A Multiport Isolated Resonant LLC Converter for Grid-Tied Renewable Energy Powered Bidirectional EV Charger

This paper proposes an integrated bidirectional multiport DC-DC converter for battery charging of plug-in electric vehicles, which can integrate the photovoltaic (PV) system, traction batteries, and the AC grid. The presented converter is more reliable than the conventional topologies because both PV panels and the grid can simultaneously or separately deliver power to high-voltage batteries. In addition, the topology is bidirectional and can transfer power from batteries to the AC grid by employing a half-bridge CLLC converter with fewer switches. Moreover, a unified controller along with optimum maximum power point tracking (MPPT) algorithm is utilized to control the converter. The converter topology, control system, and operating scenarios are analyzed by using state space modeling. The performance of the whole system is evaluated by testing the converter’s operation in different conditions using MATLAB/Simulink software. The simulation results demonstrate that the proposed converter can not only control the charge and discharge of the batteries according to the state of the charge, but it can also maintain the DC-link voltage of the grid side to be in constant level.