Robust ℌ∞ control for grid connected PWM inverters with LCL filters

This paper provides a robust control design based on linear matrix inequalities applied to PWM inverters with LCL filters connected to the grid under uncertain parameters. The proposed controller ensures: i) closed-loop robust stability against parameter uncertainty; ii) robust pole location with a prescribed ℌ_∞ guaranteed cost; iii) tracking of sinusoidal reference and rejection of disturbances. Simulation and experimental results show good transient and frequency responses for the closed-loop system, as well as limits of robust stability.