Abstract: This paper proposes a DC-DC converter topology with asymmetrical bidirectional power conversion capability to meet the demand for DC step-up collection in offshore wind power plant. It enables input-parallel-output- series DC voltage step-up during offshore wind power delivery, while also allowing for reverse power transmission under low capacity through modulation strategy changing when the wind farm requires power support. In this paper, the soft switching and power transmission characteristics of the converter in both forward and reverse operating modes are analyzed. Based on these analysis, corresponding control and modulation strategies are developed for output voltage regulation and serial voltage balance. By reducing the number of components to meet different forward and reverse requirements, compared with traditional bidirectional converters, the cost of the converter can be reduced. Based on simulation and experimental results, the power regulation, mode switching, and soft-switching characteristics of the proposed forward and reverse differentially converter are tested to verify the effectiveness of the proposed topology.