Converter, control method and related device

Abstract

The present application discloses a converter, a control method and related devices. The converter includes: a controller, a protection arm and three-phase power arms; the upper half-arm of each phase in the three-phase power arms includes a first switch module and a second switch module connected in series; the lower half-arm of each phase in the three-phase power arms includes a third switch module and a fourth switch module connected in series; the protection 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 both second-type switch modules; the turn-off capability of the first-type switch module is less than or equal to that of the second-type switch module; when the commutation of the first-type switch module in the three-phase power arms has failed or predicted commutation failure occurs, the second-type switch module corresponding to the first-type switch module is controlled to act to assist in completing commutation. This solution can ensure normal commutation of the converter and enable the converter to operate normally.

Description

Technical Field

[0001] This application relates to the technical field of power equipment, and specifically to a converter, a control method, and related devices. Background Art

[0002] Currently, in a power system with a relatively high voltage, a converter is used for commutation. The converter can be a bidirectional converter, which can be used as an inverter and a rectifier.

[0003] The bridge arm of the converter includes switching devices. However, due to the turn-off ability 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 by this application can ensure successful commutation.

[0005] This application provides a converter, including: 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 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 both second-type switch modules; the turn-off ability of the first-type switch module is less than or equal to that of the second-type switch module; the fifth switch module is connected in parallel at both ends of the first switch module or connected 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 connected in parallel at both ends of the fourth switch module; the controller is configured to control the corresponding second-type switch module of the first-type switch module to act to assist in commutation when the commutation of the first-type switch module in the three-phase power bridge arm has failed or the commutation failure is predicted.

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

[0007] A possible implementation, the controller is further configured to control the fifth switch module to disconnect when the running time of the fifth switch module is greater than a first time, and restore the first type of switch module that is turned off in the upper half bridge arm; when the running time of the sixth switch module is greater than the first time, control the sixth switch module to disconnect, and restore the first type of switch module that is turned off in the lower half bridge arm.

[0008] 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] A possible implementation, the first type of switch module is a semi-controlled switch module; the controller is specifically configured to turn off the first type of switch module and turn on the corresponding second 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 a failure threshold. If the first type of switch module is located in the upper half bridge arm, control the fifth switch module to turn on to complete commutation; if the first type of switch module is located in the lower half bridge arm, control the sixth switch module to turn on to complete commutation.

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

[0011] A possible implementation, the controller is further configured to control the corresponding second type of switch module of the first type of switch module to operate and bypass the faulty first type of switch module when a fault occurs in the first type of switch module in the three-phase power bridge arm.

[0012] This application also provides a control method for a converter. The converter includes: a protection bridge arm and three-phase power bridge arms; the upper half bridge arm of each phase in the three-phase power bridge arms 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 arms 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 of the first type of switch module, and the fifth switch module and the sixth switch module are both of the second type of switch module; the turn-off capability of the first type of switch module is less than or equal to that of the second type of switch module; the fifth switch module is connected in parallel at both ends of the first switch module or 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 at 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 predicted commutation failure occurs, control the corresponding second type of switch module of the first type of switch module to act to assist in completing commutation.

[0013] A possible implementation manner, wherein 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 predicted commutation fails, control the second type of switch module corresponding to the first type of switch module to act to assist in completing 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, 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. If the first type of switch module is located in the upper half bridge arm, control the fifth switch module to turn on to complete commutation; if the first type of switch module is located in the lower half bridge arm, control the sixth switch module to turn on to complete commutation.

[0014] A possible implementation manner further includes: when the running time of the fifth switch module is greater than a first time, control the fifth switch module to turn off and restore the first type of switch module turned off in the upper half bridge arm; when the running time of the sixth switch module is greater than the first time, control the sixth switch module to turn off and restore the first type of switch module turned off in the lower half bridge arm.

[0015] A possible implementation manner, wherein the first type of switch module is a semi-controlled switch module; when the commutation of the first type of switch module in the three-phase power bridge arm has failed or the predicted commutation fails, control the second type of switch module corresponding to the first type of switch module to act to assist in completing commutation, including: when the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than a failure threshold, 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. If the first type of switch module is located in the upper half bridge arm, control the fifth switch module to turn on to complete commutation; if the first type of switch module is located in the lower half bridge arm, control the sixth switch module to turn on to complete commutation.

[0016] A possible implementation manner further includes: when a fault occurs in the first type of switch module in the three-phase power bridge arm, control the second type of switch module corresponding to the first type of switch module to work and bypass the faulty first type of switch module.

[0017] The present application further provides a control device, which is characterized by including 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 further provides a computer-readable storage medium storing a computer program, and the computer program is loaded and executed by a processor to perform the method introduced above.

[0019] When the converter provided by the embodiment of the present application is operating normally in the three-phase power bridge arm, the switching module on the protection bridge arm does not work, which can reduce the overall working duration of the switching module on the protection bridge arm and improve the overall service life of the switching module on the protection bridge arm. Only when the commutation of the switching module of the three-phase power bridge arm has failed or the predicted commutation fails, the switching module of the protection bridge arm will work, enabling the switching module of the protection bridge arm to replace the switching module of the three-phase power bridge arm to complete commutation, thus ensuring normal commutation of the converter and enabling the converter to operate normally. Description of the Drawings

[0020] Figure 1 It is a schematic diagram of a converter provided by an embodiment of the present application;

[0021] Figure 2 It is a schematic diagram of another converter provided by an embodiment of the present application;

[0022] Figure 3 It is a schematic diagram of the operation of the protection bridge arm in a converter provided by an embodiment of the present application;

[0023] Figure 4 It is a schematic diagram of another converter provided by an embodiment of the present application;

[0024] Figure 5 It is a schematic diagram of another converter provided by an embodiment of the present application;

[0025] Figure 6 It is a schematic diagram of the device junction temperature provided by an embodiment of the present application;

[0026] Figure 7 It is a schematic diagram of the heat accumulation of the buffer circuit of the switching module in different operating modes provided by an embodiment of the present application;

[0027] Figure 8 It is a schematic diagram of yet another converter provided by an embodiment of the present application;

[0028] Figure 9 It is a flowchart of a control method for a converter provided by an embodiment of the present application;

[0029] Figure 10 It is a schematic diagram of a control device provided by an embodiment of the present application. Detailed Embodiments

[0030] To make the above objects, features, and advantages of the present application more obvious and understandable, the following further details the embodiments of the present application in conjunction with the drawings and specific embodiments.

[0031] See Figure 1 , which is a schematic diagram of a converter provided by an embodiment of the present application.

[0032] The converter provided by the embodiment of the present application includes: a controller (not shown in the figure), a protection arm, and three-phase power arms. The three phases include phase A, phase B, and phase C, and the output ends of the three-phase power arms are a, b, and c respectively.

[0033] In each phase of the three-phase power arms, the upper half-arm includes a first switch module and a second switch module connected in series; in each phase of the three-phase power arms, the lower half-arm includes a third switch module and a fourth switch module connected in series. As Figure 1 shown, the upper half-arm of phase A in the three-phase power arms includes a first switch module V41 and a second switch module V42 connected in series. The lower half-arm of phase A in the three-phase power arms includes a third switch module V11 and a fourth switch module V12 connected in series. The upper half-arm of phase B in the three-phase power arms includes a first switch module V61 and a second switch module V62 connected in series. The lower half-arm of phase B in the three-phase power arms includes a third switch module V31 and a fourth switch module V32 connected in series. The upper half-arm of phase C in the three-phase power arms includes a first switch module V21 and a second switch module V22 connected in series. The lower half-arm of phase C in the three-phase power arms includes a third switch module V51 and a fourth switch module V52 connected in series.

[0034] The protection arm includes a fifth switch module T1 and a sixth switch module T2.

[0035] 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 both second-type switch modules; the turn-off capability of the first-type switch module is less than or equal to that of the second-type switch module.

[0036] The fifth switch module T1 is connected in parallel across the two ends of the first switch module or across the two ends of the second switch module; Figure 1 In the figure, the case where the fifth switch module T1 is connected in parallel across the two ends of the first switch tube module is taken as an example.

[0037] The sixth switch module T2 is connected in parallel across the two ends of the third switch module or across the two ends of the fourth switch module; Figure 1 In the figure, the case where the sixth switch tube module T2 is connected in parallel across the two ends of the fourth switch module is taken as an example.

[0038] In addition, there are other implementation manners. For example, T1 is connected in parallel across the second switch module, as Figure 2 shown, T2 is connected in parallel across the third switch module, as Figure 2 shown.

[0039] A controller is used to control the operation of a second type of switching module corresponding to the first type of switching module when the commutation of the first type of switching module in a three-phase power bridge arm has failed or predicted commutation failure occurs, so as to assist in completing commutation. Here, the commutation failure does not mean that it has failed, but that it is predicted that commutation failure will occur. In order to ensure normal commutation and the normal operation of the converter, the switching module of the protection bridge arm is used to achieve commutation.

[0040] The embodiments of the present application do not specifically limit the reasons for commutation failure. For example, it can be an internal fault of the converter or an external fault.

[0041] In the converter provided by the embodiments of the present application, when the three-phase power bridge arm is working normally, the switching module on the protection bridge arm does not work. Only when the commutation of the switching module of the three-phase power bridge arm has failed or predicted commutation failure occurs, the switching module of the protection bridge arm will work. This can ensure normal commutation and the normal operation of the converter. In addition, since the switching module of the protection bridge arm does not participate in the work throughout the process and only works when needed, the power consumption of the switching module of the protection bridge arm can be reduced, and the service life of the switching module of the protection bridge arm can be improved.

[0042] See Figure 3 , which is a schematic diagram of the operation of the protection bridge arm in a converter provided by the embodiments of the present application.

[0043] When the fifth switching module T1 of the protection bridge arm works, the first switching 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 switching module T2 of the protection bridge arm works, the fourth switching module of the lower bridge arm of the three-phase bridge arm is bypassed, that is, V12, V32, and V52 do not work.

[0044] The embodiments of the present application do not specifically limit the implementation form of the first type of switching module. For example, it can be a fully controlled switching module or a semi-controlled switching module. For example, for a fully controlled switching module, an Integrated Gate-Commutated Thyristor (IGCT) module can be used to implement it. For a semi-controlled switching module, an ordinary semi-controlled thyristor module can be used to implement it. A semi-controlled thyristor means that it can only control conduction and cannot control turn-off.

[0045] The embodiments of the present application also do not specifically limit the implementation form of the second type of switching module. For example, it can be a fully controlled switching module or a semi-controlled switching module. For example, the second type of switching module can be an Insulated Gate Bipolar Transistor (IGBT) or an IGCT.

[0046] The following introduces a specific implementation manner in conjunction with the accompanying drawings.

[0047] See Figure 4 , which is a schematic diagram of another converter provided by the embodiment of the present application.

[0048] For the converter provided by the embodiment of the present application, the first type of switch module is a fully controlled switch module, and specifically, the fully controlled switch module is taken as an IGCT for introduction. Among them, the second type of switch module is taken as an IGBT for introduction.

[0049] When the IGCT module turns off, the junction temperature will rise significantly under large 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 continuously turns off actively, a large current is generated. Therefore, the IGCT will face the risk of commutation failure, which may lead to the commutation failure of the converter and affect the stable operation of the converter. Therefore, when the switch module of the three-phase power bridge arm of the converter provided by the embodiment of the present application is an IGCT, it is possible to judge whether to control the switch module of the protection bridge arm to work by heat accumulation.

[0050] The controller (not shown in the figure) 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 heat accumulation of the first type of switch module in the three-phase power bridge arm is greater than the first threshold. If the first type of switch module is located in the upper half bridge arm, control the fifth switch module to turn on to complete commutation; if the first type of switch module is located in the lower half bridge arm, control the sixth switch module to turn on to complete commutation.

[0051] The heat accumulation of the switch module in the embodiment of the present application generally refers to the heat accumulation of the buffer circuit corresponding to the switch module, and the heat accumulation of the buffer circuit can be measured in the converter. For the sake of introduction, the heat accumulation of the switch module is still used to describe below.

[0052] For example, Figure 5 in, when the heat accumulation of any one of the switch modules V41, V61, and V21 is greater than the first threshold, then turn off the switch module with heat accumulation greater than the first threshold among V41, V61, and V21, control T1 to turn on, and T1 completes commutation. V41, V61, and V21 all stop working, that is, the controller no longer sends drive signals to V41, V61, and V21.

[0053] For example, when T1 is turned on, it indicates that the switching module on the upper half-bridge arm is actively turned off, and the energy-consuming device in the buffer circuit overheats, which may cause the switching module to be unable to actively turn off next time. At this time, V41, V42, V61, V62, V21, and V22 of the switching module are all overheated at the same time. When T1 is put into use, V41, V61, and V21 completely do not participate in commutation, and the switching module will slowly cool down, and the temperature drops relatively quickly. Since V42, V62, and V22 no longer participate in the active turn-off process, the energy-consuming device in the buffer circuit does not need to absorb the energy during active turn-off and can also slowly return to the normal working area.

[0054] The converter provided by the embodiment of the present application can better alleviate the increase in the junction temperature caused by the heat generated during the active commutation of the IGCT and the heat accumulation in the buffer circuit. Taking the upper half-bridge arm of phase A as an example, when the accumulated active turn-off heat of the switching modules V41 and V42 is greater than the first threshold, the trigger signal of V41 is blocked, and at the same time, T1 is unlocked so that the trigger signal of T1 is consistent with V42, and V42 does not perform active turn-off. The commutation is completed by controllably turning off T1. The schematic diagrams of the junction temperatures of the V41 and V42 devices in different operating modes are as Figure 6 shown. See Figure 7 , which is a schematic diagram of the heat accumulation in the buffer circuit of the switching module in different operating modes provided by the embodiment of the present application.

[0055] The converter provided by the embodiment of the present application also needs to consider the safety and lifespan of the switching modules of the protection arm. For example, T1 cannot work continuously for a long time when it is working. When the heat of the switching module in parallel with T1 is less than or equal to the first threshold, T1 can be made to exit the work and the work of the switching module in parallel with T1 can be restored. It should be understood that there is generally a buffer circuit in the converter. When the switching module exits the work, the buffer circuit will cool down and the heat accumulation will decrease. Specifically, the controller is further configured to control the fifth switching module to disconnect and restore the first type of switching module that turns off the upper half-bridge arm when the running time of the fifth switching module is greater than the first time. When the running time of the sixth switching module is greater than the first time, the controller is further configured to control the sixth switching module to disconnect and restore the first type of switching module that turns off the lower half-bridge arm.

[0056] The converter provided by the above embodiment has a three-phase power bridge arm including a fully controlled switching module. The implementation manner of a three-phase power bridge arm including a semi-controlled switching module will be described below with reference to the accompanying drawings by way of example.

[0057] In the converter provided by the embodiment of the present application, the first type of switching module is a semi-controlled switching module.

[0058] The controller is specifically configured to turn off the first - type switch module and turn on the corresponding second - type switch module when the failure characteristic value of the first - type switch module in the three - phase power bridge arm is greater than the failure threshold. If the first - type switch module is located in the upper half - bridge arm, control the fifth switch module to turn on to complete commutation; if the first - type switch module is located in the lower half - bridge arm, control the sixth switch module to turn on to complete commutation.

[0059] See Figure 8 , which is a schematic diagram of another converter provided by the embodiment of the present application.

[0060] In the converter provided by the embodiment of the present application, the first - type switch module is a semi - controlled switch module, such as a thyristor module, and the second - type switch module is specifically an IGCT module.

[0061] Figure 8 Compared with Figure 4 the difference is that Figure 8 in the converter shown, the switch modules of the three - phase power bridge arm are thyristor modules. Figure 8 The working principles of T1 and T2 in Figure 4 are similar to those in

[0062] Figure 4 and will not be elaborated here. The IGCT in

[0063] judges whether commutation failure is about to occur by judging heat accumulation. When the switch module of the three - phase power bridge arm provided by the embodiment of the present application is a thyristor module, it can judge whether commutation failure is about to occur through the failure characteristic value of the thyristor module.

[0064] It should be understood that the failure characteristic value corresponding to the commutation failure of the first - type switch module is different from the failure characteristic value predicting the commutation failure of the first - type switch module.

[0065] The failure characteristic value corresponding to the already - failed commutation can be the rate of change of current, that is, use the rate of change of current to judge whether commutation failure has occurred. For example, if the rate of change of current is greater than the change threshold, it is considered that commutation failure has occurred.

[0066] The failure characteristic value predicting commutation failure can be characterized by the characteristic value of commutation voltage, AC bus voltage, three - phase power bridge arm current or the output current of the AC side of the converter. For example, the failure characteristics include at least one of the following:

[0067] Harmonic component, zero-sequence component, negative-sequence component or coordinate transformation amplitude component of commutation voltage;

[0068] Harmonic component, zero-sequence component, negative-sequence component or coordinate transformation amplitude component of AC bus voltage;

[0069] Extreme points of three-phase power bridge arm current, change rate before and after extreme points, maximum value after extreme points, non-zero duration after extreme points, or ratio of absolute value of three-phase power bridge arm current to DC current, etc.;

[0070] Extreme points of converter AC side output current, change rate before and after extreme points, maximum value after extreme points, non-zero duration after extreme points, or ratio of absolute value of converter AC side output current to DC current, etc.

[0071] The converter provided by the embodiments of the present application, except when commutation has failed or predicted commutation failure occurs in the switching modules of the three-phase power bridge arm, controls the switching modules of the protection bridge arm to assist in working. The protection bridge arm provided by the present application can also assist in working when internal faults occur in the switching modules of the three-phase power bridge arm. That is, the controller is further configured to control the second type of switching module corresponding to the first type of switching module to work when a fault occurs in the first type of switching module in the three-phase power bridge arm, and bypass the faulty first type of switching module.

[0072] It should be understood that when the controller determines that a fault has occurred in the switching module of the three-phase power bridge arm, it is necessary to select the switching module of the protection bridge arm in parallel with it according to the faulty switching module, control the switching module of the protection bridge arm to conduct, to replace the faulty switching module, and make the drive signal of the switching module of the protection bridge arm consistent with the drive signal when the faulty switching module works normally. After the faulty switching module returns to normal, stop the work of the switching module of the protection bridge arm.

[0073] Based on the converter provided in the above embodiments, the embodiments of the present application further provide a control method for a converter, which will be introduced in detail below with reference to the drawings.

[0074] See Figure 9 , which is a flowchart of the control method for the converter provided by the embodiments of the present application.

[0075] The control method of the converter provided by the embodiment of the present application, the converter includes: a protection arm and three-phase power arms; each upper half arm of the three-phase power arms includes a first switch module and a second switch module connected in series; each lower half arm of the three-phase power arms includes a third switch module and a fourth switch module connected in series; the protection 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 both second-type switch modules; the turn-off ability of the first-type switch module is less than or equal to that of the second-type switch module; the fifth switch module is connected in parallel at both ends of the first switch module or 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 at both ends of the fourth switch module;

[0076] The method includes:

[0077] S901: Determine that the commutation of the first-type switch module in the three-phase power arms has failed or predict commutation failure;

[0078] S902: Control the second-type switch module corresponding to the first-type switch module to act to assist in completing commutation.

[0079] In the converter provided by the embodiment of the present application, when the three-phase power arms are working normally, the switch modules on the protection arm do not work. Only when the commutation of the switch modules of the three-phase power arms has failed or it is predicted that there is commutation failure, the switch modules of the protection arm will work. This can ensure normal commutation and the normal operation of the converter. In addition, since the switch modules of the protection arm do not participate in the work throughout the process and only work when needed, the power consumption of the switch modules of the protection arm can be reduced and the service life of the switch modules of the protection arm can be improved.

[0080] A possible implementation manner, the first-type switch module is a fully controlled switch module; when the commutation of the first-type switch module in the three-phase power arms has failed or it is predicted that commutation failure occurs, controlling the second-type switch module corresponding to the first-type switch module to act to assist in completing commutation includes: when the heat accumulation of the first-type switch module in the three-phase power arms is greater than a first threshold, turning off the first-type switch module and turning on the second-type switch module corresponding to the first-type switch module. If the first-type switch module is located in the upper half arm, control the fifth switch module to turn on to complete commutation; if the first-type switch module is located in the lower half arm, control the sixth switch module to turn on to complete commutation.

[0081] A possible implementation further includes: when the running time of the fifth switch module is greater than a first time, controlling the fifth switch module to disconnect and restoring the first type of switch module with the upper half-bridge arm turned off; when the running 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 with the lower half-bridge arm turned off.

[0082] In a possible implementation, the first type of switch module is a semi-controlled switch module; when commutation of the first type of switch module in a three-phase power bridge arm has failed or predicted commutation failure occurs, controlling the corresponding second type of switch module of the first type of switch module to act to assist in completing commutation, including: when the failure characteristic value of the first type of switch module in the three-phase power bridge arm is greater than a failure threshold, turning off the first type of switch module and turning on the corresponding second type of switch module of the first type of switch module. If the first type of switch module is located in the upper half-bridge arm, controlling the fifth switch module to turn on to complete commutation; if the first type of switch module is located in the lower half-bridge arm, controlling the sixth switch module to turn on to complete commutation.

[0083] A possible implementation further includes: when a fault occurs in the first type of switch module in a three-phase power bridge arm, controlling the corresponding second type of switch module of the first type of switch module to work and bypassing the faulty first type of switch module.

[0084] In a possible implementation manner, refer to Figure 10 , this figure is a schematic diagram of a control device provided by an embodiment of the present application.

[0085] The control device may include a memory 1011 and a processor 1012. The processor 1012 may be connected to a power converter and may drive switches in each power conversion circuit of the power converter. As Figure 10 shown, the memory may be a random access memory (RAM), a flash memory, a read only memory (ROM), an EPROM memory, a non-volatile read only memory (Electronic Programmable ROM, EPROM), a register, a hard disk, a removable disk, etc.

[0086] The memory 1011 may store computer instructions. When the computer instructions stored in the memory 1011 are executed by the processor 1012, the processor 1012 may be used to execute the control method of the power converter. The memory 1011 may also store data, for example, information such as a preset range and a preset threshold involved in the above embodiments.

[0087] 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 a computer, the processes or functions according to the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (such as coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that the computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), or a semiconductor medium (such as a solid state disk (SSD)), etc.

[0088] The embodiments of the present application also provide a readable storage medium for storing the method provided in the above embodiments. For example, random access memory (RAM), flash memory, read only memory (ROM), EPROM memory, non-volatile read-only memory (Electronic Programmable ROM, EPROM), registers, hard disks, removable disks, or any other form of storage medium in the art.

[0089] It should be noted that the various embodiments in this specification are described in a progressive manner, and the key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0090] 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 obvious to those skilled in the art, and the general principles defined herein can 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 be accorded 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 in sequence; 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 in sequence; 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 two ends of the first switch module; The sixth switch module is connected in parallel to two 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 in sequence; 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 in sequence; 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; the sixth switch module is connected 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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