Combinational control scheme for utility interactive inverter system

This paper addresses a comparative performance analysis for a grid connected Photovoltaic (PV) inverter system using Proportional Resonant (PR), Modified Repetitive Controller (MRC) and combinational PR-MRC schemes under unbalanced and distorted grid voltage scenarios. An additional advantage of the PR controller compared to Proportional Integral (PI) is its ability to compensate multiple harmonics by adding a harmonic compensator. Using MRC controllers, the converter reference tracking performance can be enhanced and short comings associated with conventional RC controller can be alleviated. The idea behind using PR-MRC scheme is that combined desirable features can be derived from PR and MRC techniques that improve tracking error and harmonic compensation. The simulated results demonstrate the better effectiveness and feasibility for accurate current controller under variation of transient load conditions.