Research On Design And Optimization Of Homopolar Hybrid Magnetic Bearings For Flywheel Energy Storage

In recent years,energy issues have become a common topic of concern in countries around the world,among which the development and benefit of energy storage technology has become the hot topic of research.Because of the advantages of flywheel energy storage device,such as fast charging and discharging speed,strong environmental friendliness and long cycle life,it has become the research object of scholars in various countries.As the key component of the supporting system of flywheel energy storage device,the performance of magnetic bearings will directly affect many key performance of flywheel energy storage device.Given that the working environment of the flywheel energy storage device is a vacuum state,its heat dissipation conditions are poor,and the heat caused by the loss will seriously affect the reliability of the flywheel device operation.In the project,the permanent magnet biased hybrid magnetic bearing(HMB)with low loss is taken as the research object,and related research is carried out around its operating principle and mathematical model,loss and temperature rise,and key parameter optimization design.Firstly,several typical HMBs are analyzed,and the homopolar hybrid magnetic bearing(HOHMB)for flywheel energy storage is taken as the key research object,and its structure and working principle are introduced.Considering that the magnetic flux leakage phenomenon is neglected when modeling the suspension force of the magnetic suspension bearing in the past,resulting in a low accuracy of the suspension force model.In order to solve this problem,the mathematical model of the suspension force is derived by taking the edge effect into account.At the same time,the structure parameters are designed,and the electromagnetic performance is verified by the finite element software.Secondly,the calculation method of iron loss and copper loss of magnetic bearing is given,and a three-dimensional finite element loss analysis model is established based on the initial structural parameters of HOHMB.The finite element analysis software is used to analyze the core loss of HOHMB at different rotating speeds,and the core loss distribution of different rotating speeds is obtained.The analysis of the HOHMB loss lays the foundation for the temperature field research.Then,the finite element theory of temperature field analysis is introduced,and three ways of heat conduction are described.According to the basic theory of heat transfer,a three-dimensional finite element temperature field analysis model of HOHMB is established,and the calculation method of thermal parameters and heat dissipation coefficient is given.Based on the loss analysis,the temperature field of HOHMB under natural and vacuum conditions is analyzed.The results show that the temperature rise under vacuum condition is greater than that under natural conditions.Finally,based on the initial design,combined with the analysis of loss and temperature field,a multi-objective optimization design method based on GAPSO algorithm is proposed.In the multi-objective optimization of GAPSO,the parameterized model of HOHMB is established,the optimization function with the objective of suspension force,loss and volume is constructed,the corresponding optimization variables and constraints are determined,and the optimal structural parameters of HOHMB are obtained.The electromagnetic and temperature rise of the optimized HOHMB are analyzed.The analysis results verify the rationality and effectiveness of the optimization method.