An LMI Approach to Robust$H_{infty}$Guarantee Cost Control for LLCL-filtered Inverters Connected to a Weak Grid

摘要

This paper adopts a polytopic model to describe a parametric uncertain system and then proposes a direct grid current robust$H_{infty}$guarantee cost controller based on linear matrix inequalities (LMIs) for the three-phase LLCL-filtered grid-connected inverters. The$H_{infty}$controller is designed to assure robust stability and an upper bound on$H_{infty}$performance of the closed-loop system under grid impedance uncertainty and grid voltage distortion conditions. The simulation and experimental results compared with other two robust controllers with a 9.1-kW three-phase LLCL-filtered grid-connected inverter validate the feasibility and superiority of the proposed method.