A Single-Stage Electrolytic Capacitor-Less EV Charger with Single- and Three-Phase Compatibility

This article proposes a modular single-stage electrolytic capacitor-less electric vehicles charger with single and three-phase grid compatibility. The proposed single-stage structure inherently maintains dc charging current for three-phase grid. For single-phase grid, a phase module is reconfigured to operate as a power decoupling circuit, making battery current to be dc. Furthermore, the proposed single-stage on-board charger is able to achieve zero voltage switching under wide grid and battery voltage ranges with only one control variable of phase shift angle. A balancing control method is proposed to ensure pure dc battery charging under unbalanced grid conditions. An optimized design of the planar core with Litz wire for achieving low profile is presented. Finally, a 11-kW prototype of the proposed charger achieved a power density of 5.25 kW/L and demonstrated 97.01% peak efficiency.