ABB inverter (Variable-frequency Drive, VFD) is the application of inverter technology and microelectronic technology, ABB drive model by changing the motor power frequency mode to control the power of the AC motor control equipment. Inverter mainly by the composition of the rectifier (AC DC), filtering, re-rectifier (DC AC), the brake unit, drive unit, detection unit, micro-processing unit, etc.. By changing the frequency of the power supply to achieve the purpose of changing the supply voltage, according to the actual needs of the motor supply voltage, and thus they need to achieve energy efficiency, speed control purposes, the drive there are many protection functions, such as overcurrent , overvoltage, overload protection, and so on. With the continuous improvement of industrial automation, the drive has also been a very wide range of applications.