Robust adaptive PID controller for maximum power point tracking in photovoltaic systems under uncertainty

Abstract

Photovoltaic systems experience voltage and power fluctuations under varying irradiance, temperature, and load conditions, which lead to control challenges. To stabilize the output voltage and improve efficiency, a DC–DC boost converter is employed in this study. For fast and accurate maximum power point tracking (MPPT), the Incremental Conductance (IC) algorithm is combined with an adaptive control structure. The proposed framework is based on a Model Reference Adaptive PID Controller (MRAC-PID), which automatically adjusts the controller parameters and guarantees system stability analytically through the Lyapunov function. The control design approach treats the PV-converter system as having structured parametric uncertainty. This means that while the system’s general structure (second-order) and the sign of its high-frequency gain are assumed known, its actual parameter values are considered unknown and subject to wide operational variations. This approach eliminates the need for a precise, parameterized mathematical model of the system, which reduces computational complexity and simplifies implementation. The main objective is to enhance energy conversion efficiency and maintain system stability under varying irradiance, temperature, and parameter uncertainties. Simulation results in MATLAB/Simulink demonstrate that the proposed controller achieves higher accuracy, stability, and robustness than classical and optimization-based PID controllers under three operating conditions: constant irradiance, variable irradiance, and parameter uncertainty. Furthermore, under partially cloudy weather conditions, the adaptive controller extracts higher power with significantly reduced oscillations, confirming its effectiveness for practical PV applications. 1. Introduction Solar energy, as one of the most significant renewable resources, has attracted considerable attention in recent years due to its abundance, accessibility, and environmental cleanliness. Research has demonstrated that various technologies, including photovoltaic (PV) systems and concentrated solar power plants, have been developed to harness this resource, playing a key role in replacing fossil fuels [1]. Improvements in solar cell efficiency and reductions in production costs have led to the widespread adoption of PV systems in both residential and industrial applications. This trend indicates that solar energy could become one of the main sources of global electricity generation in the future [2]. Moreover, studies have shown that integrating solar systems with energy storage technologies enhances stability and efficiency while reducing dependency on the power grid. The decline in storage costs and the increase in efficiency have paved the way for broader practical utilization of solar energy [2]. Overall, solar energy is not only environmentally clean and safe but also economically viable