Adaptive step size based drift‐free P&O algorithm with power optimiser and load protection for maximum power extraction from PV panels in stand‐alone applications

Abstract

This paper presents an adaptive step size based drift-free perturb and observe algorithm with power optimiser and load protection for maximum power extraction from photovoltaic panels in stand-alone applications. The proposed algorithm consists of an adaptive step-size technique, drift mitigation technique and power optimiser and load protection technique for fast maximum power extraction with less steady-state power loss and protection features. The adaptive step-size technique continuously monitors the absolute value of change in power ( | Δ P | ) to adjust the perturbation step size ( Δ D ) for fast tracking of maximum power point, and the drift mitigation technique mitigates the confusion in selecting the correct perturbation direction that exists in the conventional perturb and observe algorithm for a sudden change in irradiance conditions. Besides, the presented power optimiser and load protection uses a closed-loop duty cycle (D) value for detecting possible underloading and overloading conditions, wherein, in case of underloading or overloading, it turns off the power optimiser to protect itself and the connected load from any damage or malfunctioning. The overall performance of the proposed algorithm, in terms of its dynamic operations, reduced steady-state power loss, and protection features are evaluated using MATLAB simulations and verified with an experimental prototype. Comparative analysis of the proposed algorithm with state-of-the-art perturb and observe techniques is carried out for validating its effectiveness and feasibility in real-time applications.