Variable frequency drive VFD VVFD Direct torque controller DTC
What is the function of a VFD with an electric motor? Variable frequency drive VFD is sometimes known as VVVFD is a special type of motor drive that runs an induction motor on the variable frequency and variable voltage. By varying the frequency and voltage of an induction motor, the variable motor speed is achieved. Variable frequency drive is also capable of ramping up or ramping down a motor. Ramping up and ramping down feature provides a motor soft starting and soft starting feature which is a very useful feature for an industrial motor to control starting torque and jerk on an induction motor. Also, the ramping-up feature reduces electrical jerk on the power line when a motor is started from a standstill. The following circuit diagram illustrates the basic electrical wiring for a VFD system. In this diagram single phase, AC input is shown and the VFD provides three-phase power to the delta-connected three-phase motor. There are several VFDs available that accept three-phase line p...