Phase-locked loop-less current controller for grid-connected photovoltaic systems

Abstract

A current controller suitable for three-phase photovoltaic systems is presented. The proposed controller ensures the injection of sinusoidal and balanced currents, with high immunity to both imbalances and harmonics present in the supply voltage, without using a phase-locked loop to synthesise the reference currents to be injected. A fully digital domain controller design is proposed, that takes into account the digital signal processing delay as part of the system to stabilise.