A Variable Frequency Drive (VFD) is capable of adjusting both the voltage and frequency of the supplying current, primarily used to control the speed of an induction motor. The process involves converting the AC from the supply line into DC using rectifiers. The pure DC is then converted back into
AC with adjustable frequency and voltage using pulse width modulation through power transistors such as IGBTs. VFDs provide complete control over the motor speed, ranging from 0 to the rated speed. Additionally, the variable voltage speed adjustment offers better starting current and acceleration.