Bidirectional thyristor direct current circuit breaker

Abstract

The invention provides a bidirectional thyristor direct-current circuit breaker. The bidirectional thyristor direct-current circuit breaker comprises a first main thyristor Tm1, a second main thyristor Tm2, a first trigger thyristor Tt1, a second trigger thyristor Tt2, a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2 and a dissipation resistor R2, according to the technical scheme, two thyristors are multiplexed. In any current direction, only one thyristor is conducted as a main switch tube, and the conduction loss is the same as that of a one-way circuit breaker. And the other thyristor is used as a trigger switch to realize reliable turn-off of the circuit breaker. The circuit breaker integrates the advantages of a T-source circuit breaker and a full-control circuit breaker, fault current can be independently and rapidly cut off without detection time delay, faults can be actively cut off through a trigger switch, and reliability of the circuit breaker is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of DC circuit breaker technology, and in particular to a bidirectional thyristor DC circuit breaker. Background Technology

[0002] DC circuit breakers are one of the most reliable protection solutions in DC systems, minimizing fault areas and ensuring the normal operation of healthy lines. However, IGBTs and MOSFETs are currently expensive, have limited capacity, and suffer from high on-state losses, which greatly restricts their development and application. Therefore, many scholars have proposed DC circuit breaker topologies based on thyristors.

[0003] Compared to solid-state circuit breakers based on IGBTs and MOS, thyristor-based circuit breakers offer higher capacity and lower cost, leading to extensive research. However, because thyristors are unidirectional conducting devices, existing circuit breakers of this type cannot achieve efficient bidirectional conduction or rapid and reliable fault current interruption. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a bidirectional thyristor DC circuit breaker that reuses two thyristors. In either current direction, only one thyristor acts as the main switch, with conduction losses the same as those of a unidirectional circuit breaker. The other thyristor acts as a trigger switch to ensure reliable circuit breaker shutdown. This circuit breaker integrates the advantages of a T-source circuit breaker and a fully controlled circuit breaker, enabling independent and rapid interruption of fault current without detection delay, and also allowing proactive fault interruption via a trigger switch, ensuring the reliability of the circuit breaker.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a bidirectional thyristor DC circuit breaker, comprising a first main thyristor. T m1 Second main thyristor T m2 First trigger thyristor T t1 Second trigger thyristor T t2 First Inductor L 1 Second inductor L 2 First capacitor C 1 Second capacitor C 2 and dissipation resistance R 2 The first main thyristor T m1 With the second main thyristor T m2Cross-reverse connection, forming a bidirectional current path; first inductor L 1 Coupled in a bidirectional current path; the first trigger thyristor T t1 With the second capacitor C 2 and the second inductor L 2 Constitutes the first main thyristor T m1 A reliable turn-off triggering path; the second trigger thyristor T t2 With the second capacitor C 2 and the first inductor L 1 constitutes the second main thyristor T m2 A reliable shutdown trigger path; the first capacitor C 1 With the second inductor L 2 Connection; the first capacitor C 1 With the second capacitor C 2 A diode is also connected between them; the circuit breaker has two functions: automatic shutdown and reliable shutdown. During normal operation, only a single main thyristor is turned on. By reusing thyristors, switching losses are reduced, and efficient bidirectional current conduction and rapid and reliable fault current shutdown are achieved.

[0006] In a preferred embodiment, the first main thyristor is in forward current mode. T m1 When the main switch is turned on, the second main thyristor is in reverse current. T m2 It is turned on as the main switch.

[0007] In a preferred embodiment, when a fault occurs, the first capacitor... C 1. Discharge, the sudden change in current passes through the second inductor. L 2 is transferred to the first inductor L 1. Then, the first main thyristor T m1 Turn off; in the first main thyristor T m1 After being turned off, the circuit breaker enters a resonant state. When the resonant current reverses direction, the circuit breaker enters a dissipative state.

[0008] In a preferred embodiment, when the automatic shutdown function fails to shut off the circuit breaker, or when it is necessary to shut off an overload current, the reliable shutdown function of the circuit breaker is activated; before the reliable shutdown function is activated, the circuit is in normal operating condition; when the reliable shutdown function is activated, the first trigger thyristor... T t1 Turn on, first main thyristor T m1 Turned off; when the first main thyristor T m1 After being turned off, the circuit breaker enters a resonant state. When the resonant current crosses zero, the first trigger thyristor... T t1 When the circuit breaker is turned off, the resonance state ends, and the circuit breaker enters the dissipation stage, where the fault energy is consumed by the dissipation resistor.

[0009] In a preferred embodiment, the first capacitor C 1 Second capacitor C 2 With the second inductor L 2 To form a resonant circuit, dissipation resistor R 2 Connect to the end of the resonant circuit.

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. Higher operating efficiency: Reduced switching losses by reusing thyristors. 2. Fewer switching devices: By reusing thyristors, the number of switching devices is reduced, thus lowering device costs.

[0011] 3. Faster response speed: When a short circuit occurs near the circuit breaker, the capacitor... C 1. Rapid discharge: The circuit breaker can automatically and quickly cut off the fault current.

[0012] 4. More reliable fault shutdown: When a short circuit occurs at a location far from the circuit breaker, the thyristor... T t1 Or thyristor T t2 On (when the current direction is to the right) T t1 Conduction occurs; when the current direction is to the left. T t2 (Conduct) C 2. By triggering the discharge path, the main thyristor is reliably turned off. Attached Figure Description

[0013] Figure 1 This is a topology diagram of a bidirectional DC circuit breaker according to a preferred embodiment of the present invention; Figure 2 This is an equivalent circuit diagram of automatic shutdown and controllable shutdown according to a preferred embodiment of the present invention; wherein, (a) is a schematic diagram of normal operation, and (b) is a schematic diagram of the first capacitor when a fault occurs. C 1 The diagram shows the discharge state, (c) is the circuit breaker entering the resonance state, (d) is the circuit breaker starting the reliable shutdown function, (e) is the circuit breaker entering the resonance state, and (f) is the circuit breaker entering the dissipation state. Figure 3 The main waveform diagrams for automatic shutdown and controllable shutdown in a preferred embodiment of the present invention are shown; wherein, (a) is during automatic shutdown, and (b) is during reliable shutdown function activation; Figure 4 This is a comparison chart of the efficiency of a bidirectional DC circuit breaker according to a preferred embodiment of the present invention with that of an existing conventional circuit breaker. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0016] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application; as used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise; furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0017] The high-efficiency bidirectional DC circuit breaker with fast and reliable turn-off capability proposed in this invention is as follows: Figure 1 As shown. A bidirectional thyristor DC circuit breaker includes a first main thyristor. T m1 Second main thyristor T m2 First trigger thyristor T t1 Second trigger thyristor T t2 First Inductor L 1 Second inductor L 2 First capacitor C 1 Second capacitor C 2and dissipation resistance R 2 The first main thyristor T m1 With the second main thyristor T m2 Cross-reverse connection, forming a bidirectional current path; first inductor L 1 Coupled in a bidirectional current path; the first trigger thyristor T t1 With the second capacitor C 2 and the second inductor L 2 Constitutes the first main thyristor T m1 A reliable turn-off triggering path; the second trigger thyristor T t2 With the second capacitor C 2 and the first inductor L 1 constitutes the second main thyristor T m2 A reliable shutdown trigger path; the first capacitor C 1 With the second inductor L 2 Connection; the first capacitor C 1 With the second capacitor C 2 A diode is also connected between them; the circuit breaker has two functions: automatic shutdown and reliable shutdown. During normal operation, only a single main thyristor is turned on. By reusing thyristors, switching losses are reduced, and efficient bidirectional current conduction and rapid and reliable fault current shutdown are achieved.

[0018] This circuit breaker has both automatic shutdown and reliable shutdown functions. Automatic shutdown ensures that the circuit breaker operates quickly when a short circuit occurs near the circuit breaker, suppressing the rapid rise of the fault current. When a short circuit occurs at a greater distance from the circuit breaker, the reliable shutdown function can reliably shut off the fault current regardless of line parameters.

[0019] The operation process of this bidirectional DC circuit breaker is as follows: Figure 2 As shown.

[0020] When the bidirectional DC circuit breaker is working normally, such as Figure 2 As shown in (a), current flows through only one main thyristor. For the automatic shutdown function, the main waveforms are as follows: Figure 3 As shown in (a). The specific process is as follows: When a fault occurs C 1. Discharge, such as Figure 2As shown in (b), the sudden change in current passes through the second inductor. L 2 is transferred to the first inductor L 1. Then, the first main thyristor T m1 Turn off. In the first main thyristor tube T m1 After being turned off, the circuit breaker enters a resonant state, such as... Figure 2 As shown in (c). When the resonant current reverses direction, the circuit breaker enters a dissipation state, as... Figure 2 As shown in (f).

[0021] When the automatic shutdown function fails to shut off the circuit breaker, or when it is necessary to shut off an overload current, the reliable shutdown function of the circuit breaker is activated. The main waveforms are as follows: Figure 3 As shown in (b). Before the reliable shutdown function is activated, the circuit is in normal operating condition as follows: Figure 2 As shown in (a). When the reliable shutdown function is activated, the first trigger thyristor... T t1 Turn on, first main thyristor T m1 It is switched off. The equivalent circuit diagram is as follows: Figure 2 As shown in (d). When the first main thyristor T m1 After being turned off, the circuit breaker enters a resonant state, such as... Figure 2 As shown in (e). When the resonant current crosses zero, the first trigger thyristor... T t1 When the circuit breaker is turned off, the resonant state ends, and the circuit breaker enters the dissipation phase, such as... Figure 2 As shown in (f), the fault energy is consumed by the dissipation resistor.

[0022] The bidirectional DC circuit breaker (BDFCB) of this invention has an efficiency comparable to that of conventional circuit breakers. Figure 4 As shown.

[0023] The main comparisons are shown in Table 1.

[0024] Table 1 Figure 4 Comparison of BDFCB and circuit breakers

[0025] Usage process or method The bidirectional DC circuit breaker of this invention triggers corresponding disconnection mechanisms based on different fault types: When power flows in the forward direction, i.e. Figure 3 As shown: When a near-terminal short circuit occurs, the current rises rapidly, triggering the automatic shutdown function. First capacitor. C 1. By coupling the second inductor L 2. Rapid discharge, second inductor L2. Short-time current increase D i 2 Coupled first inductor L 1. Generates reverse current D i 1 First Inductor L 1. Current decreases when the first inductor... L When the current drops to 0, the first main thyristor T m1 When switched off, the circuit breaker enters a resonant state, and the first capacitor... C 1. First capacitor C 2 and second inductor L 2. Resonant discharge, through resistor R 2. Energy is consumed. When the resonant current reverses, the circuit enters a dissipation state and the energy is exhausted.

[0026] When the circuit is overloaded or there is a short circuit at a remote end, the first main thyristor cannot be turned off because the rise of the large inductor current in the line is not high enough. T m1 When this occurs, the reliable shutdown function is activated. The first trigger thyristor is then turned on. T t1 Second capacitor C 2. Discharge, second inductor L 2. Short-time current increase D i 2 Coupled first inductor L 1. Generates reverse current D i 1 First Inductor L 1. Current decreases when the first inductor... L When the current drops to 0, the first main thyristor T m1 When switched off, the circuit breaker enters a resonant state, and the first capacitor... C 1. First capacitor C 2 and second inductor L 2. Resonant discharge: when the resonant current crosses zero, the first trigger thyristor... T t1 Automatic shutdown occurs when the circuit enters a dissipative state and its energy is depleted.

[0027] When power flows in the reverse direction, the first inductor is used for coupling. L 1 and second trigger thyristors T t2 For the second main thyristor T m2 The same principle applies to shutting off, thus realizing the function of a bidirectional DC circuit breaker.

Claims

1. A bidirectional thyristor DC circuit breaker, characterized in that, Including the first main thyristor T m1 Second main thyristor T m2 First trigger thyristor T t1 Second trigger thyristor T t2 First Inductor L 1 Second inductor L 2 First capacitor C 1 Second capacitor C 2 and dissipation resistance R 2 The first main thyristor T m1 With the second main thyristor T m2 Cross-reverse connection, forming a bidirectional current path; first inductor L 1 Coupled in a bidirectional current path; The first trigger thyristor T t1 With the second capacitor C 2 and the second inductor L 2 Constitutes the first main thyristor T m1 A reliable shutdown triggering path; The second trigger thyristor T t2 With the second capacitor C 2 and the first inductor L 1 constitutes the second main thyristor T m2 A reliable shutdown trigger path; the first capacitor C 1 With the second inductor L 2 Connection; the first capacitor C 1 With the second capacitor C 2 A diode is also connected between them; the circuit breaker has two functions: automatic shutdown and reliable shutdown. During normal operation, only a single main thyristor is turned on. By reusing thyristors, switching losses are reduced, and efficient bidirectional current conduction and rapid and reliable fault current shutdown are achieved.

2. The bidirectional thyristor DC circuit breaker according to claim 1, characterized in that, First main thyristor under forward current T m1 When the main switch is turned on, the second main thyristor is in reverse current. T m2 It is turned on as the main switch.

3. A bidirectional thyristor DC circuit breaker according to claim 1, characterized in that, When a fault occurs, the first capacitor C 1. Discharge, the sudden change in current passes through the second inductor. L 2 is transferred to the first inductor L 1. Then, the first main thyristor T m1 Turn off; in the first main thyristor T m1 After being turned off, the circuit breaker enters a resonant state. When the resonant current reverses direction, the circuit breaker enters a dissipative state.

4. A bidirectional thyristor DC circuit breaker according to claim 3, characterized in that, When the automatic shutdown function fails to shut off the circuit breaker, or when it is necessary to shut off an overload current, the reliable shutdown function of the circuit breaker is activated. Before the reliable shutdown function is activated, the circuit is in normal operating condition. When the reliable shutdown function is activated, the first trigger thyristor... T t1 Turn on, first main thyristor T m1 Turned off; when the first main thyristor T m1 After being turned off, the circuit breaker enters a resonant state. When the resonant current crosses zero, the first trigger thyristor... T t1 When the circuit breaker is turned off, the resonance state ends, and the circuit breaker enters the dissipation stage, where the fault energy is consumed by the dissipation resistor.

5. A bidirectional thyristor DC circuit breaker according to claim 1, characterized in that, The first capacitor C 1 Second capacitor C 2 With the second inductor L 2 To form a resonant circuit, dissipation resistor R 2 Connect to the end of the resonant circuit.

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