The fan is a machine that relies on the input mechanical energy to increase the gas pressure and discharge the gas. It is a driven fluid machine. Fan is the abbreviation for gas compression and gas conveying machinery in China. Generally speaking, fans include ventilator, blower and wind generator. Fan frequency converter is a special frequency converter tailored for various types of fans. The frequency conversion speed control device is adopted to change the speed of the fan, thereby changing the air volume of the fan to meet the needs of the production process, and the operation energy consumption is the least, and the comprehensive benefit is the highest.