Parallel Operation of Solar Photovoltaic and Diesel Generator Systems: Mathematical Modeling, Control Algorithms and Experimental Analysis

Abstract

This paper presents the mathematical model, control algorithm, and experimental validation of the parallel operation of a solar photovoltaic (PV) system and a diesel generator (DG) in a hybrid power system. A novel hierarchical control architecture combining droop control with the Perturb-and-Observe (P&O) maximum power point tracking (MPPT) algorithm is proposed to optimize the coupling of both sources and ensure continuous power quality. A dynamic load-sharing model accounting for the stochastic variability of solar irradiance is developed. Simulation results for a 100 kVA system implemented in MATLAB R2023b/Simulink demonstrate that the proposed control method reduces DG fuel consumption by 31.4%, keeps voltage deviation within ±1.2%, and limits frequency deviation to ±0.3 Hz. Field validation using one year of data from a 50-kW pilot hybrid station in Tashkent region, Uzbekistan, yielded R² = 0.9873, RMSE = 1.24 kW, and MAPE = 2.14%. The annual CO₂ reduction potential was quantified at 18.7 tons, and the levelized cost of energy (LCOE) was 0.083 USD·kWh⁻¹, representing a 31.4% saving over the diesel-only baseline.