Method and device for detecting MMC (Modular Multilevel Converter) sub-module with bridge structure, and medium

Abstract

The invention discloses a bridge-structure MMC sub-module detection method and device, and a medium. The method comprises the steps of obtaining a first MMC sub-module; wherein the first MMC sub-module comprises a first target switch and a first capacitor; establishing a detection device according to the first MMC sub-module; the detection device comprises a first switch module, a first DC voltage source and a first MMC sub-module. The first capacitor is charged and discharged through the first switch module, so that the first target switch is heated to a preset temperature; and acquiring a signal of the first target switch driven by a preset multi-pulse signal to obtain a first detection result. According to the bridge-structure MMC sub-module detection method and device and the medium provided by the invention, an accurate detection result can be obtained through a mode of heating the first target switch to the preset temperature and then carrying out detection, so that the problem that a switching device in an MMC sub-module cannot be effectively detected can be solved.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a method, a device and a medium for detecting an MMC submodule of a bridge structure. Background Art

[0002] High Voltage Direct Current (HVDC) transmission technology is considered to be a reliable and efficient way of power transmission. The implementation methods of HVDC transmission include HVDC based on line commutated converter (LCC-HVDC) technology and HVDC based on voltage source converter (VSC-HVDC) technology. Among them, VSC-HVDC technology has been widely developed and recognized. The most commonly used VSC-HVDC topology is modular multilevel converter (MMC). The bridge arm of MMC adopts the sub-module cascade method. Among the factors affecting the reliability of MMC sub-modules, the reliability of switching devices (i.e. IGBT) plays a decisive role. Therefore, the research on module reliability mainly analyzes the reliability of switching devices. At present, the most commonly used method for evaluating the reliability of MMC sub-modules is offline detection. Compared with online detection and in-situ detection, offline detection can obtain more characteristic parameters of switching devices, which is conducive to the comprehensive investigation of the aging status of devices.

[0003] However, the existing offline detection mainly disassembles the MMC submodule as a whole, and then performs a double-pulse test on the IGBT module in the submodule separately after disassembly, and then reassembles it after obtaining parameters sufficient to measure the aging of the device. Although this method can obtain more aging data, the reliability of the module will be greatly reduced during the disassembly and reassembly of the MMC submodule, and the entire detection process is difficult to operate, and the time and labor costs consumed are very high, making it difficult to actually use it in daily maintenance. Summary of the invention

[0004] The present invention provides a bridge-structured MMC submodule detection method, device and medium to solve the problem that a switch device in an MMC submodule cannot be effectively detected.

[0005] In order to solve the above problems, the present invention provides a bridge-structured MMC submodule detection method, comprising:

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

[0007] Establishing a detection device according to the first MMC submodule; wherein the detection device comprises a first switch module, a first DC voltage source and the first MMC submodule;

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

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

[0010] In the present invention, since the switching performance of the device is strongly correlated with the temperature, and the parameters at different temperatures are greatly different, the first target switch is heated to a preset temperature, and then the first target switch is driven and detected to obtain the first detection result, so that the device characteristics of the first target switch itself can be brought into play to the greatest extent, and the first detection result can be ensured to be accurate and effective. In addition, since the device will have switching losses each time it switches, the energy of the switching loss will be expressed as heat. Under the same time, voltage and current conditions, the greater the switching frequency and the more switching times, the faster the device heat will rise. Therefore, by repeatedly charging and discharging the first capacitor, the current can repeatedly flow in both positive and negative directions, thereby allowing the first target switch to be quickly heated to the preset temperature, accelerating the acquisition process of the first detection result.

[0011] Compared with the prior art, this solution utilizes the switching characteristics and temperature performance of the switch and uses the first switch module in the detection device to quickly heat the first target switch to a preset temperature, thereby maximizing the performance of the first target switch and obtaining accurate first target switch detection results. In addition, this method does not require disassembly and reassembly of the MMC sub-module, and the time and labor costs are low, so it can solve the problem of not being able to effectively detect the switch devices in the MMC sub-module.

[0012] As a preferred solution, the detection device is specifically:

[0013] The detection device is a detection circuit composed of a first auxiliary detection module and the 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, the first target switch and the first capacitor;

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

[0017] The detection device in this preferred embodiment is composed of a first auxiliary detection module and a first MMC sub-module, wherein the first auxiliary detection module includes a first switch module and a first DC voltage source. Through this configuration, the opening and closing of the switch in the first switch module can be controlled to control whether the first DC voltage source is in a working state, thereby allowing the capacitor in the MMC sub-module to charge and discharge, thereby realizing switch heating.

[0018] As a preferred solution, the first switch module controls the closing and opening of a preset switch to discharge the first DC voltage source and the first capacitor in sequence, thereby charging and discharging the first capacitor, specifically:

[0019] By repeatedly controlling the first DC voltage source and the first capacitor to discharge in sequence, the first capacitor is 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 discharging of the first capacitor is achieved by controlling the first target switch and the second switch to be closed, and the first switch to be open.

[0022] This preferred solution elaborates in detail 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 disconnected, the first DC voltage source can be in a working state to charge the first capacitor; by controlling the first target switch and the second switch to be closed and the first switch to be disconnected, the first DC voltage source can be disconnected and unable to work, resulting in the first capacitor being charged and discharged; the charging and discharging is achieved by opening and closing the switch, and the operation method is simple and intuitive, and has strong controllability. The first target switch can be quickly heated by the charging and discharging method, thereby accelerating the process of obtaining the first detection result.

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

[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 a state in which the first target switch and the second switch are controlled to be closed, and the first switch is opened;

[0025] A signal of the first target switch driven by the multi-pulse signal is acquired to obtain a first detection result.

[0026] The preferred solution drives the first target switch through a multi-pulse signal, and a large number of switch characteristics of the first target switch under current can be obtained; in addition, the state in which the first target switch and the second switch are closed and the first switch is disconnected is a state in which the first DC voltage source is disconnected and cannot work. In this state, the multi-pulse signal is used to drive and detect the first target switch, which can avoid the drive detection process being affected by factors such as excessive voltage and current, and can ensure the accuracy of the first detection result.

[0027] The present invention also provides a bridge-structured MMC submodule evaluation device, which is applicable to a bridge-structured MMC submodule detection method. The MMC submodule evaluation device is specifically:

[0028] The MMC submodule evaluation device is a detection circuit composed of a second auxiliary detection 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 obtain a signal of the second target switch driven by a preset multi-pulse signal to obtain a second detection result.

[0034] This device is another detection device that can be used in the MMC sub-module detection method with a bridge structure. Based on the same detection principle, the circuit structure of the evaluation device is more complex and has more scalability. The circuit design in the evaluation device can be increased or modified to adapt to more different application requirements.

[0035] As a preferred solution, 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, specifically:

[0036] By repeatedly controlling the second DC voltage source and the second capacitor to discharge in sequence, the second capacitor is repeatedly charged and discharged, so that the second target switch is heated to a preset temperature;

[0037] The charging of the second capacitor is achieved by controlling the second target switch, the fourth switch and the fifth switch to be closed, and the third switch to be open, so that the second DC voltage source charges the second capacitor;

[0038] Allowing the second capacitor to discharge is achieved by controlling the second target switch and the third switch to be closed, and the fourth switch and the fifth switch to be opened;

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

[0040] As a preferred solution, the driving module is used to obtain a signal of the second target switch driven by a preset multi-pulse signal to obtain a second detection result, specifically:

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

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

[0043] The present invention also provides a bridge-structured MMC submodule detection device, comprising an acquisition module, a construction module, a heating module and an evaluation module;

[0044] Wherein, the acquisition module is used to acquire a first MMC submodule; wherein, the first MMC submodule includes a first target switch and a first capacitor;

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

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

[0047] The evaluation module is used to obtain a signal of the first target switch driven by a preset multi-pulse signal to obtain a first detection result.

[0048] As a preferred solution, the detection device is specifically:

[0049] The detection device is a detection circuit composed of a first auxiliary detection module and the 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, the first target switch and the first capacitor;

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

[0053] As a preferred solution, 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 discharging of the first capacitor is achieved by controlling the first target switch and the second switch to be closed, and the first switch to be open.

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

[0058] The driving unit is used to drive the first target switch by sending the multi-pulse signal using 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 controlled to be closed, and the first switch is disconnected;

[0059] The evaluation unit is used to obtain a signal of the first target switch driven by the multi-pulse signal to obtain a first detection result.

[0060] The present invention also provides a storage medium, on which a computer program is stored. The computer program is called and executed by a computer to implement the above-mentioned bridge-structured MMC submodule detection method. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a flow chart of a bridge-structured MMC submodule detection method provided by an embodiment of the present invention;

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

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

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

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

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

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

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

[0069] Fig. 9 is a second representation diagram of a capacitor discharge process provided by an embodiment of the present invention;

[0070] Fig.10 is a second timing diagram of the driving voltage of each switch tube provided by an embodiment of the present invention;

[0071] Fig.11 It is a structural schematic diagram of an MMC submodule detection device of a bridge structure provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0072] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

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

[0074] The bridge-structured MMC submodule detection method described in the embodiment of the present invention is mainly applied to the situation where the switch characteristics inside the MMC submodule need to be measured without destroying the packaging of the MMC submodule.

[0075] Embodiment 1:

[0076] See also Figure 1 The embodiment of the present invention provides a bridge-structured MMC submodule detection method, including S1 to S2, and the specific implementation steps are as follows:

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

[0078] Step S1 of the embodiment of the present invention is specifically:

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

[0080] To apply the embodiments of the present invention, please refer to Figure 2 , Figure 2: is a structural diagram of a half-bridge MMC submodule provided in an embodiment of the present invention, which represents the first MMC submodule obtained, and the first MMC submodule includes two crimped insulated gate bipolar transistor (IGBT) modules and a capacitor, specifically, including a switch device 1 S1, a switch device 2 S2 (a first target switch), a drive port 1 D1, a drive port 2 D2 (a first target drive port) and a first capacitor C; wherein the drive port 1 D1 and the drive port 2 D2 provide drive signals for the IGBT module;

[0081] The purpose of the embodiment of the present invention is to obtain the switch detection characteristics of the switch device 2 S2 in the MMC sub-module.

[0082] It should be noted that, in the embodiment of the present invention, the DC voltage source VDC represents the first DC voltage source, the first capacitor C represents the first capacitor, the switching device 2 S2 represents the first target switch, the driving port 2 D2 represents the first target driving port, the switching device 3 S3 represents the first switch, and the switching device 4 S4 represents the second switch.

[0083] S2. Establish a detection device according to 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 the embodiment of the present invention, S2 includes S2.1 to S2.3, specifically:

[0085] S2.1. Establish a detection device according to the first MMC submodule.

[0086] To apply the embodiments of the present invention, please refer to Figure 3 , Figure 3 1 is a first topological structure diagram of a detection device provided in an embodiment of the present invention, which shows a 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 switch device three S3 (first switch), a switch device four S4 (second switch), a drive port three D3, a drive port four D4, a DC voltage source VDC, a resistor R and an inductor L;

[0090] Among them, the switch device three S3 and the switch device four S4 form a half-bridge structure, the DC voltage source VDC is connected in parallel at both ends of the half bridge, the midpoint of the half bridge is connected to the power port one P1 of the first MMC sub-module, and the resistor R and the inductor L are connected in series and in parallel between the first power port P1 and the second power port P2.

[0091] S2.2. Install a set of heat sinks in the detection device, and install a set of fixtures for applying pressure to each switching device and two IGBT drive circuits.

[0092] S2.3. Completely discharge the first capacitor C in the detection device, adjust the mechanical pressure of the fixture within the rated standard range, set the working environment temperature of the detection device to normal temperature through the heat sink, and make the driving voltages of the two IGBT driving circuits low, that is, the IGBTs are both 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 a preset temperature; wherein the first switch module controls the closing and opening of the preset switch to discharge the first DC voltage source and the first capacitor in sequence, thereby realizing the charging and discharging of the first capacitor.

[0094] Step S3 of the embodiment of the present invention is specifically:

[0095] By repeatedly controlling the DC voltage source VDC and the first capacitor C to discharge in sequence, the first capacitor C is repeatedly charged and discharged;

[0096] The charging of the first capacitor C is achieved by controlling the switch device 2 S2 and the switch device 3 S3 to be closed, and the switch device 4 S4 to be opened, 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 switch device 2 S2 and the switch device 4 S4 to be closed, and the switch device 3 S3 to be opened.

[0098] To apply the embodiments of the present invention, please refer to Figure 4 , Figure 4 1 is a first representation diagram of the capacitor charging process provided by an embodiment of the present invention. The circuit diagram shown in the red part represents the process of charging the first capacitor C, specifically: by opening the switch device 2 S2 and the switch device 3 S3, disconnecting the switch device 1 S1 and the switch device 4 S4, and making D1~D4 all in the off state, thereby allowing the DC voltage source VDC to discharge and charge the first capacitor C.

[0099] To apply the embodiments of the present invention, please refer to Figure 5 , Figure 5It is the first representation diagram of the capacitor discharge process provided by an embodiment of the present invention. The circuit diagram shown in the red part represents the discharge process of the first capacitor C, specifically: by opening the switch device 2 S2 and the switch device 4 S4, disconnecting the switch device 1 S1 and the switch device 3 S3, and making D1~D4 all in the off state, so that the DC voltage source VDC is disconnected and cannot work, thereby achieving the discharge of the first capacitor C.

[0100] This embodiment elaborates on the process of charging and discharging the first capacitor C. By controlling the switch device 2 S2 and the switch device 3 S3 to be closed, and the switch device 4 S4 to be disconnected, the DC voltage source VDC can be in a working state, thereby charging the first capacitor C. By controlling the switch device 2 S2 and the switch device 4 S4 to be closed, and the switch device 3 S3 to be disconnected, the DC voltage source VDC can be disconnected and unable to work, resulting in the first capacitor C being charged and discharged. The charging and discharging is realized by opening and closing the switch. The operation method is simple and intuitive, and has strong controllability. The switch device 2 S2 can be quickly heated by the charging and discharging method, thereby accelerating the process of obtaining the first detection result.

[0101] S4. Acquire a signal of the first target switch driven by a preset multi-pulse signal to obtain a first detection result.

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

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

[0104] In this embodiment, the switch device 2 S2 is driven by a multi-pulse signal, so that a large number of switching characteristics of the switch device 2 S2 under current can be obtained; in addition, the state in which the switch device 2 S2 and the switch device 4 S4 are closed and the switch device 3 S3 is disconnected is a state in which the DC voltage source VDC is disconnected and cannot work. In this state, the drive detection of the switch device 2 S2 is performed using a multi-pulse signal, which can avoid the drive detection process being affected by factors such as excessive voltage and current, and can ensure the accuracy of the first detection result.

[0105] S4.2. Obtain the signal of the second switch device S2 driven by the multi-pulse signal to obtain a 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 zero.

[0107] This embodiment can prevent accidental electric shock and ensure the safety of users by discharging the first capacitor C and the inductor L after the multi-pulse test.

[0108] To apply the embodiments of the present invention, please refer to Figure 6 , Figure 6 It is the first timing diagram of the driving voltage of each switch tube provided by the embodiment of the present invention, wherein T1 is the initial stage, which refers to the stage in which the initial debugging is completed in step S2.3; T2 is the self-heating stage, which refers to step S3, the stage in which each switch device is self-heated by repeatedly charging and discharging the capacitor; T3 is the multi-pulse test stage, which refers to step S4.1, the stage in which the second switch device S2 is driven by a multi-pulse signal; T4 is the discharge stage, which refers to step S4.3, the stage in which the first capacitor C and the inductor L are discharged after the multi-pulse test is completed; Figure 6 That is, it shows the driving voltage timing diagram of the switch device 1 S1 to the switch device 4 S4 in the above-mentioned process T1 to T4.

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

[0110] In the embodiment of the present invention, since the switching performance of the device is strongly correlated with the temperature, the parameters at different temperatures are quite different. Therefore, by heating the switch device 2 S2 to a preset temperature, and then driving and detecting the switch device 2 S2 to obtain the first detection result, the device characteristics of the switch device 2 S2 can be brought into play to the greatest extent, and the first detection result can be ensured to be accurate and effective. In addition, since the device will have switching losses each time it switches, the energy of the switching losses will be expressed as heat. Under the same time, voltage and current conditions, the greater the switching frequency and the more switching times, the faster the device heat will rise. Therefore, by repeatedly charging and discharging the first capacitor C, the current can repeatedly flow in both positive and negative directions, thereby allowing the switch device 2 S2 to be quickly heated to the preset temperature, accelerating the acquisition process of the first detection result.

[0111] In addition, by controlling the on and off of each switch tube in the MMC sub-module, its switching characteristics are measured, and at the same time, additional reliability problems are avoided when disassembling the sub-module; the MMC sub-module is tested as a whole object, and the crimped IGBT is heated by multiple pulses. The dynamic characteristics of the upper tube IGBT device S2 inside the MMC sub-module under actual working conditions can be detected, so the problem of not being able to effectively detect the crimped IGBT (switching device) in the MMC sub-module can be solved.

[0112] Embodiment 2:

[0113] See also Figure 7 , Figure 7is a second topological structure diagram of the detection device provided by an embodiment of the present invention. An embodiment of the present invention provides an MMC submodule evaluation device with a bridge structure, such as Figure 7 As shown, the device is applicable to a bridge-structured MMC submodule detection method as described in Example 1, and the MMC submodule evaluation device is specifically:

[0114] The MMC submodule evaluation device is a detection circuit composed of a second auxiliary detection 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 driving 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 that the second target switch is heated to a preset temperature;

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

[0120] It should be noted that this device is another construction form of the detection device in Example 1, and is suitable for a bridge-structured MMC sub-module detection method described in Example 1. Therefore, the following only describes this device from two perspectives: the composition of the device and how to achieve heating of the switching device.

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

[0122] In one embodiment, the MMC submodule evaluation device is specifically:

[0123] The evaluation device is a detection circuit composed of a second auxiliary detection 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 a switch device three S3, a switch device four S4, a switch device five S5, a switch device six S6, a drive port three D3, a drive port four D4, a drive port five D5, a drive port six D6, a DC voltage source VDC, a resistor R and an inductor L;

[0126] The second MMC submodule includes a switch device 1 S1, a switch device 2 S2 (a second target switch), a drive port 1 D1, a drive port 2 D2 (a second target drive port) and a second capacitor C; wherein the drive port 1 D1 and the drive port 2 D2 provide a drive signal for the IGBT module;

[0127] Among them, switch device three S3, switch device four S4, switch device five S5 and switch device six S6 form a full-bridge structure, a DC voltage source VDC is connected in parallel at both ends of the full bridge, and the two bridge arms of the full bridge are respectively connected to the first power port P1 and the third power port P3 of the sub-module, and the resistor and the inductor are connected in series and in parallel between the first power port P1 and the second power port P2.

[0128] In one embodiment, the specific control process of repeatedly charging and discharging the second capacitor C so as 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 in sequence, the second capacitor C is repeatedly charged and discharged;

[0130] The charging of the second capacitor C is achieved by controlling the switch device 2 S2, the switch device 4 S4 and the switch device 5 S5 to be closed, and the switch device 1 S1, the switch device 3 S3 and the switch device 6 S6 to be disconnected, 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 switch device 2 S2 and the switch device 3 S3 to be closed, and the switch device 1 S1, the switch device 4 S4, the switch device 5 S5 and the switch device 6 S6 to be opened.

[0132] To apply the embodiments of the present invention, please refer to Figure 8 , Figure 81 is a second representation diagram of the capacitor charging process provided by an embodiment of the present invention. The circuit diagram shown in the red part represents the process of charging the second capacitor C, specifically: controlling the switch device 2 S2, the switch device 4 S4 and the switch device 5 S5 to be closed, and the switch device 1 S1, the switch device 3 S3 and the switch device 6 S6 to be disconnected, and making D1~D6 all in the off state, thereby allowing the DC voltage source VDC to discharge and charge the second capacitor C.

[0133] To apply the embodiments of the present invention, please refer to Fig. 9 , Fig. 9 1 is a second representation diagram of the capacitor discharge process provided by an embodiment of the present invention. The circuit diagram shown in the red part represents the discharge process of the second capacitor C, specifically: controlling the switch device 2 S2 and the switch device 3 S3 to be closed, and the switch device 1 S1, the switch device 4 S4, the switch device 5 S5 and the switch device 6 S6 to be disconnected, and making D1~D4 and D6 all in the off state, and making D5 in the on working state, so that the DC voltage source VDC is disconnected and cannot work, thereby achieving the discharge of the second capacitor C.

[0134] To apply the embodiments of the present invention, please refer to Fig.10 , Fig.10 It is the second timing diagram of the driving voltage of each switch tube provided in an embodiment of the present invention, which represents the driving voltage timing diagram of switch device 1 S1 to switch device 6 S6 during T1 to T4 when using the present device and applying a bridge-structured MMC sub-module detection method as described in Example 1.

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

[0136] This device is another detection device that can be used in the MMC sub-module detection method with a bridge structure. Based on the same detection principle, the circuit structure of the evaluation device is more complex and has more scalability. The circuit design in the evaluation device can be increased or modified to adapt to more different application requirements.

[0137] Embodiment three:

[0138] See also Fig.11 , an embodiment of the present invention provides a bridge-structured MMC submodule detection device, including an acquisition module 10, a construction module 20, a heating module 30 and an evaluation module 40;

[0139] Wherein, the acquisition module 10 is used to acquire the first MMC submodule; wherein the first MMC submodule includes a first target switch and a first capacitor;

[0140] A construction module 20 is used to establish a detection device according to 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 switch module, so that the first target switch is heated to a preset temperature; wherein the first switch module controls the closing and opening of the preset switch to discharge the first DC voltage source and the first capacitor in sequence, so as to charge and discharge the first capacitor;

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

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

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

[0145] To apply the embodiments of the present invention, please refer to Figure 2 , Figure 2 : is a structural diagram of a half-bridge MMC submodule provided in an embodiment of the present invention, which represents the first MMC submodule obtained, and the first MMC submodule includes two crimped insulated gate bipolar transistor (IGBT) modules and a capacitor, specifically, including a switch device 1 S1, a switch device 2 S2 (a first target switch), a drive port 1 D1, a drive port 2 D2 (a first target drive port) and a first capacitor C; wherein the drive port 1 D1 and the drive port 2 D2 provide drive signals for the IGBT module;

[0146] The purpose of the embodiment of the present invention is to obtain the switch detection characteristics of the switch device 2 S2 in the MMC sub-module.

[0147] It should be noted that, in the embodiment of the present invention, the DC voltage source VDC represents the first DC voltage source, the first capacitor C represents the first capacitor, the switching device 2 S2 represents the first target switch, the driving port 2 D2 represents the first target driving port, the switching device 3 S3 represents the first switch, and the switching device 4 S4 represents the second switch.

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

[0149] The device construction unit is used to establish a detection device according to the first MMC submodule.

[0150] To apply the embodiments of the present invention, please refer to Figure 3 , Figure 3 : is a structural diagram of a half-bridge MMC submodule provided by an embodiment of the present invention, which shows 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 switch device three S3 (first switch), a switch device four S4 (second switch), a drive port three D3, a drive port four D4, a DC voltage source VDC, a resistor R and an inductor L;

[0154] Among them, the switch device three S3 and the switch device four S4 form a half-bridge structure, the DC voltage source VDC is connected in parallel at both ends of the half bridge, the midpoint of the half bridge is connected to the power port one P1 of the first MMC sub-module, and the resistor R and the inductor L are connected in series and in parallel between the first power port P1 and the second power port P2.

[0155] The accessory installation unit is used to install a set of heat sinks in the detection device, and to install a set of fixtures for applying 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 within the rated standard range, set the working environment temperature of the detection device to normal temperature through the heat sink, and make the driving voltages of the two IGBT driving circuits low, that is, the IGBTs are in the off state.

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

[0158] By repeatedly controlling the DC voltage source VDC and the first capacitor C to discharge in sequence, the first capacitor C is repeatedly charged and discharged;

[0159] The charging of the first capacitor C is achieved by controlling the switch device 2 S2 and the switch device 3 S3 to be closed, and the switch device 4 S4 to be opened, 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 switch device 2 S2 and the switch device 4 S4 to be closed, and the switch device 3 S3 to be opened.

[0161] To apply the embodiments of the present invention, please refer to Figure 4 , Figure 4 1 is a first representation diagram of the capacitor charging process provided by an embodiment of the present invention. The circuit diagram shown in the red part represents the process of charging the first capacitor C, specifically: by opening the switch device 2 S2 and the switch device 3 S3, disconnecting the switch device 1 S1 and the switch device 4 S4, and making D1~D4 all in the off state, thereby allowing the DC voltage source VDC to discharge and charge the first capacitor C.

[0162] To apply the embodiments of the present invention, please refer to Figure 5 , Figure 5 It is the first representation diagram of the capacitor discharge process provided by an embodiment of the present invention. The circuit diagram shown in the red part represents the discharge process of the first capacitor C, specifically: by opening the switch device 2 S2 and the switch device 4 S4, disconnecting the switch device 1 S1 and the switch device 3 S3, and making D1~D4 all in the off state, so that the DC voltage source VDC is disconnected and cannot work, thereby achieving the discharge of the first capacitor C.

[0163] This embodiment elaborates on the process of charging and discharging the first capacitor C. By controlling the switch device 2 S2 and the switch device 3 S3 to be closed, and the switch device 4 S4 to be disconnected, the DC voltage source VDC can be in a working state, thereby charging the first capacitor C. By controlling the switch device 2 S2 and the switch device 4 S4 to be closed, and the switch device 3 S3 to be disconnected, the DC voltage source VDC can be disconnected and unable to work, resulting in the first capacitor C being charged and discharged. The charging and discharging is realized by opening and closing the switch. The operation method is simple and intuitive, and has strong controllability. The switch device 2 S2 can be quickly heated by the charging and discharging method, thereby accelerating the process of obtaining 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 switch device 2 S2 by sending a multi-pulse signal through the drive port 2 D2 using the IGBT driving circuit in a preset state; wherein the preset state refers to a state in which the switch device 2 S2 and the switch device 4 S4 are controlled to be closed, and the switch device 3 S3 is disconnected, that is, a circuit state in which the first capacitor C is discharged;

[0166] In this embodiment, the switch device 2 S2 is driven by a multi-pulse signal, so that a large number of switching characteristics of the switch device 2 S2 under current can be obtained; in addition, the state in which the switch device 2 S2 and the switch device 4 S4 are closed and the switch device 3 S3 is disconnected is a state in which the DC voltage source VDC is disconnected and cannot work. In this state, the drive detection of the switch device 2 S2 is performed using a multi-pulse signal, which can avoid the drive detection process being affected by factors such as excessive voltage and current, and can ensure the accuracy of the first detection result.

[0167] The evaluation unit is used to obtain the signal of the second switch device S2 driven by the multi-pulse signal to obtain a 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 zero.

[0169] This embodiment can prevent accidental electric shock and ensure the safety of users by discharging the first capacitor C and the inductor L after the multi-pulse test.

[0170] To apply the embodiments of the present invention, please refer to Figure 6 , Figure 6 It is the first timing diagram of the driving voltage of each switch tube provided by the embodiment of the present invention, wherein T1 is the initial stage, which refers to the stage in which the initial debugging is completed in step S2.3; T2 is the self-heating stage, which refers to step S3, the stage in which each switch device is self-heated by repeatedly charging and discharging the capacitor; T3 is the multi-pulse test stage, which refers to step S4.1, the stage in which the second switch device S2 is driven by a multi-pulse signal; T4 is the discharge stage, which refers to step S4.3, the stage in which the first capacitor C and the inductor L are discharged after the multi-pulse test is completed; Figure 6 That is, it shows the driving voltage timing diagram of the switch device 1 S1 to the switch device 4 S4 in the above-mentioned process T1 to T4.

[0171] In general, 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 the temperature, the parameters at different temperatures are quite different. Therefore, by heating the switch device S2 to a preset temperature, the switch device S2 is driven and tested to obtain the first test result, which can maximize the device characteristics of the switch device S2 itself and ensure that the first test result is accurate and effective. In addition, since the device will have switching losses each time it switches, the energy of the switching loss will be expressed as heat. Under the same time, voltage and current conditions, the greater the switching frequency and the more switching times, the faster the device heat will rise. Therefore, by repeatedly charging and discharging the first capacitor C, the current can repeatedly flow in both positive and negative directions, thereby allowing the switch device S2 to be quickly heated to the preset temperature, accelerating the process of obtaining the first test result;

[0173] In addition, by controlling the on and off of each switch tube in the MMC sub-module, its switching characteristics are measured, and at the same time, additional reliability problems are avoided when disassembling the sub-module; the MMC sub-module is tested as a whole object, and the crimped IGBT is heated by multiple pulses. The dynamic characteristics of the upper tube IGBT device S2 inside the MMC sub-module under actual working conditions can be detected, so the problem of not being able to effectively detect the crimped IGBT (switching device) in the MMC sub-module can be solved.

[0174] Embodiment 4:

[0175] An embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the MMC submodule detection method of a bridge structure;

[0176] Wherein, if the MMC submodule detection method of a bridge structure is implemented in the form of a software functional unit and used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium, etc.

[0177] The above are preferred embodiments of the present invention. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A bridge-structured MMC submodule detection method, It is characterized in that include: Acquire a first MMC submodule; wherein the first MMC submodule includes a first target switch and a first capacitor; Establishing a detection device according to the first MMC submodule; wherein the detection device comprises a first switch module, a first DC voltage source and the first MMC submodule; The first switch module allows the first capacitor to be charged and discharged, so that the first target switch is heated to a preset temperature; wherein the first switch module controls the closing and opening of a preset switch to discharge the first DC voltage source and the first capacitor in sequence, so as to achieve charging and discharging of the first capacitor; A signal of the first target switch driven by a preset multi-pulse signal is acquired to obtain a first detection result.

2. A bridge-structured MMC submodule detection method as claimed in claim 1, It is characterized in that The detection device is specifically: The detection device is a detection circuit composed of a first auxiliary detection module and the first MMC submodule; 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; The first MMC submodule includes a first target drive port, the first target switch and the first capacitor; The first auxiliary detection module includes the first switch module and the first DC voltage source, and the first switch module includes a first switch and a second switch.

3. A bridge-structured MMC submodule detection method as claimed in claim 2, It is characterized in that The first switch module controls the closing and opening of a preset switch to discharge the first DC voltage source and the first capacitor in sequence, thereby charging and discharging the first capacitor. Specifically, By repeatedly controlling the first DC voltage source and the first capacitor to discharge in sequence, the first capacitor is repeatedly charged and discharged; 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; The discharging of the first capacitor is achieved by controlling the first target switch and the second switch to be closed, and the first switch to be open.

4. A bridge-structured MMC submodule detection method as claimed in claim 2, It is characterized in that The signal of the first target switch driven by a preset multi-pulse signal is obtained to obtain a first detection result, which is specifically: 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 a state in which the first target switch and the second switch are controlled to be closed, and the first switch is opened; A signal of the first target switch driven by the multi-pulse signal is acquired to obtain a first detection result.

5. A bridge-structured MMC submodule evaluation device, It is characterized in that A method for detecting an MMC submodule of a bridge structure is applicable, wherein the MMC submodule evaluation device is specifically: The MMC submodule evaluation device is a detection circuit composed of a second auxiliary detection module and a second MMC submodule; 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; The second MMC submodule includes a second target drive port, a second target switch and a second capacitor; The second auxiliary detection module includes a second switch module, a drive module and a second DC voltage source; 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 obtain a signal of the second target switch driven by a preset multi-pulse signal to obtain a second detection result.

6. A bridge-structured MMC submodule evaluation device as claimed in claim 5, It is characterized in that 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, specifically: By repeatedly controlling the second DC voltage source and the second capacitor to discharge in sequence, the second capacitor is repeatedly charged and discharged, so that the second target switch is heated to a preset temperature; The charging of the second capacitor is achieved by controlling the second target switch, the fourth switch and the fifth switch to be closed, and the third switch to be open, so that the second DC voltage source charges the second capacitor; Allowing the second capacitor to discharge is achieved by controlling the second target switch and the third switch to be closed, and the fourth switch and the fifth switch to be opened; The third switch, the fourth switch and the fifth switch are all preset switches in the second switch module.

7. A bridge-structured MMC submodule evaluation device as claimed in claim 5, It is characterized in that The driving module is used to obtain a signal of the second target switch driven by a preset multi-pulse signal to obtain a second detection result, which is specifically: The driving module is used to drive the second target switch by sending the multi-pulse signal using the second target driving port under a preset state, and obtain a signal of the second target switch driven by the multi-pulse signal to obtain the second detection result; The preset state refers to a state in which the second target switch and the third switch are controlled to be closed, and the fourth switch and the fifth switch are controlled to be open.

8. A bridge-structured MMC submodule detection device, It is characterized in that It includes acquisition module, construction module, heating module and evaluation module; Wherein, the acquisition module is used to acquire a first MMC submodule; wherein, the first MMC submodule includes a first target switch and a first capacitor; The construction module is used to establish a detection device according to the first MMC sub-module; wherein the detection device includes a first switch module, a first DC voltage source and the first MMC sub-module; The heating module is used to charge and discharge the first capacitor through the first switch module, so that the first target switch is heated to a preset temperature; wherein the first switch module controls the closing and opening of a preset switch to discharge the first DC voltage source and the first capacitor in sequence, so as to charge and discharge the first capacitor; The evaluation module is used to obtain a signal of the first target switch driven by a preset multi-pulse signal to obtain a first detection result.

9. A bridge-structured MMC submodule detection device as claimed in claim 8, It is characterized in that The detection device is specifically: The detection device is a detection circuit composed of a first auxiliary detection module and the first MMC submodule; 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; The first MMC submodule includes a first target drive port, the first target switch and the first capacitor; The first auxiliary detection module includes the first switch module and the first DC voltage source, and the first switch module includes a first switch and a second switch.

10. A bridge-structured MMC submodule detection device as claimed in claim 9, It is characterized in that The heating module includes a charging and discharging unit; 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; 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; The discharging of the first capacitor is achieved by controlling the first target switch and the second switch to be closed, and the first switch to be open.

11. The MMC submodule detection device of a bridge structure as claimed in claim 9, It is characterized in that The evaluation module includes a driving unit and an evaluation unit; The driving unit is used to drive the first target switch by sending the multi-pulse signal using 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 controlled to be closed, and the first switch is disconnected; The evaluation unit is used to obtain a signal of the first target switch driven by the multi-pulse signal to obtain a first detection result.

12. A storage medium, It is 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 claims 1 to 4 above in a bridge structure.

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