Flexible PQ control for single-phase grid-tied photovoltaic inverter

This paper presents a flexible control technique of active and reactive power for single phase grid-tied photovoltaic inverter, supplied from PV array, based on quarter cycle phase delay methodology to generate the fictitious quadrature signal in order to emulate the PQ theory of three-phase systems. The investigated scheme is characterized by independent control of active and reactive power owing to the independent PQ reference signals that can satisfy the features and new functions of modern grid-tied inverters fed from renewable energy resources. The study is conducted on 10 kW PV array using PSIM program. The obtained results demonstrate the high capability to provide quick and accurate control of the injected active and reactive power to the main grid. The harmonic spectra of power components and the resultant grid current indicate that the single-phase PQ control scheme guarantees and satisfies the power quality requirements and constrains, which permits application of such scheme on a wide scale integrated with other PV inverters where independent PQ reference signals would be generated locally by energy management unit in case of microgrid, or from remote data center in case of smart grid.