Modelling, Simulation, and Energy Management of an EV Charging Station Integrated with a DC Motor-Based Microgrid

Abstract

The global surge in electric vehicle (EV) adoption has created an urgent need for intelligent, resilient, and sustainable charging infrastructure. This work develops an integrated modelling and control framework for an EV charging station built around a DC motor-coupled microgrid, a configuration that more accurately reflects real-world auxiliary load behaviour in deployed charging infrastructure. The proposed system architecture incorporates photovoltaic (PV) generation, lithium-ion battery energy storage, DC motor loads representing electromechanical auxiliary systems, and EV charging units interconnected through a common DC bus. Accurate mathematical models are developed for each subsystem, including the solar PV module (single-diode model), battery dynamics using Shepherd’s model, DC motor electromagnetic and mechanical equations, and EV charging demand with stochastic arrival patterns. A hybrid Energy Management Strategy (EMS) is formulated, integrating rule-based decision logic for real-time responsiveness with a multi-objective optimization layer targeting minimization of grid energy cost, battery state-of-charge (SOC) deviation, and power losses. MATLAB/Simulink validation over a 24-hour duty cycle quantifies a 23.4% reduction in grid energy draw, a 31.2% gain in PV utilisation rate, and DC bus voltage deviations confined to ±0.8% across all tested loading transients, including simultaneous multi-EV connection and motor startup events. The modular 48V DC bus architecture scales directly to higher-voltage fast-charging deployments and is validated as both practically implementable and computationally tractable for embedded EMS execution.