Hybrid control strategy of grid-tied inverter for harmonic and reactive power compensation

In this paper, a photovoltaic inverter control strategy with harmonic suppression is proposed for the power quality problem of micro-grid with PV. The reference current is composed of the harmonic detection and DC side voltage regulation. Considering the limited capacity of the inverter in practical application, a control priority developed for the composite function of PV inverter to guarantee the whole active power transferring and the flexible harmonic compensation partially. The instantaneous active power component, the fundamental positive sequence reactive component and the harmonic component are detected by generalized theory of the instantaneous reactive power to realize the strategy. In the normal operation, the proposed control strategy of the PV inverter can suppress the harmonic current on the grid side and compensate reactive power besides transferring the active power. The proposed control strategy could improve the power quality and maximum utilization of the inverter greatly. The simulation results verify the effectiveness and feasibility of the proposed strategy.