Voltage-Fed Three-Phase Semi-Dual Active Bridge DC-DC Converter Utilizing Varying Operating Modes with High Conversion Efficiency

A novel high-frequency isolated three-phase voltage-fed semi-dual active bridge DC-DC converter is proposed for unidirectional power flow with wide input variations and high voltage interface. A varying operating mode control independently implemented by phase shift and duty cycle control is subsequently raised to handle the stability and improve the conversion efficiency of the converter under the light load conditions. A variety of different operating modes are illustrated and compared in detail. The power expressions and the root mean square expressions of the leakage inductor current of different modes are derived and the optimal modes are consequently selected. The gating signal falling edge compensation of secondary side switches is implemented to further improve the conversion efficiency. The zero voltage switching conditions based on current polarity is also derived. A 1.6 kW prototype was built to verify the effectiveness of the proposed topology and control strategy. The experimental results show that the proposed converter using the proposed control strategy can achieve stability throughout the input and load variations. Moreover, seamless transition can also be achieved, the dynamic performance is good, and high conversion efficiency can be guaranteed.