DC microgrid energy optimization

Abstract

Microgrids that generate electricity using photovoltaic panels or wind turbines and batteries, provide a viable solution to meet low to moderate energy needs in rural, remote and informal settlements. However, these solutions are limited because they depend on the availability of sunlight or wind. To solve these limitations, researchers have proposed hybrid systems that combine multiple energy sources and can be more efficient than battery-powered photovoltaic or wind systems. These hybrid systems use dynamic dispatching to optimize the overall cost and performance of the microgrid. Energy management systems are widely used to achieve this dynamic energy distribution, including load profiling and intelligent decision-making for energy distribution. While many energy management systems focusing on automated demand side management have been deployed worldwide to optimize microgrids, less work has been done in South Africa. This research is focused on designing a hybrid PV-driven battery and fuel cell backup system, initially concentrating on sizing the PV, battery, and fuel cell. The focus then shifts to developing an energy management system. The proposed system follows a low-power provision in a 48 VDC format, offering electricity for lighting, computing, entertainment devices, and communication modules. Seven rural households were chosen for the study, collectively consuming 8.64 kWh/day. The efficacy of the microgrid is examined with and without demand-side management and considering the impact of load scheduling. The findings revealed that reducing energy demand by the demand side led to an increase in current and output power due to the proportional relationship between current and power, while the bus voltage remained constant at 48V DC. Furthermore, an increase in loads resulted in a decrease in output power. The simulation was carried out using the MATLAB® Simulink™ environment.