Enhancing THD in G2V Electric Vehicle Systems via Phase-Shift Modulation and SMC Optimized with PSO

This paper proposes a control strategy for reducing Total Harmonic Distortion (THD)  during Grid-to-Vehicle (G2V) charging in bidirectional electric vehicle (EV) systems. The targeted system features an AC-DC active front-end converter coupled with a DC-DC resonant converter. The proposed strategy integrates Phase-Shift Modulation (PSM) with a Sliding Mode Controller (SMC) where the  parameters are tuned offline using Particle Swarm Optimization (PSO) to minimize an Integral Time-Weighted Absolute Error (ITAE) and current harmonic cost function. The PSO-tuned SMC regulates phase-shift angles to suppress switching harmonics, maintain transient stability, and improve dynamic response under load variations.

​Simulation studies conducted in MATLAB/Simulink validate the performance of the proposed method against conventional dual-phase-shift PWM. In G2V operating mode, the primary-side converter current THD measured at the grid interface coupling point is reduced from 5.74% to 4.07%, bringing grid-side current harmonics within the 5% limit specified by IEEE Std 519-2014. The secondary-side resonant coil current THD decreases from 5.14% to 2.86%.

Overall, the results establish that the integration of PSO‑tuned SMC with phase‑shift modulation provides a promising solution for next‑generation bidirectional EV charging systems. The proposed method ensures compliance with grid standards, improves system performance, and supports the broader vision of smart‑grid deployment with enhanced power quality and reliability.