DC Microgrid Power Management by Cascaded PI Control of HESS

Abstract

The best alternative for fossil fuel generation is found from Renewable energy sources (RES). A Microgrid gaining hedge importance and is considered as a reliable solution for the expected deficiency in the power requirement. Microgrids generally consist of renewable power sources such as wind, solar and hydro. Those RES are a high potential source of power for future micro-grid systems but have low efficiency. However, the major drawback of Renewable energy sources (RESs) is the intermittent issue because of the rapid fluctuations in generation and most of the RES are highly nonlinear in nature. The main objective of this paper is to maintain the constant DC bus voltage irrespective of generation with appropriate control of the hybrid energy storage system (HESS). In this paper, A islanded DC microgrid having a primary source as PV integrated with a HESS is modelled. The hybrid energy storage system gives backup power support when the PV is unable to meet the demand with the help of a DC-DC bidirectional converter and maintained a constant DC bus voltage. A control strategy is proposed with cascaded PI. To ensure proper robust control two case studies are modelled and verified with simulation.