Abstract: This paper describes the characteristics of the driver test system and presents a detailed implementation block diagram, interface circuit design, and software module design. The driver test system is simple and quick to operate, powerful in function, and has good interactivity, portability, and scalability. It is an essential instrument for fault detection. Key words: test system; driver; fault diagnosis 1. Introduction AC speed control systems typically use IGBT pulse width modulation drivers to control the actuator motor to operate in four quadrants , thereby meeting the high precision and high real-time requirements of the control system. The driver is the core part of the AC speed control unit in the control system, and its quality and performance directly affect the precision and performance of the entire control system. However, during use, if the driver malfunctions, it will affect the normal operation of the entire control system. Therefore, it is necessary to design and develop a comprehensive driver performance testing system to quickly troubleshoot and ensure the performance quality of the control system. 2. Driver Working Principle and Testing System Technical Characteristics [align=center] Figure 1: Driver Speed ​​Regulation System Principle Block Diagram[/align] Driver speed regulation can generally be divided into four parts: rectification, DC holding, inversion, and control. The current regulator compares and adjusts the actual current value with the given value. The speed regulator obtains the actual speed value through the speed measuring motor and rotor position detection, and adjusts the speed value accordingly. The driver is a high-power precision device, which may interfere with the outside world and affect normal operation. Noise signals generated by other devices on the same power supply may also enter the driver through radiation and power conduction. At the same time, the high-order harmonics and electromagnetic noise generated by the driver can easily affect the power grid and surrounding equipment. Eliminating interference and ensuring normal operation of the equipment is a major feature and challenge of this system. The design adopts a standard grounding method and connects filter devices at the front and rear ends of the driver. A surge current limiting circuit is connected in series in the circuit to effectively avoid mutual interference and ensure the accuracy and reliability of each test signal. The testing system employs both online and offline testing methods. The software implements intelligent processing modules, and an expert system provides solutions to testing problems. 3. Hardware Circuit Implementation of the Driver Testing System This testing system mainly includes a computer-based control console and a testing platform that houses the driver under test, simulated loads, and specialized measuring instruments. The circuit design employs a pulse-type anti-interference and redundancy design to ensure accurate and reliable hardware design. The specific connection diagram is as follows: [align=center] Figure 2: Driver Testing System Connection Diagram[/align] 3.1 Startup Circuit The startup circuit provides the operating voltage to the driver under test. Three current-limiting resistors are connected in series in the circuit to prevent surge current. Simultaneously, the contactor, thermal relay, and filter ensure stable and reliable voltage quality. During power-on, only the control computer needs to issue a power-on command; the contactor will then activate, completing the power-on process and achieving a safe and reliable "soft start." A schematic diagram of the startup circuit is shown below. [align=center]Figure 3: Startup Circuit Diagram[/align] 3.2 Enable and Detection Circuit To ensure the driver under test is in a controllable state, the pulse enable and drive enable of the driver under test are controlled through the software interface. Simultaneously, the enable status is displayed on the display interface, making operation more intuitive. Driver power-on and enable are communicated via serial port, and the driver's working status is detected in real time through the serial port. The serial communication uses a PCL745 communication card, which has strong anti-interference capabilities through differential input and can directly communicate with the ADAM module without the need for a 232 or 485 conversion module. The specific connection diagram is as follows. [align=center]Figure 4: Enable and Detection Module Connection Diagram[/align] 4. Test System Software Features The test system software is developed according to software engineering requirements, striving to be powerful, stable, and reliable. The software is also expanded to include expert system functionality. 4.1 Human-Machine Interface The interface is the presentation form of the test system and a window for users to analyze and judge. Users can set self-test items and test items, and can also print and diagnose faults. The test items are set in the human-computer interaction interface. The computer sends speed commands to the driver under test. Data obtained through a dedicated interface and other testing equipment is analyzed and compared online by the testing software to give a conclusion on whether it is qualified or not. At the same time, it calls the knowledge of the expert diagnostic knowledge base to diagnose faults and provides solutions to the faults. The composition of the human-computer interaction interface module is shown in Figure 5. [align=center] Figure 5: Human-computer interaction interface module diagram[/align] 4.2 Dynamic Link Library of the Test System The dynamic link library of the test system adopts the standard access method ODBC (Open Database Connectivity) to establish a set of dynamic link libraries (DLLs), namely the driver basic information database and the dedicated diagnostic knowledge base. The driver basic information database mainly contains the driver technical parameters, and the expert diagnostic knowledge base mainly analyzes typical driver faults. If the user needs to expand the content of the expert diagnostic knowledge base, it can be added through the human-computer interface. 4.2 Important Project Tests 4.2.1 External Current Limit Reduction Test Applying a -10V voltage to the XX terminal of the driver under test disables the overcurrent monitoring function of the speed controller. According to the current reduction characteristic curve, the maximum output current is limited to 40%Imax. Setting the speed setpoint to -5V, enabling the driver for 3 minutes and then turning it off, the waveform at the detection port is measured. The Iist amplitude should be 4 + 0.4V, and the "overcurrent" indicator light should not illuminate. The current reduction characteristic curve is shown in Figure 6. [align=center] Figure 6: Current Reduction Characteristic Curve[/align] 4.2.2 I²t Monitoring Test The I²t function approximates the square of the actual current value and then integrates the result. If the actual current value is 1.1 times the rated value, the integrator integrates negatively; otherwise, it integrates positively. For specific testing, a test power board was used instead of the driver's power module. The corresponding switch was turned off, and a -1V voltage was applied to the XX terminal. From the XX characteristic curve, the maximum output current is 100%'I[sub]max[/sub]. In this test interface, the speed setpoint was set to -5V, the driver enable was on, and the I[sub]ist[/sub] waveform at the W-hole was measured. The recorded data was input into the corresponding unit, and the background software calculated and gave a conclusion on whether it passed or failed (the final trend of the I[sub]ist[/sub] amplitude decrease should be 1.1I[sub]N[/sub], and the maximum amplitude holding time T should be [missing value]. 5. Conclusion The driver testing system can test drivers in both offline and online states. The testing system can help debugging personnel quickly determine and understand the driver status during debugging or use, and propose solutions. It is simple and quick to operate, with good human-computer interaction. The system follows the principles of generalization, standardization, and modular design, and has good interactivity, portability, and scalability. The completion of this testing system greatly facilitates the maintenance of drivers. A portable driver testing system is also under research and design and will be completed soon. 6. References [1] Yu Jinsong et al. Development trend of US military automatic test system [J]. Beijing: Measurement and Control Technology, 2001, 12 (20) [2] Li Xingshan et al. Automatic test system integration technology [M]. Beijing: Electronic Industry Press, 2004 [3] Sun Xu. Automatic test system and programmable instrument [M]. Beijing: Electronic Industry Press, 1990