A test platform and test method for a flexible direct current power module

Abstract

A kind of test platform and test method for flexible HVDC power module, the test platform includes HMI touch screen, HMI touch screen is connected with PLC master control, digital quantity input interface and digital quantity output interface of distribution and control unit are connected with the digital quantity output interface and digital quantity input interface of PLC master control, high voltage input interface of distribution and control unit is connected with the high voltage output interface of program-controlled high voltage source, high voltage output interface of distribution and control unit is connected with the high voltage input interface of module to be measured, the high voltage input interface of voltage transmitter is connected with the DC side high voltage output interface of module to be measured, the analog quantity output interface of voltage transmitter is connected with the analog quantity input interface of PLC master control, the slave station interface of FPGA core board is connected with the master station interface of PLC master control, the AC sampling input interface of FPGA core board is connected with the AC output interface of module to be measured, the high voltage control interface of program-controlled high voltage source is connected with the output interface of PLC master control;The application discloses the working method of the test platform.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible direct current power module testing, in particular to a test platform and test method for semi-bridge and full-bridge power modules in the field of flexible direct current transmission and distribution. BACKGROUND

[0002] MMC (modular multilevel converter, MMC) is the core equipment responsible for realizing the conversion of electrical energy between AC and DC in a flexible direct current transmission system. The power module, as the smallest basic unit of the converter valve, is very sensitive to temperature, voltage, current and their rates of change. In order to ensure the reliable operation of the flexible direct current transmission project, a series of tests must be conducted to examine whether the power module is safe and reliable during the module testing stage in the factory, the installation stage at the converter station and the maintenance stage at the converter station.

[0003] If other routine tests are performed without going through the above steps, it may result in damage to the power module or the routine test equipment, causing waste of efficiency and cost. In order to more efficiently and safely test the reliability of the power module, it is necessary to design an intelligent test platform for the above routine tests.

[0004] At present, the flexible direct current power module test system in this field mostly has the following shortcomings:

[0005] The operation panel has the shortcomings of single function, low test voltage level, test results only with panel indicator light display or manual adjustment of oscilloscope to capture waveforms, unfriendly operation interface, low efficiency, not conducive to problem finding and repair, no single test and whole machine test mode selection function, test results cannot be stored and traced, and the test process is not conducive to process quality control. SUMMARY

[0006] The present application aims to overcome the above-mentioned shortcomings of the prior art in flexible direct current power module testing, and provides a test platform and test method for flexible direct current power modules.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A kind of test platform for flexible HVDC power module, including HMI touch screen 1, PLC host 2, power distribution and control unit 3, voltage transmitter 4, FPGA core board 5, program-controlled high voltage source 6 and module to be measured 7;The HMI touch screen 1 is connected with the network interface of PLC host 2 by Ethernet, the digital quantity input (DI) interface and digital quantity output (DO) interface of power distribution and control unit 3 are connected with the digital quantity output (DO) interface and digital quantity input (DI) interface of PLC host 2, the high voltage input interface of power distribution and control unit 3 is connected with the high voltage output interface of program-controlled high voltage source 6, the high voltage output interface of power distribution and control unit 3 is connected with the high voltage input interface of module to be measured 7, the high voltage input interface of voltage transmitter 4 is connected with the DC side high voltage output interface of module to be measured 7, the analog quantity output (AO) interface of voltage transmitter 4 is connected with the analog quantity input (AI) interface of PLC host 2, the RS485 slave station interface of FPGA core board 5 is connected with the RS485 master station interface of PLC host 2, the alternating current sampling input interface of FPGA core board 5 is connected with the alternating current output interface of module to be measured 7, the high voltage control interface of program-controlled high voltage source 6 is connected with the output (AO) interface of PLC host 2.

[0009] The working method of the test platform for flexible HVDC power module is as follows:

[0010] Step 1: system power-on, the test platform takes 220V alternating current from commercial power as the total power input of the test platform, after power distribution, on the one hand, 220V alternating current is sent to program-controlled high voltage source 5 input, the output of program-controlled high voltage source 5 is distributed and controlled by power distribution and control unit 3 to provide bus input for module to be measured 7, and module to be measured 7 is provided with working voltage by the bus;

[0011] Step 2: module to be measured test, mainly divided into the following three parts:

[0012] ①Wave control: the test personnel issues IGBT test instruction by operating HMI touch screen 1, PLC host 2 analyzes the operation instruction issued by HMI touch screen 1, on the one hand, PLC host 2 adjusts the voltage output by program-controlled high voltage source 6 to match the test project of module to be measured, and charges the bus capacitor of module to be measured 7 through power distribution and control unit 3, on the other hand, PLC host 2 sends the parsed instruction to FPGA core board 5, FPGA core board 5 converts the instruction into wave control signal, and finally sends the driving wave signal to module to be measured 7 through optical fiber for driving IGBT to work;

[0013] ② IGBT dynamic test: the FPGA core board 5 tests whether the AC voltage signal output by the IGBT is normal according to the sent driving waveform, and uploads the test result to the PLC host 2, and the PLC host 2 uploads the test information to the HMI touch screen 1 for judgment and summary, and the IO state of the to-be-tested module 7 is also fed back to the PLC host 2 through the FPGA core board 5;

[0014] ③ Software and hardware overvoltage test: the PLC host 2 controls the program-controlled high-voltage source 6 to output test voltages required by the software and hardware overvoltage test, and monitors whether the bus voltage of the to-be-tested module 7 has reached the threshold requirement in real time through the voltage transmitter 4, and judges whether the software and hardware overvoltage test result is normal through the PLC host 2 reading the software and hardware overvoltage state bit returned by the to-be-tested module 7;

[0015] Step 3: Discharge of the to-be-tested module: after the above test process is completed, the PLC host 2 first issues a command to disconnect the loop connecting the to-be-tested module 7 and the program-controlled high-voltage source 6, and then controls the program-controlled high-voltage source 6 to close the output, and automatically cuts in the discharge resistor between the bus capacitor for fast discharge. The voltage value of the bus capacitor during the discharge process is transmitted back to the PLC host 2 in real time through the voltage transmitter 4, and the PLC host 2 uploads it to the HMI touch screen 1 and displays it on the HMI touch screen 1.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] The test personnel only need to perform test selection operation on the upper computer HMI touch screen, and the test platform can automatically send instructions to the PLC host, and the PLC host analyzes the instructions and controls the program-controlled high-voltage source to output to charge the bus capacitor of the to-be-tested module, and receives the state information feedback from the to-be-tested module. The PLC host controls the FPGA core board to send the driving test pulse of the IGBT, and cooperates with the AC side high-voltage sampling unit to test the software and hardware overvoltage and undervoltage, wave generation, bypass switch action and feedback test requirements of the to-be-tested module. All tests are automatically completed by the test platform, and have a series of advantages such as high intelligentization degree and friendly man-machine interface;

[0018] Further, the test platform can select one-key whole machine test and single test two modes according to actual test needs, and perform HMI touch screen man-machine interactive selection operation according to use needs. The one-key whole machine test includes: thyristor test, IGBT driving wave generation test, bus sampling and software and hardware overvoltage and undervoltage test, bypass switch action and feedback test, module water-cooled plate NTC temperature sampling test, and power supply test. The single test means that only the above test items can be tested.

[0019] Further, during the test process of the test platform, the HMI configuration picture synchronously and dynamically displays the current test result information of the to-be-tested module, the interface is friendly, the test coverage is wide, the test voltage level is high, after the test is completed, the PLC master control automatically controls the discharge of the bus capacitor, and the next to-be-tested module is conveniently and safely replaced for test;

[0020] Further, the test platform circuit structure is modularized, easy to realize, high and low voltage isolation, safe and reliable, the HMI industrial touch screen has rich interfaces and powerful expansion functions, test records are automatically generated into report forms, and the report forms can be traced and uploaded to the MES system. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A structure block diagram of the test platform for the flexible direct current power module.

[0022] Figure 2 A working method flowchart of the test platform for the flexible direct current power module. DETAILED DESCRIPTION

[0023] In order to enable the personnel in the technical field to better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the working flowchart in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by other personnel in the field without creative labor should belong to the protection scope of the present application.

[0024] The present application will be further described in detail below in combination with the drawings:

[0025] Reference is made to Figure 1The application discloses a test platform for a flexible direct current power module, which comprises an HMI touch screen 1, a PLC host 2, a power distribution and control unit 3, a voltage transmitter 4, an FPGA core board 5, a program-controlled high-voltage source 6 and a module to be tested 7. The HMI touch screen 1 is connected with the network port of the PLC host 2 through Ethernet. The digital quantity input interface and the digital quantity output interface of the power distribution and control unit 3 are connected with the digital quantity output interface and the digital quantity input interface of the PLC host 2. The high-voltage input interface of the power distribution and control unit 3 is connected with the high-voltage output interface of the program-controlled high-voltage source 6. The high-voltage output interface of the power distribution and control unit 3 is connected with the high-voltage input interface of the module to be tested 7. The high-voltage input interface of the voltage transmitter 4 is connected with the DC side high-voltage output interface of the module to be tested 7. The analog quantity output interface of the voltage transmitter 4 is connected with the analog quantity input interface of the PLC host 2. The RS485 slave station interface of the FPGA core board 5 is connected with the RS485 master station interface of the PLC host 2. The alternating current sampling input interface of the FPGA core board 5 is connected with the alternating current output interface of the module to be tested 7. The high-voltage control interface of the program-controlled high-voltage source 6 is connected with the output interface of the PLC host 2.

[0026] Referring to the accompanying drawings Figure 2 The working method of the test platform is as follows:

[0027] Step 1: system power-on, the test platform takes 220V alternating current from the mains as the total power input of the test platform. After power distribution, on one hand, 220V alternating current is sent to the program-controlled high-voltage source 5 input. The output of the program-controlled high-voltage source 5 is controlled and distributed to provide bus input for the module to be tested 7. The module to be tested 7 is provided with working voltage by the bus. On the other hand, 220V alternating current is converted into isolated 24V DC voltage. After power distribution and control by the power distribution and control unit 3, the voltage transmitter 4, the FPGA core board 5, the PLC host 2 and the HMI touch screen 1 are powered.

[0028] Step 2: module to be tested, mainly divided into the following three parts:

[0029] ①Wave control: the tester issues an IGBT test instruction by operating the HMI touch screen 1. The PLC host 2 analyzes the operation instruction issued by the HMI touch screen 1. On one hand, the PLC host 2 adjusts the voltage output by the program-controlled high-voltage source 6 to match the test item of the module to be tested. After power distribution and control by the power distribution and control unit 3, the bus capacitor of the module to be tested 7 is charged. On the other hand, the PLC host 2 sends the analyzed instruction to the FPGA core board 5. The FPGA core board 5 converts the instruction into a wave control signal. Finally, the driving wave signal is sent to the module to be tested 7 through optical fiber for driving IGBT to work.

[0030] ② IGBT dynamic test: the FPGA core board 5 tests whether the AC voltage signal output by the IGBT is normal according to the sent driving waveform, and uploads the test result to the PLC host 2, and the PLC host 2 uploads the test information to the HMI touch screen 1 for judgment and summary, and the IO state of the to-be-tested module 7 is also fed back to the PLC host 2 through the FPGA core board 5;

[0031] ③ Software and hardware overvoltage test: the PLC host 2 controls the program-controlled high-voltage source 6 to output the test voltage required by the software and hardware overvoltage test, and monitors whether the bus voltage of the to-be-tested module 7 has reached the threshold requirement in real time through the voltage transmitter 4, and judges whether the software and hardware overvoltage test result is normal through the PLC host 2 reading the software and hardware overvoltage state bit returned by the to-be-tested module 7.

[0032] Step 3: Discharge of the to-be-tested module: after the above test process is completed, the PLC host 2 first issues a command to disconnect the loop connected between the to-be-tested module 7 and the program-controlled high-voltage source 6, and then controls the program-controlled high-voltage source 6 to close the output, and automatically cuts in the discharge resistor between the bus capacitor to perform fast discharge. The voltage value of the bus capacitor during the discharge process is transmitted back to the PLC host 2 in real time through the voltage transmitter 4, and the PLC host 2 uploads it to the HMI touch screen 1 and displays it on the HMI touch screen 1.

[0033] The main functions and roles of each module are as follows:

[0034] The PLC host 2 is used to receive the test instructions issued by the upper computer HMI touch screen 1, control the peripheral program-controlled high-voltage source 6, high-voltage contactor, voltage transmitter 4, and communicate with the FPGA core board 5 through Modbus. By analyzing the operation instructions issued by the HMI touch screen 1, the bus capacitor charging of the to-be-tested module 7, each test of the to-be-tested module 7, automatic discharge, test data recording and uploading work are automatically completed.

[0035] The FPGA core board 5 is used to receive the test instructions sent by the upper-level PLC host 2, generate driving waveforms for testing IGBT according to test requirements, and send them to the IGBT drive side of the to-be-tested module 7 through optical fiber.

[0036] On the other hand, the FPGA core board 5 is also used to complete the internal state information acquisition of the to-be-tested module 7 and the high-voltage signal acquisition of the AC side, and report the actually acquired AC side voltage value and the state information of the to-be-tested module 7 to the PLC host 2 through Modbus communication, and the PLC host 2 forwards the information to the upper computer HMI touch screen 1 through Ethernet to generate an electronic report and support online printing.

[0037] The program-controlled high-voltage source 6 is used for generating a direct-current high-voltage signal for testing the module 7 to be tested, and charges the direct-current side bus capacitor of the module 7 to be tested through a high-voltage vacuum contactor control, and outputs a direct-current voltage in a range of 0-4000V continuously adjustable, which can meet the voltage grade requirement of the software and hardware overvoltage protection test of the module to be tested.

[0038] The voltage transmitter 4 is used for testing the voltage between the direct-current bus capacitors in real time, and converts the test result into a 0-10V small signal to be reported to the PLC main control 2 through an AI channel, and the PLC main control 2 compares the direct-current side voltage value collected by the module 7 to be tested with the direct-current side voltage value actually measured by the voltage transmitter 4, and is used for judging whether the direct-current sampling precision of the module 7 to be tested is within the relative precision of ±0.5% of the nominal voltage value.

[0039] The power distribution and control unit 3 mainly functions to distribute the isolated 24V direct-current voltage output by the leakage protector and the switching power supply after the circuit control through the input 220V alternating current voltage, and controls the vacuum circuit breaker to control the on-off of the high-voltage loop through the intermediate relay after the isolation of the digital output interface output by the PLC main control 2.

[0040] The above content is only for illustrating the technical idea of the present application, and cannot limit the protection scope of the present application, and any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A working method for a test platform of a flexible DC power module, the test platform comprising an HMI touch screen (1), a PLC host (2), a power distribution and control unit (3), a voltage transmitter (4), an FPGA core board (5), a programmed high-voltage source (6), and a module to be tested (7); the HMI touch screen (1) is connected to the network port of the PLC host (2) through Ethernet, the digital quantity input DI interface and the digital quantity output DO interface of the power distribution and control unit (3) are connected to the digital quantity output DO interface and the digital quantity input DI interface of the PLC host (2), the high-voltage input interface of the power distribution and control unit (3) is connected to the high-voltage output interface of the programmed high-voltage source (6), the high-voltage output interface of the power distribution and control unit (3) is connected to the high-voltage input interface of the module to be tested (7), the high-voltage input interface of the voltage transmitter (4) is connected to the DC side high-voltage output interface of the module to be tested (7), the analog quantity output AO interface of the voltage transmitter (4) is connected to the analog quantity input AI interface of the PLC host (2), the RS485 slave station interface of the FPGA core board (5) is connected to the RS485 master station interface of the PLC host (2), the AC sampling input interface of the FPGA core board (5) is connected to the AC output interface of the module to be tested (7), and the high-voltage control interface of the programmed high-voltage source (6) is connected to the output AO interface of the PLC host (2); the PLC host (2) is used for receiving the test instruction issued by the HMI touch screen (1), controlling the peripheral programmed high-voltage source (6), high-voltage contactor, and voltage transmitter (4), and performing Modbus communication with the FPGA core board (5); by analyzing the operation instruction issued by the HMI touch screen (1), the bus capacitor charging of the module to be tested (7), each test of the module to be tested (7), automatic discharge, test data recording, and uploading work are automatically completed; characterized in that the working method comprises the following steps: Step 1: system power-on, the test platform takes 220V AC power from the mains as the total power input of the test platform, after power distribution, on the one hand, 220V AC power is sent to the input of the programmed high-voltage source (6), the output of the programmed high-voltage source (6) is distributed and controlled by the power distribution and control unit (3) to provide bus input for the module to be tested (7), and the module to be tested (7) is provided with working voltage by the bus; on the other hand, 220V AC power is converted into isolated 24V DC voltage through the power distribution and control unit (3) to supply power to the voltage transmitter (4), the FPGA core board (5), the PLC host (2), and the HMI touch screen (1); Step 2: module to be tested, mainly divided into the following three parts: ①Wave control: the tester issues an IGBT test instruction by operating the HMI touch screen (1), and the PLC master (2) analyzes the operation instruction issued by the HMI touch screen (1). On the one hand, the PLC master (2) adjusts the output voltage of the program-controlled high-voltage source (6) to match the test item of the module to be tested, and charges the bus capacitor of the module to be tested (7) through the power distribution and control unit (3) after the test item. On the other hand, the PLC master (2) sends the parsed instruction to the FPGA core board (5), and the FPGA core board (5) converts the instruction into a wave control signal. Finally, the driving wave signal is sent to the module to be tested (7) through an optical fiber for driving the IGBT to work; ②IGBT dynamic test: the FPGA core board (5) tests whether the AC voltage signal output by the IGBT is normal according to the sent driving waveform, and uploads the test result to the PLC master (2). The PLC master (2) uploads the test information to the HMI touch screen (1) for judgment and summary. At the same time, the IO state of the module to be tested (7) is also fed back to the PLC master (2) through the FPGA core board (5); ③Software and hardware overvoltage test: the PLC master (2) controls the program-controlled high-voltage source (6) to output test voltages required by software and hardware overvoltage tests, and monitors whether the bus voltage of the module to be tested (7) has reached the threshold requirement in real time through the voltage transmitter (4). The PLC master (2) reads the software and hardware overvoltage state bits returned by the module to be tested (7) to determine whether the software and hardware overvoltage test result is normal; Step 3: Discharge of the module to be tested: after the above test process is completed, the PLC master (2) first issues an instruction to disconnect the loop connecting the module to be tested (7) and the program-controlled high-voltage source (6), and then controls the program-controlled high-voltage source (6) to close the output, and automatically cuts in the discharge resistor between the bus capacitor for rapid discharge. The voltage value of the bus capacitor during the discharge process is transmitted back to the PLC master (2) in real time through the voltage transmitter (4), and the PLC master (2) uploads it to the HMI touch screen (1) and displays it on the HMI touch screen (1).

2. The working method of the test platform for the flexible direct current power module according to claim 1, characterized in that: The FPGA core board (5) is used to receive the test instruction sent by the upper-level PLC master (2), generate a driving waveform for testing the IGBT according to the test requirement, and send it to the IGBT drive side of the module to be tested (7) through an optical fiber. On the other hand, the FPGA core board (5) is also used to complete the acquisition of internal state information of the module to be tested (7) and the acquisition of high-voltage signals on the AC side. The actual acquired AC side voltage value and the state information of the module to be tested (7) are reported to the PLC master (2) through Modbus communication, and the PLC master (2) forwards the information to the HMI touch screen (1) through Ethernet for recording and generating a test report.

3. The method of claim 1, wherein: The program-controlled high-voltage source (6) is used to generate a DC high-voltage signal for testing the module to be tested (7), and charges the DC side bus capacitor of the module to be tested (7) after control by a high-voltage vacuum contactor. The output DC voltage range is 0-4000V continuously adjustable, meeting the requirements of the module to be tested (7) for software and hardware overvoltage protection test voltage level.

4. The method of claim 1, wherein: The voltage transmitter (4) is used for testing the voltage between the two ends of the DC bus capacitor in real time, converting the test result into a 0-10V small signal and reporting it to the PLC master control (2) through an AI channel, and the PLC master control (2) compares the DC side voltage value collected by the to-be-tested module (7) with the DC side voltage value actually measured by the voltage transmitter (4), so as to judge whether the DC sampling precision of the to-be-tested module (7) is within the relative precision of ±0.5% of the nominal voltage value.

5. The method of claim 1, wherein: The power distribution and control unit (3) functions to distribute the isolated 24V DC voltage output by the leakage protector and the switching power supply after being controlled by the circuit breaker, and controls the high-voltage loop on-off control of the vacuum circuit breaker through the intermediate relay after the digital output DO interface output of the PLC master control (2) is isolated.

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