Research On Optimal Sizing And Energy Management Of DC Micro-grid

In recent years, in order to improve the energy structure, renewable energy and distributed generation are widely used, the micro-grid has been developed rapidly. AC micro-grid is the main section of research in micro-grid, but with a large number of DC load s and DC distributed generations are put into use in daily life, DC micro-grid showing unique advantages. In this paper, an improved differential evolution algorithm and fuzzy control maximum membership principle are used to solve the optimal sizing and energy management model of selected DC micro-grid system, at the same time, the power allocation method of hybrid energy storage system in DC micro-grid also been studied, The main contents are as follows:Select a DC micro-grid structure, detailing the different types of distributed generations, study their characteristics and equivalent model. And propose a power allocation scheme based on battery’s phased constant power discharge for the hybrid energy storage system contains of battery and super capacitor, which can make full use of battery and super capacitor’s advantages and extend battery’s use life in the case of storage needs of the DC micro-grid have been meet.Establish an optimal sizing model in the DC micro-grid system, based on the total load data and environmental factors all year, set the type and capacity of distributed generations as variables, consider a variety of constraints, set the lowest annual costs of investment and operating as target. Chose improved differential evolution algorithm to solve this model under the environment of Matlab. The optimal sizing result of DC micro-grid with single energy storage and hybrid energy storage systems are obtained and analyzed, provide references for the actual construction of DC micro-grid, and verify the superiority of the hybrid energy storage system.Establish a energy management model in the DC micro-grid system, set the power output of each distributed generations in typical day ’s micro-grid operation as optimization variables, set the costs of operation and maintenance and loss of power supply probability as targets, the model’s solving also based on the improved differential evolution algorithm. Firstly, use multi-objective non-inferior sort to obtain a series of Pareto solutions of micro-grid operation, then use the maximum membership degree principle of fuzzy control access the single solution with the greatest overall satisfaction between economy and reliability, prove that the micro-grid operation can get effective compromise between economy and reliability, through the analysis of the operation status corresponding to the optimal solutions, the energy management optimization method proposed was verified to be rationality and practicability.