A Bridgeless, Stacked Switch-Pair-Based AC/DC On-Board High-Voltage EV Charger With Minimal Storage Capacitance Featuring Continuous Secondary-Side High-Frequency Rectifier Control

In this article, a fully soft-switched single-stage bridgeless stacked switches-based rectifier with reduced storage capacitance and minimized low-frequency output voltage ripple for high-voltage (HV) electric vehicle (EV) systems is proposed. Generally, bulky dc-link and filter electrolytic-type capacitors used in ac-dc converters reduce the converter’s reliability and life span. To address this issue, a bridgeless ac-dc isolated converter with stacked switches configuration on both the primary and secondary sides that employ a continuous secondary-side duty ratio control to reduce the low-frequency output voltage ripple is presented. A front-end primary-side duty ratio control for achieving power factor correction (PFC) for the integrated bridgeless boost PFC is also employed. The stacked switches-based configuration of the converter reduces the voltage stress of the switches to half of the dc-link voltage, making the converter suitable for HV battery systems. Soft-switching operation is guaranteed for all semiconductor devices. In addition, the output voltage regulation is achieved through a variable frequency (VF) control on the primary-side switches. The steady-state and dynamic performance of the proposed converter and the designed control system are verified using a 1.1-kW, 120-
${V}_{\text {rms}}$
/800-
${V}_{\text {dc}}$
, and 100–120-kHz SiC proof-of-Concept prototype in the laboratory.