Introduction to PWM Fed Speed Control of Induction Motor Using PC Project:
The main objective of this project is to control the speed of an induction motor with pulse modulation technique; this paper deals an innovative way of induction motor speed control mechanism rather than the conventional approaches like stator/rotor resistance control, frequency control method and pole changing method. Here we use sinusoidal pulse width modulation technique and the control operations are monitored by using PC.
A speed encoder is used to detect the speed of the induction motor, IGBT switches in PWM inverter as their switching devices, in this technique several pulses are generated in a single half cycle, and the width of these pulses are varied in accordance to the amplitude of the reference signal, the width of the pulse at the end of the half cycle is maximum, and reduces on the either side.
The carrier wave and the reference wave are coupled in an comparator and pulses generated when the amplitude of the carrier sinusoidal signal is lower than the reference signal, the carrier frequency is controlled by the modulation index M, the peripheral hardware components used in this circuit are Induction Motor, PIC (16F877A) Microcontroller is used here provided with an EPROM memory, Power Supply Unit, Opt-coupler is used for short optical transmission path to transfer an electronic signal between transmitter and the receiver, LCD, transistor TRIAC i.e.
Triode is an electronic component which is equivalent to two silicon-controlled rectifiers joined in inverse parallel in order to conduct current in the both directions, With a Current sensor, voltage sensing unit. This overall circuit is operated at a power supply of 5v dc so we need to step down the 230v ac into 12v ac by a step down transformer and rectified into 5v dc by a full bridge rectifier and a voltage regulator. This new method is a low cost, highly reliable and accurate device with minimum risk.
Download PWM Fed Speed Control of Induction Motor Using PC Final Year ECE Major Project Report.