Current Reduction Method for Dual Active Bridge Converter in Non-linear Dead-time Compensation Method

Abstract

This paper proposes a control method for a dual active bridge (DAB) converter, which achieves both a reduction in the non-linear transmission power error due to the dead-time and a reduction in the inductor current with a three-level operation. The non-linear transmission power error is compensated by designing a zero current period in the inductor current with the three-level operation. In addition, an inductor current reduction method for the three-level operation is also proposed. In the non-linear transmission power error compensation method, the inductor current is reduced by suppressing the circulating current by considering the zero-current period to be the dead-time. The validity of the proposed method is confirmed using a 2.0-kW prototype. The experimental results show that the transmission power error is reduced by up to 85.1%. In addition, the inductor current is reduced by up to 64.1% and the loss is reduced by up to 58.6%. Moreover, the DC offset is eliminated by utilizing the voltage polarity reverse phenomenon in the voltage control.