Self-charging current-limiting alternating-current solid-state circuit breaker

Abstract

The invention relates to a self-charging current-limiting type alternating current solid-state circuit breaker, which belongs to the technical field of circuit breakers and comprises a forced commutation branch, a current limiting branch, a current limiting branch, a current limiting branch, a current limiting branch and a current limiting branch, and is characterized in that the forced commutation branch is used for injecting reverse current into the current through branch or the current limiting branch when a short-circuit fault occurs; the energy consumption branch circuit is used for consuming the current when the current of the through-current branch circuit or the current limiting branch circuit is reduced to a safe turn-off range; and the self-charging branch is used for charging the capacitor in the forced commutation branch. According to the self-charging current-limiting type AC solid-state circuit breaker provided by the invention, when a short-circuit fault occurs, the forced commutation branch can inject a reverse current into the through-current branch or the current-limiting branch, and when the current of the through-current branch or the current-limiting branch is reduced to a safe turn-off range, the current of the energy-consuming branch is consumed, so that the cut-off process of the short-circuit fault is completed; the short-circuit turn-off capability of the solid-state switch can be improved, the number of semiconductor devices connected in parallel is reduced, and the cost of the solid-state circuit breaker is reduced while the turn-off capacity is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit breakers, and in particular to a self-charging current-limiting AC solid-state circuit breaker. Background Art

[0002] Traditional circuit breakers are usually mechanical, consisting of moving contacts, static contacts and an actuating mechanism. The circuit is broken by separating the moving and static contacts to form a gap. However, circuit breakers with this structure usually have a long actuation time (ms level), and the breaking process is accompanied by the generation of arcs, causing problems such as contact wear, accelerating equipment aging, and reducing mechanical life.

[0003] In recent years, the widespread use of power electronic devices has promoted the development of solid-state circuit breakers. Compared with traditional mechanical circuit breakers, solid-state circuit breakers are small in size, fast in breaking speed, and arc-free, which have great advantages in the medium and low voltage fields. However, due to the limited capacity of fully controlled devices such as insulated-gate bipolar transistors (IGBT) and metal-oxide-semiconductor field-effect transistors (MOSFET), there are great limitations on the improvement of the shutdown capability of solid-state circuit breakers. When multiple devices are connected in parallel to improve the shutdown capability of solid-state circuit breakers, parallel devices will produce problems such as dynamic uneven current and gate oscillation, which also limits the shutdown capability of the device when applied to solid-state switches. Summary of the invention

[0004] In view of this, it is necessary to provide a self-charging current-limiting AC solid-state circuit breaker to solve the problem of insufficient shutoff capability of existing solid-state switches.

[0005] In order to solve the above problems, the present invention provides a self-charging current-limiting AC solid-state circuit breaker, comprising: Current-passing branch, forced commutation branch, self-charging branch, current-limiting branch and energy-consuming branch; The forced commutation branch is used to inject a reverse current into the current-passing branch or the current-limiting branch when a short-circuit fault occurs; The energy consumption branch is used to consume the current when the current of the current-passing branch or the current-limiting branch drops to a safe shutdown range; The self-charging branch is used to charge the capacitor in the forced commutation branch.

[0006] In a possible implementation, the flow branch includes: a first diode, a second diode, a third diode, a fourth diode and a first semiconductor switch; The first diode is connected to the fourth diode via the first semiconductor switch; The second diode is connected to the third diode via the first semiconductor switch; The forced commutation branch, the self-charging branch, the current limiting branch, and the energy consumption branch are respectively connected in parallel with the first semiconductor switch.

[0007] In a possible implementation, the forced commutation branch includes: The capacitor and the second semiconductor switch are connected in sequence.

[0008] In a possible implementation, the current limiting branch includes: A first inductor and a third semiconductor switch are connected in sequence.

[0009] In a possible implementation, the self-charging branch includes: The current limiting branch, the second inductor and the fifth diode; The second inductor is connected to the fifth diode.

[0010] In a possible implementation, the energy consumption branch includes: A metal oxide arrester, the first inductor, the second inductor, a resistor and a fourth semiconductor switch; The resistor is connected to the fourth semiconductor switch.

[0011] In a possible implementation manner, the first semiconductor switch, the second semiconductor switch, the third semiconductor switch, and the fourth semiconductor switch are all fully-controlled semiconductor switches with low conduction losses.

[0012] In a possible implementation manner, the first inductor and the second inductor are mutually coupled inductors.

[0013] In a possible implementation, when a short circuit fault occurs, the second semiconductor switch is turned on, and the forced commutation branch injects a reverse current into the pass branch; When the current in the conduction branch drops to a safe shutdown range, the first semiconductor switch is turned off to dissipate the current in the energy consumption circuit.

[0014] In a possible implementation, when a short circuit fault occurs, the first semiconductor switch is turned off, the second semiconductor switch is turned on, the third semiconductor switch is turned on, and the forced commutation branch injects a reverse current into the current limiting branch; When the current of the current limiting branch drops to a safe shutdown range, the third semiconductor switch is turned off to allow the current to be dissipated in the energy consumption circuit.

[0015] The beneficial effects of the present invention are as follows: the self-charging current-limiting AC solid-state circuit breaker provided by the present invention comprises a flow branch, a forced commutation branch, a self-charging branch, a current limiting branch and an energy consumption branch. When a short circuit fault occurs, the forced commutation branch can inject a reverse current into the flow branch or the current limiting branch, and when the current in the flow branch or the current limiting branch drops to a safe shutoff range, the current of the flow branch or the current limiting branch is consumed by the energy consumption branch. As the energy stored in the system is continuously dissipated, the current gradually drops to zero, completing the short circuit fault breaking process, and charging the capacitor in the forced commutation branch through the self-charging branch. The capacitor does not need an external circuit to charge it. The capacitor is used to inject a reverse current to reduce the size of the current turned off by the semiconductor switch, thereby improving the short circuit breaking capability of the solid-state switch, reducing the number of semiconductor devices connected in parallel, and reducing the cost of the solid-state circuit breaker while improving the breaking capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A structural schematic diagram of an embodiment of a self-charging current-limiting AC solid-state circuit breaker provided by the present invention; Figure 2 One of the schematic diagrams of the breaking process of the circuit breaker provided by the present invention when it is generally shut down; Figure 3 The second schematic diagram of the breaking process of the circuit breaker provided by the present invention when it is generally shut down; Figure 4 The third schematic diagram of the breaking process of the circuit breaker provided by the present invention when it is generally shut down; Figure 5 One of the schematic diagrams of the breaking process of the circuit breaker provided by the present invention when the circuit breaker is closed with current limiting; Figure 6 The second schematic diagram of the breaking process of the circuit breaker provided by the present invention during current limiting shutdown; Figure 7 The third schematic diagram of the breaking process of the circuit breaker provided by the present invention during current limiting shutdown; Figure 8 This is one of the schematic diagrams of the circuit breaker capacitor self-charging process provided by the present invention; Fig. 9 The second schematic diagram of the circuit breaker capacitor self-charging process provided by the present invention. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0019] In the description of the embodiments of the present invention, unless otherwise specified, "multiple" means two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may mean: A exists alone, A and B exist at the same time, and B exists alone.

[0020] The descriptions of "first", "second", etc. involved in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the technical features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0021] Figure 1 A structural schematic diagram of an embodiment of a self-charging current-limiting AC solid-state circuit breaker provided by the present invention is shown in FIG. Figure 1 As shown, the self-charging current limiting AC solid-state circuit breaker includes: Current-passing branch, forced commutation branch, self-charging branch, current-limiting branch and energy-consuming branch; The forced commutation branch is used to inject a reverse current into the current-passing branch or the current-limiting branch when a short-circuit fault occurs; The energy consumption branch is used to consume the current when the current of the current-passing branch or the current-limiting branch drops to a safe shutdown range; The self-charging branch is used to charge the capacitor in the forced commutation branch.

[0022] Compared with the prior art, the self-charging current-limiting AC solid-state circuit breaker provided in the embodiment of the present invention includes a flow branch, a forced commutation branch, a self-charging branch, a current limiting branch and an energy consumption branch. When a short circuit fault occurs, the forced commutation branch can inject a reverse current into the flow branch or the current limiting branch, and when the current in the flow branch or the current limiting branch drops to a safe shutdown range, the current of the flow branch or the current limiting branch is consumed by the energy consumption branch. As the energy stored in the system is continuously dissipated, the current gradually drops to zero, completing the short circuit fault breaking process, and charging the capacitor in the forced commutation branch through the self-charging branch. The capacitor does not need an external circuit to charge it. The capacitor is used to inject a reverse current to reduce the size of the current turned off by the semiconductor switch, so as to improve the short circuit breaking capability of the solid-state switch, reduce the number of semiconductor devices in parallel, and reduce the cost of the solid-state circuit breaker while improving the breaking capacity.

[0023] In some embodiments of the present invention, the flow branch comprises: a first diode, a second diode, a third diode, a fourth diode and a first semiconductor switch; The first diode is connected to the fourth diode via the first semiconductor switch; The second diode is connected to the third diode via the first semiconductor switch; The forced commutation branch, the self-charging branch, the current limiting branch, and the energy consumption branch are respectively connected in parallel with the first semiconductor switch.

[0024] like Figure 1 As shown, the current branch includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4 and a first semiconductor switch S main .

[0025] The first diode D1 is connected to the first semiconductor switch S main The second diode D2 is connected to the fourth diode D4 through the first semiconductor switch S main Connected to the third diode D3.

[0026] When the system is normally flowing, the first semiconductor switch S main Keep the trigger state, the positive half-cycle current of the AC power source flows through the first diode D1 and the first semiconductor switch S main and the fourth diode D4, the negative half cycle current flows through the second diode D2, the first semiconductor switch S main and a third diode D3.

[0027] D1, D4 and D2, D3 are turned on alternately to maintain normal working current. At this time, no current flows through other branches.

[0028] In some embodiments of the present invention, the forced commutation branch comprises: The capacitor and the second semiconductor switch are connected in sequence.

[0029] like Figure 1 As shown, the forced commutation branch includes a capacitor C and a second semiconductor switch S commutation The forced commutation branch can use the commutation capacitor C to inject reverse current into the current-passing branch and the current-limiting branch.

[0030] The self-charging current-limiting AC solid-state circuit breaker provided in the embodiment of the present invention can inject reverse current into the semiconductor switch by utilizing the commutation capacitor to reduce the size of the current turned off by the semiconductor switch, thereby improving the short-circuit turning-off capability of the solid-state switch, reducing the number of semiconductor devices connected in parallel, and reducing the cost of the solid-state circuit breaker while improving the breaking capacity.

[0031] In some embodiments of the present invention, the current limiting branch includes: A first inductor and a third semiconductor switch are connected in sequence.

[0032] like Figure 1 As shown, the current limiting branch includes a first inductor N1 and a third semiconductor switch S charge The first inductor N1 can limit the rising rate of the short-circuit fault current.

[0033] The self-charging current-limiting AC solid-state circuit breaker provided in the embodiment of the present invention can interrupt the rated current, and at the same time can use the first inductor N1 to limit the fault current rise rate, and use the forced commutation branch to improve the breaking capacity of the semiconductor switch device to interrupt the short-circuit fault.

[0034] In some embodiments of the present invention, the self-charging branch includes: The current limiting branch, the second inductor and the fifth diode; The second inductor is connected to the fifth diode.

[0035] In some embodiments of the present invention, the first inductor and the second inductor are mutually coupled inductors.

[0036] like Figure 1 As shown, the self-charging branch includes a current limiting branch (a first inductor N1 and a third semiconductor switch S charge ), the second inductor N2 and the fifth diode D5.

[0037] The first inductor N1 and the second inductor N2 are mutually coupled inductors. The first inductor N1 induces a current in the second inductor N2 to charge the capacitor C. The fifth diode D5 can prevent the capacitor C from injecting a reverse current into the second inductor N2.

[0038] When the capacitor C needs to be charged, the first semiconductor switch S is controlled at the same time. main Turn off, the third semiconductor switch S charge After a certain period of time, the first semiconductor switch S is controlled at the same time. main Open, the third semiconductor switch S charge If the first inductor N1 is turned off, a current can be induced in the second inductor N2 to charge the commutation capacitor C.

[0039] In the self-charging current-limiting AC solid-state circuit breaker provided in the embodiment of the present invention, the capacitor C does not need to be charged by an external circuit, and can be self-charged by taking energy from the line, thereby using the commutation capacitor to inject a reverse current into the semiconductor switch to reduce the size of the current turned off by the semiconductor switch, thereby improving the short-circuit turning-off capability of the solid-state switch, reducing the number of semiconductor devices connected in parallel, and reducing the cost of the solid-state circuit breaker while improving the breaking capacity.

[0040] In some embodiments of the present invention, the energy consumption branch includes: A metal oxide arrester, the first inductor, the second inductor, a resistor and a fourth semiconductor switch; The resistor is connected to the fourth semiconductor switch.

[0041] like Figure 1 As shown, the energy consumption branch includes a metal oxide arrester MOV, a first inductor N1, a second inductor N2, a resistor R and a fourth semiconductor switch S dissipation .

[0042] The resistor R and the fourth semiconductor switch S dissipation Connect the metal oxide arrester MOV with the first semiconductor switch S main Connect in parallel.

[0043] When the current limiting branch is used for current limiting shutdown, the second inductor N2 and the fourth semiconductor switch S dissipation The loop composed of and resistor R can dissipate some energy.

[0044] The self-charging current-limiting AC solid-state circuit breaker provided in the embodiment of the present invention consumes the current of the current-carrying branch or the current-limiting branch through the energy-consuming branch. As the energy stored in the system is continuously dissipated, the current gradually drops to zero, completing the breaking process of the short-circuit fault.

[0045] In some embodiments of the present invention, the first semiconductor switch, the second semiconductor switch, the third semiconductor switch and the fourth semiconductor switch are all fully-controlled semiconductor switches with low conduction losses.

[0046] The first semiconductor switch S main , the second semiconductor switch S commutation, the third semiconductor switch S charge and the fourth semiconductor switch S dissipation Both are fully controlled semiconductor switches with low conduction losses.

[0047] A fully controlled semiconductor switch is a semiconductor device whose conduction and cutoff can be completely controlled by a control signal. It has the characteristics of low conduction loss. In the on state, it can conduct current with lower energy loss, thereby improving the efficiency of the circuit and reducing energy consumption.

[0048] The first semiconductor switch, the second semiconductor switch, the third semiconductor switch and the fourth semiconductor switch may be MOSFET, IGBT or bipolar junction transistor (BJT) or the like.

[0049] MOSFET is usually used in low voltage and medium voltage applications, with fast switching speed and low on-resistance. IGBT is suitable for high voltage and high current applications, combining the advantages of MOSFET's high input impedance and BJT's low saturation voltage drop. BJT is often used in situations that require high current amplification and lower cost.

[0050] Since the first semiconductor switch, the second semiconductor switch, the third semiconductor switch and the fourth semiconductor switch are all fully controlled semiconductor switches with low conduction loss, the current flow in the circuit can be effectively controlled to achieve accurate management of the circuit state. In addition, due to their low conduction loss characteristics, they can also help improve the energy efficiency of the entire system and reduce unnecessary heat generation.

[0051] In some embodiments of the present invention, when a short circuit fault occurs, the second semiconductor switch is turned on, and the forced commutation branch injects a reverse current into the pass branch; When the current in the conduction branch drops to a safe shutdown range, the first semiconductor switch is turned off to dissipate the current in the energy consumption circuit.

[0052] When a short circuit fault occurs in the system, the self-charging current-limiting AC solid-state circuit breaker provided by the present invention has two shutoff modes, namely general shutoff and current-limiting shutoff.

[0053] The general shutdown is as follows: When a short circuit occurs, the second semiconductor switch S is controlled commutation is turned on, the capacitor C in the commutation branch is forced to conduct to the first semiconductor switch S main The reverse current is injected into the current-carrying branch.

[0054] S main When the current of the branch (current-carrying branch) drops to the safe shutdown range, the first semiconductor switch S is controlled mainThe current is turned off and transferred to the metal oxide surge arrester MOV in the energy consumption circuit for dissipation. As the energy stored in the system is continuously dissipated, the current gradually drops to zero, and the entire short-circuit fault interruption process ends.

[0055] The self-charging current-limiting AC solid-state circuit breaker provided in the embodiment of the present invention can interrupt the rated current, utilize the forced commutation branch to improve the interruption capacity of the semiconductor switch device, and interrupt the short-circuit fault.

[0056] In some embodiments of the present invention, when a short circuit fault occurs, the first semiconductor switch is turned off, the second semiconductor switch is turned on, the third semiconductor switch is turned on, and the forced commutation branch injects a reverse current into the current limiting branch; When the current of the current limiting branch drops to a safe shutdown range, the third semiconductor switch is turned off to allow the current to be dissipated in the energy consumption circuit.

[0057] The current limiting shutdown is as follows: When a short circuit occurs, the first semiconductor switch S is controlled at the same time. main Turn off and control the second semiconductor switch S commutation and the third semiconductor switch S charge is turned on, then the main current flows through the third semiconductor switch S charge .

[0058] The capacitor C in the forced commutation branch is connected to the third semiconductor switch S charge The current limiting branch injects reverse current, S charge When the current of the branch (current limiting shutdown branch) drops to the safe shutdown range, the third semiconductor switch S is controlled charge When turned off, the current is diverted to the energy-consuming circuit for dissipation.

[0059] Among them, part of the current is induced to N2 and the fourth semiconductor switch S through the coupled inductors N1 and N2. dissipation The current is dissipated in the circuit with resistor R, and the other part is transferred to the metal oxide arrester MOV for dissipation. As the energy stored in the system is continuously dissipated, the current gradually drops to zero, and the entire short-circuit fault interruption process ends.

[0060] The self-charging current-limiting AC solid-state circuit breaker provided in the embodiment of the present invention can interrupt the rated current, use the coupled inductor to limit the short-circuit fault current rise rate, and use the forced commutation branch to improve the breaking capacity of the semiconductor switch device to interrupt the short-circuit fault.

[0061] For example, Figure 2 This is one of the schematic diagrams of the breaking process of the circuit breaker provided by the present invention when it is generally shut down. Figure 3 The second schematic diagram of the breaking process of the circuit breaker provided by the present invention when it is generally shut down, Figure 4 The third schematic diagram of the breaking process of the circuit breaker provided by the present invention during general shut-down is shown below in conjunction with Figures 2 to 4 The breaking process of the circuit breaker provided by the present invention when it is generally shut down is described in detail.

[0062] like Figure 2 As shown, in the normal flow state of the system, the positive half-wave current of the AC power source flows through the first diode D1, the first semiconductor switch Smain and the fourth diode D4.

[0063] like Figure 3 As shown, after a short circuit fault is detected, the second semiconductor switch Scommutation is turned on, and the capacitor C injects a reverse current into the current-carrying branch where the first semiconductor switch Smain is located. When the current of the Smain branch (main branch) drops to a safe shutdown range, the first semiconductor switch Smain is controlled to be turned off.

[0064] like Figure 4 As shown, when the turn-off overvoltage at both ends of the first semiconductor switch Smain reaches the varistor of the metal oxide arrester MOV in the energy consumption branch, the metal oxide arrester MOV is activated, and the current is rapidly transferred to the energy consumption branch. As the system stored energy is continuously dissipated, the current gradually drops to zero, and the entire short-circuit fault breaking process ends.

[0065] For example, Figure 5 This is one of the schematic diagrams of the breaking process of the circuit breaker provided by the present invention when the circuit breaker is closed with current limiting. Figure 6 The second schematic diagram of the breaking process of the circuit breaker provided by the present invention during current limiting shutdown is shown in FIG. Figure 7 The third schematic diagram of the breaking process of the circuit breaker during current limiting shutdown provided by the present invention is shown below in combination with Figures 5 to 7 The breaking process of the circuit breaker provided by the present invention during current limiting shutdown is described in detail.

[0066] like Figure 5 As shown, in the normal flow state of the system, the positive half-wave current of the AC power source flows through the first diode D1, the first semiconductor switch Smain and the fourth diode D4.

[0067] like Figure 6 As shown, after a short circuit fault is detected, the first semiconductor switch Smain is turned off, the second semiconductor switch Scommutation and the third semiconductor switch Scharge are turned on, and the capacitor C injects a reverse current into the third semiconductor switch Scharge branch. When the current of the third semiconductor switch Scharge branch (current limiting shutdown branch) drops to a safe shutdown range, the third semiconductor switch Scharge is controlled to be turned off.

[0068] like Figure 7As shown, when the overvoltage at both ends of the first semiconductor switch Smain reaches the varistor of the metal oxide arrester MOV in the energy consumption branch, the metal oxide arrester MOV is activated and the current is quickly transferred to the energy consumption branch. After the third semiconductor switch Scharge is turned off, part of the energy is induced to the second inductor N2, the fourth semiconductor switch Sdissipation and the resistor R loop through the coupling inductor N1N2 and dissipated. As the system stored energy is continuously dissipated, the current gradually drops to zero, and the entire short-circuit fault interruption process ends.

[0069] For example, Figure 8 This is one of the schematic diagrams of the circuit breaker capacitor self-charging process provided by the present invention. Fig. 9 The second schematic diagram of the circuit breaker capacitor self-charging process provided by the present invention is shown below in combination with Figures 8 to 9 The circuit breaker capacitor self-charging process provided by the present invention is described in detail.

[0070] like Figure 8 As shown, in the normal flow state of the system, the first semiconductor switch Smain is turned off and the third semiconductor switch Scharge is turned on at the same time, and the positive half-wave current of the AC power source flows through the first diode D1, the first inductor N1, the third semiconductor switch Scharge and the fourth diode D4.

[0071] like Fig. 9 As shown, when enough energy is stored in the first inductor N1, the first semiconductor switch Smain is turned on and the third semiconductor switch Scharge is turned off, and current can be induced in the second inductor N2 through the first inductor N1 to charge the commutation capacitor C. The system returns to a normal current flow state.

[0072] That is, the present invention proposes a solution for improving the short-circuit shutdown capability of a solid-state switch by utilizing self-charging capacitor commutation. The capacitor does not need an external circuit to charge it, and can draw energy from the line for self-charging. The commutation capacitor is used to inject a reverse current into the semiconductor switch to reduce the size of the current turned off by the semiconductor switch. This can improve the short-circuit shutdown capability of the solid-state switch, reduce the number of semiconductor devices connected in parallel, and reduce the cost of the solid-state circuit breaker while increasing the breaking capacity.

[0073] The self-charging current-limiting AC solid-state circuit breaker provided by the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the self-charging current-limiting AC solid-state circuit breaker of the present invention and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A self-charging current-limiting AC solid-state circuit breaker, characterized in that: include: Current-passing branch, forced commutation branch, self-charging branch, current-limiting branch and energy-consuming branch; The forced commutation branch is used to inject a reverse current into the current-passing branch or the current-limiting branch when a short-circuit fault occurs; The energy consumption branch is used to consume the current when the current of the current-passing branch or the current-limiting branch drops to a safe shutdown range; The self-charging branch is used to charge the capacitor in the forced commutation branch.

2. The self-charging current-limiting AC solid-state circuit breaker according to claim 1, characterized in that: The through-flow branch comprises: a first diode, a second diode, a third diode, a fourth diode and a first semiconductor switch; The first diode is connected to the fourth diode via the first semiconductor switch; The second diode is connected to the third diode via the first semiconductor switch; The forced commutation branch, the self-charging branch, the current limiting branch, and the energy consumption branch are respectively connected in parallel with the first semiconductor switch.

3. The self-charging current-limiting AC solid-state circuit breaker according to claim 2, characterized in that: The forced commutation branch comprises: The capacitor and the second semiconductor switch are connected in sequence.

4. The self-charging current-limiting AC solid-state circuit breaker according to claim 3 is characterized in that: The current limiting branch comprises: A first inductor and a third semiconductor switch are connected in sequence.

5. The self-charging current-limiting AC solid-state circuit breaker according to claim 4, characterized in that: The self-charging branch comprises: The current limiting branch, the second inductor and the fifth diode; The second inductor is connected to the fifth diode.

6. The self-charging current-limiting AC solid-state circuit breaker according to claim 5, characterized in that: The energy consumption branch includes: A metal oxide arrester, the first inductor, the second inductor, a resistor and a fourth semiconductor switch; The resistor is connected to the fourth semiconductor switch.

7. The self-charging current-limiting AC solid-state circuit breaker according to claim 6, characterized in that: The first semiconductor switch, the second semiconductor switch, the third semiconductor switch and the fourth semiconductor switch are all fully controllable semiconductor switches with low conduction loss.

8. The self-charging current-limiting AC solid-state circuit breaker according to claim 7, characterized in that: The first inductor and the second inductor are mutually coupled inductors.

9. The self-charging current-limiting AC solid-state circuit breaker according to claim 8, characterized in that: When a short circuit fault occurs, the second semiconductor switch is turned on, and the forced commutation branch injects a reverse current into the current-passing branch; When the current in the conduction branch drops to a safe shutdown range, the first semiconductor switch is turned off to dissipate the current in the energy consumption circuit.

10. The self-charging current-limiting AC solid-state circuit breaker according to claim 8, characterized in that: When a short circuit fault occurs, the first semiconductor switch is turned off, the second semiconductor switch is turned on, the third semiconductor switch is turned on, and the forced commutation branch injects a reverse current into the current limiting branch; When the current of the current limiting branch drops to a safe shutdown range, the third semiconductor switch is turned off to allow the current to be dissipated in the energy consumption circuit.

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