A new topology for operating three-phase induction motors connected to single-phase supply

This paper presents a simple and low cost single-phase to three-phase cycloconverter topology for driving an induction motor with a single-phase ac supply. Only seven naturally communicated thyristors and one phase balancer capacitor are employed, so the resulting cycloconverter-motor drive system is cheap and compact. Using discrete hopping frequency technique, a single-phase to three-phase modulation strategy base on open-loop VVVF and VVCF control is proposed. The cycloconvertor can start the motor with high starting torque, and can bring the motor up to full speed. The effectiveness of the modulation strategy and the feasibility of the cycloconverter have been verified by both the simulation and experiment results.