Robust state feedback current controller with harmonic compensation for single stage grid connected PV inverter with LCL filter

The paper presents the robust state feedback output current controller for single stage grid connected photovoltaic array (PV) inverter interfaced to grid through LCL filter. The robust state feedback current controller is based on mixed H2/H with regional pole placement constraints approach. The controller enhances the system performance and robustness to grid disturbances as well as also enhances the power quality with the help of robust harmonic compensator utilizing resonant controller tuned for fundamental, 5 th and 7 th harmonics. It also mitigates the need of passive damping for LCL resonance. The state feedback current control is formulated in stationary reference frame and obtained by solving linear matrix inequalities (LMI). Simulation results tests the controller performance under different solar irradiance and linear load conditions as well as grid voltage disturbances.