Double modulation control scheme for a DC/DC converter applied to a battery charger

In this study, a novel control scheme for controlling a self-oscillating half-bridge series resonant converter for DC source and secondary battery interface is proposed. This new control scheme is used to control and regulate the DC output current of the converter. The proposed control scheme has the advantages of not only wide power regulation range, but also ease of output current control. In addition, it can achieve a stable and efficient zero-voltage-switching (ZVS) in a whole load range. The control principles of the proposed method are described in detail and its validity is verified through simulated and experimental results based on a 24 V 125 Ah battery charger. The maximum charging efficiency of the proposed topology during the overall charging period exceeds 90%.