永磁电动悬浮多工况下的电磁力特性研究

Investigation of Electromagnetic Force Characteristics of Permanent Magnet Electrodynamic Suspension under Multi-Operation Conditions

永磁电动悬浮系统由于自身弱阻尼的特点,运行过程中磁体的姿态易受外界扰动而发生改变,从而影响系统的电磁力特性。该文针对磁体倾斜、横移、偏转等工况,采用解析计算、仿真分析、实验验证相结合的方法来研究系统电磁力特性。首先阐述系统的结构及原理,推导Halbach永磁体阵列在水平、倾斜、偏转状态下的磁场分布函数,建立适用于系统多工况的三维解析模型;其次,搭建三维仿真模型,仿真结果验证了解析模型的正确性,并结合解析模型对比分析系统典型工况下的浮阻特性和悬浮能力;最后,依托组内自研的最高设计时速为600km/h的动轨实验台,分析了系统在固定参数下的电磁力特性和垂向自稳定能力,并验证解析模型的准确性及磁体在不同横移位置的电磁力特性。

Due to the weak damping properties of permanent magnet electrodynamic suspension(PMEDS)system,the position and orientation of the onboard magnets are easily disturbed under external forces,thereby affecting the electromagnetic force characteristics of the system.Several studies have been carried out on the electromagnetic force characteristics of the PMEDS system under a normal condition in which magnets are in a horizontal state.The influence of the position and orientation of the magnets on the electromagnetic force characteristics is rarely considered.To investigate the electromagnetic force characteristics under various typical operating conditions such as magnets tilt,lateral deviation,and deflection,a comprehensive analysis is performed through analytical calculations,simulation analyses,and experimental verifications.Firstly,the fundamental structure and principles of the PMEDS system are introduced.Then,the magnetic field distribution functions for Halbach permanent magnet arrays in horizontal,tilted,and deflected states are derived using the Biot-Savart Law,as well as coordinate translation and rotation transformation.Based on the magnetic vector potential,a comprehensive three-dimensional analytical model is developed to accommodate various operating conditions.Secondly,a three-dimensional finite element simulation model is developed.The comparison between the analytical calculations and simulation results for magnetic field and electromagnetic force under identical parameters demonstrates the accuracy and reliability of the analytical model.Combined analytical calculations with simulations,the levitation-drag characteristics of the system are analyzed at different air gaps,as well as the influence of air gap and conductive plate width on levitation and drag forces under the normal condition.The results reveal that the PMEDS system exhibits vertical self-stability ability,and the evolution of levitation and drag forces with air gap follows an exponential function.With the increasing conductive plate width,the levitation force initially increases and then stabilizes,while the drag force first increases and then decreases.Furthermore,the influence of magnet tilt,deflection and lateral deviation on the electromagnetic force are analyzed.Compared with the normal condition,the levitation force and drag force increase slightly under the magnets tilt condition.Additionally,the lateral force is generated.With increasing speed,it increases first and then decreases.As the tilt angle increases,the levitation force,drag force and lateral force all increase.When the magnets are deflected,the levitation force and drag force decrease,with a further decrease as the deflection angle increases.Lateral deviation of the magnets from the conductive plate generates a lateral force,exacerbating the deviation.The lateral force increases with the increase of the speed and tends to be stable.As the deviation distance increases,both the levitation force and drag force linearly decrease,while the lateral force initially increases and then decreases,reaching its maximum at approximately one-third of the magnet width.Finally,using a high-speed rotary test rig with a maximum design speed of 600 km/h,the electromagnetic forces under various speeds at the given air gap are tested under normal and deviated conditions.By comparing the results from analysis,simulation and experiment,the accuracy of the analytical model and simulation is verified.Besides,the electromagnetic forces under vertical and lateral movement of magnets are also tested.The results confirm the vertical self-stability ability of the PM EDS system and the variation of electromagnetic forces with lateral deviation distance.