This paper presents a novel ZVS bidirectional 1 kW class DC-DC converter used for a photovoltaic (PV) system. The proposed circuit is based on a boost&buckboost converter, which consists of a boost converter and a buckboost converter. Bidirectional soft switching is realized by using of coupled inductors and auxiliary switches in the circuit. From the analysis of the circuit operation, ZVS conditions of the switches are derived. In the experiment, the maximum efficiency of the proposed converter during forward power flow was 97.1% on output power of 320 W.