A novel digital peak-current-mode self-sustained oscillating control (PCM-SSOC) technique for a Dual-Active Bridge DC/DC converter

This paper presents a peak-current mode self-sustained oscillating control (SSOC) technique for a Dual-Active Bridge (DAB) DC/DC converter. The proposed control approach is able to significantly improve the performance of the bi-directional DAB DC/DC converter over a very wide range of operating conditions. Basically, the proposed PCM-SSOC scheme adaptively regulates the respective phase-shifts for each bridge, as well as the switching frequency of the converter for different operating conditions in order to achieve an optimal performance. In this control technique, the timing signal is produced based on the transformer primary current, which is a feedback to the control system to determine the switching instants of the power MOSFETs. Therefore, the control system automatically tunes the control variables for different operating conditions. Comprehensive mathematical analysis based on the geometric viewpoint of the control system of the proposed PCM-SSOC scheme is presented, which provides a very good insight into designing the control system. Experimental results provided from an experimental prototype confirm the superiority of the converter performance compared to the conventional fixed-frequency phase-shift control approach.