Introduction to PWM Fed Speed Control of Induction Motor Using PC Project:

This project presents a new concept in electric load monitoring systems, in order to facilitate the good energy usage characteristics, here in this paper we implemented a new approach  in speed control of induction motors rather than conventional speed control approaches like  pole changing, stator resistance control, rotor resistance control, and frequency control methods.

In this new technique pulse width modulation the width of each pulse is varied based on the reference sine wave voltage, in this we produce several pulses in every half cycle, and maximum at the end of each half cycles and decreases, increases on either side of the half cycle, in pulse width modulation technique we can use triangular , trapezoidal, square wave as an carrier wave, this carrier wave is mixed with the reference sinusoidal wave having higher amplitude than the carrier wave in an comparator .

The pulses are generated by continuous on/off operations of the   IGBT’s, the output frequency is based upon the reference signal frequency by controlling modulation index, thus by varying the amplitude of the sine wave in its maximum and minimum ranges we can control the output voltage, now in this project we regulate the speed of an single phase induction drive by varying the supply frequency using  pulse width modulation technique based inverter controlled by the PC, our system consists of  a Microcontroller, opt-coupler, MAX232 data sheet, transistor TRIAC and  LCD to display  the obtained output.

This prototype is designed using visual basic, MPLAB, It operates at 5v dc supply, so we need to step down the 230v ac into 12v ac by a step down transformer and rectified into 5v dc by the help of full bridge rectifier, and then feed to the proposed circuit.

The entire phenomenon is clearly explained in the coming sections, the experimental results revealed that low cost, high efficient speed control system, with minimum risk in operation, and finds house hold applications because it uses pc to control the speed. 

Download  PWM Fed Speed Control of Induction Motor Using PC ECE Project Report.