What is a Variable Frequency drive?

Variable frequency drive also called frequency inverter, AC drive etc. It is an electric device to change utility power source to variable frequency to control AC motor in variable speed operation. There are several ways to define a VFD. Base on main circuit working methods, it can be divided into voltage type VFD and current VFD; Base on switching methods, it can be divided into PAM control drive, PWM control drive and high carrier frequency PWM control drive; Base on working principle, it can be divided into V/F control VFD, slip frequency control and vector control VFD, etc.; Base on usage, it can be divided into general-purpose VFD, high-performance dedicated VFD, High-frequency VFD, single phase VFD and three-phase variable frequency drive.