Design of State Observer for a Grid-Connected Inverter with LCL Filter using a Hybrid-SOGI Resonant Controller

The preliminary premise of Observer Design for a three-phase grid-connected VSI with LCL filter is the necessity of reducing the number of sensors used to measure the various physical parameters of the overall system. These parameters are mainly measured for the purpose of real-time display (RTD) through any graphic user interface (GUI) or any other display methodologies and also to implement feedback or feedforward control algorithms. In this paper, a full-state observer is designed and incorporated with Hybrid-SOGI Resonant Controller for reference tracking and also Independent Active and Reactive Power Control at the point of common coupling (PCC) even with harmonic polluted grid.