Photovoltaic and Battery sourced Multiport Converter fed Dual Active Bridge DC/DC converter with Multimode operation for Off-grid Electric Vehicle Charging Application

Abstract

In this paper, a multiport converter (MPC) fed bi-directional dual active bridge (DAB) DC-DC for charging an electric vehicle (EV) in an off-grid application is proposed. The MPC is with hybrid sources namely photo voltaic (PV) and battery. Further, these sources operate in different modes i.e., single input single output (SISO), single input dual output (SIDO), and dual input single output (DISO). In the SISO mode, two sub-operating modes are available. In the first sub-operating mode of SISO, the photovoltaic (PV) array alone supplies the load when the battery state of charge (SOC) is more than 95$\%$ during the daytime. In the second sub-operating of SISO, the battery is also able to serve the load during night-time when solar PV is not available. In the SIDO mode, the power output from the PV array is capable of meeting the load requirements and simultaneously supplying surplus energy to the battery for its charging purpose. In the DISO mode, the load is supported by both the solar PV and the battery concurrently. A centralized controller is developed to operate the MPC in all modes. The output of the MPC is fed to a bi-directional DAB DC-DC converter. In the present work, an optimized dual phase-shift (DPS) control scheme is aimed at reducing reactive power in the system and extending the ZVS range of operation. To validate the proposed MPC with different modes of operation and DAB DC-DC converter control scheme, a comprehensive simulation study is conducted using MATLAB/Simulink. The simulation setup involves a 3.8 kW system and considers different charging rates for an Electric Vehicle (EV).