Design and Performance Validation of a DC-Coupled Hybrid Solar-Wind Off-Grid Electric Vehicle Charging Station for Developing Country Deployment

Abstract

This paper presents the design, modelling, and performance validation of a DC-coupled hybrid solar-wind off-grid electric vehicle (EV) charging station for deployment in developing-country contexts. The system integrates a 78.1 kW photovoltaic array, a 20-kW permanent-magnet synchronous generator (PMSG) wind turbine, a 150-kWh lithium iron phosphate (LFP) battery bank, an EV charging port, and a bidirectional DC-DC converter with PI-regulated charge/discharge control on a common 600 V DC bus. A detailed transient-level MATLAB/Simulink model is developed, incorporating perturb-and-observe maximum-power-point-tracking (MPPT) for both PV and wind branches, hierarchical rule-based energy management with hysteresis on filtered PV power, and PI-regulated DC bus voltage control. The characterisation exercises coordinated four-branch operation under a step-loss generation scenario, demonstrating: DC bus voltage regulation within ±5% of the 600 V reference across both Charge and Discharge modes; sub-100 ms bus-voltage recovery after mode-transition disturbances (19 ms to ±5%, 37 ms to ±2%); wind-branch delivered-power tracking across a validated P–D operating envelope; and continuous 25 kW EV charging maintained throughout the generation-loss transient. The validated Simulink model and rule-based control baseline established in this paper are intended to inform subsequent development of a two-stage distributionally robust optimisation (TSDRO) energy management framework for the same architecture, reported in forthcoming work.