Averaged current mode control for maximum power point tracking in high-gain photovoltaic applications

Abstract

Efficient extraction of the maximum power from photovoltaic (PV) systems under inherently variable weather conditions is a key issue that has been tackled in recent years. Maximum power extraction techniques are relevant for increasing the penetration of PV systems into electric systems. This paper presents an averaged current mode control strategy as a maximum power extraction technique in a photovoltaic high step-up dc–dc converter, which can be applied to dc microgrids or ac networks through power inverters. Since the generated power of a photovoltaic system is related to the terminal voltage, power extraction is given through the regulation of the converter’s input voltage. For this purpose, in the proposed averaged current mode control, the inner current loop uses the inductor current as a feedback signal, which improves the dynamic behavior of the converter with a simple gain. Meanwhile, the outer voltage loop is built with a proportional-integrative controller for regulation. The converter and control strategy are able to track rapid irradiance changes. They are also able to maintain the photovoltaic voltage regulation under dc bus voltage variations. The performance of the proposed control scheme is validated experimentally with a 100 W converter prototype.