Optimal Harmonic Mitigation Technique for High Power IM Drives

Abstract

The reduction of harmonic torque and ripples in low-switching VFI-based induction motor (IM) drives is a crucial consideration for improving efficiency, service life, drive damage, potential shaft failure for high power/speed drives and overall performance. In literature, existing solutions to these issues involve the implementation of standardized pulse width modulation (PWM) techniques such as sinusoid modulation technique PWM (SMT-PWM) and selective harmonic reduction PWM (SHR-PWM). However, this research proposes a P-PWM-based approach to address the reduction of harmonic magnitude and torque ripple in low-switching VFI-based IM drives. The proposed P-PWM-based approach is specifically applied for three and four-angle switching per quarter cycle (Aq), targeting the reduction of lower-order harmonic magnitude and torque ripples ranging from 6th to 6(Aq-1)th order. By relying on independent specifications and loading states, the P-PWM approach accommodates different Aq and higher-order harmonics. Extensive comparisons with SMT-PWM and SHR-PWM, supported by findings from a 1hp VFI-based IM drive using a TYPHOON-HIL-based hardware setup, demonstrate the superior performance of the P-PWM approach in terms of reducing the harmonic magnitude and torque ripples.