A Dual-Input High-Gain Bidirectional DC/DC Converter for Hybrid Energy Storage Systems in DC Grid Applications

This paper presents a dual input-port bidirectional DC/DC converter for a Hybrid Energy Storage System (HESS). The converter is non-coupled, non-isolated and it has high-gain. Thus, it does not have transformer or coupling inductances, so voltage spikes or circulating currents are not present which is reflected in its high efficiency. In addition, the DC/DC converter is totally bidirectional, so the sources can transfer the energy between them and to the load. The converter has six switches but only three of them work in each mode, so the control is relatively simple. The main applications of the proposed converter are HESS for DC microgrid applications or small electric vehicles, particularly in which the storage system is small, hence the voltage is low, but the "load" works at a much higher voltage. The article analyses the converter in steady-state and presents the small-signal model, based on that, the control loop is designed. Simulations and experimental results validate the converter.