Structured H∞ design method of PI controller for grid feeding connected voltage source inverter

This paper presents a new Structured H_∞ Design Method of proportional-integral (PI) controllers for Grid Feeding Connected Voltage Source Converters, based on MATLAB tools for tuning linear control systems in the frequency domain. The study consists in elaborating optimization of an H_∞ robust control strategy for a Voltage Source Inverter (VSI) connected to the grid through a LCL filter. The PI controller parameters are tuned using hinfstruct optimization function from the MATLAB® Robust Control Toolbox. A synchronous reference frame PI regulation strategy is used for the grid current control loop. The design of PI is validated by simulations in MATLAB®/Simulink™ and the Simulation results prove the correctness and validity of the proposed control. The robust stability and performance of the closed-loop system are analyzed to illustrate the capabilities of the new technique.