Predictive Control of Three Level Bidirectional Converter in Bipolar DC Microgrid for EV Charging Stations

This paper proposes model predictive control (MPC) of a bipolar bidirectional buck/boost converter derived from three level converter (TLC) configuration for integrating with electric vehicle charging station or battery energy storage system (BES) in bipolar dc microgrid structure. Bipolar dc microgrid considered here consists of two solar PV systems, dc loads and battery. The bidirectional power flow between grid and battery or EV charging stations is controlled considering the battery state of charge (SOC), total power generated and load demanded. Advantage of this converter is that it can address the dc grid voltage regulation and capacitance voltage balancing issues during variation of load and solar irradiation in bipolar dc microgrid. State space analysis is done and discrete model is developed. Simulation is done in Simulink MATLAB and analysed for voltage unbalance issues of bipolar dc microgrid under varying conditions of photovoltaic generations and load disturbance. Real time performance is tested and verified in hardware in loop environment using Typhoon HIL 402.