Research on Control Strategy of Bidirectional CLLC for Wide Voltage Charging and Discharging of Batteries

High power batteries are usually composed of multiple batteries connected in series, resulting in a wide voltage range. This posed a challenge to battery charging and discharging equipment. Bidirectional CLLC is a resonant converter commonly used in battery charging and discharging systems due to its advantages of electrical isolation, high efficiency, and high power density.Traditional control strategies such as frequency conversion and phase shifting cannot achieve soft switching when facing a wide voltage range, which affects efficiency.This article proposes a comprehensive control strategy that combines realtime adjustment of input bus voltage, frequency conversion control. This control strategy could ensure high efficient operation across the wide voltage range.The control strategy was simulated and experimentally validated. The results indicate that the strategy is simple and effective, with high application value.