Frequency converter is a power control equipment that uses frequency conversion technology and microelectronics technology to control AC motor by changing the frequency of motor working power supply. The frequency converter is mainly composed of rectifier (AC to DC), filter, inverter (DC to AC), braking unit, driving unit, detection unit, microprocessor unit, etc. The frequency converter adjusts the voltage and frequency of the output power supply by switching off the internal IGBT, and provides the required power supply voltage according to the actual needs of the motor, so as to achieve the purpose of energy saving and speed regulation. In addition, the frequency converter has many protection functions, such as overcurrent, overvoltage, overload protection, etc. With the continuous improvement of industrial automation, frequency converters have also been widely used.