Dual Output Voltage Balancing Strategy in EV Charging Stations Using Model Predictive Control

Electric vehicles (EVs) offer a promising solution to achieve zero tailpipe emissions in urban areas. Effective deployment of EVs requires a robust energy-management-based charging infrastructure. Bipolar DC-bus-fed charging stations are popular due to their efficient connection to distributed generation and reduced conversion steps. However, voltage imbalances in bipolar DC buses, caused by varying EV load demands, pose a challenge. This paper introduces design guidelines for EV charging stations using a dual-output voltage balancer (DOVB) with model predictive control (MPC), providing superior balancing capabilities. Unlike three-level converters, the DOVB minimizes voltage and current stress on switches and avoids shoot-through issues. System stability and robustness were evaluated to optimize control parameters. Simulation and hardware-in-loop experiments demonstrate that the proposed method effectively manages voltage imbalances, ensuring consistent supply quality in bipolar EV charging stations.