Key technologies of digital-current-controlled Bidirectional DC-DC converter in the hybrid electric vehicle

This paper focus on the most important aspects of the bi-directional DC-DC converter in the hybrid electric vehicle(HEV) for the project applications.The different operating modes of converter are introduced under all HEV´s work condition.Based on summarization, the demerits including low efficiency at light load and the uncontrolled discontinuous current when charging for the battery are derivated. Through theoretical and mathematical analysis, A new algorithm of average current controlling and digital control method in discontinuous synchronous rectifier mode with a single current sensor resistance have been proposed to realize the multi-mode bi-directional DC-DC converter. At the same time, the 800 W prototype using proposed technology is implemented for 48 V HEV application in order to verify the operational principles and advantages that improve synchronous rectifier inverse-boost converter light load efficiency. Effectiveness and feasibility of the new proposed control method is verified by experiments.So it can be applied to hybrid electric vehicle drive system.