Periodic Economic Control of a Nonisolated Microgrid

This paper presents the application of economic predictive control to minimize the cost of operating a nonisolated microgrid connected to an electric utility (EU) subject to a periodic internal demand. The microgrid considered is composed of a set of photovoltaic panels and two storage systems and it can buy and sell energy to an EU. The first storage system is composed of a cluster of batteries of lead acid, and the second storage system is based on hydrogen storage. A function that describes the economic cost of operating the plant taking into account aspects such as electric market costs, degradation of the microgrid, and amortization costs is proposed. Based on this cost and considering the periodic nature of the plant, an economic predictive controller capable of adapting to sudden changes on the cost function while guaranteeing stability and recursive feasibility has been successfully tested on a realistic nonlinear model of an experimental configurable testbed located in the laboratories of the University of Seville.