A Variable Step Size INC MPPT Method for PV Systems

TLDR

MPPT techniques maximize photovoltaic array output, with the incremental conductance algorithm favored for its high accuracy and adaptability to changing conditions. This study proposes a modified variable‑step‑size INC MPPT algorithm that automatically adjusts the step size to track the array’s maximum power point. The algorithm is simple, implementable on digital signal processors, and its design principle is supported by theoretical analysis, simulation, and experimental validation. Compared with conventional fixed‑step methods, the proposed algorithm simultaneously improves MPPT speed and accuracy, as confirmed by simulation and experimental results.

Abstract

Maximum power point tracking (MPPT) techniques are employed in photovoltaic (PV) systems to make full utilization of PV array output power which depends on solar irradiation and ambient temperature. Among all the MPPT strategies, the incremental conductance (INC) algorithm is widely used due to the high tracking accuracy at steady state and good adaptability to the rapidly changing atmospheric conditions. In this paper, a modified variable step size INC MPPT algorithm is proposed, which automatically adjusts the step size to track the PV array maximum power point. Compared with the conventional fixed step size method, the proposed approach can effectively improve the MPPT speed and accuracy simultaneously. Furthermore, it is simple and can be easily implemented in digital signal processors. A theoretical analysis and the design principle of the proposed method are provided and its feasibility is also verified by simulation and experimental results.