An improved power quality high frequency soft switched variable speed DC drive with 3-phase input

This paper presents a novel, high frequency soft switching variable speed DC drive with three phase input source. In the proposed scheme, a single switch has been deployed to operate continuously in zero current switching mode with three phase AC input source. The output of the proposed drive is continuously controllable. DC voltage required for driving DC motor in its entire speed and torque range. The proposed DC drive is capable of drawing a high-quality low harmonic input current naturally at nearly unity power factor. Comparison of experimental results of performance DC drive and input power quality using proposed technique and the earlier reported low frequency hard switched DC-drive are also presented.