Aathira Karuvaril Vijayan

The adoption of synchronous optimal pulse-width modulation (SOPWM) in two-level voltage-source inverters (2L-VSIs) offers low switching-to-fundamental-frequency ratio (SFR) operation while maintaining reduced current total harmonic distortion (THD). Despite these advantages, the performance of SOPWM is highly sensitive to signal noise in the modulation index and reference voltage angle. To prevent degradation, conventional PI controllers are conservatively tuned with slow dynamic response, which limits overall system performance. Finite control set model predictive control (FCS-MPC) integrated with SOPWM offers a promising solution, combining the fast dynamic response of FCS-MPC with the optimal steady-state performance of SOPWM. Nevertheless, the intricate tuning of weighting factors in FCS-MPC presents a significant challenge, particularly in balancing between enhanced harmonic performance and fast dynamic response. This paper introduces a simplified FCS-MPC approach that eliminates the need for complex weighting factor tuning while retaining the excellent dynamic performance of FCS-MPC and ensuring the low current THD achieved by SOPWM under steady-state conditions. The efficacy of the proposed method is validated through MATLAB/Simulink (R2023b) simulations and experimental results.

Permanent-magnet synchronous motors (PMSMs) inherently exhibit torque oscillations due to their magnetic properties, impacting performance and causing increased noise and vibrations. While pulse-width modulation techniques commonly minimize current harmonics, they often overlook torque fluctuations arising from the interaction between current and back-EMF harmonics in PMSMs. Therefore, achieving both minimal torque harmonic content and reduced switching frequency is essential to obtain a smooth torque and low switching losses. This paper introduces a novel low-frequency torque harmonic minimization optimal pulse pattern (OPP-THM) method, designed to directly minimize torque harmonics in PMSMs, rather than solely focusing on current harmonics. By considering back-EMF harmonics in the optimization of switching angles, the proposed approach effectively suppresses low-order torque harmonics without compromising the contribution of back-EMF harmonics to average torque, thereby enhancing the PMSM performance. The effectiveness of the proposed method is demonstrated through validation on a 4kW experimental PMSM drive employing field-oriented control under steady-state and transient conditions.

Electric vehicles require high-power machines, so reducing power loss becomes crucial. Compared to space vector modulation, synchronous optimal pulse width modulation (SOP) has several advantages in high-speed applications, like the capability to operate at a very low switching frequency with lower total harmonic distortion, and reduced losses. This article presents a comprehensive review after performing a systematic investigation on different inverter topologies, including two-level voltage source inverters and multilevel inverter topologies with SOP as the modulation scheme. Several optimal pulsewidth methods will be studied along with SOP design methods, including steady state and dynamic switching. More emphasis is given to the various challenges faced in implementing SOP, followed by future trends.