Robust MIMO Controller for Distributed Generation System-based Grid-tied Voltage Sourced Converter

Abstract

This paper presents a robust multi-input multi-output (R-MIMO) controller for voltage sourced converter (VSC) applied to grid-connected distributed generation system (DGS). The DGS-based VSC is coupled to grid network with LCL filter to alleviate high-frequency switching harmonics. The dynamics of the VSC-LCL-and grid system tend to disrupt operation of the grid-connected DGS-based power converter supplying active and reactive power to the grid. The proposed R-MIMO scheme is designed to overcome the adverse unstable operation of the DGS-based VSC-LCL under all grid conditions. Furthermore, the proposed R-MIMO controller inherently decoupled the real and reactive power while achieving the independent dq-axis grid current control without the need of the special LCL-active damping compensation schemes. The proposed R-MIMO scheme demonstrates robust performance over wide range of grid operating conditions and improved dynamic performance. Extensive computer simulations are conducted to confirm the efficacy of the proposed R-MIMO controller.