Topological structure of double-bridge all-solid-state high-voltage direct-current circuit breaker

Abstract

The utility model discloses a topological structure of a double-bridge all-solid-state high-voltage direct-current circuit breaker. The topological structure comprises a double-bridge module, a through-current branch module and a cutoff branch module, the double-bridge module comprises an upper full-bridge circuit composed of a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm, and a lower full-bridge circuit composed of the third bridge arm, the fourth bridge arm, a fifth bridge arm and a sixth bridge arm. The through-current branch module comprises a long-term through-current branch arranged on the upper full-bridge circuit, and the long-term through-current branch comprises a thyristor switch unit and a full-control device unit which are connected in series; the cut-off branch module comprises a main cut-off branch and an absorption branch which are arranged on the lower full-bridge circuit, the main cut-off branch comprises a crimping type IGBT unit, and the absorption branch comprises a lightning arrester MOV. The long-term through-current branch can reduce through-current loss on the premise of ensuring through-current capability and turn-off safety; and the long-term through-flow branch and the main cutoff branch are respectively shared during bidirectional normal through-flow and fault current breaking, so that the manufacturing cost can be reduced, and the energy loss can be reduced at the same time.

Description

Technical Field

[0001] This utility model relates to the field of DC circuit breaker technology, and in particular to a topology of a double-bridge all-solid-state high-voltage DC circuit breaker. Background Technology

[0002] High-voltage direct current circuit breakers are a type of direct current circuit breaker. They are mainly used to solve the problem of high difficulty in breaking multi-terminal flexible direct current transmission (VSC-MTDC) in the power industry due to low system impedance and the absence of zero-crossing point of DC current. They are commonly used in high-voltage direct current transmission systems.

[0003] Based on the differences in main circuit structure and constituent components, and in chronological order of development, high-voltage DC circuit breakers can be broadly classified into three categories: mechanical, all-solid-state, and hybrid. Mechanical high-voltage DC circuit breakers, limited by their structure and composition, are inflexible in control and cannot achieve rapid interruption of short-circuit currents. All-solid-state DC circuit breakers overcome the disadvantages of arcing during the interruption process, slow interruption response, and long response time, achieving arc-free interruption, with fast interruption speed, short interruption time, precise and controllable interruption timing, and extended circuit breaker lifespan.

[0004] However, since all-solid-state DC circuit breakers operate in the normal current-carrying state most of the time, the transient process of breaking is very short, and the on-state loss is high. In addition, the large number of IGBT devices used leads to high costs, which has become the main factor restricting their industrial application.

[0005] The current scheme has a simple branch structure, which makes it difficult to balance flow loss and shutdown capacity. Utility Model Content

[0006] Therefore, it is necessary to provide a topology for a dual-bridge all-solid-state high-voltage DC circuit breaker to address the aforementioned technical problems.

[0007] To achieve the above objectives, this utility model provides a topology for a dual-bridge all-solid-state high-voltage DC circuit breaker, comprising:

[0008] The dual-bridge module includes a first bridge arm, a second bridge arm, a third bridge arm, a fourth bridge arm, a fifth bridge arm, and a sixth bridge arm. The first bridge arm, the second bridge arm, the third bridge arm, and the fourth bridge arm constitute the upper full-bridge circuit, and the third bridge arm, the fourth bridge arm, the fifth bridge arm, and the sixth bridge arm constitute the lower full-bridge circuit.

[0009] The current-carrying branch module includes a long-term current-carrying branch set in the upper full-bridge circuit. The long-term current-carrying branch includes a thyristor switching unit and a fully controlled device unit connected in series. The thyristor switching unit is composed of n thyristors connected in series, where n≥2.

[0010] The current interruption branch module includes a main current interruption branch and an absorption branch disposed in the lower full-bridge circuit. The main current interruption branch includes a press-fit IGBT unit, and the absorption branch includes a surge arrester MOV. The press-fit IGBT unit and the surge arrester MOV are connected in parallel.

[0011] Preferably, the first end of the long-term flow branch is electrically connected to the connection node of the first bridge arm and the second bridge arm, and the second end is electrically connected to the connection node of the third bridge arm and the fourth bridge arm; the first end of the main flow-interrupting branch is electrically connected to the connection node of the third bridge arm and the fourth bridge arm, and the second end is electrically connected to the connection node of the fifth bridge arm and the sixth bridge arm.

[0012] Preferably, the fully controllable device unit is composed of at least two IGBT devices connected in series and parallel.

[0013] Preferably, a first diode is provided on the first bridge arm, a second diode is provided on the second bridge arm, a third diode is provided on the third bridge arm, a fourth diode is provided on the fourth bridge arm, a fifth diode is provided on the fifth bridge arm, and a sixth diode is provided on the sixth bridge arm.

[0014] Preferably, it also includes a first disconnect switch and a second disconnect switch, which are respectively connected to the two ends of the dual-bridge module.

[0015] Compared with existing technologies, this technical solution has at least one of the following beneficial effects:

[0016] 1. Precise triggering time, fast response time, strong shutdown capability and short turn-off time are the inherent advantages of solid-state DC circuit breakers.

[0017] 2. It has strong current carrying capacity and low current loss. The long-term current-carrying branch uses a small number of IGBTs in series and parallel and multiple thyristors in series to minimize current loss while ensuring current carrying capacity and turn-off safety.

[0018] 3. Reduced cost and reduced breaking losses: The long-term current-carrying branch and the main current-breaking branch are shared when bidirectional normal current carrying and fault current breaking, which saves half of the IGBTs in these two branches. This not only reduces the number of devices and manufacturing costs, but also reduces the energy loss of the circuit breaker during the breaking process. Attached Figure Description

[0019] Figure 1 A schematic diagram of the topology of a dual-bridge all-solid-state high-voltage DC circuit breaker provided in an embodiment;

[0020] Figure 2 The circuit diagram of the topology of the double-bridge all-solid-state high-voltage DC circuit breaker provided in the embodiment; Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0022] Please see Figure 1 This application provides a topology for a dual-bridge all-solid-state high-voltage DC circuit breaker, including a dual-bridge module, a current-carrying branch module, and a current-breaking branch module.

[0023] The dual-bridge module includes a first bridge arm A1, a second bridge arm A2, a third bridge arm A3, a fourth bridge arm A4, a fifth bridge arm A5, and a sixth bridge arm A6. The first bridge arm A1, the second bridge arm A2, the third bridge arm, and the fourth bridge arm A4 constitute the upper full-bridge circuit, while the third bridge arm A3, the fourth bridge arm A4, the fifth bridge arm A5, and the sixth bridge arm A6 constitute the lower full-bridge circuit.

[0024] The current-carrying branch module includes a long-term current-carrying branch L1 disposed in the upper full-bridge circuit. The long-term current-carrying branch L1 includes a thyristor switching unit K1 and a fully controlled device unit S1 connected in series. The thyristor switching unit K1 consists of n thyristors connected in series, where n≥2. In this embodiment, it can be set to 2. The fully controlled device unit S1 consists of at least two IGBT devices connected in series and parallel. In this embodiment, it can be set to 2. In other embodiments, the number of IGBT devices in the fully controlled device unit S1 can be less than the number of thyristors in the thyristor switching unit K1. By using a small number of IGBTs connected in series and parallel and multiple thyristors connected in series, current loss can be minimized while ensuring current carrying capacity and turn-off safety.

[0025] The current-breaking branch module includes a main current-breaking branch L2 and an absorption branch L3 located in the lower full-bridge circuit. The main current-breaking branch L2 contains a press-fit IGBT unit Q1, and the absorption branch L3 contains a surge arrester MOVF1. The press-fit IGBT unit Q1 and the surge arrester MOVF1 are connected in parallel. The surge arrester MOVF1 is a metal oxide surge arrester.

[0026] Specifically, the first end of the long-term current-carrying branch L1 is electrically connected to the connection node of the first bridge arm A1 and the second bridge arm A2, and the second end is electrically connected to the connection node of the third bridge arm A3 and the fourth bridge arm A4; the first end of the main current-cutting branch L2 is electrically connected to the connection node of the third bridge arm A3 and the fourth bridge arm A4, and the second end is electrically connected to the connection node of the fifth bridge arm A5 and the sixth bridge arm A6.

[0027] A first diode D1 is disposed on the first bridge arm A1, a second diode D2 is disposed on the second bridge arm A2, a third diode D3 is disposed on the third bridge arm A3, a fourth diode D4 is disposed on the fourth bridge arm A4, a fifth diode D5 is disposed on the fifth bridge arm A5, and a sixth diode D6 is disposed on the sixth bridge arm A6.

[0028] The long-term current-carrying branch L1 is responsible for current conduction during normal operation. The thyristor switching unit K1 consists of multiple thyristors connected in series, fully utilizing their high current-carrying capacity and high voltage withstand rating. The long-term current-carrying branch L1 can reduce the number of IGBT devices in the fully controlled device unit S1 by increasing the number of thyristors connected in series within the thyristor unit K1, while maintaining the same voltage and current rating. When the circuit breaker interrupts a fault current and generates an overvoltage, it is shared by both the thyristor unit K1 and the fully controlled device unit S1. Because of the larger number of thyristors, a greater overvoltage can be distributed, effectively protecting the IGBTs in the fully controlled device unit S1.

[0029] The fully controlled device unit S1 consists of a small number of IGBTs connected in series and parallel, which can achieve bidirectional conduction and maintain low current loss. It can also direct the current to the main interruption branch L2 in case of a fault.

[0030] The main interrupting branch L2 primarily functions to interrupt fault current. The press-fit IGBT unit Q1 features excellent disassembly and interchangeability, strong current-carrying capacity, and the ability to withstand high overvoltages.

[0031] The absorption branch L3 is used to absorb the energy generated by the main interrupting branch during the interruption of fault current, protecting circuit components from overvoltage surges. After the main interrupting branch is disconnected, the remaining energy will be absorbed by the surge arrester MOVF1.

[0032] The functions of diodes D1, D2, D3, D4, D5, and D6 are to direct the current flow in a specific direction, thereby rectifying and clamping the circuit and ensuring its normal operation.

[0033] In a preferred embodiment, a first isolating switch G1 and a second isolating switch G2 are further provided, which are respectively connected to the two ends of the dual-bridge module. The first isolating switch G1 and the second isolating switch G2 are used to isolate the circuit and disconnect the circuit from the power supply or other parts when necessary to ensure safe operation.

[0034] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

[0036] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

Claims

1. A topology of a double-bridge all-solid-state high-voltage DC circuit breaker, characterized by, The application relates to a double-bridge module, a through-flow branch module and a disconnection branch module. The double-bridge module comprises a first bridge arm (A1), a second bridge arm (A2), a third bridge arm (A3), a fourth bridge arm (A4), a fifth bridge arm (A5) and a sixth bridge arm (A6), the first bridge arm (A1), the second bridge arm (A2), the third bridge arm (A3) and the fourth bridge arm (A4) form an upper full-bridge circuit, and the third bridge arm (A3), the fourth bridge arm (A4), the fifth bridge arm (A5) and the sixth bridge arm (A6) form a lower full-bridge circuit. The through-flow branch module comprises a long-term through-flow branch (L1) arranged in the upper full-bridge circuit, the long-term through-flow branch (L1) comprises a thyristor switching unit (K1) and a fully-controlled device unit (S1) connected in series, the thyristor switching unit (K1) is composed of n thyristors connected in series, and n is greater than or equal to 2. The disconnection branch module comprises a main disconnection branch (L2) and an absorption branch (L3) arranged in the lower full-bridge circuit, the main disconnection branch (L2) comprises a press-pack IGBT unit (Q1), and the absorption branch (L3) comprises a lightning arrester MOV, the press-pack IGBT unit (Q1) and the lightning arrester MOV (F1) are arranged in parallel.

2. The topology of claim 1, wherein, The first end of the long-term through-flow branch (L1) is electrically connected to the connecting node of the first bridge arm (A1) and the second bridge arm (A2), and the second end is electrically connected to the connecting node of the third bridge arm (A3) and the fourth bridge arm (A4); the first end of the main disconnection branch (L2) is electrically connected to the connecting node of the third bridge arm (A3) and the fourth bridge arm (A4), and the second end is electrically connected to the connecting node of the fifth bridge arm (A5) and the sixth bridge arm (A6).

3. The topology of claim 1, wherein, The fully-controlled device unit (S1) is composed of at least two IGBT devices connected in series and in parallel.

4. The topology of claim 1, wherein, A first diode (D1) is arranged on the first bridge arm (A1), a second diode (D2) is arranged on the second bridge arm (A2), a third diode (D3) is arranged on the third bridge arm (A3), a fourth diode (D4) is arranged on the fourth bridge arm (A4), a fifth diode (D5) is arranged on the fifth bridge arm (A5), and a sixth diode (D6) is arranged on the sixth bridge arm (A6).

5. The topology of claim 1, wherein, The application further comprises a first disconnecting switch (G1) and a second disconnecting switch (G2), the first disconnecting switch (G1) and the second disconnecting switch (G2) are respectively connected to two ends of the double-bridge module. ​

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