Zero-voltage switching for bidirectional buck/boost converter using hybrid discontinuous current mode

Abstract

This paper proposes a hybrid current mode between Triangular current mode (TCM) and Discontinuous current mode (DCM) in order to achieve Zero-voltage switching (ZVS) for a bidirectional buck/boost DC-DC converter. In the proposed Hybrid Discontinuous Current Mode entitled HDCM, the TCM operation is applied during the zero-current interval of DCM. Therefore, both ZVS and the variable current ripple, which result in the high efficiency at wide load range, are achieved. The achievement of ZVS with HDCM is confirmed by a 600-W prototype. Compared to TCM, the Root-Mean-Square current is reduced by 47.2% at most with HDCM, which further contributes to the loss reduction. Moreover, under the condition of the same boost inductor, the efficiency of HDCM at load of 0.2 p.u. is improved by 1.5% compared to TCM.