Loss Comparison between an SPWM and Harmonic Elimination Excited Small, (<1kW) Induction Motor Drive Using Pspice Simulation and Calorimetry

Adopting square wave excitation to drive induction motors (IMs) can substantially reduce inverter switching losses. However, the low-order time harmonics inherent in the output voltage generates parasitic torques that degrade motor performance and reduce efficiency. In this paper, a novel harmonic elimination modulation technique with full voltage control is studied as an interesting and alternative means of operating small (<1 kW) IM drives efficiently. A fully verified harmonic elimination scheme, which removes the 5^th, 7^th, 11^th, 13^th and 17^th time harmonics, was implemented and applied to an IGBT driven IM. The power losses incurred in the inverter and the IM as a result of the switching scheme have been determined.