A single phase to three phase power converter for motor drive applications

A simple and low-cost converter topology for driving a three-phase motor load from a single-phase AC power supply is presented. Using only two active devices with roughly one p.u. current rating, the converter can retain nearly full starting torque during motor starting with one extra capacitor and supply excellent balanced output voltage to the motor under steady-state conditions. Under positive sequence operation, the converter has no low-frequency output harmonic distortion, high total input power factor, and reasonable input current distortion. The fundamental frequency model for the system, harmonic distortion on the motor side and the input AC line side, the rating/stress for devices, reactive component selection, and the control strategies for starting and steady-state operation are detailed. Analytical, simulation, and experimental results are presented.<>