A microcontroller based voltage space vector modulator suitable for induction motor drives

Abstract

Pulse width modulation techniques (PWM), introduced two decades ago, are the most used methods to control the voltage and frequency supplied to electrical AC machines. This paper describes a pulse width modulator based on the voltage space vectors technique that accepts voltage demands in dq coordinates and generates three phase PWM waveforms to drive a variable frequency voltage-source inverter. A scheme based on a high performance 16-bit standard microcontroller with minimum of additional hardware is used, which allows a flexible and economical solution. The output frequency of the modulator can be varied in a large range and with a good resolution. Experimental data obtained from an induction motor drive are presented.