Multisampling Maximum Power Point Tracker (MS-MPPT) to Compensate Irradiance and Temperature Changes

Abstract

This paper presents a maximum power point tracking (MPPT) method that compensates fast, though smooth, irradiance (or temperature) changes. The proposed method belongs to the family of perturb and observe (P&O) methods as the photovoltaic (PV) voltage is intentionally perturbed to induce changes on the PV power. In consequence, the slope of the $pv$ -characteristic curve can be detected, which reveals the MPP position. The perturbation is usually an increment with varying direction, which is used to update the next PV voltage reference. However, changes on irradiance (or temperature) may also cause changes on the PV power, which mix with the algorithm's intentional increment effect on the PV power. This combination of effects confuses the slope detection, which may entail a wrong decision on the next increment direction, and a considerable deviation from the MPP. The scheme presented here proposes the use of more samplings and an associated combination of increments directions before taking a decision. This additional information is used to separate the effect of irradiance (or temperature) changes from the algorithm's intentional perturbation effect. Thus, the proposed multisampling MPPT can provide effective MPP tracking despite of irradiance (or temperature) changes. The proposed scheme is experimentally tested and compared to the conventional P&O under irradiance changes.