Abstract: This paper briefly describes the variable frequency speed regulation and energy-saving principle of frequency converters, and summarizes the methods used in the selection and use of frequency converters in the Yuejin 2×50 MW power plant to solve problems such as harmonic suppression and load matching. Keywords : frequency converter; load matching; harmonic suppression Asynchronous motors are the most important power equipment in power plants. As high-energy-consuming equipment, their output power cannot change proportionally with the load. Most of it can only be adjusted by the opening of baffles or valves, while the energy consumed by the motor does not change much, resulting in energy loss. In recent years, with the maturity of frequency converter production technology and the increasingly wide application range of frequency converters, high-voltage AC variable frequency speed regulation devices have also been widely used in thermal power plants. Based on this, the condensate pump of the Yuejin 2×50MW power plant of Yimei Group selected a variable frequency speed regulation device. [b]1 Variable Frequency Speed ​​Regulation and Energy-Saving Principle 1.1 Speed ​​Regulation Principle[/b] The frequency converter mainly adopts the AC-DC-AC method, that is, first converting the power frequency AC power into DC power through a rectifier, and then converting the DC power into AC power with controllable frequency and voltage to supply the motor. A frequency converter's circuit generally consists of four parts: rectification, intermediate DC link, inversion, and control. The rectification section is a three-phase bridge uncontrolled rectifier, and the inversion section is an IGBT three-phase bridge inverter. The output is a PWM waveform, and the intermediate DC link serves for filtering, DC energy storage, and reactive power buffering. [b][align=center]For more details, please click: A Brief Analysis of Frequency Converter Speed ​​Control Devices for Condensate Pumps[/align][/b]