High Voltage Gain Multi-port Bidirectional DC-DC Converter with an Effective Multi-loop Control Strategy for PV/Battery Integrated Systems

This study proposes a novel isolated bidirectional multiport converter (MPC) based on a switched-capacitor converter and a half-bridge converter with an effective control scheme for photovoltaic (PV) powered and battery buffered systems. The proposed power electronics converter interface integrates the converters to which the ports are connected with a battery coupled common dc busbar and high frequency transformer (HFT). Thus, the three-port converter is formed without any need for an additional converter to regulate battery power flow. In addition, to transfer power from a low voltage PV energy unit to the battery and load, a single switch DC-DC converter with high voltage gain is proposed. The power flow between the ports is controlled by an effective multi-loop control scheme that is able to perform a smooth transition between the loops. In order to validate the viability and effectiveness of the proposed MPC, a 3 kW proof-of-concept model has been developed with a 3 kW PV and 220 V 12 Ah battery. The performance of the proposed converter has been analyzed for different case studies, including dynamic operating and loading conditions.