Energy Management Control Strategy for Standalone DC Microgrids

Abstract: As the demand of Electricity is increasing day by day and is already more than the production of Electricity whereas reserves of fossil-fuel are depleting, there is a strong need to shift for other sources which are renewable energy sources. Regarding this, DC micro grids and their energy management of these renewable energy sources have gained more importance which is discussed in this paper. The main objective of the proposed system is to provide uninterrupted power supply to the load systems which are located at isolated sites of remote and rural areas. The proposed system mainly deals with implementation of Energy Management System (EMS) to DC microgrid using maximum power point tracking (MPPT) algorithm. A coordinated and multivariable EMS is proposed that employs a wind turbine and a photovoltaic array as controllable generators by adjusting the pitch angle and the switching duty cycles and a storage system consisting of batteries. In order to realize constant current, constant voltage (IU) charging regime and increase the life span of batteries, the proposed EMS require being more flexible with the power curtailment feature. The proposed strategy is developed as an online nonlinear model predictive control (NMPC) algorithm based on individual MPPTs of the system. The entire designed system is modeled and simulated using MATLAB/Simulink Environment.

Keywords: Battery Management, Maximum Power Point Tracking (MPPT), Nonlinear Model Predictive Control (NMPC), Power Sharing, and Voltage Regulation.