brief introduction: Mixer is also called frequency converter (VFD), is the application of frequency conversion technology and microelectronic technology, by changing the motor working power frequency to control the AC motor power control equipment. Frequency unit is mainly composed of rectifier (AC to DC), filtering, inverter (DC to AC), braking unit, driving unit, detection unit microprocessing unit, etc.. Inverter by the internal IGBT break off to adjust the voltage and frequency of the output power supply, accor