MICROCONTROLLER BASED SPEED CONTROL OF SINUSOIDAL PWM INVERTER FED THREE PHASE INDUCTION MOTOR

This paper is concerned with Microcontroller based speed control of Sinusoidal PWM Inverter fed three phase Induction Motor. The Work involves design and fabrication of a variable frequency PWM inverter using MOSFETs, operating from a DC source. The objective is to implement variable frequency sinusoidal PWM inverter in order to control the speed of the Induction Motor using Microcontroller. When it is required to provide wide range of speed control covering about 600rpm to 1500rpm, normal three phase supply at 50Hz with voltage control alone is not successful due to the unstable region in the Torque-Slip characteristics of the motor. Hence it is necessary to go in for variable voltage and variable frequency mode of operation. The main focus of the this paper is the design and fabrication of variable voltage and variable frequency sinusoidal PWM inverter for speed control operation of Induction Motor. This drive system is simulated in MATLAB/Simulink and the simulation results are presented. After integrating the hardware and software the whole setup is tested for satisfactory operation. It is found that the three phase Induction motor is capable of running over a speed range from 600rpm to 1500rpm while driving a fixed load