Active modular converter self-check control method, electronic device and storage medium

Abstract

The present application provides a self-check control method for an active modular converter, comprising: disconnecting the AC switch; controlling the transmission power between the commutation chains, wherein one commutation chain controls the AC voltage and the other commutation chain controls the transmission power, so that the current forms a circulation between the commutation chains; and checking whether each submodule in the commutation chain operates normally. The above technical solution does not require additional costs, and can periodically make the power semiconductor devices and energy storage units in the power unit work, and form a circulation between the commutation chains through the control method. The method is simple and easy to implement, and greatly improves the reliability of the device.

Description

Technical Field

[0001] The present application relates to the technical field of high-power electronic power conversion, and in particular to an active modular converter self-check control method, electronic equipment and storage medium. Background Art

[0002] In the field of large-capacity and high-power power electronic conversion technology, multilevel converters use modular cascade technology to integrate energy storage units into sub-modules. They have the advantages of high modularity, good harmonic characteristics, and low equivalent switching frequency. They have become the standard topology in the field of high-voltage power electronics. By integrating energy storage units as sub-modules in modular multilevel converters, AC / DC power conversion and energy storage can be achieved simultaneously.

[0003] The active modular converter thus born is a feasible solution that can effectively meet the access requirements of the energy storage system and alleviate or isolate the propagation of faults between AC and DC systems. The active modular converter is put into operation or withdrawn according to the operation requirements. When it is in the withdrawn state for a long time, the power unit and the energy storage unit are in the standby state for a long time. The power unit and the energy storage unit are not working for a long time, and it is impossible to determine whether they are damaged. When the active modular converter needs to be put into operation, if the device is damaged, the equipment will not be able to achieve the voltage support and power support functions. Therefore, it is necessary to perform self-inspection on the equipment. At present, there is no better way to perform self-inspection on active modular converters. Summary of the invention

[0004] Based on this, the present application provides an active modular converter self-check control method to detect the performance of the active modular converter.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect of the present application, a self-checking control method for an active modular converter is proposed, wherein the converter comprises six commutation chains, the six commutation chains constitute a three-phase six-bridge arm converter, or comprises three commutation chains, the three commutation chains constitute an angle-connected converter, the AC side of the converter is connected to the power grid through an AC switch, wherein the commutation chain comprises N submodules connected in series, N is an integer greater than or equal to 2; the submodule comprises an energy storage unit, a power unit, an interface unit and a bypass switch; the power unit is a full-bridge circuit or a half-bridge circuit, and the AC side of the power unit is connected in parallel with a bypass switch; the energy storage unit is connected to the DC side of the power unit through the interface unit; the self-checking control method comprises:

[0007] Disconnecting the AC switch;

[0008] Controlling the transmission power between the commutation chains, wherein one commutation chain controls the AC voltage and the other commutation chain controls the transmission power, so that the current forms a circulation between the commutation chains;

[0009] Check whether each submodule in the commutation chain operates normally.

[0010] According to some embodiments, the submodule further includes a submodule control unit, and the submodule control unit obtains energy from the energy storage unit.

[0011] According to some embodiments, the interface unit includes a DC / DC converter or a filter and a DC switch connected in series; the filter includes an inductor and / or a capacitor; the DC / DC converter includes a power semiconductor device, which is an isolated or non-isolated type.

[0012] According to some embodiments, the controlling the transmission power between the commutation chains, wherein one commutation chain controls the AC voltage and another commutation chain controls the transmission power, so that the current forms a circulation between the commutation chains, includes:

[0013] Select two commutation chains as the commutation chains to be tested;

[0014] Starting the interface unit in the commutation chain under test;

[0015] Unlock the power semiconductor devices in the power unit of the commutation chain under test;

[0016] The transmission power between two commutation chains is controlled, wherein one commutation chain controls the AC voltage and the other commutation chain controls the transmission power, so that current forms a circulation between the commutation chains.

[0017] According to some embodiments, when the interface unit includes a DC / DC converter, the starting the interface unit in the commutation chain under test includes: unlocking the power semiconductor device in the interface unit;

[0018] When the interface unit includes a filter and a DC switch connected in series, starting the interface unit in the commutation chain under test includes: closing the DC switch.

[0019] According to some embodiments, the DC voltage of the converter submodule is kept stable while controlling the transmission power between the two converter chains.

[0020] According to some embodiments, during the control of the transmission power between two commutation chains, the direction of the transmission power is controlled so that the energy storage unit in the commutation chain submodule is periodically switched between charging and discharging operating conditions to maintain a stable state of charge of the energy storage unit.

[0021] According to some embodiments, the method further includes closing a submodule bypass switch when a submodule failure is detected, recording the failed submodule, and shutting down the system for maintenance when the number of failed submodules exceeds the number of redundant submodules.

[0022] In a second aspect of the present application, an electronic device is proposed, comprising: a processor; and a memory storing computer instructions, wherein when the computer instructions are executed by the processor, the processor executes the active modular inverter self-test control method described above.

[0023] The third aspect of the present application proposes a non-transitory computer storage medium storing a computer program. When the computer program is executed by multiple processors, the processors execute the active modular converter self-check control method described above.

[0024] Compared with the prior art, this application has the following beneficial effects:

[0025] (1) The method provided by the present invention does not require additional costs and can periodically operate the power semiconductor devices and energy storage units in the power unit. A loop current is formed between the commutation chains through a control method. The method is simple and easy to implement, which greatly improves the reliability of the device.

[0026] (2) When the device is performing self-test, the AC switch is disconnected, which will not affect the grid at all. If the self-test fails, the fault will be reported, and the equipment can be repaired during this period.

[0027] (3) During the self-test process, the current flows through the energy storage unit, interface unit, and power unit. When any unit of the equipment fails, it can be effectively detected, and the equipment can be fully and accurately tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without exceeding the scope of protection required by the present application.

[0029] Figure 1 An active modular converter according to an embodiment of the present application;

[0030] Figure 2 Another active modular converter according to an embodiment of the present application;

[0031] Figure 3 This is a schematic diagram of the structure of an interface unit according to an embodiment of the present application;

[0032] Figure 4This is a schematic diagram of another interface unit structure according to an embodiment of the present application;

[0033] Figure 5 A flow chart of a self-check control method for an active modular converter according to an embodiment of the present application;

[0034] Figure 6 A flow chart of a method for controlling transmission power between commutation chains according to an embodiment of the present application;

[0035] Figure 7 A structural diagram of an electronic device provided by the present application is shown. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0037] It should be understood that although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another component. Therefore, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of the present application. As used herein, the term "and / or" includes any one of the associated listed items and all combinations of one or more.

[0038] Those skilled in the art will appreciate that the drawings are only schematic diagrams of example embodiments and may not be to scale. The modules or processes in the drawings are not necessarily required to implement the present application and therefore cannot be used to limit the scope of protection of the present application.

[0039] The present invention provides a self-checking control method for an active modular converter, wherein the converter includes six converter chains constituting a three-phase six-bridge-arm converter. Figure 1 As shown, or including three commutation chains, forming an angular connection converter, such as Figure 2 As shown. The AC side of the converter is connected to the power grid through an AC switch 1, wherein the commutation chain includes N submodules 2 connected in series, where N is an integer greater than or equal to 2. Submodule 2 includes an energy storage unit 4, a power unit 5, an interface unit 6 and a bypass switch 7. The power unit 5 is a full-bridge circuit or a half-bridge circuit, wherein the full-bridge circuit includes a DC capacitor and four power semiconductor switching devices, and the half-bridge circuit includes two power semiconductor switching devices; a bypass switch is connected in parallel on the AC side of the power unit 5. The energy storage unit 4 is connected to the DC side of the power unit 5 through the interface unit 6. The energy storage unit 4 can be a battery or a supercapacitor.

[0040] In some embodiments, the submodule 2 further includes a submodule control unit, and the submodule control unit obtains energy from the energy storage unit.

[0041] In some embodiments, the interface unit connected between the energy storage unit and the power unit includes a filter 8 composed of an inductor and / or a capacitor connected in series with a DC switch 9, such as Figure 3 Or a DC / DC converter, the DC / DC converter includes a power semiconductor device, which is an isolated or non-isolated type, such as Figure 4 An embodiment of an isolated DC / DC converter is shown.

[0042] An embodiment of the present invention provides a converter self-check control method as follows Figure 5 As shown, the following steps are included:

[0043] S100: Turn off the AC switch.

[0044] S200, controlling the transmission power between the commutation chains, wherein one commutation chain controls the AC voltage and the other commutation chain controls the transmission power, so that current forms a circulation between the commutation chains.

[0045] S300, check whether each submodule in the commutation chain operates normally. That is, check the operating status of all submodules in the tested commutation chain, mainly to see whether the voltage and current of the submodule are within the normal range and whether there is any fault reported.

[0046] In some embodiments, Figure 6 As shown, controlling the transmission power between the commutation chains specifically includes the following process:

[0047] S201: Select two commutation chains as commutation chains to be tested.

[0048] S202: Start the interface unit in the commutation chain under test.

[0049] When the interface unit comprises a DC / DC converter, starting the interface unit in the commutation chain under test comprises: unlocking the power semiconductor device in the interface unit.

[0050] When the interface unit includes a filter and a DC switch connected in series, starting the interface unit in the commutation chain under test includes: closing the DC switch.

[0051] S203: Unlock the power semiconductor devices in the commutation chain power unit under test.

[0052] S204: Control the transmission power between the two commutation chains, wherein one commutation chain controls the AC voltage and the other commutation chain controls the transmission power, so that current forms a circulation between the commutation chains.

[0053] In some embodiments, while controlling the transmission power between the two converter chains, the DC voltage of the converter submodule is kept stable to ensure the safety of the test and prevent damage to the equipment.

[0054] Because the battery needs to be charged and discharged to maintain balance, continuous charging or continuous discharging will cause the battery to be overcharged or over-discharged. Therefore, in some embodiments, during the control of the transmission power between the two commutation chains, the direction of the transmission power is controlled so that the energy storage unit in the commutation chain submodule is periodically switched between the charging and discharging operating conditions to maintain a stable state of charge of the energy storage unit.

[0055] In some embodiments, the self-check control method of the active modular converter further includes: when a submodule failure is detected, closing the submodule bypass switch, recording the faulty submodule, and shutting down for maintenance when the number of faulty submodules exceeds the number of redundant submodules.

[0056] Figure 7 A structural diagram of an electronic device provided by the present application is shown.

[0057] See also Figure 7 , Figure 7 An electronic device is provided, comprising a processor and a memory. The memory stores computer instructions, and when the computer instructions are executed by the processor, the processor executes the computer instructions to achieve the following Figure 5 The method and refinement scheme shown.

[0058] It should be understood that the above device embodiments are only illustrative, and the device disclosed in the present invention can also be implemented in other ways. For example, the division of units / modules described in the above embodiments is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units, modules or components can be combined, or can be integrated into another system, or some features can be ignored or not executed.

[0059] In addition, unless otherwise specified, each functional unit / module in each embodiment of the present invention may be integrated into one unit / module, each unit / module may exist physically separately, or two or more units / modules may be integrated together. The above-mentioned integrated unit / module may be implemented in the form of hardware or in the form of a software program module.

[0060] If the integrated unit / module is implemented in the form of hardware, the hardware may be a digital circuit, an analog circuit, etc. The physical implementation of the hardware structure includes but is not limited to transistors, memristors, etc. If not otherwise specified, the processor or chip may be any appropriate hardware processor, such as a CPU, a GPU, an FPGA, a DSP, an ASIC, etc. If not otherwise specified, the on-chip cache, the off-chip memory, and the memory may be any appropriate magnetic storage medium or magneto-optical storage medium, such as a resistive random access memory RRAM (Resistive Random Access Memory), a dynamic random access memory DRAM (Dynamic Random Access Memory), a static random access memory SRAM (Static Random-Access Memory), an enhanced dynamic random access memory EDRAM (Enhanced Dynamic Random Access Memory), a high-bandwidth memory HBM (High-Bandwidth Memory), a hybrid memory cube HMC (Hybrid Memory Cube), etc.

[0061] If the integrated unit / module is implemented in the form of a software program module and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a memory and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned memory includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0062] The present application also provides a non-transitory computer storage medium storing a computer program. When the computer program is executed by a plurality of processors, the processors execute the following Figure 1 The method and refinement scheme shown.

[0063] It should be clearly understood that the present application describes how to form and use specific examples, but the present application is not limited to any details of these examples. On the contrary, based on the teaching of the content disclosed in the present application, these principles can be applied to many other embodiments.

[0064] In addition, it should be noted that the above figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, and are not intended to be limiting. It is easy to understand that the processes shown in the above figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.

[0065] The exemplary embodiments of the present application are specifically shown and described above. It should be understood that the present application is not limited to the detailed structures, configurations or implementations described herein; on the contrary, the present application is intended to cover various modifications and equivalent configurations included in the spirit and scope of the appended claims.

Claims

1. A self-check control method for an active modular converter, characterized in that: The converter includes 6 commutation chains, which constitute a three-phase six-bridge arm converter, or includes 3 commutation chains, which constitute an angle-connected converter, and the AC side of the converter is connected to the power grid through an AC switch, wherein the commutation chain includes N submodules connected in series, where N is an integer greater than or equal to 2; the submodule includes an energy storage unit, a power unit, an interface unit and a bypass switch; the power unit is a full-bridge circuit or a half-bridge circuit, and the AC side of the power unit is connected in parallel with a bypass switch; The energy storage unit is connected to the DC side of the power unit via the interface unit; The self-checking control method comprises: Disconnecting the AC switch; Controlling the transmission power between the commutation chains, wherein one commutation chain controls the AC voltage and the other commutation chain controls the transmission power, so that the current forms a circulation between the commutation chains; Check whether each submodule in the commutation chain operates normally.

2. The active modular converter self-check control method according to claim 1, characterized in that: The submodule further includes a submodule control unit, and the submodule control unit obtains energy from the energy storage unit.

3. The active modular converter self-check control method according to claim 1, characterized in that: The interface unit includes a DC / DC converter or a filter and a DC switch connected in series; the filter includes an inductor and / or a capacitor; the DC / DC converter includes a power semiconductor device, which is an isolated type or a non-isolated type.

4. The active modular converter self-check control method according to claim 1, characterized in that: The control of the transmission power between the commutation chains, wherein one commutation chain controls the AC voltage and the other commutation chain controls the transmission power, so that the current forms a circulation between the commutation chains, comprises: Select two commutation chains as the commutation chains to be tested; Starting the interface unit in the commutation chain under test; Unlock the power semiconductor devices in the power unit of the commutation chain under test; The transmission power between two commutation chains is controlled, wherein one commutation chain controls the AC voltage and the other commutation chain controls the transmission power, so that current forms a circulation between the commutation chains.

5. The self-check control method of active modular converter according to claim 4, characterized in that: When the interface unit includes a DC / DC converter, the starting of the interface unit in the commutation chain under test includes: unlocking the power semiconductor device in the interface unit; When the interface unit includes a filter and a DC switch connected in series, starting the interface unit in the commutation chain under test includes: closing the DC switch.

6. The self-check control method of active modular converter according to claim 4, characterized in that: While controlling the transmission power between the two converter chains, the DC voltage of the converter submodule is kept stable.

7. The self-check control method of active modular converter according to claim 4, characterized in that: During the control of the transmission power between the two commutation chains, the direction of the transmission power is controlled so that the energy storage unit in the commutation chain submodule is periodically switched between the charging and discharging operating conditions to maintain a stable state of charge of the energy storage unit.

8. The self-check control method of active modular converter according to claim 4, characterized in that: It also includes closing the submodule bypass switch and recording the faulty submodule when a submodule fault is detected, and shutting down for maintenance when the number of faulty submodules exceeds the number of redundant submodules.

9. An electronic device, characterized in that: include: processor; as well as A memory storing computer instructions, which, when executed by the processor, enables the processor to execute the control method described in any one of claims 1-8.

10. A non-transitory computer storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a plurality of processors, the processors are caused to execute the control method according to any one of claims 1 to 8.

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