Pulse-width Modulation Techniques in Two-level Voltage Source Inverters – State of the Art and Future Perspectives

The core of most power electronic systems involving DC/AC conversion is a voltage source inverter (VSI) that runs on some pulsewidth modulation (PWM) strategy. Numerous PWM techniques have been reported in the literature over the past few decades, each having its own merits and limitations. This paper reviews some selected areas of two-level PWM VSI, namely proper utilisation of the DC bus without deteriorating the quality of the output waveform, switching-loss reduction in the linear and over-modulation zones, common-mode voltage and PWM strategies for its reduction or elimination, distortion of the output voltage owing to dead time, and its compensation. These phenomena are explained in brief, followed by discussions on different research works relevant to these areas, and their advantages and disadvantages. Finally, the paper shows prospective directions in which research may continue in these areas in future.