Optimized Hybrid Control for the Current-Fed Semi Dual-Active-Bridge DC-DC Converter

This article proposes a variable clamp voltage control strategy for the current-fed semi dual-active-bridge dc-dc converter. For the low-voltage-side, the duty cycle of the bottom switches will be changed with the load variation. Full-load operation stability and full range of zero-voltage switching (ZVS) can be achieved. An instantaneous turn- OFF current tracking loop is designed to achieve duty cycle control and ZVS. The dc inductor current ripple can be designed smaller and the turn-OFF loss can be reduced. For the high-voltage side, the duty cycle will be calculated to avoid additional loss caused by body diodes. Besides, a coupled inductor is adopted to reduce core loss. The ZVS resonant process is analyzed in detail. The proposed control is verified to be effective by a 1-kW experimental prototype.