Energy Optimization Of Stand-alone Wind-solar Hybrid System Based On Multi-objective Evolutionary Algorithm

Renewable energy is a important direction of the world future economy and energy development. Microgrid can operate in parallel to the grid or in island.For some remote mountains and islands of isolated zone,microgrid can not only solve the power supply problem of local, and can reduce the cost of a large number of power infrastructure,which improves the living standards in those areas.The microgrid systems with wind power, photovoltaic and energy storage battery is a major component in new energy demonstration projects,that will be the research object in this paper,which includes three parts:(1) Improvement of multi-objective differential evolution algorithm.In order to avoid falling into local optimum, improve convergence rate,and simulate the natural evolutionary process.This paper introduces Chaos Theory,Weighted Sum and Parameter Adaptive to the differential evolution algorithm that based on decomposition.Finally,it achieves improved results by testing function.(2) Economy and reliability capacity configuration of distributed sources in standalone microgrid. this part analyzes operating characteristics of micro-sources respectively and builds system’s economy and reliability target functions,then studies capacity optimization configuration of the micro-sources adopting IMOEA/D,Finally this paper compares the results that obtained by IMOEA/D to other multi-objectives evolutionary algorithm such as SPEA,NSGA-Ⅱ,MOPSO and NNIA.(3) The MATLAB/Simulink simulation of distributed sources based on energy optimization control. Guided by the principle of making the most use of renewable energy,this paper builds MPPT model that based on variable-step P&O of photovoltaic power and wind generator,and energy management model of battery,which can improvethe utilization of renewable energy and power quality of system.This paper applies the IMOEA / D to the actual project, economic cost obtained by IMOEA/D is less than the results by other algorithms based on same reliability.Meanwhile the results variable-step MTTP obtained prove that it can improve efficiency and stability of system,becauese it’s tracking time and fluctuations generated in the tracking process are better than fixed-step MTTP. Finally, the battery control technology can make the output voltage within the desired voltage range, and can realize the charging and discharging mode conversion and control.