Current interrupting device and control method thereof

Abstract

The present application provides a current interrupting device and a control method thereof. The current interrupting device includes: a main branch, the main branch including at least two sets of current-passing units connected in series, wherein the current-passing units include a first mechanical switch and a first nonlinear resistor connected in parallel; a transfer branch, the transfer branch being connected in parallel with the main branch, the transfer branch including an oscillating capacitor; an isolation branch, the isolation branch being connected in series with the main branch, the isolation branch including a second mechanical switch; and an oscillating inductor and a power electronic unit, connected in series within a parallel loop of the main branch and the transfer branch, the oscillating inductor being connected in series within the main branch or the transfer branch, and the power electronic unit being connected in series within the main branch or the transfer branch.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a current interrupting device and a control method thereof. Background Art

[0002] In DC applications, due to the rapid growth of fault currents in DC transmission and distribution systems, reliable and rapid fault isolation and recovery are key to ensuring safe and stable operation. Existing DC circuit breakers include mechanical DC circuit breakers, hybrid DC circuit breakers, and all-solid-state DC circuit breakers.

[0003] Mechanical DC circuit breakers can be further divided into passive oscillation technology and active oscillation technology. Since mechanical DC circuit breakers use large-capacity capacitors, they have the disadvantages of being large in size, requiring a long time to disconnect low currents, having a high risk of reignition when the mechanical switch crosses zero, and being prone to oscillation with the DC system during the shutdown process, posing a hidden danger to the normal and safe operation of the system and other equipment.

[0004] Hybrid DC circuit breakers combine mechanical switches and power electronics technology to achieve controlled current shutdown through power electronic devices. They have characteristics such as arc-free and fast reclosing, and have good system applicability. However, the technical performance of the shutdown current and the economic performance of the equipment are both limited by fully controlled power electronic devices, which is not conducive to their large-scale promotion and application in high-voltage DC transmission systems.

[0005] Existing patent CN108475595A proposes a DC circuit breaker based on the LC active resonance principle, which can solve the problems of DC circuit breakers in the existing technology, such as high risk of mechanical switch reignition, long low-current shutdown time, significant system oscillation and high equipment cost. However, it has defects in closing / reclosing operations, requiring the addition of an additional discharge circuit or requiring the mechanical switch to withstand a large closing inrush current.

[0006] The above information disclosed in this Background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0007] In order to solve at least one of the above problems, the present application proposes a current interrupting device and a control method thereof.

[0008] According to the first aspect of the present application, at least one embodiment of the present application provides a current interrupting device, comprising: a main branch, the main branch comprising at least two groups of current-passing units connected in series, wherein the current-passing units comprise a first mechanical switch and a first nonlinear resistor connected in parallel; a transfer branch, the transfer branch being connected in parallel with the main branch, the transfer branch comprising an oscillation capacitor; an isolation branch, the isolation branch being connected in series with the main branch, the isolation branch comprising a second mechanical switch; and an oscillating inductor and a power electronic unit, connected in series in a parallel loop of the main branch and the transfer branch, the oscillating inductor being connected in series inside the main branch or inside the transfer branch, and the power electronic unit being connected in series inside the main branch or inside the transfer branch.

[0009] For example, in some embodiments of the present application, it also includes: a second nonlinear resistor, which is connected in parallel with the oscillation capacitor, or in parallel with the series branch of the oscillation capacitor and the oscillation inductor, or in parallel with the series branch of the oscillation capacitor and the power electronic unit, or in parallel with the transfer branch.

[0010] For example, in some embodiments of the present application, the power electronic unit includes one power electronic module or at least two power electronic modules connected in series.

[0011] For example, in some embodiments of the present application, the power electronic module includes: a first power electronic switch, a second power electronic switch and a first voltage source, the positive pole of the first power electronic switch is connected to the positive pole of the first voltage source, the negative pole of the first power electronic switch is connected to the positive pole of the second power electronic switch and then leads to an external wire, and the negative pole of the second power electronic switch is connected to the negative pole of the first voltage source and then leads to an external wire; or a third power electronic switch, a fourth power electronic switch, a fifth power electronic switch, a sixth power electronic switch and a second voltage source, the positive pole of the third power electronic switch is connected to the positive pole of the fifth power electronic switch and the positive pole of the second voltage source, respectively, and the negative pole of the fourth power electronic switch is connected to the positive pole of the fifth power electronic switch and the positive pole of the second voltage source, respectively. The negative electrode of the sixth power electronic switch is connected to the negative electrode of the second voltage source, the negative electrode of the third power electronic switch is connected to the positive electrode of the fourth power electronic switch and then leads to an external wire, and the negative electrode of the fifth power electronic switch is connected to the positive electrode of the sixth power electronic switch and then leads to an external wire; or a seventh power electronic switch, an eighth power electronic switch, a third voltage source and a fourth voltage source, the positive electrode of the seventh power electronic switch is connected to the positive electrode of the third voltage source, the negative electrode of the eighth power electronic switch is connected to the negative electrode of the fourth voltage source, the negative electrode of the seventh power electronic switch is connected to the positive electrode of the eighth power electronic switch and then leads to an external wire, and the negative electrode of the third voltage source is connected to the positive electrode of the fourth voltage source and then leads to an external wire.

[0012] For example, in some embodiments of the present application, the first power electronic switch, the second power electronic switch, the third power electronic switch, the fourth power electronic switch, the fifth power electronic switch, the sixth power electronic switch, the seventh power electronic switch and the eighth power electronic switch include a first-level power semiconductor device, or at least two-level power semiconductor devices are connected in series or in parallel, wherein: the power semiconductor device includes a fully-controlled power semiconductor device or a half-controlled power semiconductor device; the first voltage source, the second voltage source, the third voltage source and the fourth voltage source include at least one of a pre-charged capacitor, an energy storage battery and an AC rectifier power supply.

[0013] For example, in some embodiments of the present application, the fully-controlled power semiconductor device includes at least one of an IGBT, an IEGT, an IGCT, a MOSFET, and a GTO; and the half-controlled power semiconductor device includes a thyristor.

[0014] For example, in some embodiments of the present application, the first mechanical switch or the second mechanical switch includes one mechanical switch, or at least two mechanical switches connected in series or in parallel; the oscillation capacitor includes one capacitor, or at least two capacitors connected in series or in parallel; the oscillation inductor includes one inductor, or at least two inductors connected in series or in parallel; the first nonlinear resistor includes one nonlinear resistor, or at least two nonlinear resistors connected in series or in parallel.

[0015] According to the second aspect of the present application, at least one embodiment of the present application provides a control method for a current breaking device as described in any one of the first aspects, comprising: a. in the event of a system fault, outputting a tripping instruction to disconnect the first mechanical switch of the main branch; b. when the first mechanical switch is separated to the insulation position, triggering the power electronic unit to output a single-pulse or multi-pulse square wave voltage to stimulate the oscillation capacitor and the oscillation inductor to oscillate, so that the transfer branch generates an oscillating current with an amplitude equal to and opposite to the fault current and the oscillating current causes the first mechanical switch to cross zero and turn off; c. corresponding to the situation where the first mechanical switch is turned off at zero, the fault current is given The oscillation capacitor of the transfer branch is charged. When the voltage across the oscillation capacitor is greater than the operating voltage of the first nonlinear resistor or the second nonlinear resistor, the fault current is transferred to the first nonlinear resistor or the second nonlinear resistor, and the fault current dissipates to zero; d. Open the second mechanical switch of the isolation branch; e. Close the first mechanical switches of the main branch in groups to discharge the oscillation capacitor of the transfer branch through the first nonlinear resistor of the main branch; f. Output a reclosing command to close the second mechanical switch of the isolation branch; g. When the current interrupting device recloses on the fault system, re-execute step a.

[0016] For example, in some embodiments of the present application, it also includes: when there is no fault in the system, the first mechanical switch of the main branch is in a closed state, the second mechanical switch of the isolation branch is in a closed state, and the power electronic module of the transfer branch is in a locked state or a cut-off state.

[0017] For example, in some embodiments of the present application, opening the second mechanical switch of the isolation branch includes: executing step d during the execution of step a, step b, or step c.

[0018] The present application provides a current breaking device and a control method thereof. When the current breaking device is opened, by controlling the operating states of the internal components of the main branch and the transfer branch, the transfer branch generates an oscillating current with an amplitude equal to and a direction opposite to the fault current, thereby reliably shutting down the main branch, overcoming the problems of high risk of reignition of mechanical switches, long shutdown time for small currents, significant system oscillations, and high equipment costs, and is conducive to large-scale promotion and application in AC and DC power transmission and distribution systems; by closing multiple groups of mechanical switches in the main branch one by one, the energy of the oscillation capacitor during the last opening operation is released, effectively reducing the size of the closing / reclosing inrush current and improving the life of the mechanical switch.

[0019] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] By describing in detail exemplary embodiments thereof with reference to the accompanying drawings, the above and other objects, features and advantages of the present application will become more apparent. The drawings described below are only some embodiments of the present application, and are not intended to limit the present application.

[0021] Figure 1 A first embodiment of an exemplary current interrupting device is shown;

[0022] Figure 2 A second embodiment of an exemplary current interrupting device is shown;

[0023] Figure 3 A third embodiment of an exemplary current interrupting device is shown;

[0024] Figure 4 A fourth embodiment of an exemplary current interrupting device is shown;

[0025] Figure 5 A fifth embodiment of an exemplary current interrupting device is shown;

[0026] Figure 6A A first embodiment of an exemplary power electronic module is shown;

[0027] Figure 6B A second embodiment of an exemplary power electronic module is shown;

[0028] Figure 6C A third embodiment of an exemplary power electronic module is shown;

[0029] Figure 7 A flow chart showing an exemplary control method of a current interrupting device;

[0030] Figure 8A A circuit structure diagram of an exemplary passive power electronic module is shown in Embodiment 1;

[0031] Figure 8B A circuit structure diagram of an exemplary passive power electronic module according to embodiment 2 is shown;

[0032] Figure 8C A third embodiment of a circuit structure diagram showing an exemplary passive power electronic module;

[0033] Figure 8D A fourth embodiment of a circuit structure diagram showing an exemplary passive power electronic module;

[0034] Figure 9A A first embodiment of an extended connection diagram of an exemplary current interrupting device is shown;

[0035] Figure 9BA second embodiment showing an extended connection diagram of an exemplary current interrupting device;

[0036] Figure 9C A third embodiment of an extended connection diagram of an exemplary current interrupting device is shown. DETAILED DESCRIPTION

[0037] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the drawings represent like or similar parts, and thus repetitive description thereof will be omitted.

[0038] The described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other methods, components, materials, devices, etc. may be employed. In these cases, well-known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0039] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents, operations, or steps, nor must they be executed in the order described. For example, some operations or steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0040] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0041] Those skilled in the art will understand that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present application, and therefore cannot be used to limit the scope of protection of the present application.

[0042] The present application proposes a current interrupting device. The current interrupting device includes a main branch, a transfer branch, and an isolation branch. The main branch is connected in parallel with the transfer branch, and the isolation branch is connected in series with the main branch. The main branch includes at least two groups of current-carrying units connected in series. The current-carrying units include a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch includes an oscillating capacitor. The isolation branch includes a second mechanical switch. An oscillating inductor and a power electronic unit are connected in series within a parallel loop of the main branch and the transfer branch. The oscillating inductor is connected in series within the main branch or the transfer branch, and the power electronic unit is connected in series within the main branch or the transfer branch.

[0043] Figure 1 A first embodiment of an exemplary current interrupting device is shown.

[0044] like Figure 1 As shown, the current interrupting device includes a main branch (1), a transfer branch (2), and an isolation branch (3). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) includes at least two groups of flow units connected in series. The flow units include a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) includes an oscillation capacitor, an oscillation inductor, and a power electronic unit connected in series. The isolation branch (3) includes at least one second mechanical switch.

[0045] Figure 2 A second embodiment of an exemplary current interrupting device is shown.

[0046] like Figure 2 As shown, the current interrupting device includes a main branch (1), a transfer branch (2), an isolation branch (3) and a second nonlinear resistor (4). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) includes at least two groups of flow units connected in series. The flow units include a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) includes an oscillation capacitor, an oscillation inductor and a power electronic unit connected in series. The isolation branch (3) includes at least one second mechanical switch. The second nonlinear resistor (4) is connected in parallel with the oscillation capacitor.

[0047] Figure 3 A third embodiment of an exemplary current interrupting device is shown.

[0048] like Figure 3As shown, the current interrupting device includes a main branch (1), a transfer branch (2), an isolation branch (3) and a second nonlinear resistor (4). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) includes at least two groups of flow units connected in series. The flow units include a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) includes an oscillation capacitor, an oscillation inductor and a power electronic unit connected in series. The isolation branch (3) includes at least one second mechanical switch. The second nonlinear resistor (4) is connected in parallel with the series branch of the oscillation capacitor and the oscillation inductor.

[0049] Figure 4 A fourth embodiment of an exemplary current interrupting device is shown.

[0050] like Figure 4 As shown, the current interrupting device includes a main branch (1), a transfer branch (2), an isolation branch (3) and a second nonlinear resistor (4). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) includes at least two groups of flow units connected in series. The flow units include a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) includes an oscillation capacitor, an oscillation inductor and a power electronic unit connected in series. The isolation branch (3) includes at least one second mechanical switch. The second nonlinear resistor (4) is connected in parallel with the series branch of the oscillation capacitor and the power electronic unit.

[0051] Figure 5 A fifth embodiment of an exemplary current interrupting device is shown.

[0052] like Figure 5 As shown, the current interrupting device includes a main branch (1), a transfer branch (2), an isolation branch (3) and a second nonlinear resistor (4). The main branch (1) is connected in parallel with the transfer branch (2), and the isolation branch (3) is connected in series with the main branch (1). The main branch (1) includes at least two groups of flow units connected in series. The flow units include a first mechanical switch and a first nonlinear resistor connected in parallel. The transfer branch (2) includes an oscillation capacitor, an oscillation inductor and a power electronic unit connected in series. The isolation branch (3) includes at least one second mechanical switch. The second nonlinear resistor (4) is connected in parallel with the transfer branch (2).

[0053] According to some embodiments, the power electronic unit includes one power electronic module or at least two power electronic modules connected in series.

[0054] Figure 6A A first embodiment of an exemplary power electronic module is shown.

[0055] like Figure 6AAs shown, the power electronic module includes a first power electronic switch 1a, a second power electronic switch 2a, and a first voltage source 1b. The positive electrode of the first power electronic switch 1a is connected to the positive electrode of the first voltage source 1b, the negative electrode of the first power electronic switch 1a is connected to the positive electrode of the second power electronic switch 2a, and then an external wire is connected to the negative electrode of the second power electronic switch 2a. The negative electrode of the second power electronic switch 2a is connected to the negative electrode of the first voltage source 1b, and then an external wire is connected to the negative electrode of the first voltage source 1b.

[0056] Figure 6B A second embodiment of an exemplary power electronic module is shown.

[0057] like Figure 6B As shown, the power electronic module includes a third power electronic switch 3a, a fourth power electronic switch 4a, a fifth power electronic switch 5a, a sixth power electronic switch 6a, and a second voltage source 2b. The positive electrode of the third power electronic switch 3a is connected to the positive electrode of the fifth power electronic switch 5a and the positive electrode of the second voltage source 2b, respectively. The negative electrode of the fourth power electronic switch 4a is connected to the negative electrode of the sixth power electronic switch 6a and the negative electrode of the second voltage source 2b, respectively. The negative electrode of the third power electronic switch 3a is connected to the positive electrode of the fourth power electronic switch 4a and then leads to an external wire. The negative electrode of the fifth power electronic switch 5a is connected to the positive electrode of the sixth power electronic switch 6a and then leads to an external wire.

[0058] Figure 6C A third embodiment of an exemplary power electronic module is shown.

[0059] like Figure 6C As shown, the power electronic module includes a seventh power electronic switch 7a, an eighth power electronic switch 8a, a third voltage source 3b and a fourth voltage source 4b. The positive electrode of the seventh power electronic switch 7a is connected to the positive electrode of the third voltage source 3b, the negative electrode of the eighth power electronic switch 8a is connected to the negative electrode of the fourth voltage source 4b, the negative electrode of the seventh power electronic switch 7a is connected to the positive electrode of the eighth power electronic switch 8a and then leads to an external connection, and the negative electrode of the third voltage source 3b is connected to the positive electrode of the fourth voltage source 4b and then leads to an external connection.

[0060] According to some embodiments, the first power electronic switch 1a, the second power electronic switch 2a, the third power electronic switch 3a, the fourth power electronic switch 4a, the fifth power electronic switch 5a, the sixth power electronic switch 6a, the seventh power electronic switch 7a, and the eighth power electronic switch 8a include a single-stage power semiconductor device, or at least two stages of power semiconductor devices connected in series or in parallel. The power semiconductor devices include fully controlled power semiconductor devices or partially controlled power semiconductor devices. Fully controlled power semiconductor devices include at least one of IGBTs, IEGTs, IGCTs, MOSFETs, and GTOs. Half-controlled power semiconductor devices include thyristors.

[0061] The first voltage source 1b, the second voltage source 2b, the third voltage source 3b, and the fourth voltage source 4b include at least one of a pre-charged capacitor, an energy storage battery, and an AC rectifier power supply. To protect the voltage source from overvoltage damage during current shutdown, overvoltage protection measures, such as lightning arresters or chopper circuits, may be connected in parallel across the voltage source.

[0062] The first or second mechanical switch includes one mechanical switch, or at least two mechanical switches connected in series or in parallel. These are typically fast-acting switches, which can utilize electromagnetic repulsion, permanent magnetism, or explosive mechanisms. When multiple fast switches are connected in series, an RC circuit is typically connected in parallel next to each fast switch to improve voltage balancing.

[0063] The oscillation capacitor includes one capacitor, or at least two capacitors connected in series or in parallel.

[0064] The oscillating inductor includes one inductor, or at least two inductors connected in series or in parallel.

[0065] The first nonlinear resistor includes one nonlinear resistor, or at least two nonlinear resistors connected in series or in parallel. The nonlinear resistor is usually a zinc oxide arrester.

[0066] Figure 7 A flow chart of an exemplary control method of a current interrupting device is shown.

[0067] When the system does not have a fault, the initial state of the current interrupting device is closed, the current flows through the main branch (1) and the isolation branch (3), the first mechanical switch of the main branch (1) is in a closed state, the second mechanical switch of the isolation branch (3) is in a closed state, and the power electronic module of the transfer branch (2) is in a locked state or a cut-off state. When a fault occurs in the system, the following opening and reclosing operations are performed.

[0068] In step S701, a tripping command is output to disconnect the first mechanical switch of the main branch.

[0069] The current interrupting device receives the tripping command and opens the first mechanical switch of the main branch.

[0070] In step S702, when the first mechanical switch is separated to the insulation position, the power electronic unit is triggered to output a single-pulse or multi-pulse square wave voltage to excite the oscillation capacitor and the oscillation inductor to oscillate, so that the transfer branch generates an oscillating current with an amplitude equal to and opposite to the fault current. The oscillating current causes the first mechanical switch to cross zero and turn off.

[0071] According to some embodiments, when the current interrupting device is used for a load switch, the load current that is usually shut off is relatively small, and the power electronic unit can be designed to have a single-pulse output, with a pulse frequency close to the resonant frequency of the oscillating capacitor and the oscillating inductor, and the generated single-pulse current peak value is greater than the load current amplitude; when the current interrupting device is used for a circuit breaker, the fault current that is usually shut off is relatively large, and the power electronic unit can be designed to have a multi-pulse output, with a pulse frequency close to the resonant frequency of the oscillating capacitor and the oscillating inductor, and the continuously increasing current peak value generated by multiple oscillations is greater than the fault current amplitude.

[0072] In step S703, corresponding to the case where the first mechanical switch is turned off at zero point, the fault current charges the oscillation capacitor of the transfer branch. When the voltage across the oscillation capacitor is greater than the operating voltage of the first nonlinear resistor or the second nonlinear resistor, the fault current is transferred to the first nonlinear resistor or the second nonlinear resistor, and the fault current dissipates to zero.

[0073] In step S704 , the second mechanical switch of the isolation branch is opened.

[0074] According to some embodiments, the step of opening the second mechanical switch of the isolation branch may be performed when executing steps S701 , S702 , and S703 .

[0075] In step S705 , the first mechanical switches of the main branch are closed group by group, so that the oscillation capacitor of the transfer branch is discharged through the first nonlinear resistor of the main branch.

[0076] In step S706, a reclosing instruction is output to close the second mechanical switch of the isolation branch.

[0077] In the case that the current interrupting device is overlapped with the faulty system, the opening operation is performed again and step S701 is re-executed; if the current interrupting device is overlapped with the normal system, the reclosing is successful.

[0078] The current breaking device and control method provided in the present application, when the current breaking device is opened, by controlling the operating status of the internal components of the main branch and the transfer branch, the transfer branch generates an oscillating current with an amplitude equal to and a direction opposite to the fault current, thereby reliably shutting down the main branch, overcoming the problems of high risk of reignition of mechanical switches, long shutdown time for small currents, significant system oscillations, and high equipment costs, and is conducive to large-scale promotion and application in AC and DC power transmission and distribution systems; by closing multiple groups of mechanical switches in the main branch one by one, the energy release of the oscillation capacitor during the last opening operation is realized, effectively reducing the size of the closing / reclosing inrush current and improving the life of the mechanical switch.

[0079] According to some embodiments, the oscillating inductor in the transfer branch of the present application can be arranged in the main branch. An oscillating inductor can be directly connected in series in the main branch, or an oscillating inductor can be connected in series in each current-passing unit. The oscillating inductor arranged in the main branch can be a linear inductor or a saturated inductor.

[0080] According to some embodiments, the power electronic unit in the transfer branch of the present application can also be arranged in the main branch. Multiple power electronic modules can be directly connected in series in the main branch, or multiple power electronic modules can be connected in series in each flow unit. In this case, in addition to the active power electronic module topology in Figure 6, the power electronic module can also be Figures 8A-8D The passive power electronic module topology is shown.

[0081] Figure 8A The circuit structure diagram of an exemplary passive power electronic module in embodiment 1 is shown, including two power electronic switches and a nonlinear resistor connected in parallel and end to end in series.

[0082] Figure 8B The circuit structure diagram of the exemplary passive power electronic module in embodiment 2 is shown, including two end-to-end parallel power electronic switches and a nonlinear resistor connected in parallel.

[0083] Figure 8C A circuit structure diagram of an exemplary passive power electronic module, embodiment 3, is shown, including four power electronic switches and a nonlinear resistor. The four power electronic switches form a full-bridge circuit, and the nonlinear resistor is connected in parallel to the DC side of the full-bridge circuit.

[0084] Figure 8D A fourth embodiment of the circuit structure diagram of an exemplary passive power electronic module is shown, which includes four diodes, a power electronic switch and a nonlinear resistor. The four diodes constitute a diode full-bridge circuit, the power electronic switch is connected in parallel to the DC side of the diode full-bridge circuit, and the nonlinear resistor is connected in parallel to the DC side or the AC side of the full-bridge circuit.

[0085] This application can realize flexible expansion by connecting multiple current interrupting devices in a modular manner, such as Figure 9A As shown, it can meet the application requirements of high-voltage systems or the requirements of compact engineering structure design.

[0086] The present application can also realize flexible expansion by modularizing the parallel connection of the main branch and the transfer branch, such as Figure 9B As shown, it can meet the application requirements of high-voltage systems or the requirements of compact engineering structure design.

[0087] This application can also use modular series connection to achieve flexible expansion of the transfer branch, such as Figure 9C As shown, it can meet the application requirements of high-voltage systems or the requirements of compact engineering structure design.

[0088] It should be clearly understood that this application describes how to form and use specific examples, but this application is not limited to any details of these examples. On the contrary, based on the teaching of the content disclosed in this application, these principles can be applied to many other embodiments.

[0089] Furthermore, it should be noted that the aforementioned figures are merely illustrative of the processes included in the methods according to exemplary embodiments of the present application and are not intended to be limiting. It is readily understood that the processes illustrated in the aforementioned figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0090] While the exemplary embodiments of the present application have been specifically illustrated and described above, it should be understood that the present application is not limited to the detailed structures, configurations, or implementations described herein; rather, the present application is intended to encompass various modifications and equivalent configurations within the spirit and scope of the appended claims.

Claims

1. A current interrupting device, characterized in that: include: a main branch, the main branch comprising at least two groups of flow-through units connected in series, wherein the flow-through units comprise a first mechanical switch and a first nonlinear resistor connected in parallel; a transfer branch, the transfer branch being connected in parallel with the main branch, the transfer branch comprising an oscillation capacitor; an isolation branch, the isolation branch being connected in series with the main branch, the isolation branch comprising a second mechanical switch; and An oscillating inductor and a power electronic unit are connected in series within a parallel loop of the main branch and the transfer branch, the oscillating inductor is connected in series inside the main branch or inside the transfer branch, and the power electronic unit is connected in series inside the main branch or inside the transfer branch; The main branch is used to discharge the oscillation capacitor through the first nonlinear resistor by closing the first mechanical switches group by group in the event of a system failure; The power electronic unit is used to output a single-pulse or multi-pulse square wave voltage to excite the oscillation capacitor and the oscillation inductor to oscillate when a fault occurs in the system.

2. The current interrupting device according to claim 1, characterized in that: Also includes: a second nonlinear resistor, wherein the second nonlinear resistor is connected in parallel with the oscillation capacitor, or in parallel with the series branch of the oscillation capacitor and the oscillation inductor, or in parallel with the series branch of the oscillation capacitor and the power electronic unit, or in parallel with the transfer branch.

3. The current interrupting device according to claim 1, characterized in that: The power electronic unit includes one power electronic module or at least two power electronic modules connected in series.

4. The current interrupting device according to claim 3, characterized in that: The power electronics module comprises: a first power electronic switch, a second power electronic switch, and a first voltage source, wherein the positive electrode of the first power electronic switch is connected to the positive electrode of the first voltage source, the negative electrode of the first power electronic switch is connected to the positive electrode of the second power electronic switch and then leads to an external wire, and the negative electrode of the second power electronic switch is connected to the negative electrode of the first voltage source and then leads to an external wire; or a third power electronic switch, a fourth power electronic switch, a fifth power electronic switch, a sixth power electronic switch, and a second voltage source, wherein the positive electrode of the third power electronic switch is connected to the positive electrode of the fifth power electronic switch and the positive electrode of the second voltage source, respectively, the negative electrode of the fourth power electronic switch is connected to the negative electrode of the sixth power electronic switch and the negative electrode of the second voltage source, respectively, the negative electrode of the third power electronic switch is connected to the positive electrode of the fourth power electronic switch and then leads to an external wire, and the negative electrode of the fifth power electronic switch is connected to the positive electrode of the sixth power electronic switch and then leads to an external wire; or a seventh power electronic switch, an eighth power electronic switch, a third voltage source, and a fourth voltage source, wherein the positive electrode of the seventh power electronic switch is connected to the positive electrode of the third voltage source, the negative electrode of the eighth power electronic switch is connected to the negative electrode of the fourth voltage source, the negative electrode of the seventh power electronic switch is connected to the positive electrode of the eighth power electronic switch and then leads to an external wire, and the negative electrode of the third voltage source is connected to the positive electrode of the fourth voltage source and then leads to an external wire.

5. The current interrupting device according to claim 4, characterized in that: The first power electronic switch, the second power electronic switch, the third power electronic switch, the fourth power electronic switch, the fifth power electronic switch, the sixth power electronic switch, the seventh power electronic switch, and the eighth power electronic switch include one-stage power semiconductor devices, or at least two-stage power semiconductor devices connected in series or in parallel, wherein: The power semiconductor device includes a fully controlled power semiconductor device or a half-controlled power semiconductor device; The first voltage source, the second voltage source, the third voltage source and the fourth voltage source include at least one of a pre-charge capacitor, an energy storage battery and an AC rectifier power supply.

6. The current interrupting device according to claim 5, characterized in that: The fully controlled power semiconductor device includes at least one of IGBT, IEGT, IGCT, MOSFET and GTO; The half-controlled power semiconductor device includes a thyristor.

7. The current interrupting device according to claim 1, characterized in that: The first mechanical switch or the second mechanical switch includes one mechanical switch, or at least two mechanical switches connected in series or in parallel; The oscillation capacitor comprises one capacitor, or at least two capacitors connected in series or in parallel; The oscillating inductor includes one inductor, or at least two inductors connected in series or in parallel; The first nonlinear resistor includes one nonlinear resistor, or at least two nonlinear resistors connected in series or in parallel.

8. A method for controlling a current interrupting device according to any one of claims 1 to 7, characterized in that: include: a. In the event of a system failure, output a trip command to disconnect the first mechanical switch of the main branch; b. When the first mechanical switch is opened to the insulation open position, triggering the power electronic unit to output a single-pulse or multi-pulse square wave voltage to excite the oscillation capacitor and the oscillation inductor to oscillate, causing the transfer branch to generate an oscillating current with an amplitude equal to and a direction opposite to the fault current, and the oscillating current causes the first mechanical switch to turn off through zero; c. In response to the zero-crossing shutdown of the first mechanical switch, the fault current charges the oscillation capacitor of the transfer branch. When the voltage across the oscillation capacitor is greater than the operating voltage of the first nonlinear resistor or the second nonlinear resistor, the fault current is transferred to the first nonlinear resistor or the second nonlinear resistor, and the fault current dissipates to zero. d. Opening the second mechanical switch of the isolation branch; e. Closing the first mechanical switches of the main branches in groups, so that the oscillation capacitors of the transfer branches discharge through the first nonlinear resistors of the main branches; f. outputting a reclosing command to close the second mechanical switch of the isolation branch; g. When the current interrupting device overlaps with the faulty system, re-execute step a.

9. The control method according to claim 8, wherein: Also includes: When no system failure occurs, the first mechanical switch of the main branch is in a closed state, the second mechanical switch of the isolation branch is in a closed state, and the power electronic module of the transfer branch is in a locked state or a cut-off state.

10. The control method according to claim 8, wherein: The second mechanical switch for opening the isolation branch comprises: During the execution of step a, step b or step c, execute step d.

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