Investigation of PWM Techniques for High-Frequency Harmonics Loss Performance in Dual-Three Phase Asymmetrical Machines

Abstract

Dual three-phase asymmetrical machines are more sensitive to voltage pulses from pulse width modulation (PWM) compared to conventional three-phase machines. This sensitivity results in substantial current harmonics, which cause increased machine losses, significant current distortion, and excessive vibration. This article presents a comprehensive investigation into the high-frequency harmonic losses introduced by PWM techniques applied to voltage supply machine drives. To ensure a fair comparison, the computational burden among different PWM technique groups is standardized through a general carrier-based PWM approach. An analytical high-frequency harmonic loss model is introduced, expressed through machine parameters and the harmonic components of current and voltage. A corresponding equivalent loss resistance circuit is also discussed. Four existing PWM techniques, widely examined for their distinct current distortion performance, are evaluated. Extensive simulation and experimental results confirm the correctness of the analytical comparisons.