A High Voltage-Gain Bidirectional DC–DC Converter With Full-Range ZVS Using Decoupling Control Strategy

In this paper, a high voltage-gain bidirectional dc-dc converter is proposed with zero voltage switching (ZVS) and low circulating current for the interface between the energy storage system and dc microgrid bus. A current doubler is located in the low-voltage side (LVS), and a voltage doubler is located in the high-voltage side (HVS). Therefore, high voltage gain is accomplished without a transformer of the high turns ratio. The interleaved input structure is employed to reduce the current ripple and helps to achieve voltage matching (VM) on both sides of the transformer. In the view of decoupling pulsewidth modulation plus phase shift (PPS) control strategy with two control variables, the proposed topology can achieve VM and power control through the decoupling regulations of duty cycle and phase shift angle. By analyzing the resonant process during the dead time, a fixed delta is selected to generate a bias current for full-range ZVS with low circulation losses. The optimal design is given for component parameters to accomplish full-range soft switching and circulation loss reduction. An 800-W prototype of 48-60-V input and 240-V output is constructed with 30-kHz switching frequency to verify the effectiveness of the proposed converter and the associated control strategy. The accordance between the analysis and experimental results further testifies the advantages.