MOSFETs and bridging resistors and capacitors, offers significant advantages. The high performance of the silicon carbide MOSFETs results in higher efficiency, lower losses, and better thermal stability for the entire circuit, reducing heat dissipation requirements and system size. The addition of bridging resistors and capacitors further optimizes the circuit's transient response and power quality, improving its reliability and stability.

[0067] Specifically, the filter output control module includes a three-phase LC filter unit and three relay output units. Each relay output unit is electrically connected to one of the LC filter units, and each phase of the LC filter unit is electrically connected to the three-phase three-channel electronic switch group. At the same time, the three-phase LC filter units and the three relay output units are electrically connected to the central processing module.

[0068] Furthermore, the three-phase multi-level detection module includes a main current detection group, a leakage current detection group, an output voltage detection group, and a fault arc detection group. The main current detection group is electrically connected to the three-phase output DC relay group after passing through the leakage current detection group, the output voltage detection group, and the fault arc detection group. The main current detection group, leakage current detection group, output voltage detection group, and fault arc detection group are also electrically connected to the central processing module. It should be noted that the main current detection group directly monitors the main current in the three-phase circuit in real time. After preliminary processing of the detected current signal, it transmits the signal to the subsequent leakage current detection group, output voltage detection group, and fault arc detection group, providing them with basic current data for further analysis. Simultaneously, it directly transmits the processed current data to the central processing module. Based on the data provided by the main current detection group, the central processing module monitors the load status of the power system in real time and determines whether there are abnormal phenomena such as overload or underload. When the main current exceeds the set safety threshold, the central processing module prepares in advance and, based on feedback from other detection groups, determines whether protective measures are necessary, such as controlling the three-phase output DC relay group to cut off the circuit. The leakage current detection group can promptly detect insulation faults in the circuit, accurately detecting even small leakage currents, greatly improving the safety of the power system. Timely disconnection of leakage circuits effectively prevents electric shock accidents and protects personal safety. Furthermore, preventing leakage reduces energy waste and improves power system efficiency. The output voltage detection group monitors voltage changes in real time, promptly detecting voltage anomalies such as overvoltage and undervoltage. Timely voltage adjustments protect electrical equipment from voltage fluctuations, extending equipment lifespan and improving the reliability and stability of the power system. Accurate voltage detection also helps ensure the performance of electrical equipment and improves power quality. The fault arc detection group is a crucial line of defense against electrical fires. It can detect and address fault arcs in their early stages, effectively preventing electrical fires. By quickly cutting off the circuit, it stops the arc from continuing to burn, protecting personnel and property. The application of fault arc detection technology has greatly improved the safety of power systems, especially in places with high fire protection requirements, such as shopping malls, hospitals, and schools, where it has significant application value.

[0069] It should be noted that the central processing module includes a front-end detection channel, a back-end detection channel, a wireless transmission and display channel, and a central processing unit. The central processing unit is electrically connected to the front-end detection channel, the back-end detection channel, and the wireless transmission and display channel. The front-end detection channel is also electrically connected to the three-phase input DC relay group, the three-phase three-channel electronic switch group, and the filter output control module. The back-end detection channel is also electrically connected to the three-phase multi-stage detection module and the three-phase output DC relay group. It can be understood that the front-end detection channel senses the operating status of the three-phase input DC relay group, the three-phase three-channel electronic switch group, and the filter output control module in real time. It continuously collects electrical parameters of these components, such as input current, voltage, and switch status, and transmits this raw data to the central processing unit after preliminary processing and formatting. The central processing unit monitors the front-end operation of the protector in real time based on the information provided by the front-end detection channel. The back-end detection channel is mainly responsible for collecting and processing information from the three-phase multi-stage detection module and the three-phase output DC relay group. The three-phase multi-level detection module monitors various parameters of the power system in real time, such as main current, leakage current, output voltage, and fault arcs. The subsequent detection channels integrate and analyze this data, extracting key information before transmitting it to the central processing unit. Based on the data provided by the subsequent detection channels, the central processing unit determines whether the power system's operating status is normal and whether there are any potential faults. If a fault is detected, the central processing unit sends a circuit-breaking command to the three-phase output DC relay group through the subsequent detection channels to protect the load equipment and the power system. Simultaneously, the subsequent detection channels also feed back the on / off status of the relay group to the central processing unit, allowing the central processing unit to monitor the execution of protection actions in real time. The wireless transmission and display channel can transmit important information processed by the central processing unit, such as the power system's operating status, fault alarm information, and protection action records, to remote monitoring terminals or mobile devices via wireless communication technology. It can also receive control commands and parameter setting information from external devices and transmit them to the central processing unit. The central processing unit receives a large amount of real-time data from the preceding and subsequent detection channels and performs in-depth analysis and processing of this data. It uses advanced algorithms and preset protection strategies to determine whether the power system is operating normally and to identify various fault types and abnormal situations.

[0070] In this embodiment, the front-end detection channel includes a power detection unit, a PWM drive generator, a low-pass filter, and a temperature detection unit. The power detection unit is electrically connected to the three-phase input DC relay group and the central processing unit, respectively. The drive terminal of the PWM drive generator is electrically connected to the three-phase three-channel electronic switch group, and the input terminal of the PWM drive generator is electrically connected to the central processing unit. The low-pass filter and the temperature detection unit are electrically connected to the filter output control module, respectively, and the control terminals of the low-pass filter and the temperature detection unit are electrically connected to the central processing unit. It should be noted that the power detection unit has high-precision power parameter detection capabilities, enabling it to promptly detect minor power fluctuations and potential faults. By monitoring the power status in real time, it can provide accurate power information to the protector, allowing the protector to react quickly when power abnormalities occur, avoiding equipment damage and data loss due to power problems. The PWM drive generator generates precise pulse width modulation (PWM) signals according to the control commands sent by the central processing unit. These PWM signals have specific parameters such as frequency and duty cycle, enabling precise control of the on / off state and conduction time of the three-phase three-channel electronic switch group. The central processing unit calculates appropriate PWM parameters based on the actual needs and operating status of the power system and transmits them to the PWM driver generator. The low-pass filter effectively removes high-frequency noise and spurious signals, improving signal quality and reliability. By purifying the output signal, malfunctions and measurement errors caused by noise interference can be avoided, improving the performance and accuracy of the protector. The temperature detection unit can monitor the temperature of the filtered output control module in real time and accurately, promptly detecting abnormal temperatures. By taking timely measures such as heat dissipation or power reduction, equipment damage due to overheating can be effectively prevented, extending equipment lifespan and reducing maintenance costs.

[0071] Furthermore, the subsequent detection channel includes a current detection processing unit and a voltage and fault arc detection processing unit. The current detection processing unit is electrically connected to the main current detection group and the leakage current detection group, respectively. The voltage and fault arc detection processing unit is electrically connected to the output voltage detection group and the fault arc detection group, respectively. The current detection processing unit and the voltage and fault arc detection processing unit are also electrically connected to the central processing unit. It should be noted that the current detection processing unit has high-precision current detection capabilities, enabling it to acquire main current and leakage current information in real time and accurately. Through real-time monitoring and analysis of the current, it can promptly detect current anomalies, providing crucial information for power system fault diagnosis and protection. The accurate monitoring of the output voltage by the voltage and fault arc detection processing unit ensures that the load equipment operates under a stable voltage environment, preventing equipment damage caused by voltage anomalies.

[0072] It should be noted that the wireless transmission display channel includes a display control unit and a wireless transmission unit, and the display control unit is electrically connected to the wireless transmission unit and the central processing unit respectively.

[0073] In this embodiment, the central processing unit is an MCU processor or a DSP processor. The wireless transmission unit is a DTU communication unit.

[0074] The three-phase four-wire power supply enters the DC power supply merging relays KM1 and KM2 after passing through circuit breaker Q1. When using AC power, relays KM1 and KM2 are open. Only when using DC power do relays KM1 and KM2 close, causing the three sets of three-channel bidirectional electronic switches to form a single electronic switch. Their relationship is that they operate in combination. Then, the high-frequency current passes through an LC low-channel filter to remove the high-frequency signal before being output.

[0075] Relays KM3, KM4, and KM5 are physical isolation channels that physically isolate the power supply after the power supply stage. After the power supply passes through the main current detection channel, the current required for each phase is obtained. The leakage current detection detects the residual current in the three-phase four-wire output line and sends it to the output voltage detector. The detector sends the monitored voltage to the MCU for processing. The MCU processor adjusts the PWM pulse width according to the required voltage.

[0076] The power detection unit analyzes the input voltage type and level. When the input is AC, it disconnects relays KM1 and KM2; when the input is DC, relays KM1 and KM2 are energized. The PWM signal generator analyzes the input voltage type. When the input is DC voltage, the PWM signal generator combines the three electronic switches into one channel. In this case, the signal provided by the PWM signal generator is a synchronous, in-phase signal. When the input voltage is a three-phase AC voltage, the PWM signal generator will perform PWM modulation with a 120-degree offset, modulating it into a three-phase pulse signal.

[0077] The temperature detection unit sends the detected analog temperature signal to the DSP / MCU for processing, while the current detection unit and the voltage fault arc detection unit work together to send the acquired current signal to the MCU / DSP for processing.

[0078] Please see Figure 5 and Figure 6In the combined mode, when the inputs A / B / C / N are three-phase four-wire AC power, relays KM1 / KM2 are open. The three-phase AC power is modulated by electronic switch group K1 / K2 / K3. In the rise / fall mode, switches U1 / U2, U4 / U5, and U7 / U8 operate in alternating mode, while switches U3 / U6 / U9 operate in normally closed mode. When operating in short-circuit arc extinguishing mode, switches U3 / U6 / U9 and U2 / U5 / U8 operate in alternating mode. After filtering by low-pass filters LC1 / LC2 / LC3, the output voltage waveform is inverted.

[0079] Please see Figure 6 The power supply for phase A is input to the merging relay via J4. Simultaneously, point 1 of the merging relay is connected to bridge 1 of the three-channel electronic switch for phase A. The power supply for phase B is directly connected to point 2 of the relay for phase A, and simultaneously input to bridge 4 of the three-channel electronic switch for phase B. Point B is also connected to point 1 of the merging relay for phase C, and power supply C is input to bridge 7 of the merging relay for phase C. Thus, when three-phase power is input, each power supply group will enter its corresponding three-channel bidirectional electronic switch. When the power input is DC voltage, the relays for phases A and B will engage, merging the power supply channels for phases A, B, and C into a single channel, increasing the output current.

[0080] Please see Figures 7 to 9 When a three-phase four-wire AC power supply is input, bridges 3 / 6 / 9 of phases A / B / C are closed, and bridges 1 / 4 / 7 and 2 / 5 / 8 of phases A / B / C receive complementary PWM modulation pulses. When the function requires buck mode, the PWM modulation pulses of bridges 1 / 4 / 7 of phases A / B / C vary between 0% and 50%, and the PWM modulation pulses of bridges 2 / 5 / 8 of phases A / B / C vary between 50% and 90%. When the function requires boost mode, the PWM modulation pulses of bridges 1 / 4 / 7 of phases A / B / C vary between 50% and 90%, and the PWM modulation pulses of bridges 2 / 5 / 8 of phases A / B / C vary between 0% and 50%. When the function does not require voltage regulation, bridges 1 / 2 / 4 / 5 / 7 / 8 of phases A / B / C are closed, and bridges 3 / 6 / 9 of phases A / B / C are open, at which time the equal output function mode is performed. When an arc extinguishing function is required due to a short circuit in the output, bridges 1 / 4 / 7 of phases A / B / C of the power supply are disconnected, and bridges 2 / 5 / 8 / 3 / 6 / 9 of phases A / B / C of the power supply are closed. At this time, the residual current in the output line is discharged through bridges 2 / 5 / 8 / 3 / 6 / 9 of phases A / B / C of the power supply.

[0081] Please see Figure 10When a DC voltage is input, relays KM1 and KM2 are fully activated, and all three bidirectional electronic switches of the power supply (A / B / C) operate in parallel to increase the output current. The PWM of bridges 1 / 4 / 7 and 2 / 5 / 8 of the power supply work in a complementary manner, and the DC voltage is output inverted.

[0082] Please see Figure 11 and Figure 12 When the output is short-circuited and the arc extinguishing function is activated, bridges 1 / 4 / 7 of the three-channel bidirectional electronic switch are turned off, while bridges 2 / 5 / 8 / 3 / 6 / 9 are turned on to discharge the remaining charge.

[0083] Please see Figure 13 When the three-phase L-type high-speed electronic current interruption intelligent protector is in waveform correction mode, the 1 / 4 / 7 bridge and 2 / 5 / 8 bridge of the power supply enter the PWM interleaved complementary modulation mode, which eliminates the voltage at the peak position and fills the voltage gap.

[0084] Please see Figure 14 When the three-phase L-type high-speed electronic current interruption intelligent protector is in the short-circuit current and fault arc detection, it adopts the current following comparison method and uses precision operational amplifier rectification and amplification to effectively avoid the distinction between starting current and short-circuit current. At the same time, it uses LC resonance detection for fault arc detection. When the periodic current is greater than the resonant cavity current, it is regarded as a fault arc. It uses three sets of precision rectification circuits to shape the AC current signal into a 12-pulse pulse signal and compare it with the reference current. When the current at any point reaches the reference line, it shuts off its output within 100NS (nanoseconds).

[0085] Please see Figure 15 When the three-phase L-type high-speed electronic circuit breaker enters the BUCK-BOOST step-up / step-down voltage regulation mode, the drive waveforms of bridges 1 / 4 / 7 and 2 / 5 / 8 of the power supply are shown. When the three-phase L-type high-speed electronic circuit breaker is in step-down mode, the duty cycle of bridges 1 / 4 / 7 is less than that of bridges 2 / 5 / 8. When in step-up mode, the duty cycle of bridges 1 / 4 / 7 is greater than that of bridges 2 / 5 / 8. Bridges 3 / 6 / 9 of the power supply are always in the ON state.

[0086] Please see Figure 16 When the three-phase L-type high-speed electronic current interruption intelligent protector enters the arcing state, bridges 1 / 4 / 7 of the power supply are in the off state, while bridges 2 / 5 / 8 / 3 / 6 / 9 of the power supply are in the on state to discharge the remaining current.

[0087] Please see Figures 17-23The auxiliary power supply adopts a half-bridge topology. The main power supply enters through the J1 interface, then passes through fast-acting fuses F1, F2, and F3 to the EMC filter. It then passes through diodes D3, D4, D5, D11, D12, and D13, along with capacitors C1 and C9, to form a symmetrical DC voltage. This voltage is then passed through the startup circuit to form the startup voltage. The PWM driver U1 generates the first-stage PWM drive signal Q1+ / Q1-, driving the half-bridge driver transformer T1 to supply the main power MOSFETs U2 / U5. This drive signal passes through the half-bridge converter and is combined with three +15V power supplies to power the fan, relays, and the main output circuit. A delay circuit ensures delayed operation of subsequent circuits after a power outage. A voltage regulator stabilizes the +15V power supply. A diode-isolated power supply drives the three-channel bidirectional electronic switches and the mainboard circuitry to supply main power. Transformers T4 / T5 / T6 / T7 form diode-isolated power supplies to three sets of three-channel bidirectional power bridges and three sets of isolated positive and negative power supplies to the mainboard.

[0088] Please see Figures 20-22 The secondary windings of transformers T4 to T7 generate 16 sets of isolated power supplies. After rectification by bridge rectifier diodes, transformers T1_1 to T1_16 generate power supplies VCC1 to VCC8. DC power supplies VCC11 to VCC88 supply power to the subsequent voltage regulator chips.

[0089] Please see Figures 20-22 The power supplies VCC1-VCC8 and DC power supplies VCC11-VCC88 are fed into power bridge regulator chips A, B, and C, respectively. This generates three +20V and three -5V power supplies (only two are shown here as they function identically). The DC power supplies VCC55-VCC88 are fed into regulator chips U1, U5, U9, U13, and U17, respectively, generating +12V, -12V, +5V, -5V, and +3.3V power supplies to power the motherboard.

[0090] Please see Figures 20-22 GA_UP, GB_UP, GC_UP, GA_Z, GB_Z, GC_Z, GA_DOWN, GB_DOWN, GC_DOWN are drive pulse signals sent by the DSP or MCU, respectively. After passing through the driver chips U1-U9, they are sent to the push-pull driver and then to the three-channel bidirectional electronic switch via GATE1-GATE9 for control output.

[0091] Please see Figure 24The three-phase current signals A / B / C from the current transformer are amplified by the operational amplifiers U1A / U4A / U7A and then sent to three sets of precision rectifier amplifier circuits for comparison with the MCU processor / DSP processor. When the current signal reaches the analog value of the main current short circuit, the high-speed latch-up amplifiers U3A / U3B, U6A / U6B, and U9A / U9B will shut down the output.

[0092] Please see Figures 24-25 The MCU processes the data collected from each part. It then sends the obtained data values ​​and instructions to each unit, and adds PWM to pins 81-88 and pin 7 of the DSP to control three sets of three-channel bidirectional electronic switches.

[0093] Since the leakage current acquisition, power supply voltage acquisition, current acquisition, and communication sections are similar to those of the L-type high-speed electronic interruption smart protector, they will not be described in detail.

[0094] This invention employs a three-channel bidirectional electronic switch (SIC) for practical three-phase vector voltage regulation, eliminating the need for power frequency transformers, thus saving costs, reducing size, and improving efficiency. It utilizes a nine-channel bidirectional BUCK-BOOST mode, enabling stepless vector voltage regulation of AC and DC. The front-end stage uses a combined approach, allowing for input of different AC and DC power supplies. Three independent channels of silicon carbide bidirectional electronic switches provide independent arc extinguishing for the A, B, and C voltage groups. This effectively suppresses the electrical fire hazards caused by short circuits or faults in three-phase four-wire power supplies.

[0095] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A three-phase L-type intelligent protector, characterized in that, The utility model relates to a kind of three-phase input DC relay group, three-phase three-channel electronic switch group, filter output control module, three-phase multistage detection module, three-phase output DC relay group and central processing module, The input end of the three-phase input DC relay group is connected with three-phase alternating current respectively, the output end of the three-phase input DC relay group is electrically connected with the three-phase three-channel electronic switch group, the output end of the three-phase three-channel electronic switch group is electrically connected with the filter output control module, the output end of the filter output control module is electrically connected with the three-phase multistage detection module, the input end of the three-phase output DC relay group is electrically connected with the three-phase multistage detection module, and the output end of the three-phase output DC relay group is used for outputting voltage.The central processing module is electrically connected with the three-phase input DC relay group, three-phase three-channel electronic switch group, filter output control module, three-phase multistage detection module and three-phase output DC relay group respectively. The three-phase three-channel electronic switch group includes T-shaped electronic switch group connected with ABC phase respectively, and in one T-shaped electronic switch group, the T-shaped electronic switch group includes first double silicon carbide MOS tube group K1, second double silicon carbide MOS tube group K2, third double silicon carbide MOS tube group K3 and connecting inductor L, the input end of the first double silicon carbide MOS tube group K1 is electrically connected with the output end of the three-phase input DC relay group, the output end of the first double silicon carbide MOS tube group K1 is connected with the input end of the second double silicon carbide MOS tube group K2 and one end of the connecting inductor L, the other end of the connecting inductor L is electrically connected with the input end of the third double silicon carbide MOS tube group K3, the output end of the second double silicon carbide MOS tube group K2 is electrically connected with the input end of the filter output control module, and the output end of the third double silicon carbide MOS tube group K3 is grounded. The filter output control module includes three-phase LC filter unit and three relay output units, each relay output unit is electrically connected with one LC filter unit respectively, and each phase LC filter unit is electrically connected with the three-phase three-channel electronic switch group, and three-phase LC filter unit and three relay output units are electrically connected with the central processing module respectively.

2. The three-phase L-type smart protector according to claim 1, characterized in that, The three-phase multistage detection module includes main current detection group, leakage current detection group, output voltage detection group and fault arc detection group, the main current detection group is electrically connected with the three-phase output DC relay group through the leakage current detection group, output voltage detection group and fault arc detection group, and the main current detection group, leakage current detection group, output voltage detection group and fault arc detection group are electrically connected with the central processing module respectively.

3. The three-phase L-type smart protector according to claim 1, characterized in that, ​ 4. The three-phase L-type smart protector according to claim 3, characterized in that, The central processing module comprises a front-stage detection channel, a rear-stage detection channel, a wireless transmission display channel and a central processing unit, the central processing unit is electrically connected with the front-stage detection channel, the rear-stage detection channel and the wireless transmission display channel respectively, the front-stage detection channel is further electrically connected with the three-phase input DC relay group, the three-phase three-channel electronic switch group and the filter output control module respectively, and the rear-stage detection channel is further electrically connected with the three-phase multi-stage detection module and the three-phase output DC relay group respectively.

5. The three-phase L-type smart protector according to claim 4, characterized in that, The front-stage detection channel comprises a power supply detection unit, a PWM drive generator, a low-pass filter and a temperature detection unit, the power supply detection unit is electrically connected with the three-phase input DC relay group and the central processing unit respectively, the drive end of the PWM drive generator is electrically connected with the three-phase three-channel electronic switch group, the input end of the PWM drive generator is electrically connected with the central processing unit, the low-pass filter and the temperature detection unit are electrically connected with the filter output control module respectively, and the control end of the low-pass filter and the temperature detection unit is electrically connected with the central processing unit.

6. The three-phase L-type smart protector according to claim 4, characterized in that, The rear-stage detection channel comprises a current detection processing unit and a voltage and fault arc detection processing unit, the current detection processing unit is electrically connected with the main current detection group and the leakage current detection group respectively, the voltage and fault arc detection processing unit is electrically connected with the output voltage detection group and the fault arc detection group respectively, and the current detection processing unit and the voltage and fault arc detection processing unit are further electrically connected with the central processing unit respectively.

7. The three-phase L-type smart protector according to claim 4, characterized in that, The wireless transmission display channel comprises a display control unit and a wireless transmission unit, and the display control unit is electrically connected with the wireless transmission unit and the central processing unit respectively.

8. The three-phase L-type smart protector of claim 4, wherein, The central processing unit is an MCU processor or a DSP processor.

9. The three-phase L-type smart protector of claim 7, wherein, The wireless transmission unit is a DTU communication unit.

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