DC Bias Suppression Strategy in Dual Active Bridge Based on Triple Phase Shift Control

摘要

A novel control method for eliminating DC bias of dual active bridge (DAB)converter under triple phase shift (TPS)control is proposed. This paper firstly analyzes three most representative working modes of TPS control, and the proportional relationship between the DC bias current and the duty cycle of the active bridges is derived. Secondly the transformer DC bias current detection circuit is designed, and the output voltage duty ratio of the active bridges is accurately controlled in real time according to the magnitude of the bias current to ensure the volt-second balance of the high-frequency transformer windings. Thus the magnetic saturation problem due to DC bias is effectively eliminated, and the reliability of the system is improved. Finally, the simulation results verify the correctness and feasibility of the proposed control method.