Study On The Storage Characteristics Of Off Grid Wind Power System Based On Exergy Balance Model

Wind energy,as a clean and pollution-free renewable energy,has attracted the attention of all countries in the world.The wind power industry is developing at an unprecedented speed,especially the small and medium-sized off grid wind power generation system plays an increasingly important role in wind power generation.However,due to the randomness and instability of wind power,the output power quality of wind power generation system is not high,and the system productivity efficiency is low,which seriously restricts the development of wind power industry.With the development of energy storage technology,applying energy storage technology to wind power system can improve the efficiency of energy utilization and power quality.Aiming at the low power quality and system efficiency of wind power system,this study takes off grid wind power system as the research object,uses energy storage technology,and adopts the method of combining experiment and simulation to study the power storage characteristics of wind power system.Firstly,the wind power system test platform is built,in order to better understand the matching characteristics of wind turbines and the impact of wind turbines on power quality,the wind tunnel test is carried out;at the same time,in order to determine the difference and connection between the charging and discharging characteristics of lead-acid and lead-carbon batteries,the battery charging and discharging experiments are carried out;then,the simulation model of wind power system is established by using Matlab / Simulink software to determine the power stored in the wind power system In addition,according to the selected power quality index,carry out the comparison experiment with or without energy storage device,and combine the simulation results to explore the specific effect of energy storage device on improving the power quality of the system;finally,establish the wind power system exergy balance model based on exergy analysis method,in order to determine the loss of each part of the system,carry out the system exergy characteristic acquisition experiment Then determine the influencing factors of the efficiency,and use the weight analysis to explore the influence degree of each factor on the efficiency of the system,combined with the multi-objective optimization method to propose optimization measures.The specific research contents are as follows:1.Analysis on the matching performance of wind turbine and the influence of wind turbine on power quality.Using wind tunnel to explore the matching characteristics of wind turbine,provide guidance for motor to replace wind turbine,and analyze the impact of wind turbine on power quality index,so as to provide theoretical guidance for energy storage experiment to explore the impact of energy storage on power quality.2.Analysis of battery charging and discharging characteristics.The lead-acid battery and lead-carbon battery are respectively connected to the wind power system to conduct the battery charge and discharge data collection experiment,specifically comparative analysis of the battery charge and discharge current,terminal voltage and state of charge changes,in order to provide data support for the experimental and simulation parameter settings and subsequent analysis.3.Wind power system simulation analysis.According to different modules,the wind power system simulation model is established,and through the simulation of the system operation,the changes of battery current,terminal voltage and state of charge in the system operation are analyzed,the mechanism of its effect on the system and the user end is further explored,and the power quality(voltage fluctuation D,voltage deviation,frequency deviation,power factor cos? four indicators)is extracted and processed It is used for the comparative analysis of power quality simulation and experiment.4.Analysis of the impact of energy storage on power quality.Based on the simulation results,four power quality indexes,voltage fluctuation,voltage deviation,frequency deviation and power factor,are analyzed to find out their changing rules.5.Analysis and optimization of the impact of energy storage on the efficiency of wind power system.Based on the second law of thermodynamics,this paper analyzes the effective energy of wind power system by means of exergy analysis method,establishes the exergy balance model of wind power system,analyzes the exergy loss distribution of the system,arranges the exergy characteristic collection experiment of the system in combination with exergy balance model,determines the influencing factors of the system exergy loss,and probes into the influence degree of each influencing factor on the efficiency of the system by means of weight analysis,and then uses the response surface method(RSM)Combined with the multi-objective genetic algorithm(MOGA),a multi-objective optimization method is proposed to optimize the operation conditions.