A new approach to enhance power quality for medium voltage AC drives

A new approach to medium-voltage variable-frequency static ac drives offers improvements in power quality. Harmonic current injection into the power lines is below the most severe requirements of IEEE Standard 519-1992, The power factor of this new type of drive exceeds 94% at full load and is above 90% at 10% load. Motor voltage and current waveforms are improved so that torque pulsations are reduced, peak voltage stress on motor insulation does not exceed peak input line voltage, and no zero sequence voltage is imposed, Drive efficiency exceeds 96%. This paper describes the new approach and some of the results achieved.