A method, apparatus and medium for testing MMC submodules with a bridge structure

Abstract

This invention discloses a method, apparatus, and medium for detecting bridge-structured MMC submodules. The method includes: acquiring a first MMC submodule; wherein the first MMC submodule includes a first target switch and a first capacitor; establishing a detection device based on the first MMC submodule; wherein the detection device includes a first switch module, a first DC voltage source, and the first MMC submodule; charging and discharging the first capacitor through the first switch module to heat the first target switch to a preset temperature; acquiring the signal of the first target switch under a preset multi-pulse signal drive to obtain a first detection result. This invention proposes a method, apparatus, and medium for detecting bridge-structured MMC submodules. By heating the first target switch to a preset temperature before detection, accurate detection results can be obtained, thus solving the problem of ineffective detection of switching devices in MMC submodules.

Description

Technical Field

[0001] This invention relates to the field of power technology, and in particular to a method, apparatus and medium for detecting MMC submodules with a bridge structure. Background Technology

[0002] High Voltage Direct Current (HVDC) transmission technology is considered a reliable and efficient power transmission method. HVDC transmission implementation methods include HVDC (LCC-HVDC) technology based on line commutation converters and HVDC (VSC-HVDC) technology based on voltage source converters. Among these, VSC-HVDC technology has been widely developed and recognized. The most commonly used topology in VSC-HVDC is the Modular Multilevel Converter (MMC). The bridge arms of the MMC employ a sub-module cascaded approach. Among the factors affecting the reliability of MMC sub-modules, the reliability of the switching devices (i.e., IGBTs) plays a decisive role. Therefore, studying module reliability mainly involves analyzing the reliability of the switching devices. Currently, the most commonly used method for MMC sub-module reliability assessment is offline testing. Compared to online and in-situ testing, offline testing can obtain more characteristic parameters of the switching devices, which is beneficial for comprehensively examining the aging state of the devices.

[0003] However, existing offline testing mainly involves disassembling the MMC submodule as a whole, performing a double-pulse test on the IGBT module in the submodule after disassembly, obtaining sufficient parameters to measure device aging, and then reassembling it. Although this method can obtain more aging data, it greatly reduces the reliability of the module during the disassembly and reassembly of the MMC submodule. Moreover, the entire testing process is difficult to operate and consumes a lot of time and manpower, making it difficult to apply in daily maintenance. Summary of the Invention

[0004] This invention provides a method, apparatus, and medium for testing MMC submodules with a bridge structure, in order to solve the problem of the inability to effectively test the switching devices in MMC submodules.

[0005] To address the above problems, this invention provides a method for detecting MMC submodules with a bridge structure, comprising:

[0006] Obtain the first MMC submodule; wherein the first MMC submodule includes a first target switch and a first capacitor;

[0007] A detection device is established based on the first MMC submodule; wherein the detection device includes a first switch module, a first DC voltage source, and the first MMC submodule;

[0008] The first capacitor is charged and discharged by the first switching module, so that the first target switch is heated to a preset temperature; wherein, the first switching module controls the closing and opening of the preset switch to discharge the first DC voltage source and the first capacitor in sequence, thereby enabling the first capacitor to charge and discharge.

[0009] The signal of the first target switch driven by a preset multi-pulse signal is obtained to obtain the first detection result.

[0010] In this invention, since the switching performance of the device is strongly correlated with temperature, and the parameters differ significantly at different temperatures, heating the first target switch to a preset temperature and then driving and detecting it to obtain the first detection result maximizes the device characteristics of the first target switch and ensures the accuracy and effectiveness of the first detection result. Furthermore, since each switching process of the device incurs switching losses, which manifest as heat, under the same time, voltage, and current conditions, the higher the switching frequency and the more times the device switches, the faster the heat rises. Therefore, by repeatedly charging and discharging the first capacitor, the current can flow repeatedly in both directions, thereby rapidly heating the first target switch to the preset temperature and accelerating the acquisition of the first detection result.

[0011] Compared to existing technologies, this solution utilizes the switching characteristics and temperature performance of the switch. The first switch module in the detection device can quickly heat the first target switch to a preset temperature, thereby maximizing the performance of the first target switch and obtaining accurate detection results. Furthermore, this method does not require disassembly and reassembly of the MMC submodule, resulting in lower time and labor costs. Therefore, it can solve the problem of not being able to effectively detect the switching devices in the MMC submodule.

[0012] As a preferred embodiment, the detection device specifically comprises:

[0013] The detection device is a detection circuit composed of a first auxiliary detection module and a first MMC submodule;

[0014] The first port of the first auxiliary detection module is connected to the first power port of the first MMC submodule, the second port of the first auxiliary detection module is connected to the second power port of the first MMC submodule, and the third port of the first auxiliary detection module is connected to the third power port of the first MMC submodule.

[0015] The first MMC submodule includes a first target drive port, a first target switch, and a first capacitor;

[0016] The first auxiliary detection module includes the first switch module and the first DC voltage source. The first switch module includes a first switch and a second switch.

[0017] The detection device in this preferred embodiment consists of a first auxiliary detection module and a first MMC submodule. The first auxiliary detection module includes a first switch module and a first DC voltage source. With this configuration, the opening and closing of the switch in the first switch module can be controlled, thereby controlling whether the first DC voltage source is in working state, so that the capacitor in the MMC submodule can be charged and discharged, realizing switch heating.

[0018] As a preferred embodiment, the first switch module controls the closing and opening of a preset switch to sequentially discharge the first DC voltage source and the first capacitor, thereby enabling the first capacitor to charge and discharge. Specifically:

[0019] By repeatedly controlling the first DC voltage source and the first capacitor to discharge sequentially, the first capacitor can be repeatedly charged and discharged.

[0020] The charging of the first capacitor is achieved by controlling the first target switch and the first switch to be closed, and the second switch to be open, so that the first DC voltage source charges the first capacitor.

[0021] The discharge of the first capacitor is achieved by controlling the first target switch and the second switch to close, while the first switch is opened.

[0022] This preferred embodiment details the process of charging and discharging the first capacitor. By controlling the first target switch and the first switch to be closed, and the second switch to be open, the first DC voltage source can be put into operation, thus charging the first capacitor. By controlling the first target switch and the second switch to be closed, and the first switch to be open, the first DC voltage source can be disconnected and cannot work, causing the first capacitor to be forced to discharge. This charging and discharging is achieved by opening and closing the switches. This operation method is simple, intuitive, and highly controllable. The charging and discharging method can quickly heat the first target switch, accelerating the acquisition of the first detection result.

[0023] As a preferred embodiment, the signal of the first target switch driven by a preset multi-pulse signal is obtained to obtain the first detection result, specifically as follows:

[0024] In a preset state, the first target drive port is used to send the multi-pulse signal to drive the first target switch; wherein, the preset state refers to the state in which the first target switch and the second switch are closed, and the first switch is open;

[0025] The signal of the first target switch under the drive of the multi-pulse signal is obtained to obtain the first detection result.

[0026] This preferred solution drives the first target switch with a multi-pulse signal, which can obtain a large number of switching characteristics of the first target switch under current. In addition, the first target switch and the second switch are closed, and the state of the first switch being open is the state in which the first DC voltage source is disconnected and cannot work. In this state, using a multi-pulse signal to drive and detect the first target switch can avoid the influence of excessively high voltage, current and other factors on the driving and detection process, and can ensure the accuracy of the first detection result.

[0027] This invention also provides a bridge-structure MMC submodule testing device, applicable to a bridge-structure MMC submodule testing method, wherein the MMC submodule testing device specifically comprises:

[0028] The MMC submodule testing device is a testing circuit composed of a second auxiliary testing module and a second MMC submodule;

[0029] The first port of the second auxiliary detection module is connected to the first power port of the second MMC submodule, the second port of the second auxiliary detection module is connected to the second power port of the second MMC submodule, and the third port of the second auxiliary detection module is connected to the third power port of the second MMC submodule.

[0030] The second MMC submodule includes a second target drive port, a second target switch, and a second capacitor;

[0031] The second auxiliary detection module includes a second switch module, a drive module, and a second DC voltage source;

[0032] The second switch module is used to charge and discharge the second capacitor by controlling the opening and closing of the switch, so that the second target switch is heated to a preset temperature;

[0033] The driving module is used to acquire the signal of the second target switch under the drive of a preset multi-pulse signal to obtain a second detection result.

[0034] This device is another testing device that can be used in the bridge-structure MMC submodule testing method. While adopting the same testing principle, the circuit structure of this testing device is more complex and has greater scalability. The circuit design in the testing device can be added or modified to adapt to more different application needs.

[0035] As a preferred embodiment, the second switch module is used to charge and discharge the second capacitor by controlling the opening and closing of the switch, thereby heating the second target switch to a preset temperature, specifically:

[0036] By repeatedly controlling the second DC voltage source and the second capacitor to discharge sequentially, the second capacitor is repeatedly charged and discharged, thereby heating the second target switch to a preset temperature.

[0037] The second capacitor is charged by controlling the second target switch, the fourth switch, and the fifth switch to close, and the third switch to open, so that the second DC voltage source charges the second capacitor.

[0038] Discharging the second capacitor is achieved by controlling the second target switch and the third switch to close, and the fourth switch and the fifth switch to open.

[0039] The third switch, the fourth switch, and the fifth switch are all preset switches in the second switch module.

[0040] As a preferred embodiment, the driving module is used to acquire the signal of the second target switch under the drive of a preset multi-pulse signal to obtain a second detection result, specifically as follows:

[0041] The driving module is used to drive the second target switch by sending the multi-pulse signal through the second target driving port in a preset state, and to obtain the signal of the second target switch under the drive of the multi-pulse signal to obtain the second detection result;

[0042] The preset state refers to the state in which the second target switch and the third switch are closed, and the fourth switch and the fifth switch are open.

[0043] The present invention also provides a bridge-type MMC submodule testing device, including an acquisition module, a construction module, a heating module and a testing module;

[0044] The acquisition module is used to acquire a first MMC sub-module; wherein the first MMC sub-module includes a first target switch and a first capacitor;

[0045] The construction module is used to establish a detection device based on the first MMC submodule; wherein the detection device includes a first switch module, a first DC voltage source, and the first MMC submodule;

[0046] The heating module is used to charge and discharge the first capacitor through the first switching module, so as to heat the first target switch to a preset temperature; wherein, the first switching module controls the closing and opening of the preset switch to discharge the first DC voltage source and the first capacitor in sequence, thereby enabling the first capacitor to charge and discharge.

[0047] The evaluation module is used to acquire the signal of the first target switch under the drive of a preset multi-pulse signal, and obtain the first detection result.

[0048] As a preferred embodiment, the detection device specifically comprises:

[0049] The detection device is a detection circuit composed of a first auxiliary detection module and a first MMC submodule;

[0050] The first port of the first auxiliary detection module is connected to the first power port of the first MMC submodule, the second port of the first auxiliary detection module is connected to the second power port of the first MMC submodule, and the third port of the first auxiliary detection module is connected to the third power port of the first MMC submodule.

[0051] The first MMC submodule includes a first target drive port, a first target switch, and a first capacitor;

[0052] The first auxiliary detection module includes the first switch module and the first DC voltage source. The first switch module includes a first switch and a second switch.

[0053] As a preferred embodiment, the heating module includes a charging and discharging unit;

[0054] The charging and discharging unit is used to repeatedly charge and discharge the first capacitor by repeatedly controlling the first DC voltage source and the first capacitor to discharge in sequence.

[0055] The charging of the first capacitor is achieved by controlling the first target switch and the first switch to be closed, and the second switch to be open, so that the first DC voltage source charges the first capacitor.

[0056] The discharge of the first capacitor is achieved by controlling the first target switch and the second switch to close, while the first switch is opened.

[0057] As a preferred embodiment, the evaluation module includes a driving unit and an evaluation unit;

[0058] The driving unit is configured to drive the first target switch by sending the multi-pulse signal through the first target driving port in a preset state; wherein the preset state refers to a state in which the first target switch and the second switch are closed, and the first switch is open.

[0059] The evaluation unit is used to acquire the signal of the first target switch under the drive of the multi-pulse signal and obtain the first detection result.

[0060] The present invention also provides a storage medium storing a computer program, which is called and executed by a computer to implement the bridge-structure MMC submodule detection method described above. Attached Figure Description

[0061] Figure 1 This is a flowchart illustrating a bridge-structure MMC submodule detection method provided in an embodiment of the present invention;

[0062] Figure 2 This is a structural diagram of the half-bridge MMC submodule provided in an embodiment of the present invention;

[0063] Figure 3 This is a first structural diagram of the detection device topology provided in an embodiment of the present invention;

[0064] Figure 4 This is a first diagram illustrating the capacitor charging process provided in an embodiment of the present invention;

[0065] Figure 5 This is a first diagram illustrating the capacitor discharge process provided in an embodiment of the present invention;

[0066] Figure 6 This is a first timing diagram of the driving voltage of each switch provided in an embodiment of the present invention;

[0067] Figure 7 This is a second topological structure diagram of the detection device provided in an embodiment of the present invention;

[0068] Figure 8 This is a second diagram illustrating the capacitor charging process provided in an embodiment of the present invention;

[0069] Figure 9 This is a second diagram illustrating the capacitor discharge process provided in an embodiment of the present invention;

[0070] Figure 10 This is a second timing diagram of the drive voltage of each switch provided in an embodiment of the present invention;

[0071] Figure 11 This is a schematic diagram of a bridge-type MMC submodule detection device provided in an embodiment of the present invention. Detailed Implementation

[0072] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0073] In the description of this application, it should be understood that the terms "first," "second," "third," "fourth," and "fifth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," "third," "fourth," and "fifth" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "several" means two or more.

[0074] The bridge-structure MMC submodule testing method described in this invention is mainly applied to situations where it is necessary to measure the switching characteristics inside the MMC submodule without damaging the MMC submodule package.

[0075] Example 1:

[0076] Please see Figure 1 The present invention provides a method for detecting MMC submodules with a bridge structure, including S1 to S2, and the specific implementation steps are as follows:

[0077] S1. Obtain the first MMC submodule; wherein the first MMC submodule includes a first target switch and a first capacitor.

[0078] Step S1 in this embodiment of the invention specifically includes:

[0079] Obtain the first MMC submodule; wherein the first MMC submodule includes a DC voltage source VDC and a first capacitor C.

[0080] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 2 , Figure 2This is a structural diagram of a half-bridge MMC submodule provided in an embodiment of the present invention, representing the obtained first MMC submodule. The first MMC submodule includes two press-fit insulated gate bipolar transistor (IGBT) modules and a capacitor. Specifically, it includes a first switching device S1, a second switching device S2 (first target switch), a first driving port D1, a second driving port D2 (first target driving port), and a first capacitor C; wherein, the first driving port D1 and the second driving port D2 provide driving signals for the IGBT modules.

[0081] The purpose of this invention is to obtain the switching detection characteristics of the switching device S2 in the MMC submodule.

[0082] It should be noted that, in the embodiments of the present invention, the first DC voltage source is represented by DC voltage source VDC, the first capacitor is represented by first capacitor C, the first target switch is represented by switch device two S2, the first target drive port is represented by drive port two D2, the first switch is represented by switch device three S3, and the second switch is represented by switch device four S4.

[0083] S2. Establish a detection device based on the first MMC submodule; wherein the detection device includes a first switch module, a first DC voltage source and a first MMC submodule.

[0084] In step S2 of this embodiment of the invention, S2 includes S2.1 to S2.3, specifically as follows:

[0085] S2.1 Establish a detection device based on the first MMC submodule.

[0086] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 3 , Figure 3 This is a first structural diagram of the detection device topology provided in an embodiment of the present invention, which represents the detection device, specifically:

[0087] The detection device is a detection circuit composed of a first auxiliary detection circuit and a first MMC submodule;

[0088] The first port of the first auxiliary detection circuit is connected to the first power port P1 of the first MMC submodule, the second port of the first auxiliary detection circuit is connected to the second power port P2 of the first MMC submodule, and the third port of the first auxiliary detection circuit is connected to the third power port P3 of the first MMC submodule.

[0089] The first auxiliary detection circuit includes a three-switching device S3 (first switch), a four-switching device S4 (second switch), a three-drive port D3, a four-drive port D4, a DC voltage source VDC, a resistor R, and an inductor L;

[0090] Among them, switching device three S3 and switching device four S4 form a half-bridge structure. A DC voltage source VDC is connected in parallel across the two ends of the half-bridge. The midpoint of the half-bridge is connected to the power port one P1 of the first MMC submodule. Resistor R and inductor L are connected in series and then in parallel between the first power port P1 and the second power port P2.

[0091] S2.2 Install a heat sink in the testing device, and install a set of fixtures and two IGBT drive circuits to apply pressure to each switching device.

[0092] S2.3. Discharge the first capacitor C in the detection device completely, adjust the mechanical pressure of the fixture to within the rated standard range, set the ambient temperature of the detection device to room temperature through the heat sink, and set the driving voltage of both IGBT drive circuits to low level, that is, both IGBTs are in the off state.

[0093] S3. The first capacitor is charged and discharged through the first switch module, so that the first target switch is heated to the preset temperature; wherein, the first switch module controls the closing and opening of the preset switch to make the first DC voltage source and the first capacitor discharge in sequence, thereby enabling the first capacitor to charge and discharge.

[0094] Step S3 in this embodiment of the invention is specifically as follows:

[0095] By repeatedly controlling the DC voltage source VDC and the first capacitor C to discharge sequentially, the first capacitor C can be repeatedly charged and discharged.

[0096] The charging of the first capacitor C is achieved by controlling the closing of switch devices S2 and S3 and the opening of switch device S4, so that the DC voltage source VDC charges the first capacitor C.

[0097] The discharge of the first capacitor C is achieved by controlling the closing of switch devices S2 and S4, and the opening of switch device S3.

[0098] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 4 , Figure 4 This is a first diagram illustrating the capacitor charging process provided in an embodiment of the present invention. The circuit diagram shown in red represents the process of charging the first capacitor C. Specifically, by turning on switch device two S2 and switch device three S3, turning off switch device one S1 and switch device four S4, and keeping D1 to D4 in the off state, the DC voltage source VDC is discharged to charge the first capacitor C.

[0099] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 5 , Figure 5This is a first diagram illustrating the capacitor discharge process provided in an embodiment of the present invention. The circuit diagram shown in red represents the discharge process of the first capacitor C. Specifically, by turning on switch device two S2 and switch device four S4, turning off switch device one S1 and switch device three S3, and keeping D1 to D4 in the off state, the DC voltage source VDC is disconnected and cannot work, thereby realizing the discharge of the first capacitor C.

[0100] This embodiment details the charging and discharging process of the first capacitor C. By controlling the closing of switch devices S2 and S3, and the opening of switch device S4, the DC voltage source VDC can be put into operation, thus charging the first capacitor C. By controlling the closing of switch devices S2 and S4, and the opening of switch device S3, the DC voltage source VDC can be disconnected and cannot work, causing the first capacitor C to be forced to discharge. This charging and discharging is achieved by switching on and off, which is simple, intuitive, and highly controllable. The charging and discharging process can quickly heat switch device S2, accelerating the acquisition of the first detection result.

[0101] S4. Obtain the signal of the first target switch under the preset multi-pulse signal drive to obtain the first detection result.

[0102] In step S4 of this embodiment of the invention, S4 includes S4.1 to S4.3, specifically as follows:

[0103] S4.1 In the preset state, the IGBT drive circuit is used to send a multi-pulse signal through drive port 2 D2 to drive switch device 2 S2; wherein, the preset state refers to the state in which switch device 2 S2 and switch device 4 S4 are closed and switch device 3 S3 is open, that is, the circuit state in which the first capacitor C is discharged.

[0104] In this embodiment, a large number of switching characteristics of switch device S2 under current can be obtained by driving switch device S2 with a multi-pulse signal. In addition, the state in which switch device S2 and switch device S4 are closed and switch device S3 is open is the state in which the DC voltage source VDC is disconnected and cannot work. In this state, using a multi-pulse signal to drive and detect switch device S2 can avoid the influence of excessive voltage, current and other factors on the drive and detection process, and can ensure the accuracy of the first detection result.

[0105] S4.2 Obtain the signal of switching device S2 under the drive of multi-pulse signal to obtain the first detection result.

[0106] S4.3 After the multi-pulse test is completed, the first capacitor C and the inductor L are discharged so that the voltage and current of the first capacitor C and the inductor L are 0.

[0107] This embodiment prevents accidental electric shock and ensures user safety by discharging the first capacitor C and inductor L after the multi-pulse test.

[0108] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 6 , Figure 6 This is a first timing diagram of the driving voltage of each switch provided in an embodiment of the present invention. T1 is the initial stage, referring to the stage where initial debugging is completed in step S2.3; T2 is the self-heating stage, referring to the stage where, in step S3, the switching devices self-heat by repeatedly charging and discharging the capacitor; T3 is the multi-pulse test stage, referring to the stage where, in step S4.1, the switching device S2 is driven using a multi-pulse signal; and T4 is the discharge stage, referring to the stage where, after the multi-pulse test, the first capacitor C and inductor L are completely discharged. Figure 6 This refers to the timing diagram of the driving voltages of switching devices S1 to S4 during the above T1 to T4 processes.

[0109] Overall, the embodiments of the present invention have the following beneficial effects:

[0110] In this embodiment of the invention, since the switching performance of the device is strongly correlated with temperature, and the parameters differ significantly at different temperatures, heating the switching device S2 to a preset temperature to drive and detect it to obtain the first detection result maximizes the device characteristics of the switching device S2 and ensures the accuracy and effectiveness of the first detection result. Furthermore, since each switching process incurs switching losses, which manifest as heat, under the same time, voltage, and current conditions, the higher the switching frequency and the more times the device switches, the faster the heat rises. Therefore, by repeatedly charging and discharging the first capacitor C, the current can flow repeatedly in both directions, thereby rapidly heating the switching device S2 to the preset temperature and accelerating the acquisition of the first detection result.

[0111] Furthermore, by controlling the on / off state of each switching transistor in the MMC submodule, its switching characteristics can be measured, while avoiding the introduction of additional reliability issues when disassembling the submodule. The MMC submodule is tested as a whole, and the dynamic characteristics of the upper IGBT device S2 inside the MMC submodule under actual operating conditions can be detected by heating the press-fit IGBT with multiple pulses. Therefore, it can solve the problem of not being able to effectively test the press-fit IGBT (switching device) in the MMC submodule.

[0112] Example 2:

[0113] Please see Figure 7 , Figure 7This is a second structural diagram of the detection device topology provided in an embodiment of the present invention. The embodiment of the present invention provides a bridge-structured MMC submodule testing device, such as... Figure 7 As shown, this device is applicable to a bridge-structure MMC submodule testing method as described in Embodiment 1. The MMC submodule testing device specifically comprises:

[0114] The MMC submodule testing device is a testing circuit consisting of a second auxiliary testing module and a second MMC submodule;

[0115] The first port of the second auxiliary detection module is connected to the first power port of the second MMC submodule, the second port of the second auxiliary detection module is connected to the second power port of the second MMC submodule, and the third port of the second auxiliary detection module is connected to the third power port of the second MMC submodule.

[0116] The second MMC submodule includes a second target drive port, a second target switch, and a second capacitor;

[0117] The second auxiliary detection module includes a second switch module, a drive module, and a second DC voltage source;

[0118] The second switch module is used to charge and discharge the second capacitor by controlling the opening and closing of the switch, so as to heat the second target switch to a preset temperature.

[0119] The driving module is used to acquire the signal of the second target switch under the drive of a preset multi-pulse signal to obtain the second detection result.

[0120] It should be noted that this device is another construction form of the detection device in Embodiment 1, and is applicable to the MMC submodule detection method with a bridge structure described in Embodiment 1. Therefore, the following will only describe this device from the perspectives of its composition and how to achieve the heating of the switching device.

[0121] It should be noted that, in the embodiments of the present invention, the second DC voltage source is represented by DC voltage source VDC, the second capacitor is represented by second capacitor C, the second target switch is represented by switching device S2, and the second target drive port is represented by drive port D2.

[0122] In one embodiment, the MMC submodule testing device specifically comprises:

[0123] The testing device consists of a second auxiliary testing circuit and a second MMC submodule.

[0124] The first port of the second auxiliary detection circuit is connected to the first power port P1 of the second MMC submodule, the second port of the second auxiliary detection circuit is connected to the second power port P2 of the second MMC submodule, and the third port of the second auxiliary detection circuit is connected to the third power port P3 of the second MMC submodule.

[0125] The second auxiliary detection circuit includes switching device 3 S3, switching device 4 S4, switching device 5 S5, switching device 6 S6, drive port 3 D3, drive port 4 D4, drive port 5 D5, drive port 6 D6, DC voltage source VDC, resistor R and inductor L;

[0126] The second MMC submodule includes a first switching device S1, a second switching device S2 (second target switch), a first driving port D1, a second driving port D2 (second target driving port), and a second capacitor C; wherein, the first driving port D1 and the second driving port D2 provide driving signals for the IGBT module.

[0127] Among them, switching device 3 S3, switching device 4 S4, switching device 5 S5 and switching device 6 S6 form a full bridge structure. A DC voltage source VDC is connected in parallel across the two ends of the full bridge. The two arms of the full bridge are connected to the first power port P1 and the third power port P3 of the submodule, respectively. The resistor and inductor are connected in series and then in parallel between the first power port P1 and the second power port P2.

[0128] In one embodiment, the specific control process for repeatedly charging and discharging the second capacitor C to heat the second target switch to a preset temperature is as follows:

[0129] By repeatedly controlling the DC voltage source VDC and the second capacitor C to discharge sequentially, the second capacitor C can be repeatedly charged and discharged.

[0130] The second capacitor C is charged by controlling the closing of switches S2, S4, and S5, and the opening of switches S1, S3, and S6, so that the DC voltage source VDC charges the second capacitor C.

[0131] The discharge of the second capacitor C is achieved by controlling the closing of switches S2 and S3, and the opening of switches S1, S4, S5 and S6.

[0132] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 8 , Figure 8This is a second diagram illustrating the capacitor charging process provided in an embodiment of the present invention. The circuit diagram shown in red represents the process of charging the second capacitor C. Specifically, it involves closing control switches S2, S4, and S5, while opening switches S1, S3, and S6, and keeping switches D1 to D6 in the off state, thereby allowing the DC voltage source VDC to discharge and charge the second capacitor C.

[0133] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 9 , Figure 9 This is a second diagram illustrating the capacitor discharge process provided in an embodiment of the present invention. The circuit diagram shown in red represents the discharge process of the second capacitor C. Specifically, it involves closing control switches S2 and S3, while opening switches S1, S4, S5, and S6, and setting switches D1 to D4 and D6 to be in the off state, and setting switch D5 to be in the on state. This disconnects the DC voltage source VDC, preventing it from working and thus allowing the second capacitor C to discharge.

[0134] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 10 , Figure 10 This is a second timing diagram of the driving voltage of each switch provided in an embodiment of the present invention. It shows the driving voltage timing diagram of switch device 1 S1 to switch device 6 S6 during the T1 to T4 process when using this device and applying the MMC submodule detection method of bridge structure as described in Embodiment 1.

[0135] Overall, the embodiments of the present invention have the following beneficial effects:

[0136] This device is another testing device that can be used in the bridge-structure MMC submodule testing method. While adopting the same testing principle, the circuit structure of this testing device is more complex and has greater scalability. The circuit design in the testing device can be added or modified to adapt to more different application needs.

[0137] Example 3:

[0138] Please see Figure 11 The present invention provides a bridge-structured MMC submodule testing device, including an acquisition module 10, a construction module 20, a heating module 30 and a testing module 40;

[0139] The acquisition module 10 is used to acquire the first MMC sub-module; wherein the first MMC sub-module includes a first target switch and a first capacitor;

[0140] The construction module 20 is used to build a detection device based on the first MMC submodule; wherein the detection device includes a first switch module, a first DC voltage source and a first MMC submodule;

[0141] The heating module 30 is used to charge and discharge the first capacitor through the first switching module, so as to heat the first target switch to a preset temperature; wherein, the first switching module controls the closing and opening of the preset switch to discharge the first DC voltage source and the first capacitor in sequence, thereby enabling the first capacitor to charge and discharge.

[0142] The evaluation module 40 is used to acquire the signal of the first target switch under the drive of a preset multi-pulse signal and obtain the first detection result.

[0143] In one embodiment, the acquisition module 10 specifically comprises:

[0144] Obtain the first MMC submodule; wherein the first MMC submodule includes a DC voltage source VDC and a first capacitor C.

[0145] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 2 , Figure 2 This is a structural diagram of a half-bridge MMC submodule provided in an embodiment of the present invention, representing the obtained first MMC submodule. The first MMC submodule includes two press-fit insulated gate bipolar transistor (IGBT) modules and a capacitor. Specifically, it includes a first switching device S1, a second switching device S2 (first target switch), a first driving port D1, a second driving port D2 (first target driving port), and a first capacitor C; wherein, the first driving port D1 and the second driving port D2 provide driving signals for the IGBT modules.

[0146] The purpose of this invention is to obtain the switching detection characteristics of the switching device S2 in the MMC submodule.

[0147] It should be noted that, in the embodiments of the present invention, the first DC voltage source is represented by DC voltage source VDC, the first capacitor is represented by first capacitor C, the first target switch is represented by switch device two S2, the first target drive port is represented by drive port two D2, the first switch is represented by switch device three S3, and the second switch is represented by switch device four S4.

[0148] In one embodiment, the building module 20 includes a device building unit, an accessory installation unit, and an initial adjustment unit;

[0149] The device construction unit is used to build a detection device based on the first MMC submodule.

[0150] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 3 , Figure 3 This is a structural diagram of a half-bridge MMC submodule provided in an embodiment of the present invention, representing a detection device, specifically:

[0151] The detection device is a detection circuit composed of a first auxiliary detection circuit and a first MMC submodule;

[0152] The first port of the first auxiliary detection circuit is connected to the first power port P1 of the first MMC submodule, the second port of the first auxiliary detection circuit is connected to the second power port P2 of the first MMC submodule, and the third port of the first auxiliary detection circuit is connected to the third power port P3 of the first MMC submodule.

[0153] The first auxiliary detection circuit includes a three-switching device S3 (first switch), a four-switching device S4 (second switch), a three-drive port D3, a four-drive port D4, a DC voltage source VDC, a resistor R, and an inductor L;

[0154] Among them, switching device three S3 and switching device four S4 form a half-bridge structure. A DC voltage source VDC is connected in parallel across the two ends of the half-bridge. The midpoint of the half-bridge is connected to the power port one P1 of the first MMC submodule. Resistor R and inductor L are connected in series and then in parallel between the first power port P1 and the second power port P2.

[0155] The accessory mounting unit is used to install a heat sink in the testing device, as well as a set of clamps that apply pressure to each switching device and two IGBT drive circuits.

[0156] The initial adjustment unit is used to discharge the first capacitor C in the detection device, adjust the mechanical pressure of the fixture to within the rated standard range, set the ambient temperature of the detection device to room temperature through the heat sink, and set the drive voltage of both IGBT drive circuits to a low level, that is, both IGBTs are in the off state.

[0157] In one embodiment, the heating module 30 specifically comprises:

[0158] By repeatedly controlling the DC voltage source VDC and the first capacitor C to discharge sequentially, the first capacitor C can be repeatedly charged and discharged.

[0159] The charging of the first capacitor C is achieved by controlling the closing of switch devices S2 and S3 and the opening of switch device S4, so that the DC voltage source VDC charges the first capacitor C.

[0160] The discharge of the first capacitor C is achieved by controlling the closing of switch devices S2 and S4, and the opening of switch device S3.

[0161] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 4 , Figure 4 This is a first diagram illustrating the capacitor charging process provided in an embodiment of the present invention. The circuit diagram shown in red represents the process of charging the first capacitor C. Specifically, by turning on switch device two S2 and switch device three S3, turning off switch device one S1 and switch device four S4, and keeping D1 to D4 in the off state, the DC voltage source VDC is discharged to charge the first capacitor C.

[0162] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 5 , Figure 5 This is a first diagram illustrating the capacitor discharge process provided in an embodiment of the present invention. The circuit diagram shown in red represents the discharge process of the first capacitor C. Specifically, by turning on switch device two S2 and switch device four S4, turning off switch device one S1 and switch device three S3, and keeping D1 to D4 in the off state, the DC voltage source VDC is disconnected and cannot work, thereby realizing the discharge of the first capacitor C.

[0163] This embodiment details the charging and discharging process of the first capacitor C. By controlling the closing of switch devices S2 and S3, and the opening of switch device S4, the DC voltage source VDC can be put into operation, thus charging the first capacitor C. By controlling the closing of switch devices S2 and S4, and the opening of switch device S3, the DC voltage source VDC can be disconnected and cannot work, causing the first capacitor C to be forced to discharge. This charging and discharging is achieved by switching on and off, which is simple, intuitive, and highly controllable. The charging and discharging process can quickly heat switch device S2, accelerating the acquisition of the first detection result.

[0164] In one embodiment, the evaluation module 40 includes a driving unit, an evaluation unit, and an adjustment unit;

[0165] The driving unit is used to drive the switching device S2 by sending a multi-pulse signal through the driving port D2 in a preset state using the IGBT driving circuit. The preset state refers to the state in which the switching device S2 and the switching device S4 are closed and the switching device S3 is open, that is, the circuit state in which the first capacitor C is discharged.

[0166] In this embodiment, a large number of switching characteristics of switch device S2 under current can be obtained by driving switch device S2 with a multi-pulse signal. In addition, the state in which switch device S2 and switch device S4 are closed and switch device S3 is open is the state in which the DC voltage source VDC is disconnected and cannot work. In this state, using a multi-pulse signal to drive and detect switch device S2 can avoid the influence of excessive voltage, current and other factors on the drive and detection process, and can ensure the accuracy of the first detection result.

[0167] The evaluation unit is used to acquire the signal of the switching device S2 under the drive of a multi-pulse signal and obtain the first detection result.

[0168] The adjustment unit is used to discharge the first capacitor C and the inductor L after the multi-pulse test is completed, so that the voltage and current of the first capacitor C and the inductor L are 0.

[0169] This embodiment prevents accidental electric shock and ensures user safety by discharging the first capacitor C and inductor L after the multi-pulse test.

[0170] For an explanation of the embodiments of the present invention, please refer to [link / reference]. Figure 6 , Figure 6 This is a first timing diagram of the driving voltage of each switch provided in an embodiment of the present invention. T1 is the initial stage, referring to the stage where initial debugging is completed in step S2.3; T2 is the self-heating stage, referring to the stage where, in step S3, the switching devices self-heat by repeatedly charging and discharging the capacitor; T3 is the multi-pulse test stage, referring to the stage where, in step S4.1, the switching device S2 is driven using a multi-pulse signal; and T4 is the discharge stage, referring to the stage where, after the multi-pulse test, the first capacitor C and inductor L are completely discharged. Figure 6 This refers to the timing diagram of the driving voltages of switching devices S1 to S4 during the above T1 to T4 processes.

[0171] Overall, the embodiments of the present invention have the following beneficial effects:

[0172] In this device, since the switching performance of the device is strongly correlated with temperature, and the parameters differ significantly at different temperatures, heating the switching device S2 to a preset temperature to drive and detect it to obtain the first detection result maximizes the device characteristics of the switching device S2 and ensures the accuracy and effectiveness of the first detection result. Furthermore, since each switching process incurs switching losses, which manifest as heat, under the same time, voltage, and current conditions, the higher the switching frequency and the more times the device switches, the faster the heat rises. Therefore, by repeatedly charging and discharging the first capacitor C, the current can flow repeatedly in both directions, thereby rapidly heating the switching device S2 to the preset temperature and accelerating the acquisition of the first detection result.

[0173] Furthermore, by controlling the on / off state of each switching transistor in the MMC submodule, its switching characteristics can be measured, while avoiding the introduction of additional reliability issues when disassembling the submodule. The MMC submodule is tested as a whole, and the dynamic characteristics of the upper IGBT device S2 inside the MMC submodule under actual operating conditions can be detected by heating the press-fit IGBT with multiple pulses. Therefore, it can solve the problem of not being able to effectively test the press-fit IGBT (switching device) in the MMC submodule.

[0174] Example 4:

[0175] This invention provides a computer-readable storage medium including a stored computer program, wherein the computer program, when running, controls the device where the computer-readable storage medium is located to execute the bridge-structured MMC submodule detection method.

[0176] The bridge-structure MMC submodule detection method, when implemented as a software functional unit and used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments can also be implemented by a computer program instructing related hardware. This computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0177] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A bridge-type structure MMC submodule testing device, characterized in that, The MMC submodule testing device is specifically as follows: The MMC submodule testing device is a testing circuit composed of a second auxiliary testing module and a second MMC submodule; The second auxiliary detection module includes a second switch module; the second switch module includes a third switch, a fourth switch, a fifth switch, and a sixth switch; the third switch, the fourth switch, the fifth switch, and the sixth switch form a full-bridge structure; wherein the third switch and the fourth switch form the left bridge arm, and the fifth switch and the sixth switch form the right bridge arm; The second MMC submodule includes a second target drive port, a second target switch, and a second capacitor; wherein the second target switch is a lower bridge arm switch; The second auxiliary detection module also includes a drive module and a second DC voltage source; The second DC voltage source is connected in parallel at both ends of the full-bridge structure; The midpoint of the left bridge arm is connected to the third power port of the second MMC submodule; The midpoint of the right bridge arm is connected to the first power port of the second MMC submodule; The second auxiliary detection module also includes a resistor and an inductor, which are connected in series and then in parallel between the first power port and the second power port of the second MMC submodule; The second switch module is used to charge and discharge the second capacitor by controlling the opening and closing of the switch, so that the second target switch is heated to a preset temperature; The driving module is used to acquire the signal of the second target switch under the drive of a preset multi-pulse signal, and obtain a second detection result; The second capacitor is charged by controlling the second target switch, the fourth switch and the fifth switch to close, and the third switch and the sixth switch to open, so that the second DC voltage source charges the second capacitor. Discharging the second capacitor is achieved by controlling the second target switch and the third switch to close, while the fourth, fifth, and sixth switches are opened.

2. The bridge-structure MMC submodule testing device as described in claim 1, characterized in that, The driving module is used to acquire the signal of the second target switch under the drive of a preset multi-pulse signal, and obtain a second detection result, specifically: The driving module is used to drive the second target switch by sending the multi-pulse signal through the second target driving port in a preset state, and to obtain the signal of the second target switch under the drive of the multi-pulse signal to obtain the second detection result; The preset state refers to the state in which the second target switch and the third switch are closed, and the fourth switch and the fifth switch are open.

3. A method for detecting MMC submodules with a bridge structure, characterized in that, The method is applicable to the bridge-type MMC submodule testing device as described in any one of claims 1-2, comprising: Obtain the second MMC submodule; wherein the second MMC submodule includes a second target drive port, a second target switch, and a second capacitor; A detection device is established based on the second MMC submodule; wherein the detection device includes a second switch module, a second DC voltage source, and the second MMC submodule; The second capacitor is charged and discharged by the second switching module, so that the second target switch is heated to a preset temperature; wherein, the second switching module controls the closing and opening of the preset switch to discharge the second DC voltage source and the second capacitor in sequence, thereby enabling the second capacitor to charge and discharge. The signal of the second target switch driven by a preset multi-pulse signal is obtained to obtain the second detection result.

4. The method for detecting MMC submodules with a bridge structure as described in claim 3, characterized in that, The step of obtaining the signal of the second target switch under the preset multi-pulse signal drive to obtain the second detection result is specifically as follows: In a preset state, the second target drive port is used to send the multi-pulse signal to drive the second target switch; wherein, the preset state refers to the state in which the second target switch and the third switch are closed, and the fourth switch and the fifth switch are open; The signal of the second target switch under the drive of the multi-pulse signal is obtained to obtain the second detection result.

5. A storage medium, characterized in that, The storage medium stores a computer program, which is called and executed by a computer to implement the MMC submodule detection method of any one of the bridge-type structures described in claims 3 to 4.

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