Advanced lower order harmonic torque suppression by P-PWM in high-performance scalar-controlled IM drives

VSI-operated IM drives at low switching per fundamental frequency in a quarter cycle (N_s) are highly prone to lower order harmonic torque in addition to torque ripple. This can lead to lower efficiency, reduced service life, wear and tear of the components, acoustic noises and vibrations, etc. It can also lead to shaft failure in the long run. Thus, it is the preeminent consideration in prevailing high-speed, motor and power drives. Presently, these problems are minimized by implementing classical PWM techniques (CB-PWM and SHE-PWM). In this present paper, a P-PWM-based approach is proposed for the reduction of the harmonic magnitude in the lower order torque and the torque ripple in VSI-operated IM drives. In this paper, a programmed pulsewidth modulation (P-PWM)-based approach is applied in the context of three switchings per fundamental frequency per quarter cycle (N_s = 3) for reducing the harmonic magnitude (lower order) and ripples in torque that are of the order of the 6th, 12th up to 6(N_s − 1)th. Since the P-PWM approach relies on independent specifications and loading states, it can accommodate different N_s and higher order harmonics. Furthermore, the P-PWM performance is implemented and extensively compared with carrier-based pulsewidth modulation (CB-PWM), and selective harmonic elimination pulsewidth modulation (SHE-PWM) for N_s = 3 and the obtained findings are supported by a 1hp VSI-based IM drive using a TYPHOON-HIL based experimental setup. The P-PWM approach surpasses the classical used PWM techniques, such as CB-PWM and SHE-PWM, both in terms of the magnitude of the harmonic and the ripples in the torque.