Converter, control method and related device

Abstract

The invention discloses a current converter, a control method and a related device. The current converter comprises a controller, a protection bridge arm and a three-phase power bridge arm, the upper half bridge arm of each phase of the three-phase power bridge arm comprises a first switch module and a second switch module which are connected in series; the lower half bridge arm of each phase of the three-phase power bridge arm comprises a third switch module and a fourth switch module which are connected in series; the protection bridge arm comprises a fifth switch module and a sixth switch module; the first switch module, the second switch module, the third switch module and the fourth switch module are first type switch modules, and the fifth switch module and the sixth switch module are second type switch modules; the turn-off capability of the first-type switch module is smaller than or equal to that of the second-type switch module; and when commutation of the first type of switch module in the three-phase power bridge arm fails or predicted commutation fails, controlling a second type of switch module corresponding to the first type of switch module to act to assist in completing commutation. According to the scheme, normal commutation of the converter can be ensured, and the converter can operate normally.

Description

Technical Field

[0001] The present application relates to the technical field of electric power equipment, and in particular to a converter, a control method and related devices. Background Art

[0002] At present, in power systems with higher voltages, converters are used for commutation. The converters may be bidirectional converters, which can be used as both inverters and rectifiers.

[0003] The bridge arm of the converter includes switching devices, but due to the turn-off capability of the switching devices, there may be a risk of commutation failure. Summary of the invention

[0004] In view of this, the converter, control method and related devices provided in the present application can ensure successful commutation.

[0005] The present application provides a converter, comprising: a controller, a protection bridge arm and a three-phase power bridge arm; the upper half bridge arm of each phase in the three-phase power bridge arm comprises a first switch module and a second switch module connected in series; the lower half bridge arm of each phase in the three-phase power bridge arm comprises a third switch module and a fourth switch module connected in series; the protection bridge arm comprises a fifth switch module and a sixth switch module; the first switch module, the second switch module, the third switch module and the fourth switch module are all first-type switch modules, and the fifth switch module and the sixth switch module are all second-type switch modules; the shutoff capacity of the first-type switch module is less than or equal to the second-type switch module; the fifth switch module is connected in parallel at both ends of the first switch module or in parallel at both ends of the second switch module; the sixth switch module is connected in parallel at both ends of the third switch module or in parallel at both ends of the fourth switch module; the controller is used to control the action of the second-type switch module corresponding to the first-type switch module in the three-phase power bridge arm when the commutation of the first-type switch module has failed or the commutation failure is predicted, so as to assist in completing the commutation.

[0006] In a possible implementation, the first type of switch module is a fully controlled switch module; the controller is specifically used to shut down the first type of switch module and turn on the second type of switch module corresponding to the first type of switch module when the heat accumulation of the first type of switch module in the three-phase power bridge arm is greater than a first threshold value; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0007] In a possible implementation, the controller is further used to control the fifth switch module to disconnect and restore the first type of switch module that is shut down the upper half bridge arm when the operating time of the fifth switch module is greater than the first time; and to control the sixth switch module to disconnect and restore the first type of switch module that is shut down the lower half bridge arm when the operating time of the sixth switch module is greater than the first time.

[0008] In a possible implementation, the first type of switch module is an integrated gate-commutated thyristor (IGCT) module, and the second type of switch module is an insulated gate bipolar transistor (IGBT) module.

[0009] In one possible implementation, the first type of switch module is a half-controlled switch module; the controller is specifically used to turn off the first type of switch module and turn on the second type of switch module corresponding to the first type of switch module when the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than the failure threshold; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0010] In a possible implementation, the second type of switch module is an integrated gate-commutated thyristor (IGCT) module.

[0011] In a possible implementation, the controller is further used to control the operation of the second type of switch module corresponding to the first type of switch module when a fault occurs in the first type of switch module in the three-phase power bridge arm, so as to bypass the faulty first type of switch module.

[0012] The present application also provides a control method for a converter, the converter comprising: a protection bridge arm and a three-phase power bridge arm; the upper half bridge arm of each phase in the three-phase power bridge arm comprises a first switch module and a second switch module connected in series; the lower half bridge arm of each phase in the three-phase power bridge arm comprises a third switch module and a fourth switch module connected in series; the protection bridge arm comprises a fifth switch module and a sixth switch module; the first switch module, the second switch module, the third switch module and the fourth switch module are all first-type switch modules, and the fifth switch module and the sixth switch module are all second-type switch modules; the shutoff capacity of the first-type switch module is less than or equal to the second-type switch module; the fifth switch module is connected in parallel at both ends of the first switch module or in parallel at both ends of the second switch module; the sixth switch module is connected in parallel at both ends of the third switch module or in parallel at both ends of the fourth switch module; the method comprises: when the commutation of the first-type switch module in the three-phase power bridge arm has failed or the commutation failure is predicted, controlling the action of the second-type switch module corresponding to the first-type switch module to assist in completing the commutation.

[0013] In one possible implementation, the first type of switch module is a fully controlled switch module; when the commutation of the first type of switch module in the three-phase power bridge arm has failed or the commutation failure is predicted, the second type of switch module corresponding to the first type of switch module is controlled to operate to assist in completing the commutation, including: when the heat accumulation of the first type of switch module in the three-phase power bridge arm is greater than a first threshold, the first type of switch module is turned off, and the second type of switch module corresponding to the first type of switch module is turned on; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0014] A possible implementation method also includes: when the operating time of the fifth switch module is greater than the first time, controlling the fifth switch module to disconnect and restoring the first type of switch module that is shut down the upper half bridge arm; when the operating time of the sixth switch module is greater than the first time, controlling the sixth switch module to disconnect and restoring the first type of switch module that is shut down the lower half bridge arm.

[0015] In one possible implementation, the first type of switch module is a half-controlled switch module; when the commutation of the first type of switch module in the three-phase power bridge arm fails or the commutation failure is predicted, the second type of switch module corresponding to the first type of switch module is controlled to operate to assist in completing the commutation, including: when the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than the failure threshold, the first type of switch module is turned off, and the second type of switch module corresponding to the first type of switch module is turned on; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0016] A possible implementation method also includes: when a first type of switch module in the three-phase power bridge arm fails, controlling a second type of switch module corresponding to the first type of switch module to operate and bypassing the failed first type of switch module.

[0017] The present application also provides a control device, characterized in that it includes a processor and a memory, the memory is used to store programs, instructions or codes, and the processor is used to execute the programs, instructions or codes in the memory to complete the method introduced above.

[0018] The present application also provides a computer-readable storage medium storing a computer program, wherein the computer program is loaded by a processor to execute the method described above.

[0019] In the converter provided by the embodiment of the present application, when the three-phase power bridge arm is working normally, the switch module on the protection bridge arm does not work, which can reduce the overall working time of the switch module of the protection bridge arm and increase the overall life of the switch module of the protection bridge arm. Only when the switch module of the three-phase power bridge arm has failed to commutate or the commutation failure is predicted, the switch module of the protection bridge arm will work, so that the switch module of the protection bridge arm replaces the switch module of the three-phase power bridge arm to complete the commutation, which can ensure the normal commutation of the converter and make the converter operate normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a converter provided in an embodiment of the present application; Figure 2 A schematic diagram of another converter provided in an embodiment of the present application; Figure 3 A schematic diagram of the operation of a protection bridge arm in a converter provided in an embodiment of the present application; Figure 4 A schematic diagram of another converter provided in an embodiment of the present application; Figure 5 A schematic diagram of another converter provided in an embodiment of the present application; Figure 6 A schematic diagram of device junction temperature provided in an embodiment of the present application; Figure 7 A schematic diagram of heat accumulation in a buffer circuit of a switch module in different operating modes provided in an embodiment of the present application; Figure 8 A schematic diagram of another converter provided in an embodiment of the present application; Fig. 9 A flowchart of a method for controlling a converter provided in an embodiment of the present application; Fig.10 A schematic diagram of a control device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0022] See also Figure 1 , which is a schematic diagram of a converter provided in an embodiment of the present application.

[0023] The converter provided in the embodiment of the present application includes: a controller (not shown in the figure), a protection bridge arm and a three-phase power bridge arm. The three phases include phase A, phase B and phase C, and the output ends of the three-phase power bridge arm are a, b and c respectively.

[0024] The upper half of each phase of the three-phase power bridge arm includes a first switch module and a second switch module connected in series; the lower half of each phase of the three-phase power bridge arm includes a third switch module and a fourth switch module connected in series. Figure 1 As shown, the upper half bridge arm of the A phase in the three-phase power bridge arm includes a first switch module V41 and a second switch module V42 connected in series. The lower half bridge arm of the A phase in the three-phase power bridge arm includes a third switch module V11 and a fourth switch module V12 connected in series. The upper half bridge arm of the B phase in the three-phase power bridge arm includes a first switch module V61 and a second switch module V62 connected in series. The lower half bridge arm of the B phase in the three-phase power bridge arm includes a third switch module V31 and a fourth switch module V32 connected in series. The upper half bridge arm of the C phase in the three-phase power bridge arm includes a first switch module V21 and a second switch module V22 connected in series. The lower half bridge arm of the C phase in the three-phase power bridge arm includes a third switch module V51 and a fourth switch module V52 connected in series.

[0025] The protection bridge arm includes a fifth switch module T1 and a sixth switch module T2.

[0026] The first switch module, the second switch module, the third switch module and the fourth switch module are all first-category switch modules, and the fifth switch module and the sixth switch module are all second-category switch modules; the shutoff capacity of the first-category switch module is less than or equal to the second-category switch module.

[0027] The fifth switch module T1 is connected in parallel to both ends of the first switch module or to both ends of the second switch module; Figure 1 In the figure, the fifth switch module T1 is connected in parallel at two ends of the first switch tube module as an example.

[0028] The sixth switch module T2 is connected in parallel to both ends of the third switch module or in parallel to both ends of the fourth switch module; Figure 1 The sixth switch tube module T2 is connected in parallel at both ends of the fourth switch module as an example.

[0029] In addition, there are other implementation methods, for example, T1 is connected in parallel to the second switch module, such as Figure 2 As shown, T2 is connected in parallel to the third switch module, such as Figure 2 shown.

[0030] The controller is used to control the action of the second type of switch module corresponding to the first type of switch module in the three-phase power bridge arm when the commutation of the first type of switch module has failed or the commutation failure is predicted to complete the commutation. The commutation failure here does not mean that it has failed, but it is predicted that the commutation failure will occur. In order to ensure normal commutation and the normal operation of the converter, the switch module of the protection bridge arm is used to achieve commutation.

[0031] The embodiment of the present application does not specifically limit the cause of the commutation failure, for example, it may be an internal fault of the converter or an external fault.

[0032] In the converter provided by the embodiment of the present application, when the three-phase power bridge arm is working normally, the switch module on the protection bridge arm does not work. The switch module of the protection bridge arm works only when the switching of the switch module of the three-phase power bridge arm has failed or the switching failure is predicted. In this way, normal switching can be guaranteed and the normal operation of the converter can be guaranteed. In addition, since the switch module of the protection bridge arm does not participate in the work throughout the whole process and only works when needed, the power consumption of the switch module of the protection bridge arm can be reduced, and the life of the switch module of the protection bridge arm can be increased.

[0033] See also Figure 3 , which is a schematic diagram of the operation of a protection bridge arm in a converter provided in an embodiment of the present application.

[0034] When the fifth switch module T1 of the protection bridge arm works, the first switch module of the upper bridge arm of the three-phase bridge arm is bypassed, that is, V41, V61 and V21 do not work. When the sixth switch module T2 of the protection bridge arm works, the fourth switch module of the lower bridge arm of the three-phase bridge arm is bypassed, that is, V12, V32 and V52 do not work.

[0035] The embodiment of the present application does not specifically limit the implementation form of the first type of switch module, for example, it can be a fully controlled switch module or a half-controlled switch module. For example, the fully controlled switch module can be implemented using an integrated gate-commutated thyristor (IGCT) module. The half-controlled switch module can be implemented using an ordinary half-controlled thyristor module, which means that the half-controlled thyristor can only control conduction but not shutdown.

[0036] The embodiment of the present application does not specifically limit the implementation form of the second type of switch module, for example, it can be a fully controlled switch module or a half-controlled switch module. For example, the second type of switch module can be an insulated gate bipolar transistor IGBT (Insulated Gate Bipolar Transistor, IGBT) or IGCT.

[0037] A specific implementation method is introduced below with reference to the accompanying drawings.

[0038] See also Figure 4 , which is a schematic diagram of another converter provided in an embodiment of the present application.

[0039] In the converter provided in the embodiment of the present application, the first type of switch module is a fully controlled switch module, and the fully controlled switch module is IGCT as an example for introduction. The second type of switch module is IGBT as an example for introduction.

[0040] The junction temperature of the IGCT module will rise significantly when it is turned off under high current, and the energy absorbed by the buffer circuit (not shown in the figure) connected in parallel with it will also rise significantly. When the IGCT is continuously and actively turned off, a large current will be generated. Therefore, the IGCT will face the risk of commutation failure, which may cause the inverter commutation failure and affect the stable operation of the inverter. Therefore, when the switch module of the three-phase power bridge arm of the converter provided in the embodiment of the present application is an IGCT, it can be determined by heat accumulation whether it is necessary to control the switch module of the protection bridge arm to work.

[0041] The controller (not shown in the figure) is specifically used to shut down the first type of switch module and turn on the second type of switch module corresponding to the first type of switch module when the heat accumulation of the first type of switch module in the three-phase power bridge arm is greater than the first threshold value; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0042] The heat accumulation of the switch module in the embodiment of the present application generally refers to the heat accumulation of the snubber circuit corresponding to the switch module, and the heat accumulation of the snubber circuit can be measured in the converter. For the sake of convenience, the heat accumulation of the switch module is still described below.

[0043] For example, Figure 5 When the heat accumulation of any one of the switch modules among V41, V61 and V21 is greater than the first threshold, the switch module among V41, V61 and V21 whose heat accumulation is greater than the first threshold is turned off, T1 is controlled to be turned on, T1 completes the phase change, and V41, V61 and V21 all quit working, that is, the controller no longer sends a driving signal to V41, V61 and V21.

[0044] For example, when T1 is turned on, it means that the switch module on the upper half bridge arm is actively shut down, and the energy-consuming devices in the buffer circuit are overheated, which may cause the switch module to be unable to actively shut down next time. At this time, V41, V42, V61, V62, V21, and V22 of the switch module are all overheated at the same time. When T1 is put into use, V41, V61, and V21 are completely non-participatory in commutation, the switch module will slowly cool down, and the temperature will drop relatively quickly. Since V42, V62, and V22 are no longer involved in the active shutdown process, the energy-consuming devices in the buffer circuit no longer need to absorb energy during active shutdown, and can slowly return to the normal working area.

[0045] The converter provided in the embodiment of the present application can effectively alleviate the junction temperature rise caused by the heat generated by the IGCT during active commutation, as well as the heat accumulation of the buffer circuit. Taking the upper half bridge arm of phase A as an example, when the active shutdown heat accumulation of the switch modules V41 and V42 is greater than the first threshold, the trigger signal of V41 is locked, and T1 is unlocked at the same time, so that the trigger signal of T1 is consistent with V42, V42 does not perform active shutdown, and the commutation is completed by controllably shutting down T1. The junction temperatures of V41 and V42 devices under different operating modes are shown as follows: Figure 6 See Figure 7 , which is a schematic diagram of heat accumulation in the buffer circuit of the switch module with different operating modes provided in an embodiment of the present application.

[0046] The converter provided by the embodiment of the present application also needs to consider the safety and life of the switch module that protects the bridge arm. For example, T1 cannot work for a long time when it is working. When the heat of the switch module in parallel with T1 is less than or equal to the first threshold, T1 can be shut down and the switch module in parallel with T1 can be restored to work. It should be understood that there is a buffer circuit in a general converter. When the switch module is shut down, the buffer circuit will cool down and the heat accumulation will decrease. Specifically, the controller is also used to control the fifth switch module to disconnect when the operating time of the fifth switch module is greater than the first time, and restore the first type of switch module that is shut down in the upper half of the bridge arm. When the operating time of the sixth switch module is greater than the first time, the controller is also used to control the sixth switch module to disconnect and restore the first type of switch module that is shut down in the lower half of the bridge arm.

[0047] The converter provided in the above embodiment has a three-phase power bridge arm including a fully-controlled switch module. The following is an example of an implementation method in which the three-phase power bridge arm includes a half-controlled switch module with reference to the accompanying drawings.

[0048] In the converter provided in the embodiment of the present application, the first type of switch module is a half-controlled switch module.

[0049] The controller is specifically used to shut down the first type of switch module and turn on the second type of switch module corresponding to the first type of switch module when the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than the failure threshold; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0050] See also Figure 8 , which is a schematic diagram of another converter provided in an embodiment of the present application.

[0051] In the converter provided in the embodiment of the present application, the first type of switch module is a half-controlled switch module, such as a thyristor module, and the second type of switch module is specifically an IGCT module.

[0052] Figure 8 and Figure 4 The difference is, Figure 8 In the converter shown, the switch modules of the three-phase power bridge arms are thyristor modules. Figure 8 The working principle of T1 and T2 is similar to Figure 4 The same is true in , so I will not go into details here.

[0053] Figure 4 The IGCT in the embodiment determines whether a phase switching failure is about to occur by judging heat accumulation. When the switch module of the three-phase power bridge arm provided in the embodiment of the present application is a thyristor module, it can be determined whether a phase switching failure is about to occur by judging the failure characteristic value of the thyristor module.

[0054] The controller is specifically used to shut down the first type of switch module and turn on the second type of switch module corresponding to the first type of switch module when the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than the failure threshold; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0055] It should be understood that the failure characteristic value corresponding to the commutation failure of the first type of switch module is different from the failure characteristic value corresponding to the prediction of the commutation failure of the first type of switch module.

[0056] The failure characteristic value corresponding to the failure may be the current change rate, that is, the current change rate is used to determine whether a commutation failure has occurred. For example, if the current change rate is greater than a change threshold, it is considered that a commutation failure has occurred.

[0057] The failure characteristic value for predicting commutation failure can be characterized by the characteristic value of commutation voltage, AC bus voltage, three-phase power bridge arm current or AC side output current of the converter. For example, the failure characteristic includes at least one of the following: Harmonic components, zero-sequence components, negative-sequence components or coordinate transformation amplitude components of the commutation voltage; Harmonic components, zero-sequence components, negative-sequence components or coordinate transformation amplitude components of the AC bus voltage; The extreme value point of the three-phase power bridge arm current, the rate of change before and after the extreme value point, the maximum value after the extreme value point, the non-zero duration after the extreme value point, or the ratio of the absolute value of the three-phase power bridge arm current to the DC current, etc.; The extreme point of the output current on the AC side of the converter, the rate of change before and after the extreme point, the maximum value after the extreme point, the non-zero duration after the extreme point, or the ratio of the absolute value of the output current on the AC side of the converter to the DC current, etc.

[0058] The converter provided in the embodiment of the present application controls the switch module of the protection bridge arm to assist in the work when the switch module of the three-phase power bridge arm has failed in commutation or predicted commutation failure. The protection bridge arm provided in the present application can also assist in the work when an internal fault occurs in the switch module of the three-phase power bridge arm. That is, the controller is also used to control the operation of the second type of switch module corresponding to the first type of switch module when a fault occurs in the first type of switch module in the three-phase power bridge arm, and bypass the faulty first type of switch module.

[0059] It should be understood that when the controller determines that the switch module of the three-phase power bridge arm fails, it needs to select the switch module of the protection bridge arm connected in parallel with the failed switch module, control the switch module of the protection bridge arm to be turned on to replace the failed switch module, and make the driving signal of the switch module of the protection bridge arm consistent with the driving signal of the normal operation of the failed switch module. After the failed switch module returns to normal, the switch module of the protection bridge arm stops working.

[0060] Based on a converter provided in the above embodiment, an embodiment of the present application further provides a control method of the converter, which is described in detail below with reference to the accompanying drawings.

[0061] See also Fig. 9 , which is a flow chart of the control method of the converter provided in an embodiment of the present application.

[0062] The control method of the converter provided in the embodiment of the present application, the converter includes: a protection bridge arm and a three-phase power bridge arm; the upper half bridge arm of each phase in the three-phase power bridge arm includes a first switch module and a second switch module connected in series; the lower half bridge arm of each phase in the three-phase power bridge arm includes a third switch module and a fourth switch module connected in series; the protection bridge arm includes a fifth switch module and a sixth switch module; the first switch module, the second switch module, the third switch module and the fourth switch module are all first-type switch modules, and the fifth switch module and the sixth switch module are all second-type switch modules; the shutoff capacity of the first-type switch module is less than or equal to the second-type switch module; the fifth switch module is connected in parallel to both ends of the first switch module or in parallel to both ends of the second switch module; the sixth switch module is connected in parallel to both ends of the third switch module or in parallel to both ends of the fourth switch module; The method includes: S901: determining that the commutation of the first type of switch module in the three-phase power bridge arm has failed or the commutation failure has been predicted; S902: Control the operation of the second type switch module corresponding to the first type switch module to assist in completing current commutation.

[0063] In the converter provided by the embodiment of the present application, when the three-phase power bridge arm is working normally, the switch module on the protection bridge arm does not work. The switch module of the protection bridge arm works only when the switching of the switch module of the three-phase power bridge arm has failed or the switching failure is predicted. In this way, normal switching can be guaranteed and the normal operation of the converter can be guaranteed. In addition, since the switch module of the protection bridge arm does not participate in the work throughout the whole process and only works when needed, the power consumption of the switch module of the protection bridge arm can be reduced, and the life of the switch module of the protection bridge arm can be increased.

[0064] In a possible implementation, the first type of switch module is a fully controlled switch module; when the commutation of the first type of switch module in the three-phase power bridge arm has failed or the commutation failure is predicted, the second type of switch module corresponding to the first type of switch module is controlled to operate to assist in completing the commutation, including: when the heat accumulation of the first type of switch module in the three-phase power bridge arm is greater than the first threshold, the first type of switch module is turned off, and the second type of switch module corresponding to the first type of switch module is turned on; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0065] A possible implementation method also includes: when the operating time of the fifth switch module is greater than the first time, controlling the fifth switch module to disconnect and restoring the first type of switch module that shuts down the upper half bridge arm; when the operating time of the sixth switch module is greater than the first time, controlling the sixth switch module to disconnect and restoring the first type of switch module that shuts down the lower half bridge arm.

[0066] A possible implementation method is that the first type of switch module is a half-controlled switch module; when the commutation of the first type of switch module in the three-phase power bridge arm has failed or the commutation failure is predicted, the second type of switch module corresponding to the first type of switch module is controlled to operate to assist in completing the commutation, including: when the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than the failure threshold, the first type of switch module is turned off, and the second type of switch module corresponding to the first type of switch module is turned on; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

[0067] A possible implementation method also includes: when a first type of switch module in a three-phase power bridge arm fails, controlling a second type of switch module corresponding to the first type of switch module to operate and bypassing the failed first type of switch module.

[0068] In one possible implementation, see Fig.10 , which is a schematic diagram of a control device provided in an embodiment of the present application.

[0069] The control device may include a memory 1011 and a processor 1012. The processor 1012 may be connected to the power converter and may drive switches in each power conversion circuit in the power converter. Fig.10 As shown, the memory may be a random access memory (RAM), a flash memory, a read only memory (ROM), an EPROM memory, an Electronic Programmable ROM (EPROM), a register, a hard disk, a removable disk, etc.

[0070] The memory 1011 can store computer instructions. When the computer instructions stored in the memory 1011 are executed by the processor 1012, the processor 1012 can be used to execute the control method of the power converter. The memory 1011 can also store data, for example, information such as the preset range and preset threshold involved in the above embodiments.

[0071] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server, data center, etc. that includes one or more available media integrated. The available medium can be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), or a semiconductor medium (e.g., a solid state drive (solid statedisk, SSD)), etc.

[0072] The present application also provides a readable storage medium for storing the method provided in the above embodiment, for example, a random access memory (RAM), a flash memory, a read only memory (ROM), an EPROM memory, an electronic programmable ROM (EPROM), a register, a hard disk, a removable disk or any other form of storage medium in the art.

[0073] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0074] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A converter, characterized in that: include: Controller, protection bridge arm and three-phase power bridge arm; The upper half bridge arm of each phase in the three-phase power bridge arm comprises a first switch module and a second switch module connected in series; the lower half bridge arm of each phase in the three-phase power bridge arm comprises a third switch module and a fourth switch module connected in series; The protection bridge arm includes a fifth switch module and a sixth switch module; The first switch module, the second switch module, the third switch module and the fourth switch module are all first-type switch modules, and the fifth switch module and the sixth switch module are all second-type switch modules; The shutoff capability of the first type of switch module is less than or equal to the second type of switch module; The fifth switch module is connected in parallel to both ends of the first switch module or connected in parallel to both ends of the second switch module; The sixth switch module is connected in parallel to both ends of the third switch module or to both ends of the fourth switch module; The controller is used to control the action of the second type of switch module corresponding to the first type of switch module in the three-phase power bridge arm to assist in completing the commutation when the commutation of the first type of switch module in the three-phase power bridge arm has failed or the commutation failure is predicted.

2. The inverter according to claim 1, characterized in that: The first type of switch module is a fully controlled switch module; The controller is specifically used to shut down the first type of switch module and turn on the second type of switch module corresponding to the first type of switch module when the heat accumulation of the first type of switch module in the three-phase power bridge arm is greater than a first threshold value; if the first type of switch module is located in the upper half of the bridge arm, control the fifth switch module to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, control the sixth switch module to be turned on to complete the commutation.

3. The inverter according to claim 2, characterized in that: The controller is further configured to control the fifth switch module to be disconnected when the operation time of the fifth switch module is greater than the first time, and to restore the first type of switch module in which the upper half bridge arm is turned off; When the operation time of the sixth switch module is greater than the first time, the sixth switch module is controlled to be disconnected, and the first type of switch module in which the lower half bridge arm is turned off is restored.

4. The converter according to any one of claims 1 to 3, characterized in that: The first type of switch module is an integrated gate commutated thyristor IGCT module, and the second type of switch module is an insulated gate bipolar transistor IGBT module.

5. The inverter according to claim 1, characterized in that: The first type of switch module is a half-controlled switch module; The controller is specifically used to shut down the first type of switch module and turn on the second type of switch module corresponding to the first type of switch module when the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than the failure threshold; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

6. The inverter according to claim 5, characterized in that: The second type of switch module is an integrated gate commutated thyristor IGCT module.

7. The inverter according to any one of claims 1 to 3, characterized in that: The controller is also used to control the operation of the second type of switch module corresponding to the first type of switch module when a fault occurs in the first type of switch module in the three-phase power bridge arm, so as to bypass the faulty first type of switch module.

8. A method for controlling a converter, characterized in that: The converter comprises: a protection bridge arm and a three-phase power bridge arm; the upper half bridge arm of each phase in the three-phase power bridge arm comprises a first switch module and a second switch module connected in series; the lower half bridge arm of each phase in the three-phase power bridge arm comprises a third switch module and a fourth switch module connected in series; the protection bridge arm comprises a fifth switch module and a sixth switch module; the first switch module, the second switch module, the third switch module and the fourth switch module are all first-type switch modules, and the fifth switch module and the sixth switch module are all second-type switch modules; the shutoff capacity of the first-type switch module is less than or equal to the second-type switch module; the fifth switch module is connected in parallel to both ends of the first switch module or in parallel to both ends of the second switch module; the sixth switch module is connected in parallel to both ends of the third switch module or in parallel to both ends of the fourth switch module; The method includes: When the commutation of the first type of switch module in the three-phase power bridge arm has failed or the commutation failure is predicted, the second type of switch module corresponding to the first type of switch module is controlled to operate to assist in completing the commutation.

9. The method according to claim 8, characterized in that The first type of switch module is a fully controlled switch module; when the commutation of the first type of switch module in the three-phase power bridge arm has failed or the commutation failure is predicted, the second type of switch module corresponding to the first type of switch module is controlled to act to assist in completing the commutation, including: When the heat accumulation of the first type of switch module in the three-phase power bridge arm is greater than a first threshold, the first type of switch module is turned off, and the second type of switch module corresponding to the first type of switch module is turned on; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

10. The method according to claim 9, characterized in that Also includes: When the operation time of the fifth switch module is greater than the first time, the fifth switch module is controlled to be disconnected, and the first type of switch module in which the upper half bridge arm is turned off is restored; When the operation time of the sixth switch module is greater than the first time, the sixth switch module is controlled to be disconnected, and the first type of switch module in which the lower half bridge arm is turned off is restored.

11. The method according to claim 8, characterized in that The first type of switch module is a half-controlled switch module; when the commutation of the first type of switch module in the three-phase power bridge arm fails or the predicted commutation fails, the second type of switch module corresponding to the first type of switch module is controlled to act to assist in completing the commutation, including: When the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than the failure threshold, the first type of switch module is turned off, and the second type of switch module corresponding to the first type of switch module is turned on; if the first type of switch module is located in the upper half of the bridge arm, the fifth switch module is controlled to be turned on to complete the commutation; if the first type of switch module is located in the lower half of the bridge arm, the sixth switch module is controlled to be turned on to complete the commutation.

12. The method according to claim 8, characterized in that Also includes: When a first-type switch module in the three-phase power bridge arm fails, a second-type switch module corresponding to the first-type switch module is controlled to operate, and the failed first-type switch module is bypassed.

13. A control device, characterized in that: It comprises a processor and a memory, wherein the memory is used to store programs, instructions or codes, and the processor is used to execute the programs, instructions or codes in the memory to complete the method according to any one of claims 8 to 12.

14. A computer-readable storage medium, characterized in that: A computer program is stored, and the computer program is loaded by a processor to execute the method according to any one of claims 8 to 12.

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