Integral-Type Terminal Sliding Mode MPPT Controller for a Standalone PV System With a DC–DC Boost Converter Under Real-Time Varying Weather Conditions

Abstract

Robust nonlinear controllers, in particular sliding mode control (SMC), have been a convenient solution for maximum power point tracking (MPPT) of photovoltaic (PV) systems, as they deal with the nonlinearity of the system and can catch the MPP in various weather conditions; however, chattering and infinite time of convergence have been related to conventional sliding mode control. In this article, we propose an integral-type terminal sliding mode MPPT (ITTSMC) controller for a PV system powering a DC load, based on the tracking error of the inductor’s current of the DC-DC boost converter, which is connected to the PV array’s output, to follow the MPP. The paper provides a theoretical study of the controller in question, demonstrating its stability and its finite-time convergence. The controller is tested under four environmental conditions, firstly, standard test conditions with a constant load, then with a variable load, secondly, a step changes in temperature and irradiance, thirdly, under real weather conditions relying on the data of temperature and irradiance of a weather station in the Faculty of Sciences and Technologies of Errachidia in the eastern south of Morocco, finally, the controller will be evaluated under realistic partial shading conditions. To assess its performance, the ITTSMC is compared to the basic terminal SMC and the classical SMC. The ITTSMC achieves an 85% reduction in reaching time, a reduction of up to 88% in chattering magnitude, and a 66% decrease in voltage RMSE compared to SMC. Moreover, it exhibits strong robustness under real environmental conditions and partial shading while ensuring high-precision MPP tracking. Overall, the ITTSMC reaches a power extraction efficiency of 99.92%, outperforming TSMC (99.81%) and classical SMC (99.64%). These quantitative improvements clearly demonstrate the superior tracking accuracy, faster transient response, and reduced chattering of the proposed control strategy.