ABSTRACT:

A new family of non-isolated zero current transition bi-directional converters is introduced. Basic non-isolated bi-directional DC-DC converters are derived by combining basic DC-DC converters and they are able to transfer energy between two DC sources using two main switches. In the proposed bi-directional converters, instead of using two independent auxiliary circuits for each main switch, same components with a single auxiliary switch is used to provide soft commutation at both modes of converter operation. In addition, the soft switching range in the proposed converters is not dependent on the duty cycle and the auxiliary circuit is applied only once in each switching cycle, which leads to a simple control circuit. Low weight, small volume, high efficiency and the ease of control are the most important benefits of the proposed converters. The proposed bi-directional buck and boost converter is fully analysed for both buck and boost operating modes. The validity of theoretical analysis is justified using experimental results of a 200 W, 50-100 V prototype converter.