Three-phase L-shaped intelligent protector

Abstract

The invention discloses a three-phase L-shaped intelligent protector which comprises a three-phase input direct-current relay set, a three-phase three-channel electronic switch set, a filtering output control module, a three-phase multi-stage detection module, a three-phase output direct-current relay set and a central processing module. The three-phase input direct-current relay group is electrically connected with the three-phase three-channel electronic switch group, the three-phase three-channel electronic switch group is electrically connected with the filtering output control module, the filtering output control module is electrically connected with the three-phase multi-stage detection module, and the three-phase output direct-current relay group is electrically connected with the three-phase multi-stage detection module. By adopting the advantages of high voltage resistance and high speed of the silicon carbide MOS, alternating current and direct current bidirectional electronic motion is realized in a common drain mode, and the mode that a traditional mechanical three-phase circuit breaker or an air switch depends on electromagnetic tripping is replaced; therefore, electrical fire hazards caused by sparks generated by overload or branch circuits are effectively inhibited.

Description

Technical Field

[0001] The present invention relates to the field of electronic circuit breakers, and in particular to a three-phase L-shaped intelligent protector. Background Art

[0002] Most electronic circuit breakers and smart protectors on the market feature an I-type structure, with L-type designs rarely seen. Furthermore, most are single-phase, with three-phase options practically nonexistent. Therefore, the development of a three-phase smart protector is crucial. As a precursor to a single-phase smart protector, it provides standard protection for three-phase, four-wire systems while also enabling voltage vector regulation. Serving as a secondary protection stage for single-phase smart protectors, it offers secondary protection for lines or loads, achieving dual protection. Suitable for any three-level protection environment, it connects to the output of a three-level switch and is suitable for homes, shopping malls, office buildings, schools, hospitals, shops, banks, government agencies, organizations, scenic spots, and many other locations requiring protection. Hospitals are particularly vulnerable to electric shock hazards, particularly in psychiatric hospitals, where patients, lacking basic cognitive skills, may accidentally touch outlets with metal objects, potentially posing an electric shock hazard. The focus is on protecting heavy loads such as three-phase motors, water pumps in scenic areas, and industrial applications such as water conservancy and energy. At the same time, it can be used in environments with dust, flammable gas, flammable liquid, mines, smelting, production plants, etc. These environments are extremely sensitive to sparks generated by electrical lines or equipment, and a small spark may bring catastrophic consequences.

[0003] Traditional Type I electronic circuit breakers, comprised of MOS and IGBTs, can only operate in single-phase environments and cannot achieve three-phase functionality. This is because the phase angles of three-phase power differ by 120 degrees, making it impossible to adjust the output voltage vector. Furthermore, silicon MOS cannot achieve high voltages, and IGBTs cannot operate at high frequencies. Therefore, these two devices can only perform simple single-phase electronic switching functions. In terms of circuit breaker and arc extinguishing, the lack of a freewheeling path prevents residual current from being discharged, resulting in significant sparks in the event of a short circuit or load failure. Summary of the Invention

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

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] A three-phase L-shaped 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.

[0007] The input ends of the three-phase input DC relay group are respectively connected to the three-phase alternating current, the output ends of the three-phase input DC relay group are electrically connected to the three-phase three-channel electronic switch group, the output ends of the three-phase three-channel electronic switch group are electrically connected to the filter output control module, the output end of the filter output control module is electrically connected to the three-phase multi-level detection module, the input end of the three-phase output DC relay group is electrically connected to the three-phase multi-level detection module, the output end of the three-phase output DC relay group is used to output voltage, and the central processing module is respectively 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 the present invention compared to the prior art are as follows:

[0009] The present invention is a three-phase L-shaped intelligent protector. By taking advantage of the high withstand voltage and high speed of silicon carbide MOS and using a common drain method to achieve AC and DC bidirectional 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 by load overload or circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0011] Figure 2 This is the functional principle diagram of the traditional circuit breaker protector;

[0012] Figure 3 This is another functional principle diagram of a circuit breaker protector in a traditional way;

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

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

[0015] Figure 6 A circuit diagram of a three-phase L-type smart protector according to one embodiment of the present invention;

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

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

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

[0019] Figure 10 A circuit diagram of the power bridge DC working mode of the present invention;

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

[0021] Figure 12 This is a waveform diagram of the present invention when the output is short-circuited and the arc extinguishing function is performed;

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

[0023] Figure 14 It is the waveform diagram of the decomposition current and the synthesis current of the present invention;

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

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

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

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

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

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

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

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

[0032] Figure 23 A circuit diagram of a secondary isolated power supply driving circuit of an auxiliary power supply of the present invention;

[0033] Figure 24 A circuit diagram of the control output of a three-phase L-type smart protector according to one embodiment of the present invention;

[0034] Figure 25 This is a circuit diagram of the MCU processor of a three-phase L-type smart protector according to one embodiment of the present invention. DETAILED DESCRIPTION

[0035] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0036] This three-phase L-shaped high-speed electronic current interrupter is an upgrade from a single-phase L-shaped high-speed electronic current interrupter. It uses silicon carbide (SIC) devices as the primary switching element. Leveraging the low internal resistance of SIC devices, it reduces switching losses, resulting in a contactless, high-voltage, high-current, AC / DC, and spark-free smart protector. The nine-unit BUCK-BOOST combination, constructed with SIC devices, independently adjusts the voltage of each phase to achieve dynamic balance during three-phase AC operation, without phase difference. It also uses a silicon carbide (SIC) common drain connection, combining single-phase electronic switches into bidirectional electronic switches. A bidirectional buck-boost method is added to achieve vector boost and buck, while also being able to operate 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 circuits, which are then output through three sets of LC low-pass filters to form three-phase AC or DC power.

[0037] The three-phase L-shaped high-speed electronic current interrupter protector is designed to eliminate the catastrophic sparks that can occur when short circuits in three-phase, four-wire power supply loads are damaged or damaged during power consumption or transmission. This two-pole protector is designed to minimize sparks caused by short circuits in three-phase, four-wire power supply loads. Connected to a main circuit breaker or circuit breaker, it utilizes nine sets of bidirectional electronic switches for high-speed interruption and freewheeling current to minimize sparks. It employs nine sets of four-phase limited PWM modulation pulses to split the three-phase, four-wire power supply into three separate phases for independent modulation. This allows for independent regulation of the A / B / C phases. The vector voltage of each phase can be independently controlled, enabling the system to replace the previously required three transformers with only three sets of bidirectional electronic switches, significantly saving costs while improving efficiency and heat dissipation. When DC input is used, three bidirectional electronic switches are combined into a single electronic switch, independently bucking and stepping up the DC voltage. This design leverages the high voltage withstand properties of silicon carbide (SIC), enabling widespread application in DC high-voltage charging stations and industrial and commercial energy storage. Since DC has no zero crossing, custom air switches or circuit breakers for DC power supply require high cost. With the gradual establishment of 1500V high-voltage platforms, conventional circuit breakers in such high-voltage environments arc when disconnecting with load, and the arc length increases with increasing voltage. Therefore, adding a snubber circuit to the bidirectional electronic switch effectively suppresses this problem. At the moment of disconnection, the circuit opens a leakage path, trapping any remaining charge within the LC resonant cavity.

[0038] The three-phase L-shaped high-speed electronic current interrupter intelligent protector combines energy metering, information communication, arc fault detection, combustible gas and smoke collection, AC / DC step-up and step-down control, leakage and residual current collection, overload, overcurrent, overvoltage, and undervoltage control. It transforms the operating principle of traditional mechanical air switches or circuit breakers, transforming from a phase-mechanical structure to an electronic architecture. This reduces the response time from milliseconds to nanoseconds, fundamentally minimizing and suppressing the sparks caused by short circuits. Because the energy of a short-circuit spark is proportional to the current multiplied by time, a short circuit in the output line of a mechanical circuit breaker generates a large spark, which can easily ignite combustible materials and combustible gases. The faster the short-circuit operation, the less energy is generated.

[0039] The three-phase L-type high-speed electronic current interrupter intelligent protector adopts the advantages of high withstand voltage and high speed of silicon carbide MOS and uses the common drain method to realize AC and DC bidirectional 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 by load overload or circuit breaker. It uses three groups of LC low-pass filters to filter out high-frequency currents, and at the same time uses the principle that the current of the inductor cannot change suddenly to allow the three-phase L-type high-speed electronic current interruption smart protector to automatically distinguish between starting current and short-circuit current, and uses a comprehensive comparison method to separate the starting current and short-circuit current. The BUCK-BOOST-PWM modulation method is used to adjust the line voltage steplessly. The rail-to-rail leakage current following technology can dissipate the residual current in the line at an extremely fast speed when there is no leakage or leakage in the line. When a person accidentally touches a live object, the three-phase three-level bidirectional electronic switch discharges the current in the line at a speed of NS (nanoseconds). The electric shock feels like the voltage released by a lighter, which is extremely slight, so as to achieve the purpose of personal safety, thereby realizing the purpose of the three-phase L-type high-speed electronic current interruption smart protector to suppress sparks when short circuits or faults occur between live wires, live wires and neutral wires, and live wires and ground wires.

[0040] This is a new type of smart protector that iteratively updates the traditional MOS-type electronic circuit breaker and IGBT-type electronic circuit breaker I-type architecture smart protector. The traditional MOS-type and IGBT-type I-type electronic circuit breaker can only be used in a single-phase power environment and cannot realize three-phase functions. Because the phase angle of three-phase power differs by 120 degrees, it is impossible to vector-adjust the output voltage. At the same time, silicon MOS cannot achieve high voltage and IGBT cannot achieve high frequency. Therefore, these two devices can only realize the simple electronic switch function of single phase. In terms of circuit breaking and arc extinguishing, due to the lack of a freewheeling channel, the residual current in the line cannot be discharged, which will still cause large sparks in the event of a short circuit or load problem.

[0041] The three-phase L-shaped high-speed electronic current interrupter protector utilizes bidirectional, back-to-back silicon carbide MOS switches. Under normal operating conditions, the three freewheeling channels are closed. They only open under abnormal conditions, particularly when the load is a three-phase asynchronous motor, where inertia can cause the motor to act as a generator. This inertia can cause the motor to reversely flow through the circuit, resulting in very high voltages and currents. In this case, the freewheeling channel of the protector becomes a discharge channel similar to an inverter, dissipating excess energy within the resonant cavity.

[0042] The three-phase L-shaped high-speed electronic current interrupter protector replaces the original bidirectional electronic switch composed of silicon MOS. Silicon MOS bidirectional electronic switches cannot achieve high voltages, with a maximum voltage of only 800V, making them unable to meet the ultimate requirements of new energy and industrial energy storage. Instead, it replaces the original bidirectional electronic switch composed of IGBTs. Because each half cycle of an IGBT bidirectional electronic switch requires the flow of electrons through the internal diode of the other IGBT, due to the internal structure of the IGBT being a PN junction, electrons cannot flow in both directions, resulting in extremely high losses in the IGBT bidirectional electronic switch. Under high current conditions, the heat loss can reach hundreds of watts or even higher.

[0043] The three-phase L-type high-speed electronic current interrupter protector uses a bidirectional electronic switch composed of silicon carbide MOS and a buck-boost-PWM modulation method to achieve stepless vector regulation of the three-phase voltage, reduce the neutral point voltage offset, and reduce the neutral line load current. The high-speed switch and the freewheeling channel form the principle of electronic arc extinguishing. If any of the A / B / C / N lines is short-circuited, the short-circuit spark is suppressed, minimizing or even eliminating the short-circuit energy.

[0044] See also Figure 2 In the traditional method, the power passes through K1 / K2 / K3 and then enters the inductor L1 / L2 / L3. The bidirectional switches K4 / K5 / K6 serve as the freewheeling channel. Although this method can only achieve voltage reduction and short-circuit arc extinguishing, it cannot realize the boost function due to the only one-level architecture and can only be used as a buck function.

[0045] See also Figure 3 In another traditional approach, power flows through circuit breaker Q1 and into a bidirectional electronic switch, K1. When voltage regulation is not required, K1 / K2 operate, while K3 remains closed. Current flows through K1 / K2 and into the relay output channel. After filtering high-frequency noise with L2 and C1, it flows through the current acquisition channel and then through the arc fault detection channel for output. When buck-boost mode is required, K1 / K2 enter PWM modulation mode, with the two bidirectional switches providing complementary outputs with a duty cycle adjustable from 10% to 90%. L2 and C1 perform high-frequency filtering and then convert the source voltage back to the desired output voltage. This approach is only applicable to single-phase AC and DC power and cannot be applied to combined three-phase AC and DC power.

[0046] The three-phase L-shaped high-speed electronic current interrupter protector of the present invention is a new type of electronic circuit breaker intelligent protector derived from the single-phase L-shaped high-speed electronic current interrupter intelligent protector. The difference is that the single-phase L-shaped high-speed electronic current interrupter intelligent protector can only modulate a single phase, while the three-phase four-wire modulation requires three groups of phases staggered by 120 degrees, and synchronous modulation is required. This has greatly improved and upgraded the technology and application areas. Most electronic circuit breakers or intelligent protectors on the market are mainly I-type structures, with almost no L-type structures. Most are single-phase, and almost no three-phase ones are available. Therefore, the research and development of three-phase intelligent protectors is particularly important. As the precursor to a single-phase smart protector, it provides primary protection for three-phase, four-wire systems while also enabling voltage vector regulation. It also serves as a secondary protection level for single-phase smart protectors, providing secondary protection for lines or loads, achieving dual protection. It is suitable for any three-level protection environment. Connected to the output of a three-level switch, it is suitable for homes, shopping malls, office buildings, schools, hospitals, shops, banks, government agencies, organizations, scenic spots, and many other areas requiring protection. Hospitals are particularly vulnerable to electric shock hazards, especially in psychiatric hospitals, where patients lack basic cognitive skills and may accidentally touch sockets with metal objects. The device is particularly effective in protecting heavy loads such as three-phase motors, scenic water pumps, and industrial environments used in water conservancy, energy, and other sectors. It is also highly effective in environments exposed to dust, flammable gases, flammable liquids, and in mines, smelting, and production plants. These environments are extremely sensitive to sparks generated by electrical lines or equipment, and even the slightest spark can have catastrophic consequences.

[0047] The three-phase L-shaped high-speed electronic current interrupter protector can act as a contactless electronic switch in the renewable energy sector. In solar energy storage and charging, because DC power lacks a zero point, the energy storage battery may shut down while still outputting current, causing arcing. This arcing varies in intensity with voltage and current. Higher voltages and greater currents increase the arc length. Traditional DC circuit breakers and vacuum switches are bulky, expensive, and have a short lifespan. The three-phase L-shaped high-speed electronic current interrupter protector utilizes a 1600V silicon carbide MOS transistor. Its internal electric field channel, rather than mechanical contacts, allows it to operate in a 1600V voltage environment, achieving its protective function.

[0048] Specifically, see Figure 1A three-phase L-shaped intelligent protector comprises 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 three-phase input DC relay group serves as the initial access and isolation function in the power system. When the system is operating normally, the central processing module issues a control signal to close the three-phase input DC relay group, directing three-phase AC power to the subsequent circuits. In the event of a system fault or maintenance or overhaul, the central processing module quickly controls the three-phase input DC relay group to disconnect, isolating the input power from the subsequent circuits and preventing further fault expansion and the risk of electric shock. The three-phase three-channel electronic switch group achieves millisecond-level response to current flow, effectively suppressing sudden current fluctuations and surges, and protecting power equipment from current overloads and voltage fluctuations. Precise current control improves the efficiency and stability of the power system and reduces energy waste. Furthermore, its multi-channel design enables the protector to adapt to different load requirements, expanding its application range. The filter output control module filters and regulates the voltage of the current processed by the three-phase three-channel electronic switch group. It utilizes a filtering circuit composed of inductors, capacitors, and other components to remove high-frequency noise and interference signals from the current, ensuring a smoother and more stable output current. Furthermore, an internal voltage-stabilizing control circuit provides real-time adjustment of the output voltage to ensure its stability and accuracy. The filtered and regulated current is then fed to the three-phase multi-level detection module, providing a high-quality signal source for subsequent testing and analysis. The multi-level detection design of the three-phase multi-level detection module enhances detection sensitivity and reliability, enabling timely detection of potential faults and abnormalities. High-precision detection data provides a strong basis for decision-making by the central processing module, enabling the protector to respond quickly and accurately. The three-phase output DC relay group features rapid disconnection and reliable isolation. It responds to fault signals within milliseconds, disconnecting the output circuit and effectively protecting load equipment from faults such as short circuits, overloads, and leakage. Its reliable isolation prevents the spread of fault current, safeguarding other equipment and personnel. Furthermore, the on / off status of the relay group provides a visual indicator of system operation, facilitating troubleshooting and repair. 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 appropriate control decisions based on pre-set protection strategies and algorithms. The central processing module then 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, achieving intelligent control of the entire protector. It can also communicate with external devices, enabling remote monitoring, parameter setting, and fault alarms.

[0049] The input ends of the three-phase input DC relay group are respectively connected to the three-phase alternating current, the output ends of the three-phase input DC relay group are electrically connected to the three-phase three-channel electronic switch group, the output ends of the three-phase three-channel electronic switch group are electrically connected to the filter output control module, the output end of the filter output control module is electrically connected to the three-phase multi-level detection module, the input end of the three-phase output DC relay group is electrically connected to the three-phase multi-level detection module, the output end of the three-phase output DC relay group is used to output voltage, and the central processing module is respectively 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 connected across phase A and phase B and a relay KM2 connected across phase B and phase C. The relay KM1 is used to control the on and off between phase A and phase B, and the relay KM2 is used to control the on and off between phase B and phase C.

[0051] It's important to note that relays KM1 and KM2 don't operate in isolation within a three-phase DC input system; rather, they work together. From a control logic perspective, they're typically driven by the same control signal or interconnected control logic. For example, when the system needs to implement a specific three-phase power switching or control function, the control circuit sends control signals to the coils of KM1 and KM2 simultaneously or in a specific sequence, based on a pre-set program or external instructions.

[0052] When KM1's coil receives a valid control signal, its internal electromagnetic system begins to operate, generating a strong electromagnetic attraction that draws the armature to action, which in turn drives the contacts to close, establishing electrical continuity between phases A and B and allowing current to flow normally between them. Conversely, when the control signal disappears or changes, the electromagnetic attraction weakens, the armature returns to its original position under the action of the return spring, and the contacts open, severing the electrical connection between phases A and B.

[0053] Similarly, the working process of KM2 is similar to that of KM1. When the coil of KM2 receives the appropriate control signal, the contacts close, and the current path between phases B and C is connected. When the control signal is removed, the contacts open, and the current path between phases B and C is blocked.

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

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

[0056] The first dual SiC MOS transistor 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 turns on according to the control signal, allowing current to flow from the input terminal. At this point, current forms a path within K1 and flows in two directions simultaneously: some current flows directly to the input terminal of the second dual SiC MOS transistor group K2; the other part of the current enters the terminal connected to the inductor L.

[0057] The connecting 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 prevents sudden changes in the current. This characteristic allows the current to gradually accumulate energy in inductor L and flow smoothly to the input of the third dual-silicon carbide MOS transistor group K3. The presence of inductor L effectively smooths current fluctuations, reduces current spikes and ripple, and provides a more stable current for subsequent circuits.

[0058] The second dual-SiC MOS transistor 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 based on the control signal. When K2 is turned on, current can smoothly pass through K2 and enter the filter output control module, providing power to the load. When K2 is turned off, the current path is cut off, preventing current from flowing to the load.

[0059] One end of the third dual silicon carbide MOS transistor group, K3, is connected to inductor L, and the other end is grounded. K3's primary function is to coordinate with K1 and K2 to achieve bidirectional current control and energy feedback. Under specific control strategies, when energy regulation or feedback within the circuit is required, K3 can be activated based on a control signal, releasing the energy stored in inductor L to ground through K3, thereby achieving control over the circuit's energy balance.

[0060] The dual SiC MOS transistor design ensures that the dual SiC MOS transistors K1 / K2 / K3 feature low on-resistance, high switching speed, and excellent voltage resistance. The low on-resistance reduces energy loss as current passes through the dual SiC MOS transistors K1 / K2 / K3, improving circuit efficiency. The high switching speed enables rapid response to changes in control signals, enabling precise current control and reducing energy loss and electromagnetic interference during switching. The energy storage function of inductor L provides additional energy support during transient circuit changes or sudden load changes, ensuring stable circuit operation and mitigating damage to the load from voltage fluctuations and current surges.

[0061] For further information, see Figure 4 and Figure 5 Taking the first dual silicon carbide MOS transistor group K1 as an example, the first dual silicon carbide MOS transistor group K1 includes a silicon carbide MOS transistor Q11, a silicon carbide MOS transistor Q12, a jumper resistor KR1, and a jumper capacitor KC1. The input end of the silicon carbide MOS transistor Q11 is electrically connected to the input end of the AC power supply, the output end of the silicon carbide MOS transistor Q11 is electrically connected to the input end of the silicon carbide MOS transistor Q12, and the output end of the silicon carbide MOS transistor Q12 is respectively connected to the input end of the second dual silicon carbide MOS transistor group K2 and one end of the connection inductor L. The jumper resistor KR1 and the jumper capacitor KC1 are connected in series. The input end of the jumper resistor KR1 is also electrically connected to the input end of the silicon carbide MOS transistor Q11, and the output end of the jumper capacitor KC1 is also electrically connected to the output end of the silicon carbide MOS transistor 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 in detail here.

[0062] Silicon carbide MOS transistor Q11 serves as a key switching element on the input side, with its input directly connected to the AC power input. When the AC power supply provides power, Q11 turns on or off based on an external control signal, controlling whether current flows from the power supply to the entire MOS transistor 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] Silicon carbide MOS transistor Q12 is connected in series with Q11, receiving current from Q11. Q12 is also regulated by the control signal, determining whether to pass the current on to the subsequent circuit, namely, the input terminal of the second dual silicon carbide MOS transistor group K2 and the terminal connected to the inductor L. Through this series connection, Q11 and Q12 collaboratively control the on / off and flow direction of the current, forming the basic current control path of K1.

[0064] Jumper resistor KR1 and jumper capacitor KC1 are connected in series, spanning the input of Q11 and the output of Q12. This jumper connection allows KR1 and KC1 to participate in the dynamics of the entire circuit. When the switching states of Q11 and Q12 change, the voltage and current in the circuit experience transient changes. The series circuit formed by KR1 and KC1 responds to these transient changes. Capacitor KC1 has charge and discharge characteristics, absorbing and releasing charge when the voltage changes, while resistor KR1 limits the current and regulates the charge and discharge rate. These two components work together to influence the transient characteristics of the circuit. Jumper resistor KR1 effectively limits current spikes, reduces electromagnetic interference, and improves the circuit's electromagnetic compatibility. Furthermore, the presence of jumper resistor KR1 improves circuit stability, preventing instabilities such as oscillation during switching, ensuring stable operation under various operating conditions. Jumper capacitor KC1 effectively reduces voltage ripple and current harmonics in the circuit, minimizing interference and damage to the load. At the same time, KC1's energy buffering function can improve the circuit's dynamic response capability. When the load changes suddenly or the power supply fluctuates, it can quickly provide or absorb energy to ensure the stable operation of the circuit.

[0065] The high electron mobility of silicon carbide material gives Q11 an extremely low on-resistance, which means that when current passes through Q11, energy loss is very small, thereby improving the efficiency of the entire circuit. Furthermore, the high switching speed of the silicon carbide MOS transistor can quickly respond to changes in control signals, reducing delay time during the switching process and making current control more precise and timely. In addition, the high-temperature stability and radiation resistance of silicon carbide material enable Q11 to operate stably in harsh environments such as high temperature and high radiation, greatly improving the reliability and stability of the circuit and extending the service life of the device.

[0066] Compared to traditional MOS tube designs, K1, which uses a combination of silicon carbide MOS tubes and jumper resistors and capacitors, offers significant advantages. The high performance of silicon carbide MOS tubes enables higher efficiency, lower losses, and better thermal stability for the entire circuit, reducing heat dissipation requirements and system size. The addition of jumper 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 unit 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. Furthermore, the main current detection group, the leakage current detection group, the output voltage detection group, and the fault arc detection group are each 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, the output voltage detection group, and the fault arc detection group, providing these detection groups with basic current data for more in-depth analysis. Furthermore, the processed current data is directly transmitted to the central processing module. Based on the data provided by the main current detection group, the central processing module obtains real-time information about the load status of the power system and determines whether there are any abnormalities such as overload or underload. When the main current exceeds the set safety threshold, the central processing module prepares for action and, based on feedback from other detection groups, comprehensively determines whether protective measures are necessary, such as controlling the three-phase output DC relay group to disconnect the circuit. The leakage current detection group can promptly detect insulation faults in the circuit, even with low leakage currents, significantly improving power system safety. Promptly disconnecting 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. By promptly adjusting the voltage, power equipment is protected from voltage fluctuations, extending its service life and improving the reliability and stability of the power system. Accurate voltage detection also helps ensure the performance of power equipment and enhance power quality. The arc fault detection group is a key line of defense in preventing electrical fires. It detects and takes timely action at the early stages of arc faults, effectively preventing fires. By quickly disconnecting the circuit, the arc is prevented from continuing to burn, protecting personnel and property. The application of arc fault detection technology has greatly improved the safety of power systems, especially in places with high fire protection requirements, such as shopping malls, hospitals, schools, etc., and has important application value.

[0069] It should be noted that the central processing module includes a pre-stage detection channel, a post-stage detection channel, a wireless transmission and display channel, and a central processing unit. The central processing unit is electrically connected to the pre-stage detection channel, post-stage detection channel, and wireless transmission and display channel, respectively. The pre-stage 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, respectively. The post-stage detection channel is also electrically connected to the three-phase multi-level detection module and the three-phase output DC relay group, respectively. It is understood that the pre-stage 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. Based on the information provided by the pre-stage detection channel, the central processing unit monitors the front-end operation of the protector in real time. The post-stage detection channel is primarily responsible for collecting and processing information from the three-phase multi-level detection module and the three-phase output DC relay group. The three-phase multi-level detection module monitors various power system parameters in real time, such as main current, leakage current, output voltage, and arc faults. The post-detection channel integrates and analyzes this data, extracting key information and transmitting it to the central processing unit. Based on the data provided by the post-detection channel, the central processing unit determines whether the power system is operating normally and whether there are potential faults. If a fault is detected, the central processing unit sends a circuit-breaking command to the three-phase output DC relay group via the post-detection channel to protect the load equipment and the power system. Simultaneously, the post-detection channel provides feedback on the relay group's on / off status to the central processing unit, allowing it to monitor the execution of protection actions in real time. The wireless transmission and display channel transmits important information processed by the central processing unit, such as the power system's operating status, fault alarm information, and protection action records, to a remote monitoring terminal or mobile device via wireless communication technology. It also receives control commands and parameter settings from external devices and transmits them to the central processing unit. The central processing unit receives large amounts of real-time data from both the pre-detection and post-detection channels and performs in-depth analysis and processing on this data. It uses advanced algorithms and preset protection strategies to determine whether the operating status of the power system is normal and identify various fault types and abnormal conditions.

[0070] In this embodiment, the pre-stage 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 end of the PWM drive generator is electrically connected to the three-phase, three-channel electronic switch group, and the input end of the PWM drive generator is electrically connected to the central processing unit. The low-pass filter and temperature detection unit are electrically connected to the filter output control module, respectively. The control ends 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, capable of promptly detecting minor power fluctuations and potential faults. By monitoring the power supply status in real time, it provides accurate power supply information to the protector, enabling it to respond quickly to power supply anomalies, thereby avoiding device damage and data loss caused by power supply problems. The PWM drive generator generates precise pulse width modulation (PWM) signals based on control instructions sent by the central processing unit. These PWM signals have specific parameters such as frequency and duty cycle, and can accurately control 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 drive generator. The low-pass filter effectively removes high-frequency noise and clutter from the signal, improving signal quality and reliability. By purifying the output signal, it avoids malfunctions and measurement errors caused by noise interference, improving the performance and accuracy of the protector. The temperature detection unit accurately monitors the temperature of the filter output control module in real time, promptly detecting temperature anomalies. Prompt measures such as heat dissipation or power reduction can effectively prevent equipment damage due to overheating, extend its service life, and reduce maintenance costs.

[0071] Furthermore, the post-stage 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, respectively. It should be noted that the current detection processing unit has a high-precision current detection capability and can obtain information on the main current and leakage current in real time and accurately. Through real-time monitoring and analysis of the current, it can promptly detect current anomalies and provide a key basis for fault diagnosis and protection of the power system. The precise monitoring of the output voltage by the voltage and fault arc detection processing unit can ensure that the load equipment operates in a stable voltage environment and avoid 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 passes through circuit breaker Q1 and enters the DC power merging relay KM1 / relay KM2. When operating with AC power, relays KM1 and KM2 are disconnected. Only when operating with DC power do relays KM1 and KM2 close, turning the three sets of three-channel bidirectional electronic switches into a single electronic switch, operating in a combined manner. The high-frequency current then passes through an LC low-pass filter to remove the high-frequency signal before being output.

[0075] Relay KM3 / Relay KM4 / Relay KM5 are physical isolation channels, which physically isolate the power supply of the power supply back stage. The power supply obtains the current required for each phase after passing through the main current detection channel. The leakage current detection detects the residual current in the three-phase four-wire output line and sends it to the output voltage detector, which 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 controls relays KM1 and KM2 to open. When the input is DC, it controls relays KM1 and KM2 to close. The PWM signal generator analyzes the input voltage type. When the input is DC, it combines the three channels of electronic switches into a single channel. The PWM signal generator then generates synchronized, in-phase signals. When the input voltage is AC three-phase, the PWM signal generator staggers the phases by 120 degrees to create a three-phase pulse signal.

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

[0078] See also Figure 5 and Figure 6In combined mode, when A / B / C / N inputs are three-phase, four-wire AC, relays KM1 and KM2 are disconnected, and the three-phase AC is modulated by electronic switch group K1 / K2 / K3. In rising / falling 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 switches U2 / U5 / U8 operate in alternating mode. After filtering by low-pass filters LC1 / LC2 / LC3, the voltage waveform is output as an inverted image.

[0079] See also Figure 6 Phase A of the power supply is input to the merging relay through J4. Point 1 of the merging relay is connected to bridge 1 of the three-channel electronic switch for phase A. Phase B's power supply is directly connected to point 2 of the phase A relay and fed into bridge 4 of the three-channel electronic switch for phase B. Point B is also connected to point 1 of the phase C merging relay, and power supply C is fed into bridge 7 of the phase C merging relay. Thus, when three-phase power is input, each group of power supplies enters its corresponding three-channel bidirectional electronic switch. When the power supply is DC, the phase A and phase B relays close, merging the A / B / C channels into a single channel to increase output current.

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

[0081] See also Figure 10When DC voltage is input, relays KM1 and KM2 are fully absorbed, and the A / B / C three-channel bidirectional electronic switches of the power supply all work in parallel to increase the output current. The 1 / 4 / 7 bridge of the power supply and the 2 / 5 / 8 bridge PWM of the power supply work complementary, and the DC voltage is output inverted.

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

[0083] See also Figure 13 When the three-phase L-type high-speed electronic current interrupter intelligent protector is in waveform correction, 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] See also Figure 14 When the three-phase L-type high-speed electronic current interrupter intelligent protector is in short-circuit current and fault arc detection, it adopts the current follower comparison method and uses precision op amp rectification amplification to effectively avoid the distinction between starting current and short-circuit current. At the same time, it adopts LC resonance detection in 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 for comparison with the reference current. When the current at any point reaches the reference line, its output is turned off within 100NS (nanoseconds).

[0085] See also Figure 15 When the three-phase L-shaped high-speed electronic current interrupter intelligent protector enters the buck-boost mode, the driving waveforms of bridges 1 / 4 / 7 and 2 / 5 / 8 are shown. When the three-phase L-shaped high-speed electronic current interrupter intelligent protector is in buck mode, the duty cycle of bridges 1 / 4 / 7 is smaller than that of bridges 2 / 5 / 8. When in boost mode, the duty cycle of bridges 1 / 4 / 7 is larger than that of bridges 2 / 5 / 8. Bridges 3 / 6 / 9 remain in the on state.

[0086] See also Figure 16 When the three-phase L-type high-speed electronic current interrupter smart protector enters the arc state, the 1 / 4 / 7 bridges of the power supply are in the closed state, and the 2 / 5 / 8 / 3 / 6 / 9 bridges of the power supply are in the on state to discharge the residual current.

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

[0088] See also Figures 20 to 22 The secondary windings of transformers T4 to T7 generate 16 groups of isolated power transformers T1_1 to T1_16, which are rectified by bridge rectifier diodes to generate power supplies VCC1 to VCC8. The DC power supplies VCC11 to VCC88 supply power to the subsequent voltage regulator chip.

[0089] See also Figures 20 to 22 Power supplies VCC1-VCC8 and DC power supplies VCC11-VCC88 are fed into power bridge A, power bridge B, and power bridge C, respectively. This generates three +20V power supplies and three -5V power supplies (only two are shown because all three have the same function). DC power supplies VCC55-VCC88 are fed into voltage regulator chips U1, U5, U9, U13, and U17, respectively, to generate +12V, -12V, +5V, -5V, and +3.3V power supplies for the motherboard.

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

[0091] See also Figure 24The A / B / C three-phase current signals sent from the current transformer are increased by the amplifier U1A / amplifier U4A / amplifier U7A op amp 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 main current short-circuit analog value, the high-speed locking amplifier U3A / U3B, amplifier U6A / U6B, and amplifier U9A / U9B will be activated to shut down the output.

[0092] See also Figures 24 and 25 The MCU calculates the data collected by each part and sends the obtained data values and instructions to each unit. It also generates PWM on pins 81-88 and 7 of the DSP to control three groups of three-channel bidirectional electronic switches.

[0093] Since the leakage current acquisition, power supply voltage acquisition, current acquisition part and communication part are similar to the L-type high-speed electronic current interruption intelligent protector, they are not described in detail.

[0094] This invention utilizes a three-channel SiC bidirectional electronic switch for three-phase vector voltage regulation, eliminating the need for a power-frequency transformer for voltage regulation, saving costs, reducing size, and improving efficiency. It also employs a nine-channel bidirectional buck-boost mode for stepless vector voltage regulation of AC and DC voltages. The front-end utilizes a combined approach to accommodate input from different AC and DC power sources. Three independent channels of SiC bidirectional electronic switches enable independent arc extinguishing for the A / B / C voltage groups. This effectively mitigates the risk of electrical fires caused by load short circuits or faults in three-phase four-wire power systems.

[0095] The above-described embodiments merely represent several embodiments of the present invention. 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 a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A three-phase L-type intelligent protector, characterized in that: include: Three-phase input DC relay group, three-phase three-channel electronic switch group, filter output control module, three-phase multi-level detection module, three-phase output DC relay group and central processing module, The input ends of the three-phase input DC relay group are respectively connected to the three-phase alternating current, the output ends of the three-phase input DC relay group are electrically connected to the three-phase three-channel electronic switch group, the output ends of the three-phase three-channel electronic switch group are electrically connected to the filter output control module, the output end of the filter output control module is electrically connected to the three-phase multi-level detection module, the input end of the three-phase output DC relay group is electrically connected to the three-phase multi-level detection module, the output end of the three-phase output DC relay group is used to output voltage, and the central processing module is respectively 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.

2. The three-phase L-shaped intelligent protector according to claim 1, characterized in that: 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 unit and the three relay output units are electrically connected to the central processing module.

3. The three-phase L-shaped intelligent protector according to claim 1, characterized in that: 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, and the main current detection group, the leakage current detection group, the output voltage detection group and the fault arc detection group are respectively electrically connected to the central processing module.

4. The three-phase L-shaped intelligent protector according to claim 3, characterized in that: The central processing module includes 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 to the front-stage detection channel, the rear-stage detection channel and the wireless transmission display channel respectively. The front-stage 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 respectively. The rear-stage detection channel is also electrically connected to the three-phase multi-level detection module and the three-phase output DC relay group respectively.

5. The three-phase L-shaped intelligent protector according to claim 4, characterized in that: The front-stage detection channel includes 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 to the three-phase input DC relay group and the central processing unit respectively. The driving end of the PWM drive generator is electrically connected to the three-phase three-channel electronic switch group. The input end 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. The control ends of the low-pass filter and the temperature detection unit are electrically connected to the central processing unit.

6. The three-phase L-shaped intelligent protector according to claim 4, characterized in that: The post-stage 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 respectively.

7. The three-phase L-shaped intelligent protector according to claim 4, characterized in that: The wireless transmission display channel includes a display control unit and a wireless transmission unit. The display control unit is electrically connected to the wireless transmission unit and the central processing unit respectively.

8. The three-phase L-shaped intelligent protector according to claim 4, characterized in that: The central processing unit is an MCU processor or a DSP processor.

9. The three-phase L-shaped intelligent protector according to claim 7, characterized in that: The wireless transmission unit is a DTU communication unit.

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