Study of Energy Control Strategies for a Standalone PV/FC/UC Microgrid in a Remote

Abstract

Remote (or rural) area electrification is one of the main concerns, especially in developing countries . This paper presents a detailed investigation of different energy control strategies for a standalone microgrid in a remote area . In this microgrid, solar energy is considered as the primary energy source. Besides, taking into consideration stochastic nature of PV systems, a backup system that comprises a fuel-cell stack is hybridized, to avoid lack of energy and improve the reliability of the load. A battery bank and a supercapacitor pack are integrated as storage units along with an electrolyzer, as an alternative for energy storage. The electrolyzer absorbs the surplus energy production of the PV system if the battery bank reaches the maximum state of charge. Refueling the fuel-cell system with the stored hydrogen and meeting the average demand shortage, when the PV production is not sufficient, protects the battery bank against overcharge and deep discharge. In this paper, the main purpose is studying the energy control strategies that have high response time. These strategies, that are employed to control the energy flow, the fuel consumption, the dynamic performance, the microgrid efficiency, the battery/supercapacitors SOC, the energy sources/storage units life span and etc., include: the state machine control strategy, the rule-based fuzzy logic control strategy, the ANFIS-based control strategy, the equivalent consumption minimization strategy, the external energy maximization strategy, and the PI-type fuzzy logic control strategy. An effective approach is used to design the state machine control strategy and the rule-based fuzzy logic control. Additionally, the performance of all the energy control strategies, during different battery SOCs, is investigated. Finally, simulation results and the performance comparison of all the strategies, under different operating conditions, are presented. Factors such as the fuel consumption, the fuel (and the fuel-cell) efficiency, and the battery (bank) state of charge, are used for assessment.