What is a VFD?

VFD varies the revolving speed of an induction motor freely by changing the power supply frequency and the power supply voltage. A power transistor is used for the main circuit and IC, and a microcomputer is used for the control circuit of VFD.

Further advanced controlling technology has been applied due to improved semiconductor devices in recent years.

Moreover, generally, VFD is also called inverter control equipment or variable voltage variable frequency (VVVF) equipment.

The fundamental configuration is shown in Figure.

After changing an alternating power source into direct current in a converter part and making it smooth, transform the direct current inversely to variable frequency alternating current at an inverter part.

A [Variable Frequency Drive (VFD)]is a type of motor controller that drives an electric motor by varying the frequency and voltage supplied to the electric motor. Other names for a VFD are variable speed drive , adjustable speed drive , adjustable frequency drive , AC drive , microdrive , and inverter .

Frequency (or hertz) is directly related to the motor’s speed (RPMs). In other words, the faster the frequency, the faster the RPMs go.

If an application does not require an electric motor to run at full speed, the VFD can be used to ramp down the frequency and voltage to meet the requirements of the electric motor’s load. As the application’s motor speed requirements change, the [VFD] can simply turn up or down the motor speed to meet the speed requirement.
Read More : VFD Basics