Abstract : Based on the working principle of automotive generators, a fully automatic generator performance testing device was designed and developed, consisting of an industrial control computer, a multi-functional data card, a frequency converter, a variable frequency motor, and an electronic load. This device enables testing of generator no-load performance, load performance, and regulator performance. Traditional PID and fuzzy PID controllers are used to control the generator voltage, current, and speed, ensuring the speed, accuracy, and robustness of the testing process. Keywords : Automotive generator; Industrial control computer; Automatic testing device; Fuzzy PID control Automotive generator manufacturers need to conduct rigorous factory performance tests on generators after product assembly. Chinese automotive generator manufacturers generally import motor performance testing equipment from abroad. These devices are highly reliable, stable, and accurate in performance testing, but their operation is not intuitive and convenient, and they are expensive and difficult to maintain. Domestically produced high-precision motor performance testing systems are generally used in automotive electrical research institutes and certification bodies; their reliability and stability are difficult to meet the requirements of complex motor production lines. Therefore, an automatic automotive generator performance testing device was designed and developed. This paper focuses on the characteristics of automotive generator factory performance testing and designs and develops an automatic automotive generator performance testing device. This device uses a combination of traditional PID and fuzzy PID controllers to control the generator voltage, current, and speed, ensuring testing speed, accuracy, and robustness. 1. Generator Working Principle and Performance Testing Automotive generators are generally three-phase synchronous AC generators. Electrical equipment in a vehicle is powered by the generator and battery connected in parallel. When the engine starts, the battery supplies power to the starting system, ignition system, instrument system, etc., and provides excitation current to the generator. After the engine starts running, it drives the generator through the transmission. When the generator speed increases to a point where its terminal voltage is higher than the battery's electromotive force, the generator not only supplies power to the electrical equipment independently but also charges the battery. The excitation current is also self-sufficient in the generator, and excess energy is stored in the battery. Under the conditions of a fixed structure and constant magnetic field strength, the output voltage of an AC generator is directly proportional to its speed. In a car, to ensure the normal operation of the electrical equipment and battery, the generator must have a stable output voltage; therefore, a voltage regulator is used to control the generator output voltage within a specified range. [b][align=center]For details, please click: Automatic Testing Device for Factory Performance of Automotive Generators[/align][/b]