Speed control using closed loop variable frequency drive

There are various starting methods to start induction motors among them variable frequency System has more advantages. For controlling the speed of the induction motor we are using pwm technique based on current signature techniques as a feedback of closed loop system. For a all control methods rely on the pwm voltage waveform to control the motor. The difference between control methods lies in how they calculate the motors voltage needs at any given moment. Among these methods we are doing v/f control because it has advantages over all other methods. Hence we are controlling the speed of the motor by using variable frequency system.