Fast Photovoltaic-System Voltage- or Current-Oriented MPPT Employing a Predictive Digital Current-Controlled Converter

Abstract

In this paper, a photovoltaic (PV)-system maximum power point (MPP) tracking (MPPT) control strategy employing a predictive digital current-controlled converter implemented in conventional hardware resources is presented. Two current programmed controllers (finite-state predictive control and valley current control) have been integrated into a system with current- or voltage-oriented MPPT. The modifications applied to the perturb-and-observe algorithm enable the MPP tracker to interact rapidly with the controller accounting also for abrupt irradiance drops by considering voltage and current limitations. The implementation of digital control in PV systems entails significant advantages of speed and accuracy, although the controller converges correctly at the MPP under irradiance variations featuring fast dynamic response. The proposed controller scheme has been experimentally demonstrated on a digitally current-controlled boost converter delivering power from a PV system.