Modeling And Efficiency Optimization Control Of Scroll Expander

Wind power,photovoltaic and other renewable energy technologies have strong volatility and intermittence,which is the key element to restrict their large-scale development and application.And energy storage technology is an important way to solve these problems.Among them,compressed air energy storage as a physical energy storage method has become the current research focus in the field of energy storage for the advantages of long life,large capacity and low environmental cost.As the key equipment of energy conversion of compressed air energy storage system,the accurate modeling and optimal control of expander is very important to improve the overall performance of the energy storage system.Therefore,in this paper,the core energy conversion equipment scroll expander in the Micro-compressed air energy storage system,is taken as the research object.Based on the establishment of its accurate mathematical model to analyze the change rule of its expansion efficiency under different working conditions,and the efficiency optimization control strategy of the equipment is mainly studied.The main research work of this paper includes:A neural network modeling method for scroll expander is given.Firstly,to make error processing of the collected data,and then the neural network model of scroll expander is obtained by training the experimental data with long short-term memory.Finally,an analytical model for calculating the expansion efficiency is presented by fitting the output data of the neural network model.The simulation results show that the neural network modeling method can reduce the mechanism analysis process and modeling complexity of modelling process,improve the modeling accuracy.At the same time,it has a higher accuracy in the non data acquisition section,which can be used to accurately describe the variable operating conditions and optimal control of a scroll expander.Combined with thermodynamic exergy analysis,the ratio of the output power of the device to the maximum input power of the compressed air is calculated as the expansion efficiency of the scroll expander.On this basis,a detailed analysis is made for single unit expansion efficiency of scroll expander under different inlet temperature,inlet pressure and rotating speed,the variation of expansion efficiency is discussed when throttle loss and air leakage loss are taken into account,it provides a theoretical basis for the formulation of efficiency optimization control strategy.A hybrid efficiency optimization control strategy based on model control and tracking control for power generation system of scroll expander is designed.This strategy combines model control with trace control,Firstly,genetic algorithm is used to optimize the reference points of throttle pressure and rotating speed under load power.Then,using the variable step size maximum efficiency tracking control strategy near the reference point of rotating speed,the actual maximum expansion efficiency point under the current working condition is optimized.Finally,in the building of the compressed air energy storage experiment platform of the test results show that the proposed scroll expander power system efficiency optimization control strategy can control system in balancing the load power at the same time make the system run in high efficient area,both the control model of rapid and the accuracy of the tracking control,can effectively improve the overall energy conversion rate of compressed air energy storage system.