Solid state circuit breaker

Abstract

The embodiment of the utility model relates to a solid-state circuit breaker, which comprises an input end connected to a power supply; the power electronic switch is connected in series in the main loop, and the power electronic switch comprises a first switching device and a second switching device; the relay is connected to the output end of the solid-state circuit breaker, and the relay is used for adjusting the voltage of the output end of the solid-state circuit breaker; and the MCU is used for controlling the on and off of the electronic power switch and the relay.

Description

Technical Field

[0001] This disclosure relates to the field of electrical equipment, and more specifically, to a solid-state circuit breaker. Background Technology

[0002] With the continuous advancement and innovation of power electronics technology, solid-state circuit breakers are finding increasingly diverse and widespread applications in power systems. Compared to traditional DC circuit breakers, their operating modes and performance characteristics have undergone significant improvements and changes. Traditional DC circuit breakers, in their design and operation, often do not require specialized detection of the output voltage because their operating principle is relatively simple, primarily relying on mechanical contacts to achieve circuit switching. However, solid-state circuit breakers not only possess the function of mechanical isolation breaks but also introduce the concept of electronic breaks. This characteristic gives solid-state circuit breakers greater flexibility and precision in controlling the switching of circuits.

[0003] Therefore, in order to ensure that solid-state circuit breakers can operate safely and reliably and accurately reflect their working status, it is necessary to detect the output voltage of the solid-state circuit breaker while detecting the input voltage. This will allow users to determine the voltage level on the load side in a timely manner and make timely judgments. Utility Model Content

[0004] According to an embodiment of the present invention, a solid-state circuit breaker is provided, which includes an input terminal connected to a power supply; a power electronic switch connected in series in the main circuit, the power electronic switch including a first switching device and a second switching device; a relay connected to the output terminal of the solid-state circuit breaker, the relay being used to regulate the voltage at the output terminal of the solid-state circuit breaker; and a microcontroller unit (MCU) for controlling the closing and opening of the power electronic switch and the relay.

[0005] According to an embodiment of the present invention, the solid-state circuit breaker further includes a first disconnecting switch and a second disconnecting switch. The first disconnecting switch is connected between the positive terminal of the power supply and the power electronic switch, and the second disconnecting switch is connected between the negative terminal of the power supply and the relay.

[0006] According to an embodiment of the present invention, when the power electronic switch is in the open state and the first disconnecting switch and the second disconnecting switch are in the closed state, if the solid-state circuit breaker is not de-energized, the MCU is configured to control the relay to close.

[0007] According to an embodiment of the present invention, when the power electronic switch is in the open state and the first disconnecting switch and the second disconnecting switch are in the closed state, if the solid-state circuit breaker loses power and there is a load after the solid-state circuit breaker, the MCU is configured to: disable the reverse connection protection function of the solid-state circuit breaker, and control the relay to close after a predetermined time period.

[0008] According to an embodiment of this utility model, the load configured after the solid-state circuit breaker is either a resistor or an inductor.

[0009] According to an embodiment of the present invention, the MCU is also configured to control the relay to disconnect before the MCU controls the power electronic switch to perform the next closing operation.

[0010] According to an embodiment of the present invention, when the power electronic switch is in the open state and the first disconnecting switch and the second disconnecting switch are in the closed state, the MCU is further configured to detect the voltage at the input and output terminals of the solid-state circuit breaker and determine the on-resistance of the solid-state circuit breaker in order to determine the leakage current of the solid-state circuit breaker.

[0011] According to an embodiment of the present invention, the MCU is powered by an isolated power supply formed by a transformer based on the voltage of the power supply; wherein: the input terminal of the transformer is connected to the power supply; and the output terminal of the transformer is connected to the MCU.

[0012] According to embodiments of this invention, when the power electronic switch in the solid-state circuit breaker is in the open state and the disconnecting switch is in the closed state, the microcontroller unit (MCU) can respond differently based on whether the solid-state circuit breaker is powered down and the type of load configured in the downstream stage, thereby achieving accurate voltage detection and preventing erroneous tripping of the solid-state circuit breaker. Furthermore, the MCU can also be configured to determine the leakage current of the solid-state circuit breaker, thereby ensuring that the solid-state circuit breaker is in normal operating condition and ensuring safety. Attached Figure Description

[0013] The above and other aspects, features, and advantages of specific embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0014] Figure 1 A schematic block diagram of a solid-state circuit breaker according to an embodiment of the present invention is shown;

[0015] Figure 2 A schematic diagram of the circuit structure of a solid-state circuit breaker according to an embodiment of the present invention is shown; and

[0016] Figure 3 The diagram shows a circuit structure of voltage detection logic and leakage current diagnosis logic when the power electronic switch of the solid-state circuit breaker is in the open state and the isolating switch is in the closed state, according to an embodiment of the present invention. Detailed Implementation

[0017] The present invention will now be described in detail with reference to exemplary embodiments thereof. However, the present invention is not limited to the embodiments described herein, and may be embodied in many different forms. The described embodiments are only intended to make this disclosure thorough and complete, and to fully convey the concept of the present invention to those skilled in the art. Features of the various embodiments described may be combined with or substituted for each other, unless expressly excluded or should be excluded based on the context.

[0018] In embodiments of this novel invention, unless otherwise explicitly stated, "connection" or "connection" does not necessarily mean "direct connection" or "direct contact," but only requires electrical connection. Furthermore, the terms "first," "second," or similar expressions used herein are for descriptive and distinguishing purposes only and do not indicate any priority or order, nor should they be construed as indicating or implying the relative importance of the corresponding components, nor do they represent whether the described parameter values ​​are the same or different.

[0019] In solid-state circuit breakers, if only one isolated power supply is used to detect the output voltage on the output side, the output voltage will be incorrectly detected due to changes in the floating ground when the power electronic switch of the solid-state circuit breaker opens. This leads to inaccurate voltage detection at the output side, which may cause users to suspect safety issues. Therefore, it is necessary to provide isolated power supplies on both the input and output sides of the solid-state switch to detect the voltage. However, this requires excessive isolation devices and power supplies.

[0020] Furthermore, when the power electronic switch of the solid-state circuit breaker is in the open state and the isolating switch is in the closed state (hereinafter referred to as standby state), the voltage at the output terminal of the solid-state circuit breaker should be 0V; otherwise, users will consider it unsafe.

[0021] Figure 1 A schematic block diagram of a solid-state circuit breaker 10 according to the present invention is shown.

[0022] like Figure 1 As shown, the solid-state circuit breaker 10 includes: an input terminal connected to a power supply (not shown); a power electronic switch 11 connected in series in the main circuit, the power electronic switch 11 including a first switching device and a second switching device; a relay 12 connected to the output terminal of the solid-state circuit breaker 10, the relay 12 being used to regulate the voltage at the output terminal of the solid-state circuit breaker 10; and a microcontroller unit 13 for controlling the closing and opening of the power electronic switch 11 and the relay 12.

[0023] According to an embodiment of this utility model, when the solid-state circuit breaker 10 is in standby mode, if the solid-state circuit breaker 10 is not powered off, the MCU 13 can close the relay 12 to make the output voltage 0V, thereby accurately detecting the output voltage of the solid-state circuit breaker 10 and avoiding the user's perception of unsafety.

[0024] Additionally, if the solid-state circuit breaker suddenly loses power, a voltage close to the input voltage will still exist across the filter capacitor at the moment of power loss. This voltage will be further divided by the series voltage division of components in the circuit, resulting in a negative voltage at the output. Therefore, when configuring inductive or resistive loads, the reverse connection protection function of the solid-state circuit breaker should be disabled upon power loss; otherwise, the circuit breaker may trip incorrectly due to the negative voltage at the output. However, if the solid-state circuit breaker is connected to a capacitive load or a bidirectional charging pile load, since the output side is connected to a capacitor, no negative voltage will appear after the solid-state circuit breaker loses power, and therefore, disabling the reverse connection protection function is not necessary.

[0025] According to an embodiment of this utility model, if the solid-state circuit breaker 10 suddenly loses power and its downstream is configured with a resistor-type or inductive-type load, the reverse connection protection function can be turned off by the MCU 13 to prevent the solid-state circuit breaker 10 from tripping erroneously. After a predetermined time period, the relay 12 is closed by the MCU 13 so that the voltage at the output terminal is 0V, thereby accurately detecting the output voltage of the solid-state circuit breaker 10.

[0026] According to an embodiment of the present invention, before the MCU 13 controls the power electronic switch 11 to perform the next closing operation, the MCU 13 can also be configured to control the relay 12 to open, thereby ensuring that the load configured after the solid-state circuit breaker 10 is powered on for the second time can work normally.

[0027] According to an embodiment of the present invention, the MCU 13 can also be configured to determine the leakage current of the solid-state circuit breaker 10, thereby ensuring that the solid-state circuit breaker 10 is in normal working condition and ensuring safety.

[0028] In one embodiment, the first switching device and the second switching device may be MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of other types of first and second switching devices to achieve the above-described functions, such as insulated-gate bipolar transistors (IGBTs), and these implementations all fall within the scope of this disclosure.

[0029] Figure 2 A schematic diagram 20 of the circuit structure of a solid-state circuit breaker 10 according to an embodiment of the present invention is shown.

[0030] like Figure 2 As shown, the solid-state circuit breaker 10 includes a DC input power supply DC, a first disconnecting switch CB1, a second disconnecting switch CB2, a power electronic switch 11 including a first switching device Q6 and a second switching device Q3, a relay 12, an MCU 13, operational amplifiers 141-143, voltage divider resistors R3-R6, capacitors C1 and C2, and several other resistors. Vin+ and Vin- are the input terminals, representing the positive and negative terminals of the power supply, respectively, while Vout+ and Vout- are the output terminals, representing the positive and negative terminals, respectively. The output terminals Vout+ and Vout- can be connected to a load.

[0031] According to an embodiment of this utility model, the first disconnecting switch CB1 and the second disconnecting switch CB2 can be connected in series on the positive and negative lines, respectively, to ensure complete circuit disconnection. The first disconnecting switch CB1 can be connected between the positive terminal Vin+ of the power supply and the power electronic switch 11, and the second disconnecting switch can be connected between the negative terminal Vin- of the power supply and the relay 12. The first disconnecting switch CB1 and the second disconnecting switch CB2 can reliably turn the circuit off and on by manual or automatic opening and closing. In one embodiment, the first disconnecting switch CB2 and the second disconnecting switch CB2 can be intelligent mechanical switches. It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of other types of disconnecting switches to achieve the above functions, and these implementations all fall within the scope of this disclosure.

[0032] According to an embodiment of this utility model, the first switching device Q6 and the second switching device Q3 can be main power MOSFETs. They have low on-resistance, can withstand large current surges, and are responsible for controlling the conduction and closure of the main circuit. When Q6 and Q3 are closed, a large current from the main circuit flows into Q6 and Q3, ensuring the normal operation of the circuit. It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of using other numbers of switching devices to achieve the above functions, and all such implementations fall within the scope of this disclosure.

[0033] According to embodiments of this invention, R3, R4, R5, and R6 can be high-resistance voltage divider resistors, which are evenly distributed and used to divide the voltage in the circuit. The equal resistance values ​​of these resistors ensure uniform voltage distribution, thereby protecting subsequent circuits from excessive voltage surges. According to embodiments of this invention, the resistance values ​​of R3, R4, R5, and R6 should be greater than 2 megohms, for example, 3 megohms. It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of using other numbers and resistance values ​​of voltage divider resistors to achieve the above functions, and all such implementations fall within the scope of this disclosure.

[0034] According to an embodiment of this utility model, capacitors C1 and C2 can be connected in parallel with the first switching device Q6 and the second switching device Q3, respectively. In one embodiment, capacitors C1 and C2 can be filter capacitors, which can improve the stability and reliability of the circuit, improve high-frequency characteristics, and provide filtering, energy storage, and other functions. It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of using other numbers and types of capacitors to achieve the above functions, and all such implementations fall within the scope of this disclosure.

[0035] According to an embodiment of this utility model, relay 12 can be a normally closed contact relay with sufficient dielectric strength. It is in an open state when energized, and the sufficient dielectric strength ensures that the relay can operate safely and reliably in high-voltage environments without breakdown or other faults. According to an embodiment of this utility model, when the solid-state circuit breaker 10 is in standby mode, closing relay 12 can make the output voltage 0V, thereby accurately detecting the output voltage of the solid-state circuit breaker 10 and preventing erroneous tripping of the solid-state circuit breaker 10. Specific operation of relay 12 will be referred to below. Figure 3 Expand.

[0036] According to an embodiment of this utility model, the MCU 13 can be used to control the closing and opening of the power electronic switch 11 and the relay 12, and to control the reversing protection function of the solid-state circuit breaker 10. Furthermore, the MCU 13 can be configured to detect the voltage at the input and output terminals of the solid-state circuit breaker 10 and determine the on-resistance of the solid-state circuit breaker 10 to determine the leakage current of the solid-state circuit breaker 10. Specific operation of the MCU 13 will be described below. Figure 3 Expand.

[0037] According to an embodiment of this utility model, the output terminals of operational amplifiers 141-143 can be respectively connected to the input terminals of MCU 13. Operational amplifiers 141-143 can be used to convert the acquired voltage signals into voltage signals that can be processed by MCU 13. In one embodiment, operational amplifier 141 can be used to input the voltage signal acquired from the input terminal to MCU 13 after conversion, thereby realizing voltage detection at the input terminal. Similarly, operational amplifier 142 can be used to input the voltage signal acquired from the output terminal to MCU 13 after conversion, thereby realizing voltage detection at the output terminal.

[0038] According to embodiments of this invention, the MCU 13 and operational amplifiers 141-143, among other control devices, can be powered by an isolated power supply generated by the main circuit. The purpose of the isolated power supply is to electrically isolate these control devices from other parts of the main circuit, preventing mutual interference. This design ensures electrical isolation between the control devices and the main circuit, improving system stability and safety. Furthermore, due to the use of an isolated power supply, these control devices form a floating ground system. Floating ground means that their potential is not directly electrically connected to the ground potential and is in a relatively independent state.

[0039] According to an embodiment of this invention, a transformer can be used to convert the power supply voltage of the main circuit into a low-voltage power supply required by control devices such as MCU 13 and operational amplifiers 141-143, thereby achieving isolation. The input terminal of the transformer can be connected to a DC input power supply, and the output terminal can be connected to control devices such as MCU 13 and operational amplifiers 141-143. By adjusting the turns ratio of the transformer, the required output voltage can be obtained.

[0040] According to embodiments of the present invention, such as Figure 2 As shown, when the first isolating switch CB1, the second isolating switch CB2, and Q6 and Q3 in the main circuit are closed, the circuit enters the conducting state. Since MCU 13 and operational amplifiers 141-143 are all powered by isolated power supplies, their internal potentials are connected. From the perspective of circuit equivalence, the entire system can be equivalent to R3, R6, R4, and R5 respectively connected to the MCU ground ( Figure 2 (The inverted triangle shown in the image) is connected in parallel.

[0041] According to an embodiment of this utility model, assuming the system input voltage is 1000V, since the resistance values ​​of R3, R6, R4, and R5 are equal, based on the voltage characteristics of parallel circuits and the voltage divider principle, the voltage of the entire MCU's floating ground system relative to ground is half of the system input voltage, i.e., 500V. In this case, because the circuit is in a conducting state, the current can smoothly flow through the main circuit, and there is no additional voltage division or loss affecting the output voltage. Therefore, the measured value of the output voltage is equal to the input voltage, i.e., the output voltage is 1000V.

[0042] Figure 3 A schematic diagram of the circuit structure 30 of the voltage detection logic and leakage current diagnosis logic when the solid-state circuit breaker 10 is in standby state, according to an embodiment of the present invention, is shown.

[0043] Figure 3 The circuit shown contains electronic components and Figure 2 The same applies as shown, so I will not repeat it here. Figure 3The "X" indicates that Q6 and Q3 are disconnected at this time.

[0044] like Figure 3 As shown, when the first disconnecting switch CB1 and the second disconnecting switch CB2 of the solid-state circuit breaker 10 are closed and Q6 and Q3 are open, the solid-state circuit breaker 10 is in standby mode. At this time, the main circuit is open. Similarly, since the MCU13 and operational amplifiers 141-143 are powered by isolated power supplies, their internal potentials are connected. At this time, the equivalent circuit of the entire system is formed by R11, R12 in parallel with the equivalent internal resistances of Q6 and Q3, and the total equivalent resistance after parallel connection is then connected in series with R5 and R6.

[0045] According to an embodiment of this utility model, Q6 and Q3 are silicon carbide (SIC) devices. Since the equivalent resistance range of SIC devices is known, when the equivalent resistance of the SIC device approaches infinity, according to the voltage division principle of series circuits, the output voltage is approximately 500V after voltage division calculation.

[0046] The above analysis shows that when the solid-state circuit breaker 10 is in standby mode, its output terminal is essentially a voltage source with an internal resistance in the megaohm range. Although this voltage will not generate a destructive current due to its very high internal resistance, it can still be detected when using a multimeter to check the output terminal. This phenomenon may cause users to have unsafe associations.

[0047] Furthermore, when the solid-state circuit breaker 10 is in standby mode, if a sudden power outage occurs, the energy stored in the filter capacitors C1 or C2 in the circuit cannot be released in time. At the moment of power failure, a voltage close to the input voltage will still exist across the capacitor. Observing from the output terminal, since the capacitor voltage is divided by R3, R4, R5, R6, Q3, and R16 in series, a negative voltage will appear at the output terminal. Moreover, since the time constant of the circuit composed of these resistors and capacitors can be very large, this means that the capacitor discharges very slowly, resulting in a long time for the negative voltage to disappear. For the solid-state circuit breaker 10 with reverse wiring protection, this prolonged negative voltage can cause the solid-state circuit breaker 10 to trip erroneously, thus affecting the normal operation of the solid-state circuit breaker 10.

[0048] To solve the above problems, according to an embodiment of this utility model, a relay with a normally closed contact and sufficient dielectric strength can be connected in parallel at the output terminal, for example... Figure 3The relay 12 shown is used when the solid-state circuit breaker 10 is in standby mode. If the solid-state circuit breaker 10 is not powered down, the relay 12 can be closed by the MCU 13, thereby short-circuiting the output terminal and rapidly reducing its voltage to 0V. This allows for accurate detection of the output voltage of the solid-state circuit breaker 10, avoiding safety concerns for users due to detected output voltage.

[0049] According to an embodiment of this utility model, when the solid-state circuit breaker 10 is in standby mode, if the solid-state circuit breaker 10 suddenly loses power and its downstream load is of the resistive or inductive type, the MCU will immediately control the solid-state circuit breaker 10 to disable the reverse connection protection function after the power failure. Furthermore, the solid-state circuit breaker 10 has no other protection functions after the power failure. After a predetermined time, such as 10ms, the MCU 13 can control the relay 12 to close. At this time, due to the closing of the relay 12, the voltage at the output terminal will rapidly drop to 0V due to a direct short circuit, thereby accurately detecting the output voltage of the solid-state circuit breaker 10 and preventing the user from suspecting any safety issues.

[0050] However, according to embodiments of this invention, when the solid-state circuit breaker 10 is in standby mode, if the downstream load of the solid-state circuit breaker 10 is a capacitor-type load or a bidirectional charging pile-type load, since the output terminal is connected to a capacitor, this circuit structure will not produce a negative voltage during power failure, thus preventing the solid-state circuit breaker 10 from tripping erroneously. Therefore, it is not necessary to disable the reverse connection protection function in this situation.

[0051] According to an embodiment of this utility model, before the MCU 13 controls Q6 and Q3 to prepare for the next closing, it is necessary to first control the relay 12 to open. The purpose of this is to ensure that the output voltage of the solid-state circuit breaker 10 can be restored to a high voltage after the second power-on, thereby ensuring that the load configured downstream can work normally.

[0052] Furthermore, when the solid-state circuit breaker 10 is in standby mode, both IEC 60947-10 and UL 489I standards require a maximum leakage current value for solid-state circuit breakers. Therefore, it is necessary to ensure that the leakage current value of the solid-state circuit breaker 10 meets the standard to ensure product safety. According to an embodiment of this invention, the leakage current of the solid-state circuit breaker 10 can be determined by detecting the voltage at the output terminal of the solid-state circuit breaker 10 and determining its on-resistance.

[0053] According to an embodiment of this utility model, the on-resistance of Q6 and Q3 can be set as follows: ,like Figure 3R18 is the sensing resistor, and R15 is the equivalent impedance of operational amplifier 142. Therefore, based on the equivalent circuit of the solid-state circuit breaker 10 in standby mode as analyzed above, equation 1 can be derived:

[0054] (Equation 1)

[0055] Since the resistance values ​​of R11, R12, R18, R5, R6, and R15 are all known, the on-resistance of Q6 and Q3 can be calculated from the Vout and Vin voltages detected by MCU 13, as shown in Equation 2:

[0056] (Equation 2)

[0057] According to an embodiment of this utility model, the on-resistances of Q6 and Q3 are obtained through Equation 2. By calculating the voltage drops across Q6 and Q3 based on the Vout and Vin voltages, the leakage current of the solid-state circuit breaker 10 can be determined, ensuring that the leakage current of the solid-state circuit breaker 10 meets the standard and guarantees product safety. In one embodiment, the calculations of Equations 1 and 2 above are both performed in the MCU 13.

[0058] It should be noted that, for clarity and simplicity, only the parts related to the embodiments of the present invention are shown in the accompanying drawings. However, those skilled in the art should understand that the devices or apparatus shown in the drawings may include other necessary elements.

[0059] The block diagrams of circuits, devices, apparatuses, equipment, and systems involved in this utility model are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these circuits, devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner that achieves the desired purpose. The quantities involved in this utility model are merely illustrative.

[0060] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0061] Those skilled in the art should understand that the specific embodiments described above are merely examples and not limitations. Various modifications, combinations, partial combinations, and substitutions can be made to the embodiments of this disclosure according to design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents, and thus fall within the scope of the rights to be protected by this disclosure.

Claims

1. A solid-state circuit breaker, characterized in that, include: The input terminal is connected to the power supply. A power electronic switch is connected in series in the main circuit, and the power electronic switch includes a first switching device and a second switching device; A relay, connected to the output terminal of the solid-state circuit breaker, is used to regulate the voltage at the output terminal of the solid-state circuit breaker; and The microcontroller unit (MCU) is used to control the closing and opening of the power electronic switch and the relay.

2. The solid-state circuit breaker according to claim 1, characterized in that: The solid-state circuit breaker further includes a first disconnecting switch and a second disconnecting switch, wherein the first disconnecting switch is connected between the positive terminal of the power supply and the power electronic switch, and the second disconnecting switch is connected between the negative terminal of the power supply and the relay.

3. The solid-state circuit breaker according to claim 2, characterized in that: When the power electronic switch is in the open state and the first disconnecting switch and the second disconnecting switch are in the closed state, if the solid-state circuit breaker is not de-energized, the MCU is configured to control the relay to close.

4. The solid-state circuit breaker according to claim 2, characterized in that: When the power electronic switch is in the open state and the first disconnecting switch and the second disconnecting switch are in the closed state, if the solid-state circuit breaker loses power and a load is configured downstream of the solid-state circuit breaker, the MCU is configured as follows: Turn off the reverse connection protection function of the solid-state circuit breaker, and After a predetermined time period, the relay is controlled to close.

5. The solid-state circuit breaker according to claim 4, characterized in that: The load type configured after the solid-state circuit breaker is either resistor type or inductor type.

6. The solid-state circuit breaker according to claim 3 or 5, characterized in that: Before the MCU controls the power electronic switch to perform the next closing operation, the MCU is also configured to control the relay to open.

7. The solid-state circuit breaker according to claim 2, characterized in that: When the power electronic switch is in the open state and the first disconnecting switch and the second disconnecting switch are in the closed state, the MCU is also configured to detect the voltage at the input and output terminals of the solid-state circuit breaker and determine the on-resistance of the solid-state circuit breaker in order to determine the leakage current of the solid-state circuit breaker.

8. The solid-state circuit breaker according to claim 7, characterized in that: The MCU is powered by an isolated power supply formed by a transformer based on the voltage of the power supply; in: The input terminal of the transformer is connected to the power supply; and The output terminal of the transformer is connected to the MCU.

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