Abstract : A low-power general-purpose frequency converter was developed using the highly integrated dedicated chip SA866 and the intelligent power module PS21255. Experiments and practical applications show that the frequency converter has good performance, low price, and high reliability. Keywords : Frequency converter; Sine wave pulse width modulation; Dedicated integrated circuit; Intelligent power module 0 Introduction Due to the rapid development of power electronics technology, AC variable frequency speed control has become the mainstream of electrical drives, gradually replacing traditional DC drives. From a cost-performance perspective, AC variable frequency speed control devices are already superior to DC speed control devices. Variable frequency speed control (VFD) for asynchronous motors not only achieves smooth adjustment but also possesses many advantages unmatched by other AC speed control systems. AC VFDs offer superior performance in frequency range, dynamic response, speed control accuracy, low-frequency torque, slip compensation, communication functions, intelligent control, power factor, efficiency, and ease of use compared to other AC speed control methods. Furthermore, their small size, light weight, versatility, comprehensive protection functions, high reliability, and simple operation have made them popular in industries such as steel, metallurgy, mining, petroleum, chemical, pharmaceutical, textile, machinery, power, light industry, papermaking, printing, tobacco, and water supply, resulting in significant social benefits. While VFDs offer numerous advantages, their early high cost and reliability issues deterred many users. Reducing costs and improving reliability have always been crucial issues for AC VFDs. This paper addresses the requirements for VFDs of general small-power AC asynchronous motors and develops a new type of general-purpose VFD using the SA866 multi-functional, highly integrated dedicated SPWM control chip (released in the late 1990s) and the PS21255 intelligent power module. Its overall structure is simple, and it has relatively complete functions, meeting the requirements of low cost, high reliability, and high performance for frequency converters in automated production lines of household appliances such as air conditioners and washing machines, as well as small-scale textile and plastic processing industries. It has already been applied in production in several factories in Guangdong and Jiangsu provinces. [b] [align=center]For more details, please click: Design of a Small-Power General-Purpose Frequency Converter[/align][/b]