Robust State-Feedback Local Voltage Control for Islanded Uncertain DC Microgrids Using LPV Modeling

This paper proposes a decentralized robust primary voltage control scheme for autonomous DC microgrids (DCMGs) to achieve robust stability and robust performance. The studied microgrid consists of distributed energy resources (DERs), which are modeled with a linear parameter varying (LPV) structure, and each of them is assumed to have a local constant power load (CPL), constant impedance load (CIL), and constant current load (CCL). One of the main advantages of the suggested controller is the scalability of the design method and the full decentralized structure of internal voltage control. The suggested control unit ensures the robust stability and optimal performance of the islanded DC microgrid under different sources of uncertainties, which the LPV modeling approach can model. Every primary voltage control unit is obtained by computing a unique convex optimization problem, which leads to robust stability and optimal performance under various disturbances. In the first step, we consider a perturbed LPV state space model for each distributed generation (DG) and model various uncertainties at the vertices of a polytope. In the next step, we aim to achieve all control goals by designing a robust primary state-feedback controller for a polytopic-based linear time-invariant (LTI) system with pole placement constraints and
${{\boldsymbol{H}}}_\infty$
performance. Eventually, we convert the resulting optimization problem to a linear matrix inequality (LMI) problem and derive the primary robust voltage controller for DG units. To assess the effectiveness of the suggested robust controller, we have implemented several simulation scenarios in MATLAB.