Multiport bidirectional DC-DC converter for PV powered electric vehicle equipped with battery and supercapacitor

Abstract

This study presents a novel quasi-Z-source converter integrated isolated multiport bidirectional DC-DC converter topology for a photovoltaic (PV) powered and battery/supercapacitor buffered electric vehicle (EV). The proposed topology can provide uninterrupted power to the electric motor of EV and regain the braking energy with the capability of bidirectional power flow. The system integrates quasi-Z-source and H-bridge converters with an existing switch. Thus, a four-port converter is achieved without any need for individual converters or additional switches. Besides, the high-gain quasi-Z-source converter allows the reduction of the rated voltages of the battery and supercapacitor packs, as well as allows using a high-frequency transformer (HFT) with a low turn ratio. The isolation between ports is provided by a secondary centre-tapped HFT. The secondary side of the HFT is equipped with a controlled full-wave rectifier to provide bidirectional power flow. In addition, a power flow management and corresponding control scheme are suggested. The performance of the proposed system has been evaluated for different operational changes. Results show that it properly performs the power flow between the ports under steady-state and transient conditions. The power flow capabilities and efficiency values validate the viability and effectiveness of the proposed system.