Coordinated energy management for an islanded microgrid with multi-energy and multi-storage units

Abstract

Battery energy storage system is an attractive solution for stand-alone microgrid to make up the intermittent power of renewable energy sources. However, most studies on energy management are focused on the one-battery-unit condition while two or more battery units are recommended for system redundancy. In this paper, a coordinated energy management scheme has been proposed for an islanded microgrid, which consists of multiple renewable energy sources, battery energy storage units with different capacity and auxiliary sources such as diesel generators. The scheme aims at global optimization for power control as well as the improvement of security and economy of system, which takes into account both the state of charge (SOC) constraint of battery units and the global optimization of maximum available power of distributed generations. In order to achieve the SOC balance, the idea of hierarchical processing is adopted that the multi-battery system has been classified into various charging/discharging priority based on the SOC and capacity of single unit. Furthermore, the maximal utilization of renewable energy and the minimal run time of auxiliary units are realized under the premise of satisfying the load demand. The effectiveness and functions of the proposed energy management scheme is verified by simulation results.