Flexible direct current converter valve power module testing device and testing method

Abstract

The invention discloses a flexible direct current converter valve power module testing device and a testing method, and aims to solve the problem that a thyristor in a sub-module is not tested in an existing flexible direct current converter valve sub-module test. The flexible direct current converter valve power module testing device only needs to be electrically connected with a to-be-tested thyristor correspondingly during testing, sampling detection of sub-module loop total current and thyristor current is achieved conveniently and rapidly through the sampling probe, the purpose of accurately judging whether the sub-module thyristor can be triggered normally or not is achieved, the testing process is convenient and rapid, and the testing efficiency is improved. Complex wiring and operation are not needed, and the problem that special tests of thyristors are missing in existing sub-module detection is effectively solved. And meanwhile, the qualification judgment threshold of the thyristor is set according to the total current of the sub-module loop, so that the invalid calculation power in the detection process can be avoided, the judgment operation efficiency of the controller is improved, and the data operation and data volume in the intermediate process are reduced. In addition, report data are reliably stored in the controller and the upper computer, so that later tracking and tracing are facilitated.

Description

Technical Field

[0001] This invention relates to the field of flexible DC converter valve testing technology, specifically to a testing device and method for a flexible DC converter valve power module. Background Technology

[0002] Flexible DC converter valves are core equipment in flexible DC transmission systems, enabling efficient conversion between AC and DC power and flexible control of voltage, current, reactive power, and active power output and input. Modular multilevel converters, on the other hand, are voltage source converters based on a cascaded submodule structure. By connecting multiple submodules in series, multilevel outputs can be formed, and this structure has become the mainstream topology for flexible DC engineering construction.

[0003] For the half-bridge and full-bridge submodule topologies commonly used in flexible DC engineering, please refer to [link / reference]. Figure 1 As shown. The thyristor is the core component of the flexible DC-DC valve submodule, and its performance directly affects the operational stability and reliability of the flexible DC-DC converter valve. For conditions such as DC faults in the system, a thyristor is connected in parallel to the lower tube of the flexible DC-DC valve submodule. When the arm current of the modular multilevel converter (MMC) exceeds a set value, the valve control sends a thyristor turn-on command to the submodule, sharing the current of the anti-parallel diode in the lower tube through the thyristor to protect the submodule's safety.

[0004] However, in the process of implementing the technical solution in the embodiments of this application, the inventors of this application discovered that in the current on-site operation and maintenance of flexible DC valves, the thyristors in the sub-modules of flexible DC valves are subject to special testing due to the lack of sampling tests. This makes it impossible to effectively identify risks and investigate hidden dangers in the thyristors in the sub-modules, making it difficult to ensure that the thyristors in the sub-modules can be triggered normally, which poses a significant safety hazard.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the background technology of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] In view of at least one of the above technical problems, this disclosure provides a test device and test method for a flexible DC converter valve power module, which aims to solve the problem of missing thyristor testing in the existing flexible DC valve sub-module test.

[0007] According to one aspect of this disclosure, a power module testing device for a flexible DC converter valve is provided, comprising a power input terminal, a voltage conversion module electrically connected to the power output terminal, a thyristor triggering test unit for connecting a thyristor under test (TUT) and electrically connected to the voltage conversion module, a thyristor control board power supply unit electrically connected to the thyristor control board, a current acquisition unit for acquiring the thyristor current of the TUT submodule and the total current of the submodule circuit, a control unit for communicating with a host computer and the thyristor control board, and an IGBT drive unit electrically connected to the control unit for controlling the on / off state of the thyristor triggering test unit; the thyristor triggering test unit includes a current limiting module, an RC filter module, a buffer module for absorbing instantaneous energy, an IGBT module for generating trigger test pulses, and a test circuit relay electrically connected to the control unit, forming a thyristor triggering test circuit.

[0008] In some embodiments of this disclosure, a power switch and a switch indicator light for indicating the corresponding switch status of the power switch are connected in series at the power input terminal.

[0009] In some embodiments of this disclosure, the voltage conversion module includes a 400V DC power supply unit electrically connected to the thyristor trigger test unit, a 220V DC power supply unit electrically connected to the thyristor control board power supply unit, a 15V DC power supply unit electrically connected to the IGBT drive unit, and a 24V DC power supply unit electrically connected to the current acquisition unit and the control unit, respectively.

[0010] In some embodiments of this disclosure, the thyristor control board power supply unit includes a power supply circuit relay electrically connected to the control unit.

[0011] In some embodiments of this disclosure, the IGBT driving unit includes a driving board that is electrically connected to the control unit and the IGBT module respectively, and is used to drive the IGBT module when the control unit issues a test command. The driving board is electrically connected to the voltage conversion module via a high-voltage isolated power supply.

[0012] In some embodiments of this disclosure, the current acquisition unit includes a sampling board connected to a sampling probe and used to convert the sampling signal into a digital signal, and the output terminal of the sampling board is communicatively connected to the control unit.

[0013] In some embodiments of this disclosure, the current limiting module includes a current limiting resistor; the buffer module includes a buffer diode connected in parallel in the test circuit; and the IGBT module includes an IGBT electrically connected to the IGBT drive unit and provided with an anti-parallel diode.

[0014] According to another aspect of this disclosure, a test method for a flexible DC-DC converter valve power module is provided, which is implemented based on the aforementioned test device for a flexible DC-DC converter valve power module, and includes the following steps in sequence: (1) Connect the power input terminal of the flexible DC converter valve power module test device to the power supply and establish communication between the PC host computer and the control unit; (2) After receiving the start signal output by the PC host computer, the control unit controls the thyristor control board power supply unit to conduct and supply power to the thyristor control board. (3) The PC host computer sends a trigger signal to the control unit. After receiving the trigger signal, the control unit outputs a thyristor trigger control command to the thyristor control board. After the thyristor is triggered, the control unit controls the test circuit relay to turn on, and then the control unit outputs a drive signal to the IGBT drive unit to control the IGBT module to turn on. (4) The current acquisition unit acquires the thyristor current of the tested submodule and the total current of the submodule circuit respectively. The thyristor is qualified based on the current of the lower diode corresponding to the difference between the total current of the submodule circuit and the thyristor current.

[0015] In some embodiments of this disclosure, in step (3), the control unit waits 25-35 seconds after the thyristor is triggered. μs Then, the corresponding control circuit relay is activated; after the test circuit relay is activated, the control unit waits for 480-520 seconds. ms Then, a drive signal is output to the IGBT drive unit.

[0016] In some embodiments of this disclosure, in step (4), when the total peak current is greater than 1000A and the peak current through the thyristor is greater than 200A, the thyristor qualification judgment is initiated, and when the current through the down diode is greater than 500A and lasts for at least 50 seconds... μs When the thyristor current is within acceptable limits, it is determined that the thyristor current is qualified.

[0017] One or more technical solutions provided in this application embodiment have at least the following technical effects or advantages: The flexible DC converter valve power module testing device only needs to be electrically connected to the thyristor under test during testing. The sampling probe conveniently and quickly samples and detects the total current of the submodule circuit and the thyristor current, thereby accurately determining whether the submodule thyristor can trigger normally. The testing process is convenient and quick, requiring no complex wiring or operation, effectively solving the problem of the lack of dedicated thyristor testing in existing submodule testing. Simultaneously, setting a thyristor qualification threshold based on the total current of the submodule circuit avoids invalid computation during the testing process, improves the controller's judgment efficiency, and reduces intermediate data computation and data volume. Furthermore, by reliably storing the report data in the controller and host computer, it facilitates later traceability. Attached Figure Description

[0018] Figure 1 The diagram below shows the existing submodule topology in the background art of this application, where (a) is the half-bridge submodule topology and (b) is the full-bridge submodule topology.

[0019] Figure 2 This is a schematic block diagram of a power module testing device for a flexible DC converter valve in one embodiment of this application.

[0020] Figure 3 This is a schematic diagram of the current acquisition points of the submodule in one embodiment of this application. Detailed Implementation

[0021] The programs involved or relied upon in the following embodiments are all conventional or simple programs in this technical field, and those skilled in the art can make conventional selections or adaptive adjustments according to specific application scenarios. Unless otherwise specified, the devices involved in the following embodiments are all conventional commercially available products.

[0022] To better understand the technical solution of this application, the above technical solution will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] To address the lack of specialized testing for thyristors in submodules during the on-site operation and maintenance of flexible DC converter valves, and to facilitate effective risk identification and hazard investigation of thyristors in submodules, ensuring their proper triggering, this example discloses a power module testing device for flexible DC converter valves. This device includes a thyristor triggering test unit, a thyristor control board power supply unit, a current acquisition unit, an IGBT drive unit, and a control unit.

[0024] Specifically, considering that the operation of the submodule requires control from the thyristor control board, in this embodiment, to ensure the normal operation of the thyristor control board, the flexible DC converter valve power module testing device includes a thyristor control board power supply unit. Therefore, during the testing of the flexible DC converter valve power module, power is supplied to the thyristor control board through the thyristor control board power supply unit. See also... Figure 2 The flexible DC converter valve power module testing device is equipped with an AC power input terminal, through which a 220V AC mains power is connected as the test power input. To facilitate convenient control of the power input and avoid immediate power-on of the device after connecting to mains power, see [reference needed]. Figure 2A power switch QF1 is provided at the power input terminal, which allows the device to be powered on and off as needed. In addition, in order to accurately identify the on / off state of the power switch, a switch indicator light is also electrically connected to the power switch QF1 in this example. When the power switch is closed, the switch indicator light is powered on and illuminates; when the power switch is opened, the switch indicator light is de-energized and turns off. In addition, to enable the triggering control of the thyristors connected in parallel at the lower tube of the submodule during the testing process, a thyristor control board (SCE board) is also provided in this embodiment. Since the thyristor control board requires a 220V DC power input, the flexible DC converter valve power module testing device in this example also includes a voltage conversion module. The voltage conversion module can realize multi-level voltage conversion. Specifically, in this example, the voltage conversion module includes a 220V DC power supply unit DY2. The 220V DC power supply unit is electrically connected between the power input terminal and the power supply unit of the thyristor control board to convert 220V AC mains power into 220V DC power for the operation of the thyristor control board (SCE).

[0025] The thyristor control board power supply unit specifically includes a power supply circuit relay KM2 connected in the power supply circuit. Controlling the power supply circuit relay KM2 allows for the on / off control of the thyristor control board's power supply circuit. Furthermore, to achieve effective control of the power supply circuit relay KM2, the flexible DC converter valve power module testing device in this example also includes a control unit. Specifically, in this example, the control unit includes a controller KZB. The control signal output terminal of the controller KM2 is electrically connected to the control terminal of the power supply circuit relay KM2. Therefore, when the controller issues an on / off control command for the thyristor control board, the corresponding contact of the power supply circuit relay KM2 in the thyristor control board's power supply circuit is turned on or off, thereby controlling the thyristor control board to power on or off.

[0026] In this embodiment, see Figure 2 The flexible DC converter valve power module test device also includes a thyristor trigger test unit to supply power for testing the thyristors in the sub-module. Specifically, the thyristor trigger test unit is electrically connected to the 400V DC power supply DY1 in the voltage conversion module to convert the 220V AC power to the required 400V DC power for testing. Furthermore, the thyristor trigger test unit includes a thyristor trigger test circuit equipped with a current limiting module, an RC filter module, a buffer module, and an IGBT module. See details... Figure 2In this example, the current limiting module includes a current limiting resistor R1, which limits the current in the test circuit; the RC filter module includes a resistor R2 and a capacitor C1 connected in parallel, which filters out harmonics in the test circuit; the buffer module includes a buffer diode DC1 connected in parallel in the test circuit, which absorbs instantaneous energy in the test circuit to prevent the power supply from burning out. Furthermore, high-speed and accurate control of the test circuit's conduction can be achieved by controlling the IGBT module. Specifically, in this example, the IGBT module uses an IGBT with an anti-parallel diode (corresponding to...). Figure 2 VF1 in this example utilizes the IGBT's fast response capability and high tolerance to current and voltage to ensure accurate, controllable, and safe testing. Furthermore, to control the on / off switching of the thyristor trigger test circuit as needed, the thyristor trigger test unit in this example also includes a test circuit relay KM1 electrically connected to the thyristor trigger test circuit. The control terminal of the test circuit relay KM1 is electrically connected to the KM1 control signal output terminal of the controller KZB. The controller controls the opening and closing of the test circuit relay KM1 accordingly, thereby controlling the on / off switching of the thyristor test circuit. See also... Figure 3 By applying the output terminals AC1 and AC2 of the trigger test circuit to the anode and cathode of the thyristor connected in parallel to the lower tube of the submodule, a reliable and controllable power supply is provided for the thyristor trigger test.

[0027] In addition, to achieve drive control of the on / off state of VF1 in the IGBT module, in this embodiment, the flexible DC converter valve power module test device also includes an IGBT drive unit that is communicatively connected to the control unit for triggering the on / off state of the IGBT module, i.e., VF1. See details below. Figure 2 In this embodiment, the IGBT drive power supply specifically includes a drive board VF. The KZB control signal terminal of the drive board VF is communicatively connected to the VF1 control signal terminal of the controller KZB, and the VF1 conduction signal terminal of the drive board VF is electrically connected to the gate of VF1. Thus, the controller KZB sends drive control signals to the drive board VF through this communication path, thereby controlling the on / off state of VF1, i.e., the thyristor trigger test circuit. Considering the power supply to the drive board VF, in this example, the voltage conversion module also includes a 15V DC power supply DY3 to provide the required 15V operating voltage to the drive board VF. In this embodiment, the 15V DC power supply DY3 is specifically electrically connected to the drive board VF through a high-voltage isolation power supply DY4, thereby achieving electrical isolation between the 15V DC power supply DY3 and the drive board VF, preventing power supply damage caused by high voltage at VF1.

[0028] The current acquisition unit is used to measure the total current of the circuit and the thyristor current of the submodule under test. For details, see [link to documentation]. Figure 2In this embodiment, the current acquisition unit specifically includes a sampling board TCE. Two sampling boards TCE are used in this example to acquire the total current of the circuit of the sub-module under test and the thyristor current of the sub-module under test, respectively. Each sampling board TCE is electrically connected to a sampling probe BNC. Thus, after the sampling probe BNC is placed in the electrical circuit, the current at the sampling probe location enters the sampling board TCE via the sampling probe BNC. The sampling board TCE then converts the analog current signal input from the sampling probe BNC into a digital signal that can be calculated and judged. This digital signal is then transmitted to the controller via the KZB communication signal terminal, which is connected to the controller KZB for corresponding judgment and processing. In addition, to provide the voltage required for the operation of the two sampling boards TCE, the voltage conversion module in this example also includes a 24V DC power supply DY5. The 24V DC power output port of the 24V DC power supply DY5 is electrically connected to the power interface of each sampling board TCE.

[0029] In addition, in this embodiment, the controller KZB is also provided with a communication interface for connecting to a host computer. After communicating with the host computer through this communication interface, the test current output stored therein can be uploaded to the host computer for further storage and analysis.

[0030] This example also discloses a test method for a flexible DC converter valve power module, which is implemented based on the aforementioned flexible DC converter valve power module test device, and specifically includes the following steps: (1) Before the test begins, first connect the power input terminal of the flexible DC converter valve power module test device to the mains power to power on the test device. In addition, connect the PC host computer to the host computer communication interface of the controller KZB through the network cable to establish a communication path between the PC host computer and the control unit.

[0031] (2) After the test starts, the PC host computer sends a test command to the controller KZB. After the controller KZB receives the start signal output by the PC host computer, the controller KZB sends a conduction command to the power supply unit of the thyristor control board through its KM2 control signal output terminal. The coil of the power supply circuit relay KM2 is energized and the contacts are closed. The power supply circuit of the thyristor control board is turned on, and the thyristor control board SCE receives 220V DC power and starts working.

[0032] (3) After the thyristor control board starts, the PC host computer sends a thyristor trigger signal to the controller KZB. After the controller KZB receives the trigger signal, it outputs a thyristor trigger control command to the thyristor control board, and then the thyristor control board SCE controls the thyristor to trigger. After the thyristor is triggered, the controller waits for 25-35 seconds. μs Then, a conduction command is sent to the test circuit relay KM1 in the thyristor trigger test unit. In this example, the specific wait time is 30 seconds. μsUnder the control of the conduction command, the coil of test circuit relay KM1 closes. Subsequently, after its coil is energized, the contacts of test circuit relay KM1 close, causing test circuit relay KM1 to conduct. After the test circuit relay is conducted, the controller waits for 480-520 seconds. ms Then, a drive signal is output to the drive board VF in the IGBT drive unit. Under the drive of the drive board VF, VF1 in the thyristor trigger test circuit is turned on, thereby energizing the anode and cathode of the thyristor.

[0033] (4) See Figure 3 The sampling probes BNC1 and BNC2 of the two acquisition boards in the current acquisition unit are respectively placed... Figure 3 At the locations shown, the thyristor current and the total current of the submodule circuit are collected. The current signal is input to the sampling board TCE via a sampling probe. The sampling board TCE converts the analog current signal into a corresponding digital current signal, which is then input to the controller KZB via its KZB communication signal terminal for storage and judgment. The controller KZB determines whether the thyristor is qualified based on the difference between the total current of the submodule circuit and the thyristor current, corresponding to the lower diode current. Specifically, in this embodiment, after receiving the sampling signal from the sampling board, the controller KZB stores and uploads it to the PC host computer. Simultaneously, it calculates the difference between the total current of the submodule circuit and the thyristor current, i.e., the lower diode current. When the peak value of the total current is greater than 1000A and the peak value of the current through the thyristor is greater than 200A, the thyristor qualification judgment is initiated. Furthermore, when the lower diode current is greater than 500A and remains so for at least 50 seconds... μs At that time, the thyristor current is judged to be qualified. In addition, in this embodiment, after receiving the current signal sent by the controller KZB, the PC host computer draws a graph of the total current of the submodule circuit and the thyristor current in real time, and stores the waveform file corresponding to the currently tested thyristor for future reference.

[0034] Although some preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0035] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from the spirit and scope of its inventive concept. Therefore, if such modifications and variations to this disclosure fall within the scope of the claims of this application and their equivalents, this invention also intends to include such modifications and variations.

Claims

1. A power module testing device for a flexible DC converter valve, characterized in that, The device includes a voltage conversion module electrically connected to a power input terminal and a power output terminal, a thyristor triggering test unit electrically connected to the voltage conversion module for connecting the thyristor under test, a thyristor control board power supply unit electrically connected to the thyristor control board, a current acquisition unit for acquiring the thyristor current of the submodule under test and the total current of the submodule circuit, a control unit for communicating with the host computer and the thyristor control board, and an IGBT drive unit electrically connected to the control unit for controlling the on / off state of the thyristor triggering test unit. The thyristor trigger test unit includes a thyristor trigger test circuit comprising a current limiting module, an RC filter module, a buffer module for absorbing instantaneous energy, an IGBT module for generating trigger test pulses, and a test circuit relay electrically connected to the control unit.

2. The power module testing device for flexible DC converter valve according to claim 1, characterized in that, The power input terminal is connected in series with a power switch and a switch indicator light for indicating the corresponding switch status of the power switch.

3. The power module testing device for flexible DC converter valve according to claim 1, characterized in that, The voltage conversion module includes a 400V DC power supply unit electrically connected to the thyristor trigger test unit, a 220V DC power supply unit electrically connected to the thyristor control board power supply unit, a 15V DC power supply unit electrically connected to the IGBT drive unit, and a 24V DC power supply unit electrically connected to the current acquisition unit and the control unit, respectively.

4. The power module testing device for flexible DC converter valve according to claim 1, characterized in that, The thyristor control board power supply unit includes a power supply circuit relay that is electrically connected to the control unit.

5. The power module testing device for flexible DC converter valve according to claim 1, characterized in that, The IGBT drive unit includes a drive board that is electrically connected to the control unit and the IGBT module respectively, and is used to control the IGBT module when the control unit issues a test command. The drive board is electrically connected to the voltage conversion module through a high-voltage isolated power supply.

6. The power module testing device for flexible DC converter valve according to claim 1, characterized in that, The current acquisition unit includes a sampling board connected to a sampling probe and used to convert the sampling signal into a digital signal. The output terminal of the sampling board is communicatively connected to the control unit.

7. The power module testing device for flexible DC converter valve according to claim 1, characterized in that, The current limiting module includes a current limiting resistor; the buffer module includes a buffer diode connected in parallel in the test circuit; the IGBT module includes an IGBT electrically connected to the IGBT drive unit and equipped with an anti-parallel diode.

8. A test method for a power module of a flexible DC converter valve, characterized in that, The implementation based on the flexible DC converter valve power module testing device of claim 1 includes the following steps in sequence: (1) Connect the power input terminal of the flexible DC converter valve power module test device to the power supply and establish communication between the PC host computer and the control unit; (2) After receiving the start signal output by the PC host computer, the control unit controls the thyristor control board power supply unit to conduct and supply power to the thyristor control board. (3) The PC host computer sends a trigger signal to the control unit. After receiving the trigger signal, the control unit outputs a thyristor trigger control command to the thyristor control board. After the thyristor is triggered, the control unit controls the test circuit relay to turn on, and then the control unit outputs a drive signal to the IGBT drive unit to control the IGBT module to turn on. (4) The current acquisition unit acquires the thyristor current of the tested submodule and the total current of the submodule circuit respectively. The thyristor is qualified based on the current of the lower diode corresponding to the difference between the total current of the submodule circuit and the thyristor current.

9. The test method for the power module of the flexible DC converter valve according to claim 8, characterized in that, In step (3), after the thyristor is triggered, the control unit waits for 25-35 seconds. μs Then, the corresponding control circuit relay is activated; after the test circuit relay is activated, the control unit waits for 480-520 seconds. ms Then, a drive signal is output to the IGBT drive unit.

10. The test method for the power module of the flexible DC converter valve according to claim 8, characterized in that, In step (4), when the total peak current is greater than 1000A and the peak current through the thyristor is greater than 200A, the thyristor qualification judgment is initiated. When the current through the down diode is greater than 500A and lasts for at least 50 seconds... μs When the thyristor current is within acceptable limits, it is determined that the thyristor current is qualified.

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