Adaptive Drift-Free Hill Climbing Maximum Power Point Tracking for PV Systems

Maximum power point tracking (MPPT) is an algorithm used to maximize the output of a photovoltaic system. Conventional hill climbing (HC) is the most widely used algorithm due to its ease of implementation. However, HC encountered the trade-off problem between dynamic response and steady-state oscillation. A large duty cycle step size (Dstep) leads to a faster dynamic response but excessive steady-state oscillations, resulting in low tracking efficiency, and vice versa. Furthermore, under rapidly changing irradiance, HC can result in the incorrect perturbation direction, known as the "drift problem" which further degrades its performance. To address the issues, an adaptive drift-free hill climbing (ADFHC) algorithm is proposed in this paper. The ADFHC employs a large Dstep for fast exploration and a new variable Dstep strategy for accurate exploitation. Additionally, the drift issue is eliminated by including the change in output current (ΔI) in determining the direction of the duty cycle perturbation. Using MATLAB/Simulink, the performance of the ADFHC is analyzed and compared with that of the conventional HC for Dstep values of 1%, 5%, and 10%. The results show that ADFHC achieves 0.27 s faster tracking speed and 8.67% higher tracking efficiency compared to its closest competitor, HC with 5% D
step
.