A new nonlinear-doped beta controller for robust and resilient photovoltaic systems

Abstract

This paper presents the development of a nonlinear controller for robust and rapid maximum power point tracking (MPPT) in photovoltaic (PV) systems. Utilizing a two-stage approach, the proposed method integrates a variable step-size beta-integral backstepping control (VSS-IBSC) algorithm for initial approximation of the MPP, followed by a voltage-based incremental conductance-integral backstepping control (VINC-IBSC) algorithm for precise MPP tracking. The controller is based on the beta algorithm, doped with nonlinear features to enhance performance under variable load and irradiance conditions. The controller's stability is validated through Lyapunov's law, ensuring robustness. Simulation results demonstrate the controller's ability to achieve an MPP tracking efficiency of 99.969 % with a rapid settling time of 0.3 ms. Compared to conventional incremental conductance (INC) and sliding mode controller (SMC), the proposed controller reduces power tracking overshoot to 1.91 % (from 5.84 % for SMC) and improves tracking accuracy, with mean absolute error (MAE) and mean square error (MSE) values of 0.07 and 0.03, respectively. Further robustness is demonstrated under abrupt load variations, where the proposed controller maintains MPP power with minimal deviation. During parametric uncertainty scenarios, the controller exhibits superior response times, settling at 0.84 ms (Scenario-A) and 1.26 ms (Scenario-B), significantly outperforming INC (11.85 ms, 9.8 ms) and SMC (5.57 ms, 3.51 ms). Experimental validation under real environmental conditions corroborates the simulation results, with the proposed controller achieving an energy yield of 23.4938 W·s, compared to 22.7795 W·s (INC) and 22.5988 W·s (SMC). This novel nonlinear doped beta controller demonstrates exceptional performance, providing a robust, sensor-free solution for PV systems under dynamic and challenging conditions.