Hybrid circuit breaker and circuit system

Abstract

The invention provides a hybrid circuit breaker and a circuit system, and belongs to the technical field of circuit breakers. The hybrid circuit breaker comprises a main branch, a transfer branch and an energy consumption branch which are connected in parallel, wherein the main branch comprises a mechanical switch and an auxiliary solid-state switch which are connected in series. The auxiliary solid-state switch comprises silicon carbide MOSFETs which are connected in series reversely, and the transfer branch comprises a diode bridge switch module which comprises a plurality of groups of diode bridge IGBT modules which are connected in series. In a normal working state, current flows through the mechanical switch and the auxiliary solid-state switch of the main branch, the current is transferred to the transfer branch after the main branch is disconnected, and the current is transferred to the energy consumption branch after the transfer branch is disconnected. The SiC MOSFET is used as an auxiliary solid-state switch, under the same conduction current, the forward and reverse conduction loss and heat production of the SiC MOSFET are smaller than those of an IGBT, and the SiC material is high in high-temperature resistance and high in normal working temperature. Under the condition of long-term through-flow, the natural cooling type radiator which is cheap and small in size is used, and the radiating size and the radiating cost are reduced.

Description

Technical Field

[0001] This invention relates to the field of circuit breaker technology, and more specifically to a hybrid circuit breaker and circuit system. Background Technology

[0002] Hybrid circuit breakers are power devices that combine mechanical switches with semiconductor devices. They achieve arc-free interruption of mechanical switches by rapidly cutting off DC fault current, and are a core technology in the field of power transmission. Please refer to [reference needed]. Figure 1 The hybrid circuit breaker comprises three branches: a main branch, a transfer branch, and a power dissipation branch. The main branch includes a fast mechanical switch and an auxiliary solid-state switch (e.g., Si IGBT) for normal current flow and fault current transfer. The transfer branch includes multiple solid-state switches (e.g., anti-series Si IGBTs) for interrupting fault current. The power dissipation branch includes multiple metal oxide varistors (MOVs) for energy dissipation and voltage clamping. Under normal operating conditions, current primarily flows through the fast mechanical switch and auxiliary solid-state switch in the main branch. When a grid fault occurs, the protection device triggers, the auxiliary solid-state switch opens, and the solid-state switch in the transfer branch turns on, transferring current to the transfer branch and opening the fast mechanical switch. Subsequently, the solid-state switch in the transfer branch opens, and the fault current flows through the power dissipation branch, eliminating the voltage across the clamped solid-state switch.

[0003] In related technologies, the conduction loss of IGBTs in the main branch of hybrid circuit breakers is relatively large; Si-based devices have poor high-temperature resistance and require expensive water-cooled heat sinks; and the cost of fully controlled IGBTs with anti-series structure in the transfer branch is relatively high. Summary of the Invention

[0004] The purpose of this invention is to provide a hybrid circuit breaker that can reduce the heat dissipation cost and volume cost of the device.

[0005] To achieve the above objectives, embodiments of the present invention provide a hybrid circuit breaker, comprising a main branch, a transfer branch, and a power dissipation branch connected in parallel. The main branch includes a mechanical switch and an auxiliary solid-state switch connected in series. The auxiliary solid-state switch includes anti-series silicon carbide MOSFETs. The transfer branch includes a diode bridge switch module, which includes multiple sets of IGBT diode bridge modules connected in series. The power dissipation branch includes a metal oxide surge arrester. Under normal operating conditions, current flows through the mechanical switch and the auxiliary solid-state switch of the main branch. After the main branch is opened, the current is transferred to the transfer branch, and after the transfer branch is opened, the current is transferred to the power dissipation branch.

[0006] Optionally, the mechanical switch is used to carry current during normal operation and to withstand voltage when the main branch is disconnected. The auxiliary solid-state switch is used to assist in transferring fault current by interrupting the transferred fault current before the mechanical switch is turned off.

[0007] Optionally, the auxiliary solid-state switch further includes a natural cooling heat sink. During normal operation, the anti-series silicon carbide MOSFETs carry a rated current, generating conduction losses and heat. The natural cooling heat sink is used to dissipate heat from the anti-series silicon carbide MOSFETs.

[0008] Optionally, each of the multiple diode bridge IGBT modules includes a first group of diode modules, a Si IGBT module, and a second group of diode modules connected in parallel. The first group of diode modules and the second group of diode modules each include diodes connected in series.

[0009] Optionally, each group of diode bridge IGBT modules further includes a parallel resistor-capacitor structure. Each group of diode bridge IGBT modules is also used to lock out the IGBTs of the corresponding diode bridge IGBT module and charge the capacitor after the mechanical switch of the main branch is turned off, thus forming a transient overvoltage.

[0010] Optionally, the metal oxide surge arrester is used to absorb and dissipate the energy generated when the main branch is disconnected, and also to balance the voltage on each group of diode bridge IGBT modules in a static state.

[0011] This invention also provides a circuit system comprising the hybrid circuit breaker described above.

[0012] Optionally, the circuit system further includes a fault detection module. The hybrid circuit breaker is configured such that: when a fault occurs in the main branch, the fault current gradually increases; when the fault detection module detects that the fault current exceeds a preset threshold, it issues a command to open the auxiliary solid-state switch, close the diode bridge switch module of the transfer branch, and keep the mechanical switch closed, so as to gradually transfer the fault current in the main branch to the transfer branch; when the fault current is completely transferred to the transfer branch, the mechanical switch opens; when the fault current in the transfer branch gradually increases until the insulation distance between the moving and stationary contacts of the mechanical switch in the main branch is sufficient to withstand the transient overvoltage caused by the interruption of the fault current, the circuit system issues a command to open the diode bridge switch module, and the fault current is transferred from the transfer branch to the metal oxide surge arrester in the energy-consuming branch.

[0013] Optionally, the metal oxide surge arrester of the energy-consuming branch is triggered and consumes the inductive energy in the circuit system, gradually reducing the current of the circuit system.

[0014] Optionally, when the current of the circuit system is 0A, the hybrid circuit breaker bears the voltage of the circuit system. The mechanical switch of the main branch bears the first voltage, the auxiliary solid-state switch bears the second voltage, and each group of diode bridge IGBT modules in the transfer branch shares the third voltage.

[0015] Through the above technical solution, the hybrid circuit breaker provided in this embodiment of the invention uses a wide-bandgap semiconductor device, silicon carbide (SiC) metal-oxide-semiconductor transistor (MOSFET), as an auxiliary solid-state switch. SiC MOSFETs have low conduction losses, achieving high withstand voltage and low impedance without requiring a very thick drift region, significantly reducing the on-resistance of the drift region and thus reducing conduction losses. SiC MOSFET materials have strong high-temperature resistance; SiC MOSFETs have high power density, saving on device size and cost. Furthermore, the use of a diode bridge switch in the transfer branch further reduces device size and cost.

[0016] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of a hybrid circuit breaker in the prior art; Figure 2 This is a schematic diagram of the structure of the hybrid circuit breaker provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of an example hybrid circuit breaker with an auxiliary solid-state switch; Figure 4A This is a current schematic diagram of the circuit system provided in the embodiment of the present invention; Figure 4B This is a voltage schematic diagram of the circuit system provided in the embodiment of the present invention; Figure 5A This is a schematic diagram of the current flow direction of the circuit system provided in the embodiment of the present invention. Figure 1 ; Figure 5B This is a schematic diagram of the current flow direction of the circuit system provided in the embodiment of the present invention. Figure 2 ; Figure 5C This is a schematic diagram of the current flow direction of the circuit system provided in the embodiment of the present invention. Figure 3 ;as well as Figure 5DThis is a schematic diagram of the current flow direction of the circuit system provided in the embodiment of the present invention. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0019] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application all comply with the relevant provisions of national laws and regulations. In the embodiments of this application, certain existing industry solutions such as software, components, and models may be mentioned. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solution of this application, and do not imply that the applicant has already used or necessarily used such solutions.

[0020] Please refer to Figure 1 As mentioned earlier, the relevant hybrid circuit breaker includes a main branch, a transfer branch, and a power dissipation branch. During normal operation, current flows through the fast mechanical switch and auxiliary solid-state switch in the main branch. When a fault occurs, the fault current gradually increases until the protection device triggers. The trigger command causes the auxiliary solid-state switch to open, transferring the current. The solid-state switch in the transfer branch then conducts, transferring the fault current to the solid-state switch and opening the fast mechanical switch. When the insulation of the fast mechanical switch contacts recovers, the solid-state switch in the transfer branch opens, forcibly transferring the fault current to the metal oxide surge arrester (MOV) in the power dissipation branch, where voltage clamping and power dissipation occur. In the open state, the fault current is depleted, the hybrid circuit breaker bears the system voltage, the anti-series IGBTs in the transfer branch share the voltage, most of the voltage in the main branch is borne by the fast mechanical switch, and the auxiliary solid-state switch bears only a small voltage.

[0021] Therefore, in related technologies, auxiliary solid-state switches are mainly composed of fully controlled power electronic devices (Si IGBTs). Because Si IGBTs have high conduction losses at high current and high frequency, a large heat dissipation system is required to maintain their normal operating temperature. This not only increases cost but also increases the size and complexity of the hybrid circuit breaker. The bidirectional current transfer in the branch leads to an increase in the number of IGBTs, further increasing device cost.

[0022] Please refer to Figure 2The hybrid circuit breaker provided in this application embodiment may include a main branch, a transfer branch, and a power dissipation branch connected in parallel. The main branch includes a mechanical switch and an auxiliary solid-state switch connected in series. The auxiliary solid-state switch may include anti-series silicon carbide MOSFETs. The transfer branch may include a diode bridge switch module, which may include multiple sets of IGBT diode bridge modules connected in series. The power dissipation branch may include a metal oxide surge arrester (MOV). In this embodiment, under normal operating conditions, current flows through the mechanical switch and the auxiliary solid-state switch of the main branch. After the main branch is opened, the current is transferred to the transfer branch, and after the transfer branch is opened, the current is transferred to the power dissipation branch.

[0023] The hybrid circuit breaker provided in this invention uses a wide-bandgap semiconductor device, silicon carbide (SiC) metal-oxide-semiconductor transistor (MOSFET), as an auxiliary solid-state switch. SiC MOSFETs have low conduction losses, achieving high voltage withstand and low impedance without requiring a thick drift region, significantly reducing the on-resistance of the drift region and thus reducing conduction losses. SiC MOSFET materials also exhibit strong high-temperature resistance and high power density, saving on device size and cost. Furthermore, the use of a diode bridge switch in the transfer branch further reduces device size and cost.

[0024] The preferred mechanical switch (which can also be called a fast mechanical switch) in the embodiments of the present invention can be used to carry current in normal working condition and withstand voltage when the main branch is disconnected; the auxiliary solid-state switch can be used to assist in transferring fault current so as to interrupt the transfer of fault current before the mechanical switch is turned off.

[0025] The auxiliary solid-state switch in a preferred embodiment of the present invention may further include a natural cooling heat sink. In normal operation, the anti-connected silicon carbide MOSFETs carry a rated current, generating conduction losses and heat. The natural cooling heat sink can be used to dissipate heat from the anti-connected silicon carbide MOSFETs.

[0026] Please refer to Figure 3The auxiliary solid-state switch comprises an anti-series SiC MOSFET and a naturally cooled heatsink. Compared to an auxiliary solid-state switch composed of IGBTs, the size and cost of the heatsink are reduced. This embodiment of the invention uses SiC MOSFETs as the auxiliary solid-state switch, which reduces conduction losses and heat dissipation requirements. Due to the high-temperature resistance of SiC, its operating temperature is relatively high; therefore, a naturally cooled heatsink can be used instead of more expensive water cooling, further reducing conduction losses, decreasing the overall heatsink size, and saving costs. Based on this, in the main branch of the hybrid circuit breaker provided by this embodiment, under normal operating conditions, the current mainly flows through the fast mechanical switch and the auxiliary solid-state switch, ensuring circuit continuity. The SiC MOSFET of the auxiliary solid-state switch carries the rated current, generating conduction losses and heat. Using a naturally cooled heatsink can keep the temperature around 100°C, resulting in lower conduction losses and heat generation, higher device operating temperature and stronger heat resistance, and cost savings.

[0027] Please refer to Figure 2 In a preferred embodiment of the present invention, each of the multiple diode bridge IGBT modules may include a first group of diode modules, a Si IGBT module, and a second group of diode modules connected in parallel. The first group of diode modules and the second group of diode modules each include diodes connected in series.

[0028] In a preferred embodiment of the present invention, each group of diode bridge IGBT modules may further include a parallel resistor-capacitor structure. Each group of diode bridge IGBT modules is also used to lock the IGBTs of the corresponding diode bridge IGBT module after the mechanical switch of the main branch is turned off, thereby charging the capacitor and forming a transient overvoltage of the capacitor.

[0029] In this embodiment of the invention, when the main branch needs to be disconnected, the transfer branch quickly intervenes to transfer the current from the main branch to the energy-consuming branch, ensuring the circuit is safely disconnected. After the mechanical switch of the main branch is opened, the corresponding diode bridge IGBT module's IGBT is latched up, charging the capacitor and forming a transient overvoltage in the capacitor.

[0030] In this embodiment of the invention, the transfer branch of the hybrid circuit breaker adopts a full diode bridge and Si IGBT structure, which can reduce the cost of Si IGBT devices. Furthermore, since the cost of diodes is lower than that of fully controlled Si IGBT devices, the cost of the hybrid circuit breaker can be saved, while also allowing bidirectional conduction. Further, the transfer branch uses IGBTs, which can interrupt higher currents, and since the transfer branch does not require continuous current flow, it does not cause conduction losses. This embodiment of the invention is based on the SiC MOSFET in the main branch and the Si IGBT in the transfer branch. The two devices leverage their respective advantages in different branches: the SiC MOSFET has low conduction losses and high temperature resistance; the Si IGBT has strong turn-off capability and overload capability. The two devices complement each other, leveraging their respective advantages. Furthermore, the SiC MOSFET in the main branch uses a natural cooling heatsink, reducing the overall heatsink size and saving costs; the IGBTs in the diode bridge IGBT module of the transfer branch do not require heatsinks, and do not generate heat during normal operation as no current flows through them, thus requiring no additional heat dissipation measures.

[0031] The preferred metal oxide surge arrester of the present invention can be used to absorb and dissipate the energy generated when the main branch is disconnected, and also to balance the voltage on each group of diode bridge IGBT modules in a static state.

[0032] In this embodiment of the invention, during the circuit breaking process, the metal oxide surge arrester (MOV) of the hybrid circuit breaker absorbs and dissipates the high energy generated by the sudden interruption of current, protecting the circuit from damage. The MOV is connected in parallel across the diode bridge IGBT module to absorb the energy stored in the inductive elements of the DC system and suppress breaking overvoltage.

[0033] Accordingly, the hybrid circuit breaker provided in this application embodiment may include a main branch, a transfer branch, and a power dissipation branch connected in parallel. The main branch includes a mechanical switch and an auxiliary solid-state switch connected in series. The auxiliary solid-state switch may include anti-series silicon carbide MOSFETs. The transfer branch may include a diode bridge switch module, which may include multiple sets of IGBT diode bridge modules connected in series. The power dissipation branch may include a metal oxide surge arrester (MOV). In this embodiment, under normal operating conditions, current flows through the mechanical switch and the auxiliary solid-state switch of the main branch. After the main branch is opened, the current is transferred to the transfer branch, and after the transfer branch is opened, the current is transferred to the power dissipation branch. The hybrid circuit breaker provided in this embodiment uses SiC MOSFETs as auxiliary solid-state switches. Under the same conduction current, the forward and reverse conduction losses and heat generation of SiC MOSFETs are lower than those of IGBTs, and SiC material has strong high-temperature resistance and a high normal operating temperature. By utilizing SiC MOSFETs as auxiliary solid-state switches, the expensive and bulky water-cooled heatsink can be replaced with a cheaper and smaller natural-cooled heatsink under long-term current-carrying conditions, significantly reducing the heatsink size and cost, and improving the economic cost of the hybrid circuit breaker. In this embodiment, the transfer branch uses a diode bridge IGBT module; the cost of diodes is far less than that of IGBTs, thus greatly reducing device cost. This embodiment places the SiC MOSFET in the main branch and the IGBT in the transfer branch, leveraging the low long-term current-carrying loss and high operating temperature characteristics of the SiC MOSFET, and the high transient turn-off capability and high overload capability of the IGBT. The two devices complement each other, maximizing their respective advantages.

[0034] This invention also provides a circuit system that may include the hybrid circuit breaker described above.

[0035] For example, the circuit system can be a DC system, and a DC system includes, for example, Figure 2 The hybrid circuit breaker shown.

[0036] The preferred circuit system of this invention may further include a fault detection module. The hybrid circuit breaker may be configured such that: when a fault occurs in the main branch, the fault current gradually increases; when the fault detection module detects that the fault current exceeds a preset threshold, it issues a command to open the auxiliary solid-state switch, close the diode bridge switch module of the transfer branch, and keep the mechanical switch closed, so as to gradually transfer the fault current in the main branch to the transfer branch; when the fault current is completely transferred to the transfer branch, the mechanical switch opens; when the fault current in the transfer branch gradually increases until the insulation gap between the moving and stationary contacts of the fast mechanical switch in the main branch is sufficient to withstand the transient overvoltage caused by the interruption of the fault current, the circuit system issues a command to open the diode bridge switch module, and the fault current is transferred from the transfer branch to the metal oxide surge arrester in the energy-consuming branch.

[0037] Please refer to Figure 4A , Figure 4B and Figures 5A-5D When a hybrid circuit breaker encounters an external fault, the circuit system operates as follows: When a fault occurs on the main branch, the current gradually increases until the fault detection module detects that the fault current is too large. The fault detection module then issues a command to open the auxiliary solid-state switch, close the diode bridge switch module of the transfer branch, and keep the fast mechanical switch closed. The fault current on the main branch gradually transfers to the transfer branch. When the current has completely transferred to the transfer branch, the fast mechanical switch can open without arcing, and at this time there is no current on the main branch. This facilitates the insulation recovery of the fast mechanical switch. When the fault current gradually increases in the transfer branch until the insulation gap between the moving and stationary contacts of the transfer branch is sufficient to withstand the transient overvoltage caused by the interruption of the fault current, the DC system issues a command to open the diode bridge switch module, and the fault current is transferred from the transfer branch to the MOV of the energy-dissipating branch.

[0038] Please refer to Figure 4A and Figure 4B The horizontal axis represents time T. Figure 4A The vertical axis represents the total current of the hybrid circuit breaker. Figure 4B The vertical axis represents the total voltage of the hybrid circuit breaker. The stages shown in the figure can be represented as follows: t0-t1 stage: During normal operation, the current mainly flows through the main branch. The current flow diagram is shown below. Figure 5A As shown; t1-t2 stage: The fault current rises gradually, but does not reach the detection threshold. Therefore, the current still mainly flows through the main branch. The current flow diagram is shown below. Figure 5A As shown; During the t2-t3 phase: a fault current is detected. At this time, the auxiliary solid-state switch is turned off, the diode bridge switch module is turned on, the mechanical switch remains closed, and the current is transferred from the main branch to the transfer branch. The current flow diagram is shown below. Figure 5B As shown; During the t3-t4 stage: the fault current of the transferred branch gradually increases, and the insulation of the fast mechanical switch gradually recovers during this stage; During the t4-t5 phase: the insulation of the fast mechanical switch is fully restored, the IGBT in the diode bridge switch module is turned off, and the current gradually transfers from the IGBT to the capacitor. The voltage across the IGBT gradually increases until the voltage across the circuit breaker reaches the operating voltage of the metal oxide surge arrester in the energy-dissipating branch. The current flow diagram is shown below. Figure 5C As shown; During the t5-t6 stage: the current is transferred to the energy-consuming branch and gradually consumed by the metal oxide surge arrester until the current in the system is 0A. The current flow diagram is shown below. Figure 5D As shown.

[0039] In a preferred embodiment of the present invention, the metal oxide surge arrester of the energy-consuming branch is triggered and consumes the inductive energy in the circuit system, thereby gradually reducing the current of the circuit system.

[0040] Continuing with the example above, the MOV in the energy-consuming branch operates and consumes the inductive energy in the DC system, gradually reducing the system current until it reaches 0A.

[0041] In a preferred embodiment of the present invention, when the current of the circuit system is 0A, the hybrid circuit breaker bears the voltage of the circuit system. Specifically, the mechanical switch of the main branch bears the first voltage, the auxiliary solid-state switch bears the second voltage, and each group of diode bridge IGBT modules in the transfer branch shares the third voltage.

[0042] Continuing with the example above, when the current in the DC system is 0A, the hybrid circuit breaker bears the voltage of the DC system. Specifically, the fast mechanical switch on the main branch bears most of the voltage (i.e., the first voltage), the auxiliary solid-state switch bears a small portion of the voltage (i.e., the second voltage), and the voltage is divided equally among the diode bridge IGBT modules in the transfer branch (i.e., the third voltage).

[0043] In this embodiment of the invention, the hybrid circuit breaker can conduct normal current in both directions while simultaneously interrupting fault current in both directions, as described above. The forward and reverse circuits are similar except for the direction of the current.

[0044] It should be noted that the above circuit system can implement the hybrid circuit breaker provided in the above embodiments. For specific implementation methods, please refer to the description of the hybrid circuit breaker in the above embodiments, which will not be repeated here.

[0045] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0046] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A hybrid circuit breaker, comprising a main branch, a transfer branch, and an energy-dissipating branch connected in parallel, wherein the main branch comprises a mechanical switch and an auxiliary solid-state switch connected in series, characterized in that, The auxiliary solid-state switch includes anti-series silicon carbide MOSFETs; the transfer branch includes a diode bridge switch module, which includes multiple sets of IGBT diode bridge modules connected in series; and the power dissipation branch includes a metal oxide surge arrester. In normal operation, current flows through the mechanical switch and auxiliary solid-state switch of the main branch. After the main branch is disconnected, the current is transferred to the transfer branch, and after the transfer branch is disconnected, the current is transferred to the energy-consuming branch.

2. The hybrid circuit breaker according to claim 1, characterized in that, The mechanical switch is used to carry current during normal operation and to withstand voltage when the main branch is disconnected. The auxiliary solid-state switch is used to assist in transferring fault current, so as to interrupt the transfer of fault current before the mechanical switch is turned off.

3. The hybrid circuit breaker according to claim 1, characterized in that, The auxiliary solid-state switch also includes a natural cooling heat sink. In normal operation, the anti-series silicon carbide MOSFETs carry a rated current, generating conduction losses and heat. The natural cooling heat sink is used to dissipate heat from the anti-series silicon carbide MOSFETs.

4. The hybrid circuit breaker according to claim 1, characterized in that, Each of the multiple diode bridge IGBT modules includes a first group of diode modules, a Si IGBT module, and a second group of diode modules connected in parallel. The first group of diode modules and the second group of diode modules each consist of diodes connected in series.

5. The hybrid circuit breaker according to claim 4, characterized in that, Each group of diode bridge IGBT modules also includes a parallel resistor-capacitor structure. Each group of diode bridge IGBT modules is also used to lock the IGBT of the corresponding diode bridge IGBT module after the mechanical switch of the main branch is turned off, to charge the capacitor and form a momentary transient overvoltage.

6. The hybrid circuit breaker according to claim 1, characterized in that, The metal oxide surge arrester is used to absorb and dissipate the energy generated when the main branch is disconnected, and also to balance the voltage on each group of diode bridge IGBT modules when static.

7. A circuit system, characterized in that, The circuit system includes the hybrid circuit breaker as described in any one of claims 1-6.

8. The circuit system according to claim 7, characterized in that, The circuit system also includes a fault detection module, and the hybrid circuit breaker is configured as follows: When a fault occurs in the main branch, the fault current gradually increases. When the fault detection module detects that the fault current exceeds a preset threshold, it issues a command to open the auxiliary solid-state switch, close the diode bridge switch module of the transfer branch, and keep the mechanical switch closed, so as to gradually transfer the fault current in the main branch to the transfer branch. The mechanical switch opens when the fault current is completely transferred to the transfer branch; as well as When the fault current in the transfer branch gradually increases until the insulation gap between the moving and stationary contacts of the mechanical switch in the main branch is sufficient to withstand the transient overvoltage caused by the interruption of the fault current, the circuit system issues a command to disconnect the diode bridge switch module, and the fault current is transferred from the transfer branch to the metal oxide surge arrester in the energy dissipation branch.

9. The circuit system according to claim 8, characterized in that, The metal oxide surge arrester in the energy-consuming branch is triggered and consumes the inductive energy in the circuit system, gradually reducing the current in the circuit system.

10. The circuit system according to claim 9, characterized in that, When the current in the circuit system is 0A, the hybrid circuit breaker withstands the voltage of the circuit system. The mechanical switch of the main branch bears the first voltage, the auxiliary solid-state switch bears the second voltage, and each group of diode bridge IGBT modules in the transfer branch shares the third voltage.

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