A conduction losses optimization strategy for DAB converters in wide voltage range

Conduction losses, which are proportional to the square of rms inductor current, account for an important part of total losses for a dual active bridge (DAB) converter. A minimum rms inductor current control strategy based on Dual Phase Shift (DPS) modulation is proposed to lower the conduction losses and improve efficiency of the converter over a wide input/output voltage range. Based on the steady-state mathematical model of rms inductor current and transmission power, the minimum rms current trajectory (MCT) composed of phase-shift and PWM duty cycle is derived. The proposed control strategy make the DAB converter operate along MCT in the steady state to improve efficiency and realize fast regulation of output voltage in dynamic process. Simulation results verify that, compared with Single Phase Shift (SPS) control, significant reduction of rms current at light load, zero rms current at no-load and high dynamic performance have been achieved.