Control Strategies for a Shared Diesel Generator in an Off-Grid Hybrid Power System for Urban Areas in Pakistan

This paper presents control strategies for a hybrid off-grid power system serving an urban residential neighborhood in Pakistan, integrating solar photovoltaic (PV) generation, battery storage, and a shared diesel generator. The primary objective is to ensure power reliability and prevent generator overloading in a multi-household configuration. The system was initially optimized for component sizing and cost using HOMER Pro, followed by the development of a detailed dynamic model in MATLAB Simulink/Simscape. Building on this foundation, two complementary control schemes are designed: one for load distribution among the houses and another for battery bank charging. Simulation results demonstrate that the proposed controls stabilize the load supply—ensuring that the diesel generator consistently maintains single-phase voltage around 220 V while sharing a 2kW load per house without exceeding its capacity—and facilitate efficient battery charging on a common 48 V Direct Current (DC) bus. The diesel generator is time-shared across seven households, delivering approximately 9.65 A Root Mean Square (RMS) per active phase, which prevents overloading and ensures continuous power availability. The batteries are charged in a balanced manner whenever solar energy is insufficient, preserving system autonomy. By sharing the diesel generator, the system reduces battery size requirements, thereby lowering both capital and operational costs. This work offers a scalable, cost-effective control strategy for a PV–diesel–battery hybrid microgrid, providing a viable solution to Pakistan’s urban energy shortages.