A PWM Inverter with an Improved Output Voltage Waveform

Abstract

A three-phase variable-frequency inverter using PWM technique has been designed and constructed in which the notch positions are optimized to eliminate a fixed number of harmonics. The control circuitry designed to generate optimum notch positions uses digital techniques contrary to analog modulation techniques used in classical PWM which results in less harmonic distortion in the output waveform. The experimental results obtained are in close agreement with the theoretical predictions.