Dc-dc bidirectional converters transfer energy between two different dc sources. Soft switching in both directions of operation has been difficult in non-isolated bidirectional converters. To achieve soft switching in the main switches in such converters, usually two independent auxiliary circuits with multiple auxiliary switches are used. A ZCS PWM bidirectional converter is proposed in this paper. In the proposed bidirectional converter a novel yet simple auxiliary circuit with only one auxiliary switch has been applied to provide soft switching at both buck and boost modes of operation. The soft switching range of the proposed converter is independent of the duty cycle and operates with a simple control circuit. In this paper, description and operating principles of the proposed converter are discussed and experimental results obtained from a 500W, 100V–400V prototype are presented to validate the feasibility of the converter