A test device and method for a controllable phase-commutation valve IGBT submodule

Abstract

The present invention relates to a test device and method for a controllable phase-commutated IGBT submodule. The device includes a voltage and current acquisition unit, a power supply unit with multiple programmable power supplies, a power excitation output unit directly connected to the IGBT submodule under test, and a main control unit. The main control unit is communicatively connected to the power supply unit, the power excitation output unit, and the voltage and current acquisition unit. The power supply unit is connected to an input power source and outputs multiple programmable power supplies to the power excitation output unit. The power excitation output unit outputs the multiple programmable power supply output voltages and internal resistance selected by the power supply unit to both ends of the IGBT submodule under test and discharges the internal energy of the IGBT submodule. The main control unit is used to select different programmable power supplies according to test settings to implement calculation and judgment of the IGBT submodule test. Compared with the existing technology, the present invention has the advantages of simple test connection, comprehensive test functions, and multi-level safety protection.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic commutation, and in particular to a testing device and method for a controllable phase-commutating valve IGBT submodule. Background Art

[0002] Traditional grid-commutated high-voltage direct current (HVDC) transmission systems, known as Line Commutated Converter High Voltage Direct Curren (LCC-HVDC), have the advantages of long-distance, large-capacity transmission and controllable active power, and are widely used worldwide. However, because traditional LCC converters are mostly composed of thyristors and their buffer components connected in series, they are prone to commutation failures in situations such as AC system faults, resulting in a surge in DC current and a rapid and substantial loss of DC transmission power, affecting the stable and safe operation of the power grid. Controllable-Line-Commutated Converter (CLCC) valve technology, based on a hybrid of thyristor valves and IGBT valves, can achieve 100% resistance to commutation failures through commutation between the main branch and auxiliary branch and other control strategies, with external characteristics exactly the same as those of LCC valves. This technology has already begun engineering implementation and offers significant development advantages.

[0003] The IGBT submodule is an essential component of the CLCC converter valve, performing AC / DC energy conversion under the control of the valve base electronics (VBE). Its performance is crucial to the normal operation of the system. After installation and before system commissioning, as well as after replacing IGBTs or the "Drive Central Control Energy Acquisition Three-in-One Board," functional testing is required. This involves collecting and testing the voltage, current, and return optical signals of the IGBT submodule under various operating conditions to determine whether its functions and performance are functioning properly. However, there is currently no test equipment capable of fully functionally testing the IGBT submodule of CLCC converter valves.

[0004] Considering that CLCC converter valve technology originated from LCC converter valves, the field test equipment and test methods of IGBT submodules can refer to those of LCC thyristor valves. Currently, there are two main field test methods commonly used by domestic LCC valve manufacturers:

[0005] (1) Design an independent test fixture to output power to the thyristor through a cable, then unplug the trigger and feedback optical fibers already plugged into the thyristor valve, and replace them with test optical fibers connected to the test fixture to send test waveforms to the thyristor, thereby performing a full-function test. After the test is completed, plug the original optical fiber back in. Repeated plugging and unplugging operations may cause changes in the optical path coupling degree and contamination and damage to the optical fiber and optical components. After reinserting the engineering optical fiber, it is impossible to determine whether its function after connecting to the engineering valve base electronic equipment is normal, affecting the reliability of the equipment; (2) Reserve 1-2 pairs of long-distance optical fibers (about 150m) connected to the valve base electronic equipment on each valve tower. During the test process, this optical fiber is first connected to the test fixture, and then the test fixture supplies power to the thyristor assembly and initiates the test model and test waveform to the valve control equipment. Under this solution, the reserved optical cable must meet special requirements such as high voltage resistance, wear resistance, and long distance, and the cost is relatively high.

[0006] The function of the LCC converter valve is relatively simple compared to that of the CLCC converter valve. Both of these test methods cannot be directly applied to the on-site testing of the IGBT sub-module of the CLCC converter valve. It is urgent to solve the above problems and defects.

[0007] After searching, Chinese invention patent publication number CN 116360400 A discloses an in-the-loop test platform for a controllable phase-commutated converter valve control system, comprising an interface device and a computer simulation system, wherein the valve control system is connected to the computer simulation system via the interface device; the valve control system is used to generate thyristor valve and IGBT valve triggering timing, monitor and display the operating status of the converter valve and valve control body, protect the converter valve level, and monitor the external equipment of the converter valve; the interface device is used to convert the optical fiber type thyristor and IGBT triggering instructions issued by the valve control system into electrical signals or high-speed optical communication forms that can be recognized by the computer simulation system, and monitor the thyristor and IGBT operating status feedback from the computer simulation system in real time, realize the fault determination and body protection functions of the thyristor trigger detection board and IGBT trigger detection board, and perform operating status health management of the thyristor and IGBT under various operating conditions of the system; the computer simulation system is used to simulate the controllable phase-commutated converter valve and primary equipment, and is configured with various interfaces to achieve interconnection with the interface device. This existing patent has the problem of not testing the internal component parameters, basic operating functions and protection of the IGBT.

[0008] How to achieve simple, efficient, reliable and comprehensive on-site testing of IGBT submodules suitable for controllable phase-commutation and converter valves has become a technical problem that needs to be solved. Summary of the Invention

[0009] The purpose of the present invention is to provide a test device and method for a controllable phase-changing converter valve IGBT submodule in order to overcome the defects of the above-mentioned prior art.

[0010] The purpose of the present invention can be achieved by the following technical solutions:

[0011] According to one aspect of the present invention, a test device for a controllable commutation valve IGBT submodule is provided, the device including a voltage and current acquisition unit, characterized in that the device includes a power supply unit with multiple programmable power supplies, a power excitation output unit directly connected to the IGBT submodule under test, and a main control unit;

[0012] The main control unit is respectively connected to the power supply unit, the power excitation output unit and the voltage and current acquisition unit for communication;

[0013] The power supply unit is connected to the input power supply and outputs a variety of programmable power supplies to the power excitation output unit;

[0014] The power excitation output unit outputs the multiple programmable power output voltage selections of the power supply unit and the internal resistance selection of the power excitation output unit to both ends of the IGBT submodule under test, and discharges the internal energy of the IGBT submodule;

[0015] The main control unit is used to select different programmable power supplies according to the test settings, monitor the working status of the power excitation output unit, receive the sampled data returned by the voltage and current acquisition unit in real time, and realize the calculation and judgment of the IGBT submodule test.

[0016] Preferably, the power supply unit includes a main power input, a main protection circuit and multiple programmable power supplies, and outputs multiple programmable power supplies to the power excitation output unit and the voltage and current acquisition unit, wherein the multiple programmable power supplies include a low-voltage DC power supply, a low-voltage AC power supply and a high-voltage DC power supply;

[0017] The voltage and current acquisition unit is used to collect the output voltage and current of each programmable power supply, as well as the voltage and current at both ends of the IGBT submodule in real time, and transmit them to the main control unit;

[0018] The main control unit is also used for recording waves and automatically generating test reports.

[0019] More preferably, the device is designed with multiple protection functions, including:

[0020] The programmable power supply is designed with multi-level protection functions for input overvoltage, input overcurrent, output overvoltage, output overcurrent and equipment overtemperature;

[0021] The overall protection circuit includes overvoltage and overcurrent protection;

[0022] The power excitation output unit is internally designed with overvoltage protection, overcurrent protection and equipment emergency stop functions;

[0023] The device also includes an emergency stop switch connected to the power excitation output unit by hard wiring, which is used to directly disconnect the electrical connection between the programmable power supply and the IGBT submodule in a dangerous state.

[0024] Preferably, the IGBT submodule test includes testing of internal component parameters, basic operating function testing, and overvoltage protection function testing.

[0025] The internal component parameters include the resistance and capacitance parameters of the buffer circuit, the voltage-sharing resistor parameters, the correctness of the buffer diode crimping direction, and the correctness of the reverse diode crimping direction.

[0026] The basic operating functions include the high-voltage energy extraction of the IGBT sub-module board, the voltage detection accuracy across the IGBT, and the IGBT on-off function.

[0027] Preferably, the device also includes a human-computer interaction interface connected to the main control unit, which is used to modify and query the control parameters and protection settings of the field test device, check the recording files of the main control unit, and observe the test report.

[0028] Preferably, the device further comprises a spare optical fiber test port 7 connected to the main control unit;

[0029] The spare optical fiber test port is directly connected to the IGBT sub-module under test, and its interface is exactly the same as the IGBT sub-module communication interface in the engineering valve base electronic equipment. It is used to replace the valve base electronic equipment to output the test waveform and complete all function and performance tests of the IGBT sub-module.

[0030] According to another aspect of the present invention, a method for testing a controllable phase-changing valve IGBT sub-module is provided, which includes an on-site testing sub-method for the parameters of internal components of the IGBT sub-module, an on-site testing sub-method for the basic operating functions of the IGBT sub-module, and an on-site testing sub-method for the overvoltage protection function of the IGBT sub-module.

[0031] Preferably, the on-site testing sub-method for the parameters of components inside the IGBT sub-module comprises the following steps:

[0032] Step S11, applying a low-voltage DC power supply of a power supply unit of the test device to both ends of the IGBT submodule;

[0033] In step S12, the buffer capacitor is charged through the internal buffer resistor and the buffer diode of the power supply excitation output unit. The voltage and current acquisition unit detects the IGBT port voltage in real time, subtracts the forward conduction voltage of the buffer diode to obtain the voltage across the buffer capacitor. The main control unit calculates and determines the capacitance of the buffer capacitor and the correctness of the crimping direction of the buffer diode based on the time of the voltage rise phase and the charging current.

[0034] Step S13: After the snubber capacitor capacitance test is completed, the main control unit controls the internal discharge resistor to be connected to the IGBT submodule circuit through the power excitation output unit, thereby causing the snubber capacitor to discharge together with the snubber resistor. The voltage and current acquisition unit detects the discharge current measurement value and the real-time voltage of the IGBT submodule port in real time to calculate and determine the snubber resistor value.

[0035] Step S14: After the snubber resistor resistance test is completed, the low-voltage DC power supply is used again to charge the IGBT sub-module. The low-voltage DC power supply is then electrically disconnected from the IGBT sub-module, causing the voltage of the snubber capacitor to discharge through the snubber resistor and the grading resistor. At this time, the voltage and current acquisition unit detects the voltage across the IGBT sub-module, and the main control unit obtains the resistance value of the grading resistor Rdc based on the measured value and the discharge time curve.

[0036] In step S15, the main control unit controls the low-voltage DC power supply to be output in reverse to both ends of the IGBT sub-module through the conversion switch of the power excitation output unit. The power forms a path through the IGBT reverse diode, skipping the buffer circuit, and testing whether the direction of the reverse diode after crimping is correct.

[0037] More preferably, the on-site test sub-method for the basic operating functions of the IGBT sub-module comprises the following steps:

[0038] Step S21, applying a low-voltage AC power supply of a power supply unit of the test device to both ends of the IGBT submodule;

[0039] Step S22: slowly increase the pressure, and observe the uplink communication status and fault status of the "drive central control energy acquisition three-in-one board" that the valve base electronic device receives from the IGBT submodule through the human-machine interface of the valve base electronic device, and determine whether the IGBT submodule completes high-level energy acquisition and works normally, as well as the self-test function of the IGBT submodule;

[0040] Step S23: Maintain the low-voltage AC power output, observe the voltage value across the IGBT reported by the "drive central control energy acquisition three-in-one board" through the valve base electronic equipment human-machine interface, and complete the test of the voltage sampling accuracy across the IGBT sub-module;

[0041] Step S24, maintain the low-voltage AC power output, set the IGBT on-off signal through the human-machine interaction interface of the valve base electronic equipment, and judge whether the voltage waveform across the IGBT after the IGBT is turned on and off is normal through the recording file of the valve base electronic equipment or the recording file of the on-site test device, and complete the IGBT on-off function test.

[0042] More preferably, the on-site testing sub-method for the overvoltage protection function of the IGBT sub-module comprises the following steps:

[0043] Step S31, applying a high-voltage DC power supply of a power supply unit of a test device to both ends of the IGBT submodule;

[0044] Step S32: Slowly increase the voltage. After the IGBT submodule completes high-level energy extraction and self-test, the valve base electronic device keeps from issuing the IGBT opening instruction. Then, the voltage target value and voltage rise rate of the high-voltage DC power supply are set through the human-machine interface 5 of the test device.

[0045] In step S33, the voltage of the high-voltage DC power supply is slowly increased to the IGBT overvoltage protection self-triggering threshold, and the overvoltage protection self-triggering function of the IGBT submodule is determined to be normal through the message of the human-machine interface of the valve base electronic equipment and the recording file of the test device and the valve base electronic equipment.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The test device of the present invention is designed with multiple programmable power supply excitations to detect the port voltage and current of the IGBT sub-module under test in real time, and can realize the testing of the internal resistance and capacitance component parameters, basic control functions and protection functions of the IGBT sub-module.

[0048] 2. The present invention only requires directly connecting the two cable ends of the power excitation output unit of the test device to the exposed copper busbars at both ends of the IGBT sub-module, and setting the corresponding test mode through the human-machine interface of the valve base electronic equipment (VBE) to complete the on-site test of the IGBT sub-module function. There is no need to move the engineering operation optical fiber, nor is there any need to lay additional test optical fiber or cable. The operation is simple and efficient, ensuring the stability of the equipment.

[0049] 3. The test device of the present invention is provided with a spare optical fiber test port. The physical form and communication protocol of its interface are exactly the same as the communication interface of the IGBT sub-module in the engineering valve base electronic equipment. It can be directly connected to the IGBT sub-module under test, replacing the valve base electronic equipment to complete all function and performance tests of the IGBT sub-module. In the scenario where there is no valve base electronic equipment, there is no need to move the engineering operation optical fiber, thereby ensuring the reliability of the equipment.

[0050] 4. The present invention sets up multi-level safety protection measures to prevent output overvoltage from damaging equipment or causing personal safety.

[0051] 5. The test device of the present invention utilizes the wave recording function of the valve-controlled electronic device to detect the port voltage and IGBT trigger state of the IGBT submodule in real time, thereby further verifying the test results of the basic functions of the IGBT submodule.

[0052] 6. The testing device and method of the present invention can be extended to the testing of parameters and functions of thyristor components of conventional LCC converter valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 Schematic diagram of the main circuit topology of the controllable phase-commutation valve in the present invention;

[0054] Figure 2 This is a topological diagram of the controllable phase-commutation valve IGBT submodule in the present invention;

[0055] Figure 3 This is a connection diagram of the controllable phase-commutation valve IGBT submodule test device of the present invention;

[0056] Figure 4 Schematic diagram of a method for testing parameters of internal components of an IGBT submodule in the present invention;

[0057] Figure 5 Schematic diagram of a method for testing the basic operating functions of the IGBT submodule in the present invention;

[0058] Figure 6 Schematic diagram of a method for testing the overvoltage protection function of the IGBT submodule in the present invention;

[0059] In the accompanying drawings, 1 is the power supply unit, 2 is the power excitation output unit, 3 is the voltage and current acquisition unit, 4 is the main control unit, 5 is the human-computer interaction interface, 6 is the emergency stop switch, and 7 is the spare optical fiber test port. DETAILED DESCRIPTION

[0060] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0061] This embodiment relates to a test device for a controllable phase-commutation valve IGBT submodule. The typical design of the test device is as follows:

[0062] like Figure 1As shown in FIG, each bridge arm of the controllable commutation (CLCC) converter valve is composed of a saturable reactor, a high-voltage thyristor valve V11, a main fully controlled valve V12, an auxiliary fully controlled valve V13, and a small current thyristor valve V14 connected in series and parallel.

[0063] Among them, V12 and V13 are composed of the IGBT submodules tested in the present invention connected in series, and their internal topology is as follows: Figure 2 As shown in the figure, the IGBT submodule consists of a parallel IGBT circuit, a snubber circuit, and a voltage-sharing circuit. Each IGBT submodule includes one IGBT, an anti-parallel diode Df for the IGBT, a snubber capacitor Cd, a snubber resistor Rd, a snubber diode Dd, a voltage-sharing resistor Rdc, and a "three-in-one drive control energy acquisition board." This board draws high-voltage energy from the voltage across the IGBT to power all components on the board. It also monitors the voltage across the IGBT and the operating status of each component in real time, returning this information to the valve-based electronics (VBE) via optical fiber.

[0064] The LCC converter valve test waveform is initiated by the test fixture, requiring an optical fiber connection to the test fixture to control the thyristors. The CLCC converter valve test process has been optimized. The valve base electronics (VBE) issues test control commands to the IGBT submodule's "drive, control, and energy acquisition three-in-one board," implementing control of the IGBT submodule and various protection functions. Therefore, when testing the IGBT module, there's no need to remove the engineering optical fiber connecting the VBE and the IGBT submodule; the test fixture only needs to provide power to the IGBT submodule.

[0065] like Figure 3 The test device of the controllable phase-commutation valve IGBT submodule includes: a power supply unit 1, a power excitation output unit 2, a voltage and current acquisition unit 3, a main control unit 4, a human-computer interaction interface 5, an emergency stop switch 6 and a spare optical fiber test port 7.

[0066] The power supply unit 1 mainly includes the main power input of the field test device, the main protection circuit and several programmable power supplies. The power supply unit uses a 220Vac power input, which is very easy to obtain in engineering sites and laboratory environments, thus realizing the universality of the field test device.

[0067] Programmable power supplies mainly include low-voltage DC power supplies, low-voltage AC power supplies, and high-voltage DC power supplies.

[0068] The programmable power supply is designed with multi-level protection functions such as input overvoltage, input overcurrent, output overvoltage, output overcurrent, and equipment overtemperature. The protection setting value, working voltage, and working mode can be modified in real time by the main control unit 4 through programmable communication.

[0069] The total protection circuit of the total power supply includes overvoltage and overcurrent protection. The typical design of the low-voltage DC power supply is 0-48Vdc / 10A programmable DC power supply (output setting is adjustable); the typical design of the low-voltage AC power supply is 0-450Vac (effective value) / 50Hz programmable AC power supply (output setting is adjustable); the typical design of the high-voltage DC power supply is 0-6000Vdc programmable DC power supply (output setting is adjustable, and the output voltage has a step-by-step output function).

[0070] The LCC converter valve only involves AC power supply, and there is no need to choose between DC and AC. In order to test the IGBT submodule of the CLCC converter valve, the device introduces a power supply excitation output unit 2.

[0071] The power excitation output unit 2 selects and outputs the voltage of different programmable power supplies and the internal resistance of the power excitation output unit to both ends of the IGBT sub-module under test according to the test items.

[0072] Overvoltage and overcurrent protection are also designed inside the power excitation output unit 2 to prevent excessive output voltage from posing a threat to equipment and personnel.

[0073] The typical design of the power excitation output unit 2 includes several switching switches, MOSFET tubes, resistors, overvoltage protection, overcurrent protection, equipment emergency stop function, etc. It can select and output a variety of programmable power supply output voltages of the power supply unit 1 to both ends of the IGBT sub-module under test, and can also select internal resistors as the discharge resistors of the IGBT sub-module under test.

[0074] The voltage and current acquisition unit 3 collects the output voltage and current of each programmable power supply, as well as the voltage and current at both ends of the IGBT submodule in real time, and transmits them to the main control unit 4 for numerical calculation, test result judgment and other operations.

[0075] The main control unit 4 is the brain of the test device. It is used to select different programmable power excitation outputs to the two ends of the IGBT sub-module according to the settings, monitor the working status of the power excitation output unit 2, receive the sampling data returned by the voltage and current acquisition unit 3 in real time, and realize the calculation of the resistance and capacitance parameters of the IGBT sub-module, the judgment of the correctness of the trigger action logic, and the test of the sensitivity of the protection action, etc. It also has the function of automatically generating waveform recording and test reports.

[0076] The main control unit 4 is typically designed as an FPGA-SOC main chip architecture, has an Ethernet communication interface, communicates with the human-computer interaction interface 5, and controls and detects the status of multiple programmable power supplies through a programmable program.

[0077] The human-machine interaction interface 5 is used to modify and query the control parameters and protection settings of the field test device, view the recording files of the main control unit 4, and observe the test report.

[0078] The emergency stop switch 6 is hard-wired to the power excitation output unit 2 and can directly disconnect the electrical connection between the programmable power supply and the IGBT submodule to ensure the protection of equipment and personal safety in dangerous conditions.

[0079] The spare optical fiber test port 7 has an interface physical form and communication protocol that is exactly the same as the communication interface of the IGBT submodule in the engineering valve base electronic equipment. It can be directly connected to the IGBT submodule under test. This test device can replace the valve base electronic equipment (VBE) to send test control instructions to the IGBT submodule, thereby completing all functional and performance tests of the IGBT submodule.

[0080] After the IGBT submodules are installed, inspected, and maintained at the project site, it is necessary to efficiently and simply test the relevant parameters of the IGBT submodules before powering on the controlled commutation (CLCC) converter valve system.

[0081] The embodiment also relates to a method for on-site connection between a test device for a controllable phase-commutation converter valve IGBT submodule and a CLCC converter valve IGBT submodule.

[0082] like Figure 3 As shown, when the IGBT submodule is tested on site, it is only necessary to directly connect the alligator clips at the ends of the two cables of the rear stage of the power excitation output unit 2 of the test device to the exposed copper busbars at both ends of the IGBT submodule. There is no need to move the engineering operation optical fiber or connect a spare test optical fiber.

[0083] Set the test mode on the human-machine interface of the valve base electronic equipment (VBE) to initiate the test; the on-site test device only needs to output the corresponding power signal according to the agreement and cooperate with the test according to the agreed test sequence.

[0084] The on-site testing device detects the output voltage and current of the power supply excitation output unit 2 in real time, and can judge the parameters and operation results of the IGBT submodule components.

[0085] The valve base electronic device (VBE) detects the operating status and fault information reported by the IGBT sub-module in real time, and monitors the operating status of the IGBT.

[0086] The valve base electronic device (VBE) is equipped with a wave recording function, which can record the IGBT switching state and the voltage across the IGBT uploaded by the tested IGBT sub-module, and realize quantitative analysis of the IGBT sub-module voltage sampling accuracy and the correctness of the correspondence between the voltage across the IGBT and the IGBT action state.

[0087] This embodiment also relates to a testing method for a controllable phase-changing valve IGBT sub-module, which includes an on-site testing sub-method for the parameters of internal components of the IGBT sub-module, an on-site testing sub-method for the basic operating functions of the IGBT sub-module, and an on-site testing sub-method for the overvoltage protection function of the IGBT sub-module.

[0088] The power excitation output unit 2 selects and outputs the low-voltage DC power supply in the power supply unit 1 to both ends of the IGBT sub-module test piece, and controls its internal control switch and MOSFET tube to cooperate in action. The voltage and current acquisition unit 3 collects the voltage and output current at both ends of the test piece in real time. The main control unit 4 tests the resistance and capacitance parameters of the buffer circuit, the equalizing resistor parameters, and the correctness of the IGBT anti-parallel diode crimping direction based on the corresponding relationship between the above values and the time of change of the above parameters.

[0089] The power excitation output unit 2 selects and outputs the low-voltage AC power in the power supply unit 1 to both ends of the IGBT sub-module test piece, realizing the high-voltage energy acquisition of the IGBT sub-module's "three-in-one drive and central control energy acquisition board", the voltage detection accuracy at both ends of the IGBT, and the test of the IGBT on-off function.

[0090] The power excitation output unit 2 selects and outputs the high-voltage DC power supply in the power supply unit 1 to both ends of the IGBT submodule test piece to implement the overvoltage protection trigger function test of the IGBT submodule.

[0091] The high-voltage DC power supply excitation design voltage of the test device is set to an upper limit to prevent damage to the equipment after the overvoltage protection triggering function of the IGBT sub-module fails.

[0092] Specifically, the typical design using the low-voltage DC power supply test method is as follows:

[0093] On-site test method for parameters of internal components of IGBT submodule, such as Figure 4 As shown, the following steps are included:

[0094] Step S11, the low-voltage DC power supply of the power supply unit 1 of the test device is applied to both ends of the IGBT submodule;

[0095] In step S12, the buffer capacitor Cd is charged through the internal buffer resistor R1 and the buffer diode Dd of the power excitation output unit 2. The voltage and current acquisition unit 3 detects the IGBT port voltage in real time, subtracts the forward conduction voltage of the buffer diode Dd, and obtains the voltage across the buffer capacitor Cd. The main control unit 4 calculates and determines the capacitance of the buffer capacitor Cd and the correctness of the crimping direction of the buffer diode Dd based on the time of the voltage rise phase and the charging current.

[0096] In step S13, after the capacitance test of the buffer capacitor Cd is completed, the main control unit 4 controls the internal discharge resistor R2 of the power supply excitation output unit 2 to be connected to the IGBT submodule circuit, thereby causing the buffer capacitor Cd to discharge together with the buffer resistor Rd. The voltage and current acquisition unit 3 detects the discharge current measurement value and the real-time voltage of the IGBT submodule port in real time to calculate and determine the resistance value of the buffer resistor Rd.

[0097] In step S14, after the resistance test of the buffer resistor Rd is completed, the low-voltage DC power supply is used to charge the IGBT sub-module again, and then the low-voltage DC power supply is electrically disconnected from the IGBT sub-module, causing the voltage of the buffer capacitor Cd to discharge through the buffer resistor Rd and the grading resistor Rdc. At this time, the voltage and current acquisition unit 3 detects the voltage across the IGBT sub-module (i.e., the voltage across the grading resistor Rdc), and the main control unit 4 obtains the resistance value of the grading resistor Rdc based on the measured value and the RC discharge time curve;

[0098] In step S15, the main control unit 4 controls the low-voltage DC power supply to be output in reverse to both ends of the IGBT sub-module through the conversion switch of the source excitation output unit 2. The power supply forms a path through the IGBT reverse diode without passing through the buffer circuit to test whether the direction of the reverse diode Df after crimping is correct.

[0099] Specifically, the typical design using the low-voltage AC power supply test method is as follows:

[0100] like Figure 5 As shown, the on-site test sub-method for the basic operating functions of the IGBT sub-module includes the following steps:

[0101] Step S21: The low-voltage AC power supply of the power supply unit 1 of the test device is applied to both ends of the IGBT submodule;

[0102] Step S22: slowly increase the pressure and observe the uplink communication status and fault status of the "drive central control energy acquisition three-in-one board" received by the valve base electronic equipment through the human-machine interface of the valve base electronic equipment, so as to determine whether the IGBT submodule has completed high-level energy acquisition normally and is working normally, as well as the self-test function of the IGBT submodule;

[0103] Step S23: Maintain the low-voltage AC power output and observe the voltage value across the IGBT reported by the "drive central control energy acquisition three-in-one board" through the valve base electronic equipment human-machine interface to complete the test of the voltage sampling accuracy across the IGBT sub-module;

[0104] Step S24, maintain the low-voltage AC power output, set the IGBT on-off signal through the human-machine interface of the valve base electronic equipment (a typical design is to trigger in the positive half cycle of the AC sine waveform and continuously trigger for 5ms), and through the recording file of the valve base electronic equipment and the recording file of the on-site test device, complete the IGBT on-off function test by checking whether the voltage waveform at both ends of the IGBT is normal after the IGBT is turned on and off.

[0105] Specifically, the typical design using the high-voltage DC power supply test method is as follows:

[0106] like Figure 6 As shown, the on-site test sub-method for the overvoltage protection function of the IGBT sub-module includes the following steps:

[0107] Step S31, the high-voltage DC power supply of the power supply unit 1 of the test device is applied to both ends of the IGBT submodule;

[0108] Step S32: Slowly increase the voltage. After the IGBT submodule completes high-level energy extraction and self-test, the valve base electronic device keeps from issuing the IGBT opening instruction. Then, the voltage target value and voltage rise rate of the high-voltage DC power supply are set through the human-machine interface 5 of the test device.

[0109] In step S33, the voltage gradually increases to the IGBT overvoltage protection self-triggering threshold, and the overvoltage protection self-triggering function of the IGBT submodule is determined to be normal through the message of the valve base electronic equipment human-machine interface and the recording file of the test device and the valve base electronic equipment.

[0110] The voltage value of the high-voltage DC power supply is gradually increased to the IGBT overvoltage protection self-triggering threshold by setting the voltage target value and the rising rate on the human-machine interface 5 of the test device.

[0111] The test device of this invention cooperates with the IGBT sub-module and valve control to measure the parameters and functions of the resistor and capacitor components of the IGBT sub-module based on different power supply excitations, series auxiliary components and analog quantity acquisition. During the above-mentioned test process, the test device only needs to achieve electrical connection with the IGBT sub-module under test through two cables, which will not damage the existing optical fiber connection and does not require the laying of additional test optical fiber or cables. The operation is simple and efficient.

[0112] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A test device for a controllable phase-commutation valve IGBT submodule, the device comprising a voltage and current acquisition unit (3), characterized in that: The device comprises a power supply unit (1) for various programmable power supplies, a power supply excitation output unit (2) directly connected to the IGBT submodule under test, and a main control unit (4); The IGBT submodule is composed of an IGBT circuit, a buffer circuit, and a voltage-equalizing circuit in parallel. Each IGBT submodule contains one IGBT, one anti-parallel diode for IGBT, one buffer capacitor, one buffer resistor, one buffer diode, one voltage-equalizing resistor, and one set of three-in-one drive control energy acquisition board. This board realizes high-potential energy acquisition of the voltage across the IGBT to power all components on the board; it detects the voltage across the IGBT and the working status of each component in real time and returns it to the valve base electronic equipment through the communication optical fiber; The main control unit (4) is communicatively connected to the power supply unit (1), the power excitation output unit (2) and the voltage and current acquisition unit (3); The power supply unit (1) is connected to an input power supply and outputs a variety of programmable power supplies to the power supply excitation output unit (2); The power supply excitation output unit (2) outputs the voltage of different programmable power supplies of the power supply unit (1) to both ends of the IGBT submodule under test according to the test items; the power supply excitation output unit (2) is also used to select an internal resistor as a discharge resistor of the IGBT submodule under test; The main control unit (4) is used to select different programmable power supplies according to the test items, monitor the working status of the power supply excitation output unit (2), receive the sampled data returned by the voltage and current acquisition unit (3) in real time, and realize the calculation and judgment of the IGBT submodule test; The multiple programmable power supplies include a low-voltage DC power supply, a low-voltage AC power supply, and a high-voltage DC power supply; The voltage and current acquisition unit (3) is used to acquire the output voltage and current of each programmable power supply, as well as the voltage and current at both ends of the IGBT submodule in real time, and transmit them to the main control unit (4); The power excitation output unit (2) selectively outputs the low-voltage DC power supply to both ends of the IGBT submodule and controls the coordinated operation of the control switch and MOSFET tube inside the IGBT submodule. The main control unit (4) tests the resistance-capacitance parameters of the buffer circuit of the IGBT submodule, the parameters of the voltage-equalizing resistor, and the correctness of the crimping direction of the IGBT anti-parallel diode according to the corresponding relationship between the voltage, the output current, and the time. The power excitation output unit (2) selects and outputs the low-voltage AC power supply to both ends of the IGBT submodule, thereby realizing the high-voltage energy acquisition of the IGBT submodule's driving central control energy acquisition three-in-one board, the voltage detection accuracy at both ends of the IGBT, and the test of the IGBT on / off function; The power excitation output unit (2) selects and outputs the high-voltage DC power supply to both ends of the IGBT submodule, thereby realizing the overvoltage protection triggering function test of the IGBT submodule.

2. A test device for a controllable phase-commutation valve IGBT submodule according to claim 1, characterized in that: The power supply unit (1) includes a main power input, a main protection circuit and multiple programmable power supplies, and outputs the multiple programmable power supplies to the power excitation output unit (2) and the voltage and current acquisition unit (3); The main control unit (4) is also used for recording waves and automatically generating test reports.

3. The test device for a controllable phase-commutation valve IGBT submodule according to claim 2, characterized in that: The device is designed with multiple protection features, including: The programmable power supply is designed with multi-level protection functions for input overvoltage, input overcurrent, output overvoltage, output overcurrent and equipment overtemperature; The overall protection circuit includes overvoltage and overcurrent protection; The power supply excitation output unit (2) is internally designed with overvoltage protection, overcurrent protection and equipment emergency stop functions; The device also includes an emergency stop switch (6) connected to the power excitation output unit (2) by hard wiring, which is used to directly disconnect the electrical connection between the programmable power supply and the IGBT submodule in a dangerous state.

4. The test device for a controllable phase-commutation valve IGBT submodule according to claim 1, characterized in that: The IGBT submodule test includes the test of internal component parameters, the test of basic operation functions and the test of overvoltage protection function. The internal component parameters include the resistance and capacitance parameters of the buffer circuit, the voltage-sharing resistor parameters, the correctness of the buffer diode crimping direction, and the correctness of the reverse diode crimping direction. The basic operating functions include the high-voltage energy extraction of the IGBT sub-module board, the voltage detection accuracy across the IGBT, and the IGBT on-off function.

5. The test device for a controllable phase-commutation valve IGBT submodule according to claim 1, characterized in that: The device further comprises a human-machine interaction interface (5) connected to the main control unit (4), wherein the human-machine interaction interface (5) is used to modify and query the control parameters and protection settings of the field test device, to consult the recording file of the main control unit (4), and to observe the test report.

6. The test device for a controllable phase-commutation valve IGBT submodule according to claim 1, characterized in that: The device further comprises a spare optical fiber test port 7 connected to the main control unit (4); The spare optical fiber test port (7) is directly connected to the IGBT submodule under test, and its interface is identical to the IGBT submodule communication interface in the engineering valve base electronic equipment, and is used to replace the valve base electronic equipment to output the test waveform and complete the full function and performance test of the IGBT submodule.

7. A method using the test device of the controllable phase-commutating converter valve IGBT submodule according to claim 1, the method comprising an on-site test sub-method for the parameters of the internal components of the IGBT submodule, an on-site test sub-method for the basic operating functions of the IGBT submodule, and an on-site test sub-method for the overvoltage protection function of the IGBT submodule.

8. The method according to claim 7, characterized in that The on-site testing sub-method for the parameters of components within the IGBT sub-module comprises the following steps: Step S11, applying the low voltage DC power supply of the test device power supply unit (1) to both ends of the IGBT submodule; In step S12, the buffer capacitor is charged through the internal buffer resistor and the buffer diode of the power supply excitation output unit (2), the voltage and current acquisition unit (3) detects the IGBT port voltage in real time, and obtains the voltage across the buffer capacitor after subtracting the forward conduction voltage of the buffer diode. The main control unit (4) calculates and determines the capacitance of the buffer capacitor and determines the correctness of the crimping direction of the buffer diode based on the time of the voltage rise phase and the charging current; Step S13: After the buffer capacitor capacitance test is completed, the main control unit (4) controls the internal discharge resistor of the power supply excitation output unit (2) to be connected to the IGBT submodule circuit, thereby causing the buffer capacitor to discharge together with the buffer resistor. The voltage and current acquisition unit (3) detects the discharge current measurement value and the real-time voltage of the IGBT submodule port in real time, thereby realizing the calculation and determination of the buffer resistor value. Step S14: After the buffer resistor resistance test is completed, the low-voltage DC power supply is used again to charge the IGBT submodule, and then the low-voltage DC power supply is electrically disconnected from the IGBT submodule, causing the voltage of the buffer capacitor to discharge through the buffer resistor and the equalizing resistor. At this time, the voltage and current acquisition unit (3) detects the voltage across the IGBT submodule, and the main control unit (4) obtains the resistance value of the equalizing resistor Rdc based on the measured value and the discharge time curve; In step S15, the main control unit (4) controls the low-voltage DC power supply to be output in reverse to both ends of the IGBT submodule through the conversion switch of the power excitation output unit (2). The power supply forms a path through the IGBT reverse diode, skips the buffer circuit, and tests whether the direction of the reverse diode after crimping is correct.

9. The method according to claim 7, characterized in that The on-site test sub-method for the basic operating function of the IGBT sub-module comprises the following steps: Step S21, applying the low voltage AC power supply of the test device power supply unit (1) to both ends of the IGBT submodule; Step S22: slowly increase the pressure, and observe the uplink communication status and fault status of the three-in-one board for driving the IGBT submodule received by the valve base electronic device through the human-machine interface of the valve base electronic device, and determine whether the IGBT submodule has completed high-level energy acquisition and is working normally, as well as the self-test function of the IGBT submodule; Step S23: Maintain the low-voltage AC power output, observe the voltage value across the IGBT reported by the three-in-one board for driving the central control and energy acquisition through the human-machine interface of the valve base electronic equipment, and complete the test of the voltage sampling accuracy across the IGBT submodule; Step S24, maintain the low-voltage AC power output, set the IGBT on-off signal through the human-machine interaction interface of the valve base electronic equipment, and judge whether the voltage waveform across the IGBT after the IGBT is turned on and off is normal through the recording file of the valve base electronic equipment or the recording file of the on-site test device, and complete the IGBT on-off function test.

10. The method according to claim 7, characterized in that The on-site test sub-method for the overvoltage protection function of the IGBT sub-module comprises the following steps: Step S31, applying the high-voltage DC power supply of the test device power supply unit (1) to both ends of the IGBT submodule; Step S32: Slowly increase the voltage. After the IGBT submodule completes high-level energy extraction and self-test, the valve base electronic device keeps from issuing the IGBT opening instruction. Then, the voltage target value and voltage rise rate of the high-voltage DC power supply are set through the human-machine interface 5 of the test device. In step S33, the voltage of the high-voltage DC power supply is slowly increased to the IGBT overvoltage protection self-triggering threshold, and the overvoltage protection self-triggering function of the IGBT submodule is determined to be normal through the message of the human-machine interface of the valve base electronic equipment and the recording file of the test device and the valve base electronic equipment.

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