A Current-Fed Dual-Active-Bridge DC-DC Converter Using Extended Duty Cycle Control and Magnetic-Integrated Inductors With Optimized Voltage Mismatching Control

For a current-fed dual-active-bridge bidirectional dc-dc converter, an extended duty cycle control is proposed. The low-voltage-side (LVS) bottom switch duty cycle can operate lower than 50%. The conduction loss of switches can be reduced by using low-voltage-rating MOSFETs for the LVS. Meanwhile, a voltage mismatching control with adaptive clamp voltage regulation is proposed to achieve zero-voltage switching for all switches throughout full load range. Besides, for LVS dc inductors, a magnetic-integrated technique is used to reduce core loss, and power density can be improved by the use of only one core. The effectiveness of the proposed control is verified by the experimental results of a 1-kW laboratory prototype.