Solid-state circuit breaker and self-checking method thereof

Abstract

According to the embodiment of the invention, a solid-state circuit breaker and a self-checking method thereof are provided. The solid-state circuit breaker comprises an input end and an output end, and the input end is suitable for being connected to the mechanical switch; a first switching device connected between the input terminal and the first node; a second switching device connected between the first node and the output terminal; a third switching device and a first resistive element connected in series between the input terminal and the output terminal; the auxiliary power supply branch is connected between the first node and the second node; the anti-reverse-connection circuit is connected between the second node and the input end and between the second node and the output end, and allows current to flow from the second node to the input end and the output end in a one-way mode; a first current sensor sensing a current flowing through the second switching device and generating a first current signal; a second current sensor sensing a current flowing through the auxiliary power supply branch and generating a second current signal; and the control unit determines the working states of the first switching device and the second switching device based on the first current signal and the second current signal.

Description

Technical Field

[0001] Example embodiments of the present disclosure generally relate to the technical field of electrical equipment, and more particularly to a solid-state circuit breaker and a self-test method thereof. Background Art

[0002] Solid-state circuit breakers are the future development trend of low-voltage terminal power distribution equipment. Considering the safety of the user side, and taking into account the semiconductor properties, temperature rise, overcurrent and other factors of the solid-state circuit breaker itself, regular self-inspection of the switch devices in the solid-state circuit breaker is an important measure to ensure the safety of terminal power distribution. At present, most of the solid-state circuit breakers in the industry do not consider regular self-inspection of solid-state switching devices, or can only achieve partial self-inspection of the circuit breaker shutdown function by briefly turning off the solid-state switching device during operation. Therefore, conventional solid-state circuit breakers lack a complete self-inspection function for solid-state switching devices, which poses a safety hazard, and self-inspection in the case of power failure will affect the operation of the subsequent circuit. Summary of the invention

[0003] Embodiments of the present disclosure provide a solid-state circuit breaker and a self-test method thereof to at least partially solve the above and other potential problems.

[0004] In a first aspect of the present disclosure, a solid-state circuit breaker is provided, comprising: an input terminal and an output terminal, wherein the input terminal is suitable for connecting to a mechanical switch; a first switching device connected between the input terminal and a first node; a second switching device connected between the first node and the output terminal; a third switching device and a first resistor element connected in series between the input terminal and the output terminal; an auxiliary power supply branch connected between the first node and the second node; an anti-reverse connection circuit connected between the second node and the input terminal and between the second node and the output terminal, and configured to allow current to flow unidirectionally from the second node to the input terminal and the output terminal; a first current sensor configured to sense a current flowing through the second switching device and generate a first current signal; a second current sensor configured to sense a current flowing through the auxiliary power supply branch and generate a second current signal; and a control unit configured to determine the working states of the first switching device and the second switching device based on the first current signal and the second current signal.

[0005] In a second aspect of the present disclosure, a method for performing self-test on a solid-state circuit breaker is provided. The solid-state circuit breaker includes an input terminal and an output terminal, the input terminal is suitable for connecting to a mechanical switch; a first switching device connected between the input terminal and a first node; a second switching device connected between the first node and the output terminal; a third switching device and a first resistor element connected in series between the input terminal and the output terminal; an auxiliary power branch connected between the first node and the second node; an anti-reverse connection circuit connected between the second node and the input terminal and between the second node and the output terminal, and configured to allow current to flow unidirectionally from the second node to the input terminal and the output terminal; a first current sensor configured to sense the current flowing through the second switching device and generate a first current signal; and a second current sensor configured to sense the current flowing through the auxiliary power branch and generate a second current signal. The method includes: receiving the first current signal from the first current sensor; receiving the second current signal from the second current sensor; and determining the working state of the first switching device and the second switching device based on the first current signal and the second current signal.

[0006] According to the embodiments of the present disclosure, a self-test solution is provided for a solid-state circuit breaker, which can provide a self-test function in two situations: before the solid-state circuit breaker is powered on and during operation. This self-test solution can ensure the safe and reliable operation of the solid-state circuit breaker, and can achieve accurate self-test without powering off the subsequent circuit.

[0007] It should be understood that the contents described in this content section are not intended to limit the key features or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein:

[0009] Figure 1 A circuit schematic diagram of a solid-state circuit breaker according to an embodiment of the present disclosure is shown;

[0010] Figures 2 to 7 The self-test process of the solid-state circuit breaker according to the embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0011] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0012] In the description of the embodiments of the present disclosure, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions may be included below. The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may be included below.

[0013] As mentioned above, most of the solid-state circuit breakers in the industry currently do not consider regular self-testing of solid-state switch devices, or can only realize partial self-testing of the circuit breaker shutdown function by briefly shutting down the solid-state switch devices during operation. Therefore, conventional solid-state circuit breakers lack a complete self-testing function for solid-state switch devices, which poses a safety hazard, and self-testing in the event of a power outage will affect the operation of the subsequent circuit. The embodiments of the present disclosure provide a solid-state circuit breaker self-testing solution that can provide a self-testing function in two situations: before the solid-state circuit breaker is powered on and during operation, to ensure that the solid-state circuit breaker is safe and reliable and will not affect the operation of the subsequent circuit. The following will be combined with Figures 1 to 7 To describe the embodiments of the present disclosure.

[0014] Figure 1 A circuit schematic diagram of a solid-state circuit breaker according to an embodiment of the present disclosure is shown. Figure 1 The solid-state circuit breaker is provided only in the single-phase circuit of the main circuit as an example to describe the principle of the present disclosure. It should be understood that in the embodiments of the present disclosure, a solid-state circuit breaker can be provided for each phase circuit, or a solid-state circuit breaker can be provided in a part of a multi-phase circuit, and these implementations all fall within the scope of the present disclosure.

[0015] Figure 1 An L-phase line and an N-phase line are shown, the L-phase line is connected to the positive pole of the power source PW, the N-phase line is connected to the negative pole of the power source PW and connected to the ground GND. A mechanical switch CB1 is provided in the L-phase line, and a mechanical switch CB1 is provided in the N-phase line. A solid-state circuit breaker 100 is provided in the L-phase circuit.

[0016] like Figure 1As shown, the solid-state circuit breaker 100 described herein comprises an input terminal IN and an output terminal OUT. The input terminal IN is connected to the mechanical switch CB1, and the output terminal OUT is used to provide an output voltage Vout to a subsequent circuit.

[0017] The solid-state circuit breaker 100 further includes a first switching device Q1 and a second switching device Q2 connected in series between the input terminal IN and the output terminal OUT. The first switching device Q1 is connected between the input terminal IN and the first node N1, and the second switching device Q2 is connected between the first node N1 and the output terminal OUT. The first switching device Q1 and the second switching device Q2 are respectively formed with a freewheeling diode. The anode of the freewheeling diode of the first switching device Q1 is connected to the first node N1, and the cathode of the freewheeling diode of the first switching device Q1 is connected to the input terminal IN. The anode of the freewheeling diode of the second switching device Q2 is connected to the first node N1, and the cathode of the freewheeling diode of the second switching device Q2 is connected to the output terminal OUT.

[0018] The solid-state circuit breaker 100 further includes a third switch device Q3 and a first resistor element R1. The third switch device Q3 and the first resistor element R1 are connected in series between the input terminal IN and the output terminal OUT and form a current limiting circuit 110. The third switch device Q3 and the first resistor element R1 can be used to realize the self-test of the first switch device Q1 and the second switch device Q2 on the one hand, and can perform short circuit protection on the solid-state circuit breaker 100 on the other hand, which will be described in conjunction with the following. Figures 2 to 7 Describe in detail.

[0019] The solid-state circuit breaker 100 further includes an auxiliary power branch 120, which is connected between the first node N1 and the second node N2. In one embodiment, the auxiliary power branch 120 includes an auxiliary power supply C1 and a second resistance element R2, which are connected in series between the first node N1 and the second node N2. The auxiliary power supply C1 can be powered from the power supply PW at a position before the switches CB1 and CB2, and is used to provide a driving voltage to the control terminals of the first switching device Q1, the second switching device Q2, and the third switching device Q3.

[0020] The solid-state circuit breaker 100 further includes an anti-reverse connection circuit 130, which is connected between the second node N2 and the input terminal IN and between the second node N2 and the output terminal OUT to allow current to flow from the second node N2 to the input terminal IN and the output terminal OUT in one direction, but not in the opposite direction. In one embodiment, the anti-reverse connection circuit 130 includes a first anti-reverse connection diode D1 and a second anti-reverse connection diode D2. The anode of the first anti-reverse connection diode D1 is connected to the second node N2, and the cathode is connected to the input terminal IN. The anode of the second anti-reverse connection diode D2 is connected to the second node N2, and the cathode is connected to the output terminal.

[0021] The solid-state circuit breaker 100 further includes a first current sensor S1 for sensing a current flowing through the second switching device Q2 and generating a first current signal I1. The first current signal I1 indicates the magnitude of the current flowing through the second switching device Q2.

[0022] The solid-state circuit breaker 100 further includes a second current sensor S2 for sensing the current flowing through the auxiliary power branch 120 and generating a second current signal I2. The second current signal I2 indicates the magnitude of the current flowing through the auxiliary power branch 120.

[0023] The solid-state circuit breaker 100 further includes a control unit 140, which can receive first and second current signals I1 and I2 from the first and second current sensors S1 and S2, and determine the operating states of the first and second switching devices Q1 and Q2 based on the first and second current signals I1 and I2.

[0024] In the embodiment of the present disclosure, the solid-state circuit breaker 100 can detect the working status of the first switching device Q1 and the second switching device Q2 by using a self-test solution specially designed for the first switching device Q1 and the second switching device Q2. Moreover, the solid-state circuit breaker 100 can provide a self-test function in two occasions: before the solid-state circuit breaker is powered on and during operation. Figures 1 to 7 This is described in detail.

[0025] like Figure 1 As shown, when the mechanical switches CB1 and CB2 are in the disconnected state, the first switch device Q1, the second switch device Q2 and the third switch device Q3 are initially in the off state, and no current flows through the solid-state circuit breaker 100. At this time, the first current signal I1 detected by the first current sensor S1 and the second current signal I2 detected by the second current sensor S2 are both zero.

[0026] Figure 2 FIG. 1 shows a process of checking the second switch device Q2 before the solid-state circuit breaker 100 is powered on. When the mechanical switch CB1 switches from an open state to a closed state, the control unit 140 can detect the switching action of the mechanical switch CB1. Figure 2 As shown, the control unit 140 sends a turn-on signal to the second switching device Q2 and the third switching device Q3, forming a Figure 2The loop indicated by the dotted line with an arrow shown in the figure. The current can flow from the auxiliary power supply C1 along the loop through the second resistor element R2, the first anti-reverse diode D1, the third switch device Q3, the first resistor element R1 and the second switch device Q2 in sequence, and return to the auxiliary power supply C1. The control unit 140 receives the first current signal I1 and the second current signal I2 from the first current sensor S1 and the second current sensor S2, and determines whether the first current signal I1 and the second current signal I2 meet the first predetermined condition. The first predetermined condition includes that the first current signal I1 and the second current signal I2 are equal and not zero. The first current signal I1 and the second current signal I2 can be a predetermined value or within a predetermined range. In response to the first current signal I1 and the second current signal I2 satisfying the first predetermined condition, the control unit 140 determines that the second switch device Q2 and the third switch device Q3 can be turned on normally. On the contrary, if the first current signal I1 and the second current signal I2 do not meet the first predetermined condition, it means that the second switch device Q2 or the third switch device Q3 cannot be turned on normally. Therefore, the control unit 140 generates an alarm signal for indicating that the solid-state circuit breaker 100 has failed.

[0027] In some embodiments, Figure 2 As shown, in response to the first current signal I1 and the second current signal I2 satisfying the first predetermined condition, the control unit 140 sends a shutdown signal to the second switching device Q2. Subsequently, the control unit 140 determines whether the first current signal I1 becomes zero to determine whether the second switching device Q2 can be normally turned off. In response to the first current signal I1 becoming zero, the control unit 140 determines that the second switching device Q2 can be normally turned off. In response to the first current signal I1 not becoming zero, the control unit 140 generates an alarm signal to indicate that the second switching device Q2 cannot be normally turned off.

[0028] In some embodiments, Figure 2 As shown, in response to the first current signal I1 and the second current signal I2 satisfying the first predetermined condition, the control unit 140 sends a shutdown signal to the third switching device Q3. Subsequently, the control unit 140 determines whether the first current signal I1 becomes zero to determine whether the third switching device Q3 can be normally turned off. In response to the first current signal I1 becoming zero, the control unit 140 determines that the third switching device Q3 can be normally turned off. On the contrary, in response to the first current signal I1 not becoming zero, the control unit 140 generates an alarm signal to indicate that the third switching device Q3 cannot be normally turned off.

[0029] Figure 3 FIG. 1 shows a process of checking the first switching device Q1 before the solid-state circuit breaker 100 is powered on. As described above, when the mechanical switch CB1 switches from the open state to the closed state, the control unit 140 can detect the switching action of the mechanical switch CB1. Figure 3 As shown, the control unit 140 sends a turn-on signal to the first switching device Q1 and the third switching device Q3, forming a Figure 3 The circuit indicated by the dotted line with an arrow shown in FIG. The current can flow from the auxiliary power supply C1 along the circuit through the second resistor element R2, the second anti-reverse diode D2, the first resistor element R1, the third switch device Q3 and the first switch device Q1 in sequence, and return to the auxiliary power supply C1. The control unit 140 receives the first current signal I1 and the second current signal I2 from the first current sensor S1 and the second current sensor S2, and determines whether the first current signal I1 and the second current signal I2 meet the second predetermined condition. The second predetermined condition includes that the first current signal I1 is zero and the second current signal I2 is not zero. The second current signal I2 can be a predetermined value or within a predetermined range. In response to the first current signal I1 and the second current signal I2 meeting the second predetermined condition, the control unit 140 determines that the first switch device Q1 and the third switch device Q3 can be turned on normally. On the contrary, if the first current signal I1 and the second current signal I2 do not meet the second predetermined condition, it means that the first switch device Q1 or the third switch device Q3 cannot be turned on normally. Therefore, the control unit 140 generates an alarm signal for indicating that the solid-state circuit breaker 100 has a fault.

[0030] In some embodiments, Figure 3 As shown, in response to the first current signal I1 and the second current signal I2 satisfying the second predetermined condition, the control unit 140 sends a shutdown signal to the first switching device Q1. Subsequently, the control unit 140 determines whether the second current signal I2 becomes zero to determine whether the first switching device Q1 can be normally turned off. In response to the second current signal I2 becoming zero, the control unit 140 determines that the first switching device Q1 can be normally turned off. In response to the second current signal I2 not becoming zero, the control unit 140 generates an alarm signal to indicate that the first switching device Q1 cannot be normally turned off.

[0031] In some embodiments, Figure 3 As shown, in response to the first current signal I1 and the second current signal I2 satisfying the second predetermined condition, the control unit 140 sends a shutdown signal to the third switching device Q3. Subsequently, the control unit 140 determines whether the second current signal I2 becomes zero to determine whether the third switching device Q3 can be normally turned off. In response to the second current signal I2 becoming zero, the control unit 140 determines that the third switching device Q3 can be normally turned off. On the contrary, in response to the second current signal I2 not becoming zero, the control unit 140 generates an alarm signal to indicate that the third switching device Q3 cannot be normally turned off.

[0032] By reference Figure 2 and Figure 3The exemplary process described can determine whether the first switching device Q1 and the second switching device Q2 can be normally turned on and off before the solid-state circuit breaker 100 is powered on, and can also determine the working state of the third switching device Q3. Figure 2 and Figure 3 The described processes may be performed in sequence or separately, and the embodiments of the present disclosure are not limited thereto. As an example, when the mechanical switch CB1 switches from an open state to a closed state, the control unit 140 may first control the second switch device Q2 and the third switch device Q3 to be turned on, forming a circuit as shown in FIG. Figure 2 The loop shown. If the detected first current signal I1 and the second current signal I2 are the same predetermined value of the loop current, it means that the second switch device Q2 and the third switch device Q3 can be turned on normally. Then, the second switch device Q2 is turned off. If the detected first current signal I1 and the second current signal I2 are zero, it means that the second switch device Q2 can be turned off normally, thereby completing the self-test of the second switch device Q2. Then, the control unit 140 can control the first switch device Q1 and the third switch device Q3 to be turned on, forming the following Figure 3 The loop shown. If the detected first current signal I1 is zero and the detected second current signal I2 is a loop current of a predetermined value, it means that the first switching device Q1 can be turned on normally. Subsequently, the first switching device Q1 is turned off. If the detected first current signal I1 and the second current signal I2 are zero, it means that the first switching device Q1 can be turned off normally, thereby completing the self-test of the first switching device Q1. Subsequently, the control unit 140 can control the first switching device Q1 to be turned on and control the third switching device Q3 to be turned off. If the detected second current signal I2 is zero, it means that the third switching device Q3 can be turned off normally, thereby completing the self-test of the third switching device Q3.

[0033] Next, we will refer to Figures 4 to 7 The following describes a process of checking the working states of the first switching device Q1 and the second switching device Q2 during operation after the solid-state circuit breaker 100 is powered on.

[0034] Figure 4 FIG. 2 shows the current path in the solid-state circuit breaker 100 when the first switching device Q1 and the second switching device Q2 are turned on. Figure 4 As shown, the mechanical switches CB1 and CB2 are in a closed state, and the first switch device Q1 and the second switch device Q2 are both turned on. In this case, the main circuit is turned on, and the main circuit current flows along Figure 4The current path shown by the dotted line with an arrow in the figure flows, so that the subsequent circuit (not shown) located downstream of the solid-state circuit breaker 100 can be powered on normally. When the main circuit is turned on, the working status of the first switching device Q1 and the second switching device Q2 can be periodically detected. For example, the switch working status can be detected every day, every week, every month or in other cycles.

[0035] Figure 5 FIG. 2 shows the inspection process of the first switching device Q1 when the main circuit is turned on. Figure 5 As shown, when the mechanical switch CB1 is in a closed state and the first switching device Q1 and the second switching device Q2 are turned on, the control unit 140 sends a turn-on signal to the third switching device Q3 and sends a turn-off signal to the first switching device Q1, thereby forming a circuit along Figure 5 The two loops indicated by the dotted lines with arrows shown. The current can flow from the mechanical switch CB1 to the subsequent circuit via the third switch device Q3 and the first resistor element R1 along one loop. The current can also flow from the auxiliary power supply C1 through the second resistor element R2, the first anti-reverse diode D1, the third switch device Q3, the first resistor element R1 and the second switch device Q2 in sequence along another loop, and return to the auxiliary power supply C1. The control unit 140 receives the first current signal I1 and the second current signal I2 from the first current sensor S1 and the second current sensor S2, and determines whether the first current signal I1 and the second current signal I2 meet the third predetermined condition. The third predetermined condition includes that the second current signal I2 rises from zero to a predetermined value and the first current signal I1 decreases from the main current to the same current as the second current signal I2. In response to the first current signal I1 and the second current signal I2 satisfying the third predetermined condition, the control unit 140 determines that the first switch device Q1 can be turned off normally. On the contrary, in response to the first current signal I1 and the second current signal I2 not satisfying the third predetermined condition, the control unit 140 generates an alarm signal for indicating that a fault occurs in the solid-state circuit breaker 100 .

[0036] In some embodiments, Figure 5 As shown, in response to the second current signal I2 rising from zero to a predetermined value and the first current signal I1 decreasing from the main current to the same current as the second current signal I2, the control unit 140 sends a turn-on signal to the first switching device Q1 and sends a turn-off signal to the third switching device Q3. Subsequently, the control unit 140 determines whether the first current signal I1 is restored to the main current. In response to the first current signal I1 being restored to the main current, the control unit 140 determines that the first switching device Q1 can be turned on normally. On the contrary, in response to the first current signal I1 not being restored to the main current, the control unit 140 generates an alarm signal.

[0037] Figure 6 and Figure 7The figure shows the inspection process of the second switching device Q2 when the main circuit is turned on.

[0038] like Figure 6 As shown, when the mechanical switch CB1 is in a closed state and the first switching device Q1 and the second switching device Q2 are turned on, a turn-on signal is sent to the third switching device Q3, thereby forming a circuit along the Figure 6 The three loops indicated by the dotted lines with arrows are shown. The current can flow from the mechanical switch CB1 to the subsequent circuit via the third switch device Q3 and the first resistor element R1 along the first loop. The current can also flow from the mechanical switch CB1 to the subsequent circuit via the first switch device Q1 and the second switch device Q2 along the second loop. The current can also flow from the auxiliary power supply C1 along the third loop through the second resistor element R2, the first anti-reverse diode D1, the third switch device Q3, the first resistor element R1 and the second switch device Q2 in sequence, and return to the auxiliary power supply C1. At this time, the impedance of the first loop is R1, and the impedance of the second loop is zero, so the current flowing through the mechanical switch CB1 basically flows from the second loop. The first current signal I1 is basically equal to the main loop current, and the second current signal I2 is a predetermined value that is not zero.

[0039] like Figure 7 As shown, the second switch device Q2 is turned off, so that the third loop is blocked. The current can flow from the mechanical switch CB1 to the subsequent circuit via the third switch device Q3 and the first resistor R1 along the first loop. The current can also flow from the mechanical switch CB1 to the subsequent circuit via the freewheeling diodes of the first switch device Q1 and the second switch device Q2 along the second loop. At this time, the second current signal I2 drops from the set value to zero. However, due to the existence of the freewheeling diode of the second switch device Q2, the first current signal I1 remains substantially unchanged.

[0040] In some embodiments, Figure 6 and Figure 7As shown, when the mechanical switch CB1 is in a closed state and the first switch device Q1 and the second switch device Q2 are turned on, the control unit 140 sends a turn-on signal to the third switch device Q3 and sends a turn-off signal to the second switch device Q2. The control unit 140 receives the first current signal I1 and the second current signal I2 from the first current sensor S1 and the second current sensor S2, and determines whether the first current signal I1 and the second current signal I2 meet a fourth predetermined condition. The fourth predetermined condition includes that the second current signal I2 decreases from a predetermined value to zero and the first current signal I1 is close to the main current. In response to the first current signal I1 and the second current signal I2 meeting the fourth predetermined condition, the control unit 140 determines that the second switch device Q2 can be turned off normally. On the contrary, if the first current signal I1 and the second current signal I2 do not meet the fourth predetermined condition, it means that the second switch device Q2 cannot be turned off normally. Therefore, the control unit 140 generates an alarm signal for indicating that the solid-state circuit breaker 100 has a fault.

[0041] In some embodiments, Figure 7 As shown, in response to the first current signal I1 and the second current signal I2 satisfying the fourth predetermined condition, the control unit 140 sends a turn-off signal to the third switching device Q3 and sends a turn-on signal to the second switching device Q2. Subsequently, the control unit 140 determines whether the first current signal I1 is restored to the main current. In response to the first current signal I1 being restored to the main current, the control unit 140 determines that the second switching device Q2 can be turned on normally. On the contrary, in response to the first current signal I1 not being restored to the main current, the control unit 140 generates an alarm signal.

[0042] By reference Figures 5 to 7 The exemplary process described above can determine whether the first switching device Q1 and the second switching device Q2 can be normally turned on and off during the operation of the solid-state circuit breaker 100. It should be understood that in combination with Figures 5 to 7 The described processes may be executed in sequence or individually, and the embodiments of the present disclosure are not limited in this regard.

[0043] In some cases, a short circuit may always occur in the subsequent circuit. At this time, the current flowing through the first switch device Q1 and the second switch device Q2 increases sharply. To this end, in some embodiments, when the mechanical switch CB1 is in a closed state and the first switch device Q1 and the second switch device Q2 are turned on, in response to the first current signal I1 being greater than the short-circuit current threshold, the control unit 140 sends a turn-off signal to the first switch device Q1 and the second switch device Q2 and sends a turn-on signal to the third switch device Q3. After a predetermined period of time, the control unit 140 sends a turn-off signal to the third switch device Q3. In this way, short-circuit protection can be achieved for the subsequent circuit.

[0044] According to the embodiments of the present disclosure, the working state of the solid-state switch device can be detected before the main circuit is powered on, and accurate self-test can be achieved without powering off the subsequent circuit. The circuit structure of this solution is simple and does not require an additional excitation power supply. In addition, automatic detection can be performed regularly according to the settings during the operation of the solid-state circuit breaker.

[0045] The embodiment of the present disclosure also provides a method for performing self-test on a solid-state circuit breaker 100. The solid-state circuit breaker 100 includes an input terminal IN and an output terminal OUT; a mechanical switch CB1 connected between the input terminal IN and the input terminal IN; a first switching device Q1 connected between the input terminal IN and a first node N1; a second switching device Q2 connected between the first node N1 and the output terminal OUT; a third switching device Q3 and a first resistor element R1 connected in series between the input terminal IN and the output terminal OUT; an auxiliary power branch 120 connected between the first node N1 and the second node N2; an anti-reverse connection circuit 130 connected between the second node N2 and the input terminal IN and between the second node N2 and the output terminal OUT, and configured to allow current to flow unidirectionally from the second node N2 to the input terminal IN and the output terminal OUT; a first current sensor S1 configured to sense a current flowing through the second switching device Q2 and generate a first current signal I1; and a second current sensor S2 configured to sense a current flowing through the auxiliary power branch 120 and generate a second current signal I2. The method: receives a first current signal I1 from a first current sensor S1; receives a second current signal I2 from a second current sensor S2; and determines the operating states of a first switching device Q1 and a second switching device Q2 based on the first current signal I1 and the second current signal I2.

[0046] In some embodiments, the working state of the first switching device Q1 and the second switching device Q2 is determined by: when the mechanical switch CB1 switches from an open state to a closed state, sending a turn-on signal to the second switching device Q2 and the third switching device Q3; determining whether the first current signal I1 and the second current signal I2 satisfy a first predetermined condition, the first predetermined condition including that the first current signal I1 and the second current signal I2 are equal and not zero; in response to the first current signal I1 and the second current signal I2 satisfying the first predetermined condition, determining that the second switching device Q2 and the third switching device Q3 can be turned on normally; and in response to the first current signal I1 and the second current signal I2 not satisfying the first predetermined condition, generating an alarm signal for indicating that a fault has occurred in the solid-state circuit breaker 100.

[0047] In some embodiments, the working status of the first switching device Q1 and the second switching device Q2 is determined by: in response to the first current signal I1 and the second current signal I2 satisfying a first predetermined condition, sending a shutdown signal to the second switching device Q2; determining whether the first current signal I1 becomes zero; in response to the first current signal I1 becoming zero, determining that the second switching device Q2 can be shut down normally; and in response to the first current signal I1 not becoming zero, generating an alarm signal.

[0048] In some embodiments, the working state of the first switching device Q1 and the second switching device Q2 is determined by: when the mechanical switch CB1 switches from an open state to a closed state, sending a turn-on signal to the first switching device Q1 and the third switching device Q3; determining whether the first current signal I1 and the second current signal I2 satisfy a second predetermined condition, the second predetermined condition including that the first current signal I1 is zero and the second current signal I2 is not zero; in response to the first current signal I1 and the second current signal I2 satisfying the second predetermined condition, determining that the first switching device Q1 and the third switching device Q3 can be turned on normally; and in response to the first current signal I1 and the second current signal I2 not satisfying the second predetermined condition, generating an alarm signal for indicating that a fault has occurred in the solid-state circuit breaker 100.

[0049] In some embodiments, the working status of the first switching device Q1 and the second switching device Q2 is determined by: in response to the first current signal I1 and the second current signal I2 satisfying a second predetermined condition, sending a shutdown signal to the first switching device Q1; determining whether the second current signal I2 becomes zero; in response to the second current signal I2 becoming zero, determining that the first switching device Q1 can be normally shut down; and in response to the second current signal I2 not becoming zero, generating an alarm signal for indicating that a fault has occurred in the solid-state circuit breaker 100.

[0050] In some embodiments, the working state of the first switching device Q1 and the second switching device Q2 is determined by: when the mechanical switch CB1 is in a closed state and the first switching device Q1 and the second switching device Q2 are turned on, sending a turn-off signal to the first switching device Q1 and sending a turn-on signal to the third switching device Q3; determining whether the first current signal I1 and the second current signal I2 meet a third predetermined condition, the third predetermined condition including the second current signal I2 rising from zero to a predetermined value and the first current signal I1 decreasing from a main current to a current that is the same as the second current signal I2; in response to the first current signal I1 and the second current signal I2 meeting the third predetermined condition, determining that the first switching device Q1 can be turned off normally; and in response to the first current signal I1 and the second current signal I2 not meeting the third predetermined condition, generating an alarm signal for indicating that a fault has occurred in the solid-state circuit breaker 100.

[0051] In some embodiments, the operating states of the first switching device Q1 and the second switching device Q2 are determined by: in response to the first current signal I1 and the second current signal I2 satisfying a third predetermined condition, sending a shutdown signal to the third switching device Q3 and sending a switch-on signal to the first switching device Q1; determining whether the first current signal I1 is restored to the main current; in response to the first current signal I1 being restored to the main current, determining that the first switching device Q1 can be turned on normally; and in response to the first current signal I1 not being restored to the main current, generating an alarm signal.

[0052] In some embodiments, the working state of the first switching device Q1 and the second switching device Q2 is determined by: when the mechanical switch CB1 is in a closed state and the first switching device Q1 and the second switching device Q2 are turned on, sending a turn-on signal to the third switching device Q3 and sending a turn-off signal to the second switching device Q2; determining whether the first current signal I1 and the second current signal I2 meet a fourth predetermined condition, the fourth predetermined condition including that the second current signal I2 decreases from a predetermined value to zero and the first current signal I1 is close to the main current; in response to the first current signal I1 and the second current signal I2 meeting the fourth predetermined condition, determining that the second switching device Q2 can be turned off normally; and in response to the first current signal I1 and the second current signal I2 not meeting the fourth predetermined condition, generating an alarm signal for indicating that a fault has occurred in the solid-state circuit breaker 100.

[0053] In some embodiments, the working status of the first switching device Q1 and the second switching device Q2 is determined by: in response to the first current signal I1 and the second current signal I2 satisfying a fourth predetermined condition, sending a shutdown signal to the third switching device Q3 and sending a switch-on signal to the second switching device Q2; determining whether the first current signal I1 is restored to the main current; in response to the first current signal I1 being restored to the main current, determining that the second switching device Q2 can be turned on normally; and in response to the first current signal I1 not being restored to the main current, generating an alarm signal.

[0054] In some embodiments, the method described herein also includes: when the mechanical switch CB1 is in a closed state and the first switching device Q1 and the second switching device Q2 are turned on, in response to the first current signal I1 being greater than the short-circuit current threshold, sending a turn-off signal to the first switching device Q1 and the second switching device Q2 and sending a turn-on signal to the third switching device Q3; after a predetermined time period, sending a turn-off signal to the third switch device Q3.

[0055] The above descriptions of various implementations of the present disclosure are exemplary, non-exhaustive, and not limited to the disclosed implementations. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described implementations. The selection of terms used herein is intended to best explain the principles of the implementations, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the various implementations disclosed herein.

Claims

1. A solid-state circuit breaker, comprising: an input and an output, the input being adapted to be connected to a mechanical switch; A first switch device connected between the input terminal and the first node; A second switch device connected between the first node and the output terminal; A third switch device and a first resistance element are connected in series between the input terminal and the output terminal; an auxiliary power branch, connected between the first node and the second node; an anti-reverse connection circuit connected between the second node and the input terminal and between the second node and the output terminal, and configured to allow current to flow unidirectionally from the second node to the input terminal and the output terminal; a first current sensor configured to sense a current flowing through the second switching device and generate a first current signal; a second current sensor configured to sense a current flowing through the auxiliary power branch and generate a second current signal; as well as A control unit is configured to determine the operating states of the first switching device and the second switching device based on the first current signal and the second current signal.

2. The solid-state circuit breaker according to claim 1, wherein the control unit is further configured to: When the mechanical switch switches from an open state to a closed state, sending a switch-on signal to the second switch device and the third switch device; determining whether the first current signal and the second current signal satisfy a first predetermined condition, wherein the first predetermined condition includes that the first current signal and the second current signal are equal and not zero; In response to the first current signal and the second current signal satisfying the first predetermined condition, determining that the second switching device and the third switching device can be normally turned on; as well as In response to the first current signal and the second current signal not satisfying the first predetermined condition, an alarm signal is generated to indicate that the solid-state circuit breaker is faulty.

3. The solid-state circuit breaker according to claim 2, wherein the control unit is further configured to: In response to the first current signal and the second current signal satisfying the first predetermined condition, sending a turn-off signal to the second switching device; determining whether the first current signal becomes zero; In response to the first current signal becoming zero, determining that the second switching device can be normally turned off; as well as In response to the first current signal not becoming zero, the alarm signal is generated.

4. The solid-state circuit breaker according to claim 2, wherein the control unit is further configured to: In response to the first current signal and the second current signal satisfying the first predetermined condition, sending a turn-off signal to the third switching device; determining whether the first current signal becomes zero; In response to the first current signal becoming zero, determining that the third switching device can be turned off normally; as well as In response to the first current signal not becoming zero, the alarm signal is generated.

5. The solid-state circuit breaker according to claim 1, wherein the control unit is further configured to: When the mechanical switch switches from an open state to a closed state, sending a switch-on signal to the first switching device and the third switching device; determining whether the first current signal and the second current signal satisfy a second predetermined condition, the second predetermined condition comprising that the first current signal is zero and the second current signal is not zero; In response to the first current signal and the second current signal satisfying the second predetermined condition, determining that the first switching device and the third switching device can be normally turned on; as well as In response to the first current signal and the second current signal not satisfying the second predetermined condition, an alarm signal is generated to indicate that the solid-state circuit breaker is faulty.

6. The solid-state circuit breaker according to claim 5, wherein the control unit is further configured to: In response to the first current signal and the second current signal satisfying the second predetermined condition, sending a turn-off signal to the first switching device; determining whether the second current signal becomes zero; In response to the second current signal becoming zero, determining that the first switching device can be turned off normally; as well as In response to the second current signal not becoming zero, the alarm signal is generated.

7. The solid-state circuit breaker according to claim 5, wherein the control unit is further configured to: In response to the first current signal and the second current signal satisfying the second predetermined condition, sending a turn-off signal to the third switching device; determining whether the second current signal becomes zero; In response to the second current signal becoming zero, determining that the third switching device can be turned off normally; as well as In response to the second current signal not becoming zero, the alarm signal is generated.

8. The solid-state circuit breaker according to claim 1, wherein the control unit is further configured to: When the mechanical switch is in a closed state and the first switching device and the second switching device are turned on, sending a turn-on signal to the third switching device and sending a turn-off signal to the first switching device; determining whether the first current signal and the second current signal satisfy a third predetermined condition, the third predetermined condition comprising the second current signal rising from zero to a predetermined value and the first current signal decreasing from a main current to the same current as the second current signal; In response to the first current signal and the second current signal satisfying the third predetermined condition, determining that the first switching device can be normally turned off; as well as In response to the first current signal and the second current signal not satisfying the third predetermined condition, an alarm signal is generated to indicate that a fault has occurred in the solid-state circuit breaker.

9. The solid-state circuit breaker according to claim 8, wherein the control unit is further configured to: In response to the first current signal and the second current signal satisfying the third predetermined condition, sending an on signal to the first switching device and sending an off signal to the third switching device; determining whether the first current signal is restored to the main current; In response to the first current signal returning to the main current, determining that the first switching device can be normally turned on; and In response to the first current signal not being restored to the main current, the alarm signal is generated.

10. The solid-state circuit breaker according to claim 1, wherein the control unit is further configured to: When the mechanical switch is in a closed state and the first switching device and the second switching device are turned on, sending a turn-on signal to the third switching device and sending a turn-off signal to the second switching device; determining whether the first current signal and the second current signal satisfy a fourth predetermined condition, the fourth predetermined condition comprising that the second current signal decreases from a predetermined value to zero and the first current signal approaches a main current; In response to the first current signal and the second current signal satisfying the fourth predetermined condition, determining that the second switching device can be normally turned off; as well as In response to the first current signal and the second current signal not satisfying the fourth predetermined condition, an alarm signal is generated to indicate that the solid-state circuit breaker is faulty.

11. The solid-state circuit breaker according to claim 10, wherein the control unit is further configured to: In response to the first current signal and the second current signal satisfying the fourth predetermined condition, sending an on signal to the second switching device and sending an off signal to the third switching device; determining whether the first current signal is restored to the main current; In response to the first current signal returning to the main current, determining that the second switching device can be normally turned on; and In response to the first current signal not being restored to the main current, the alarm signal is generated.

12. The solid-state circuit breaker according to claim 1, wherein the control unit is further configured to: When the mechanical switch is in a closed state and the first switching device and the second switching device are turned on, in response to the first current signal being greater than a short-circuit current threshold, sending a turn-off signal to the first switching device and the second switching device and sending a turn-on signal to the third switching device; and After a predetermined period of time has passed, a turn-off signal is sent to the third switching device.

13. A method for performing a self-test on a solid-state circuit breaker, the solid-state circuit breaker comprising an input and an output, the input being adapted to be connected to a mechanical switch; a first switching device connected between the input and a first node; A second switch device connected between the first node and the output terminal; A third switch device and a first resistance element are connected in series between the input terminal and the output terminal; an auxiliary power branch, connected between the first node and the second node; an anti-reverse connection circuit connected between the second node and the input terminal and between the second node and the output terminal, and configured to allow current to flow unidirectionally from the second node to the input terminal and the output terminal; a first current sensor configured to sense a current flowing through the second switching device and generate a first current signal; and a second current sensor configured to sense a current flowing through the auxiliary power branch and generate a second current signal; The method comprises: receiving the first current signal from the first current sensor; receiving the second current signal from the second current sensor; and An operating state of the first switching device and the second switching device is determined based on the first current signal and the second current signal.

14. The method according to claim 13, wherein the operating states of the first switching device and the second switching device are determined by: When the mechanical switch switches from an open state to a closed state, sending a switch-on signal to the second switch device and the third switch device; determining whether the first current signal and the second current signal satisfy a first predetermined condition, wherein the first predetermined condition includes that the first current signal and the second current signal are equal and not zero; In response to the first current signal and the second current signal satisfying the first predetermined condition, determining that the second switching device and the third switching device can be normally turned on; as well as In response to the first current signal and the second current signal not satisfying the first predetermined condition, an alarm signal is generated to indicate that the solid-state circuit breaker is faulty.

15. The method according to claim 14, wherein the operating states of the first switching device and the second switching device are determined by: In response to the first current signal and the second current signal satisfying the first predetermined condition, sending a turn-off signal to the second switching device; determining whether the first current signal becomes zero; In response to the first current signal becoming zero, determining that the second switching device can be normally turned off; as well as In response to the first current signal not becoming zero, the alarm signal is generated.

16. The method according to claim 13, wherein the operating states of the first switching device and the second switching device are determined by: When the mechanical switch switches from an open state to a closed state, sending a switch-on signal to the first switching device and the third switching device; determining whether the first current signal and the second current signal satisfy a second predetermined condition, the second predetermined condition comprising that the first current signal is zero and the second current signal is not zero; In response to the first current signal and the second current signal satisfying the second predetermined condition, determining that the first switching device and the third switching device can be normally turned on; as well as In response to the first current signal and the second current signal not satisfying the second predetermined condition, an alarm signal is generated to indicate that the solid-state circuit breaker is faulty.

17. The method according to claim 16, wherein the operating states of the first switching device and the second switching device are determined by: In response to the first current signal and the second current signal satisfying the second predetermined condition, sending a turn-off signal to the first switching device; determining whether the second current signal becomes zero; In response to the second current signal becoming zero, determining that the first switching device can be turned off normally; as well as In response to the second current signal not becoming zero, the alarm signal is generated.

18. The method according to claim 13, wherein the operating states of the first switching device and the second switching device are determined by: When the mechanical switch is in a closed state and the first switching device and the second switching device are turned on, sending a turn-on signal to the third switching device and sending a turn-off signal to the first switching device; determining whether the first current signal and the second current signal satisfy a third predetermined condition, the third predetermined condition comprising the second current signal rising from zero to a predetermined value and the first current signal decreasing from a main current to the same current as the second current signal; In response to the first current signal and the second current signal satisfying the third predetermined condition, determining that the first switching device can be normally turned off; as well as In response to the first current signal and the second current signal not satisfying the third predetermined condition, an alarm signal is generated to indicate that a fault has occurred in the solid-state circuit breaker.

19. The method according to claim 18, wherein the operating states of the first switching device and the second switching device are determined by: In response to the first current signal and the second current signal satisfying the third predetermined condition, sending an on signal to the first switching device and sending an off signal to the third switching device; determining whether the first current signal is restored to the main current; In response to the first current signal returning to the main current, determining that the first switching device can be normally turned on; and In response to the first current signal not being restored to the main current, the alarm signal is generated.

20. The method according to claim 13, wherein the operating states of the first switching device and the second switching device are determined by: When the mechanical switch is in a closed state and the first switching device and the second switching device are turned on, sending a turn-on signal to the third switching device and sending a turn-off signal to the second switching device; determining whether the first current signal and the second current signal satisfy a fourth predetermined condition, the fourth predetermined condition comprising that the second current signal decreases from a predetermined value to zero and the first current signal approaches a main current; In response to the first current signal and the second current signal satisfying the fourth predetermined condition, determining that the second switching device can be normally turned off; as well as In response to the first current signal and the second current signal not satisfying the fourth predetermined condition, an alarm signal is generated to indicate that the solid-state circuit breaker is faulty.

21. The method according to claim 20, wherein the operating states of the first switching device and the second switching device are determined by: In response to the first current signal and the second current signal satisfying the fourth predetermined condition, sending an on signal to the second switching device and sending an off signal to the third switching device; determining whether the first current signal is restored to the main current; In response to the first current signal returning to the main current, determining that the second switching device can be normally turned on; and In response to the first current signal not being restored to the main current, the alarm signal is generated.

22. The method of claim 13, further comprising: When the mechanical switch is in a closed state and the first switching device and the second switching device are turned on, in response to the first current signal being greater than a short-circuit current threshold, sending a turn-off signal to the first switching device and the second switching device and sending a turn-on signal to the third switching device; and After a predetermined period of time has passed, a turn-off signal is sent to the third switching device.

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