A New Bridge-Less AC-DC Stacked-Switches Structured Bi-Directional On-Board High Voltage EV Charger with Minimal Storage Capacitances

This paper presents a new single-stage isolated bidirectional stacked switches-based CLLC resonant converter with reduced storage capacitances for High Voltage (HV) Electric Vehicle (EV) systems. In the proposed converter, two closed-loop ripple reduction control units implemented on both rectifier and inverter modes of the converter to minimize the output and DC-link voltage ripples without any additional circuit design. As a result, the bulky unreliable electrolytic-type DC-link and output filter capacitors are replaced with significantly smaller and more reliable ceramic capacitors. Moreover, a closed-loop duty ratio controller guarantees a high-quality sinusoidal input current in the rectifier mode, while output voltage regulation is realized using Variable Frequency Modulation (VFM) technique. In inverter mode, a Second Order Generalized Integrator (SOGI) Phase Lock Loop (PLL) along with a fixed-band Hysteresis Current Controller (HCC) is implemented for power transfer from the EV to the grid, making the converter robust against frequency disturbances. The converter's performance is verified through a 1kW, 120Vrms/800Vdc design.