Multi-phase current source cycloconverter using discrete amplitude modulation technique

Abstract

This paper proposed a new frequency changer, which can be regarded as a current source cycloconverter. Frequency changing is achieved by mixing two or more amplitude modulated current waves at supply frequency using power transistors. By appropriate selection of the modulation indices and phase shift between the supply voltages, the supply frequency component can be entirely suppressed. The harmonics content of the resulting current wave is found to be very low. This converter solves the problems and severe restrictions associated with the ordinary full-cycle synchronous AM modulation when applied to three-phase and multi-phase systems. The process of conversion involves only natural commutation.