Control of storage elements in an islanded microgrid with voltage-based control of DG units and loads

Abstract

• Including storage elements in the VBD control, while taking into account their state of charge in the control structure. • Cooperation between DG units, storage elements and loads for islanded microgrid control in a coherent control structure. • Microgrid control, with storage elements and without communication, based on the droop concept for stabilizing the network. Because of their small scale and large share of intermittent power sources, islanded microgrids require additional means of flexibility, such as dedicated storage. For controlling the loads and distributed generation (DG) units in an islanded microgrid, the voltage-based droop (VBD) control has been developed. This controller determines the switching actions of these units’ power electronic interfaces in order to ensure a stable islanded microgrid operation. In this paper, the VBD control is extended for storage applications, taking into account the state of charge. As the VBD control automatically fixes the priority of power changes of the microgrid elements, the storage elements are included in this priority list without inter-unit communication. This benefits the coordinated integration of DG units in the system. Simulation examples are included illustrating the transient and dynamic response of the VBD control of all grid assets. The paper also provides an experimental validation of the VBD control for both the DG units and the storage elements in an islanded microgrid.