A Switched-Inductor-Augmented Resonant DAB Converter for Achieving Wide-Range Zero Voltage Switching

A modified LCL resonant tank incorporating switch-controlled inductor (SCI) is introduced to realize a tunable resonant tank that ensures ZVS in primary side and ZCS in secondary side switches of an isolated bidirectional dual-active-bridge dc-dc converter (DAB-IBDC) under a wide range of output voltage and charging current of super-capacitor. The nominal operating point is carefully chosen to reduce conduction loss arising from circulating current. Moreover, the firing-angle of SCI is selected in such a way that it keeps ZCS at secondary side to avoid excessive ringing in voltage and current because of parasitic inductances in switches. Simulation and experimental results are shown to validate the effectiveness of the proposed resonant tank and control strategy on DAB-IBDC, which is designed to interface a 400 V dc bus to super-capacitor with voltage variation in the range of 10 V to 48 V, at maximum rated current of 10 A and rated power of 480 W. Finally, an efficiency of up to 94.23 % is achieved using proposed topology and modulation scheme.