Development and Characterization of a Simulink Model and Rule-Based Energy Management for an Off-Grid Hybrid PV–Wind EV Charging Station: A Baseline for Distributionally Robust Control

This study presents a developed and characterized Simulink model of an off-grid hybrid photovoltaic (PV) and wind electric vehicle (EV) charging station and characterizes the performance of a rule-based energy management strategy (EMS) that coordinates its four power branches. Predominantly techno-economic studies of such architectures have not provided dynamic models sufficiently to characterize transient behavior, mode transitions, or control limitations. The model integrates a 78.1 kW PV array, a 20 kW wind turbine, a 150 kWh energy-storage unit, and a 25 kW EV port on a regulated 600 V DC bus. Each subsystem is characterized in isolation; the integrated system is exercised under a 50 s four-window stepped-irradiance scenario. During high- and low-irradiance windows, the EMS coordinates all four branches successfully, with bus voltage regulated within ±7 V of a +3.7% steady-state offset. At the intermediate-irradiance window, the filtered PV power oscillates across the hysteresis band, producing 74 charge/discharge transitions in 10 s and sub-millisecond bus voltage transients reaching 903 V, exceeding the 750 V safety threshold. Remediation experiments show that a 50 ms debounce eliminates the chatter but not the transient, identifying two independent architectural limitations of the rule-based design. The dynamic model and baseline established here inform a companion two-stage distributionally robust optimization (TSDRO) controller for the same architecture.