A class of optimal and robust controller design for islanded microgrid

Abstract

This paper proposes a class of optimal and robust controller for the islanded AC microgrid (MG) system which is composed of wind turbine generator (WTG), photovoltaic generator (PV), fuel cell (FC), micro turbine (MT), battery energy storage (BES) and loads. The proposed controller has two main functions: rationally utilizing MT, FC and BES, and regulating the AC bus frequency deviation. For such islanded MG, we formulate the control system via a group of ordinary differential equations (ODEs), where we consider the power of wind and solar radiation as system disturbance inputs. The control input is designed in MT and FC. The AC bus frequency deviation is denoted as the system controlled output. The problem of rationally utilizing MT, FC and BES is formulated as an optimal control (H 2 control) problem, whereas the frequency regulation issue is formulated as an H œ control problem. Our aim is to find a controller such that both H 2 and performances are achieved, which can be viewed as solving a mixed H 2 /H m control problem. We solve it analytically via the Nash game approach. Finally, based on real-world data, numerical results are illustrated, and simulations show that our target is achieved.