Quantum Power Pulse Combination Modulation to Achieve Full Load Range ZVS of DAB Converters in Wide Voltage Gain

Zero voltage switching (ZVS) is of great importance for reducing the switching loss in the dual active bridge (DAB) converter. Traditional phase-shift control for DAB is affected by the junction capacitance of switches, leading to an inherent non-ZVS region. This letter proposes a quantum power pulse combination modulation to fill the non-ZVS gap, which regulates power through a sequence of power or nonpower pulses with integer periods. During nonpower periods, one bridge generates a zero level voltage, thus the inductor current can behave as a controllable magnetizing current by adjusting the duty cycle of the other bridge, allowing seamless transitions between the two adjacent periods. The proposed method makes DAB operate at intermittent continuous-current mode, and realize ZVS in the region of light load and wide voltage gain, especially near unity gain. As the load increases beyond a certain power, the nonpower pulses disappear naturally, and the method reverts to traditional control. Experiment results confirm that the efficiency of the DAB is significantly improved, and no dc offset occurs in the inductor current.