A Variable Frequency Drive (VFD) Controller is a device used to control the speed and torque of induction motors in industrial applications. It is an electronically-controlled, variable-speed drive system for AC motors, which regulates the motor’s speed and torque by varying the motor’s input frequency and voltage. By carefully controlling the inputs, a VFD allows precise control of motor output speed, torque, direction and acceleration. VFDs are used on HEV and EV applications, along with conventional systems such as pumps, fans, and compressors that require variable speed operation.