A High Power Interleaved Parallel Topology Full-Bridge LLC Converter for Off-Board Charger
Jianbin Chen, Chengyu Yang, Shengzong Tang, Jianjun Zou
Abstract
A interleaved parallel LLC converter is proposed as a DC/DC converter for a digital off-board charger in accordance with the high output power requirements of modern electric vehicle chargers. The proposed converter utilizes a hybrid control strategy of pulse frequency modulation (PFM) and pulse width modulation (PWM) that can greatly increase the adjustable output voltage range. As a result of these designs, a silky target voltage can be achieved. The proposed LLC converter has been rigorously analyzed and parametrically designed. To verify the design parameters of the proposed LLC converter, a laboratory prototype with an output voltage range of 40-110 V and a maximum output power of 20 kW was fabricated. The rated output voltage and rated output current are 80 V and 200 A, respectively, while its switching frequency range is 100-250 kHz and its resonant frequency is 153 kHz. This prototype exhibits incredible robustness and stability, and achieves a flexible, stability and sensitivity to automatically adapt the target output voltage value.