Modeling and Optimization of Control in Off-Grid Systems with Emphasis on the Integration of Various Components of a Solar Power Plant

Abstract

The objective of this study is to develop and optimize a comprehensive modeling and control framework for off-grid solar power systems, emphasizing coordinated integration of photovoltaic arrays, power converters, battery storage, and load management to enhance stability, efficiency, and reliability under dynamic operating conditions. This research was conducted using a simulation-based approach in the MATLAB/Simulink environment to model an integrated off-grid photovoltaic system comprising PV modules, a DC–DC boost converter, an MPPT controller, a battery energy storage system, and a dynamic load profile. The photovoltaic array was represented through a nonlinear mathematical model incorporating irradiance and temperature effects. The battery subsystem was modeled using an equivalent RC network derived from impedance analysis, including state-of-charge (SOC) estimation and thermal considerations. A pulse-based excitation method was applied to characterize battery impedance, enabling the implementation of optimized charging strategies. Environmental inputs, including constant and pseudo-random irradiance profiles, were introduced to simulate realistic operating scenarios such as cloud-induced fluctuations. System performance was evaluated through time-domain analysis of voltage stability, power extraction, SOC evolution, charging efficiency, and load-side power quality under controlled and uncontrolled conditions. The results indicate that coordinated MPPT-based control significantly improves voltage regulation, enhances maximum power extraction, and stabilizes battery charging–discharging behavior compared to uncontrolled configurations. Pulse-based charging strategies informed by impedance modeling reduce charging energy consumption and mitigate internal stress within the storage system. The integrated control framework demonstrates robustness under dynamic irradiance variations, maintaining acceptable power delivery to the load and reducing transient voltage fluctuations. Furthermore, smoother discharge profiles and improved SOC stability suggest potential extension of battery lifespan and increased overall system reliability in off-grid applications. The proposed integrated modeling and optimized control strategy substantially enhances operational stability, energy efficiency, and reliability in off-grid solar power systems, providing a scalable framework for sustainable decentralized energy deployment.