This paper presents the working principle and simulation of PWM controlled Variable Frequency Drive. The performance of VFD is also described. The simulation model is simulated using ISIS Proteus and their results are also observed. The use of Variable Frequency Drive has been increased in industrial drive for speed control of induction motors. The common applications of VFDs are in air handler, chiller, pumps and tower fans .This paper is intended to provide a basic understanding of VFD terms, VFD operations and how VFD can be controlled using Pulse width modulation.

Keywords : Principle of VFD, VFD using PWM ,Simulation Circuit and Analysis of results.