DC bias elimination for Dual-Active-Bridge DC/DC converter using TMS320F28335

Abstract

This paper proposes an novel simple anti-bias modulation technique for single phase Dual-Active-Bridge DC/DC converters. When a pulsating load occurs, the control efforts of the controller lead to sudden changes in the phase shift. In turn, this cause a momentary unbalance in the positive and negative volt-second product of the transformer. As a consequence, DC bias in the transformer current appears and takes some time to vanish. By some small changes in the setting of the pulse-width-modulation modules of the digital-signal-processor, the bias can be completely eliminated. Theoretical analysis and experimental results show that, it takes only a half of one switching period to remove the bias caused by a pulsating load change without the need of a high sampling speed or any complicated measurements or feedback.