Abstract : The widespread application of frequency converters has led to increasingly serious pollution in power systems. This paper proposes a series of methods and measures to suppress harmonic pollution from frequency converters, focusing on hardware structure, control strategy, and external filter circuits. Furthermore, this paper analyzes the power factor imbalance caused by asymmetric input current under low load conditions and proposes corresponding improvement suggestions. Keywords: Frequency converter, harmonics, power factor imbalance Keywords : Frequency convener, Harmonic, Power factor, Unbalance 1. Introduction Variable frequency drives (VFDs) are mainly used for regulating the speed of AC motors and are an ideal speed control solution. With the rapid development of China's economy, market demands for products are gradually increasing. VFD speed control, with its advantages of wide speed range, high speed accuracy, and good dynamic response, plays a role in improving product quality and production efficiency in many applications requiring precise speed control. In addition to its excellent speed control performance, it also has significant energy-saving effects. Not only in related industrial sectors, but also in home appliances, its advantages in saving electricity costs, improving appliance performance, and protecting the environment have been widely recognized and applied by users. However, while VFDs make significant contributions to energy saving, improving the human living environment, improving product quality, and increasing industrial automation, they also generate some negative effects. [b][align=center]For details, please click: The Impact of Widespread Application of VFDs on Power Systems[/align][/b]