A hybrid inverter/cycloconverter-based variable-speed three-phase induction motor drive for single-phase inputs

This paper presents a simple converter topology for driving a three-phase induction motor with a single-phase AC supply. Using only two active switches and a triac, the converter can start the motor with high starting torque and low input current, and can bring the motor up to full speed using a very cost-effective, single-phase field-oriented control strategy. The converter supplies balanced output voltages at rated frequency with virtually no output distortion and with very high input power factor. In this paper, the capability contours for different speed ranges and various operating modes are addressed; the trade-offs between output torque, torque ripple, input current distortion, and inverter rating are also explained, and the proposed control approaches are supported by simulation and test results