Voltage control for uncertain stochastic nonlinear system with application to energy Internet: Non-fragile robust H∞ approach

Abstract

In this paper, a robust control method is used to intelligently regulate the DC bus voltage deviation for an islanded microgrid (MG) within the scenario of energy Internet (EI). In order to cope with the uncertain and nonlinear nature of the power exchange in EI, a new mathematical model is formulated to present the dynamics of the islanded MG, where the state equation is expressed by a class of nonlinear stochastic differential equations (SDEs) with parameter uncertainties appearing in system coefficients and the controllers. Specifically, the nonlinearities appear in both drift and diffusion parts of such SDEs. Our aim is to design a controller such that the effects of the modelling uncertainty and the external disturbance to the DC bus voltage of the off-grid MG are minimized. Mathematically, this can be regarded as problems of solving the non-fragile robust stochastic stabilization and non-fragile robust H∞ control, both of which can be solved via the linear matrix inequality (LMI) approach sufficiently. We emphasize such new control system with its solution can also be applied into fields of industry, economics, etc. Based on real world data, numerical results are illustrated, and simulations show that our target is achieved.