D01.10 - A Single-Stage AC/DC Bridge-Less Converter with an Adaptive Control Scheme and Reduced DC-Link and Output Capacitances for High Voltage EV Systems

This paper presents a new AC/DC step-up CLLC resonant converter with a fully soft-switching operation and an adaptive control scheme that covers a wide voltage range with an extended high-efficiency range for high voltage EV systems. In the proposed converter, a closed-loop controller guarantees soft-switching operation and high-quality input current without a need for any auxiliary circuits while replacing bulky dc-link capacitors with small capacitors. Moreover, the proposed adaptive control scheme allows the converter to further narrow its switching frequency spectrum for output voltage regulation, resulting in an extended high-efficiency range. Furthermore, a variable frequency control algorithm is designed that regulates the converter’s output voltage during its modes of operation. The converter’s performance is verified through a 2kW, 120Vac/800Vdc design.