A New Approach to H-Infinity Control for Grid-Connected Inverters in Photovoltaic Generation Systems

The present study investigates the stability problem of the grid-connected inverters (GCIs) for possible variations in grid impedance. A new type of H infinity control method is proposed for the current control loop of inverters, where the third weighting function is determined using the game theory. The proposed method is applied to the GCI in a photovoltaic system and its response to variations in grid impedance is investigated. Computer simulations conducted for comparison of H infinity and PI controller indicate the effectiveness of the proposed control algorithm. Simulation results also show that the proposed algorithm significantly outperforms the PI controller under the conditions of varying grid impedance.