精密磁浮运动系统电磁力的非线性建模分析

Nonlinear Modeling and Analysis of Magnetic Force in Precision Magnetic Levitation System

为了对磁悬浮运动系统中电磁力进行精确建模,运用磁路理分析气隙边缘效应、铁芯磁阻效应和磁路漏磁通对电磁力模型的影响.推导并给出不同情况下电磁力模型的表达式,绘制不同电磁力模型之间的误差曲线.从图形曲线及定点计算数据中可以得出3点主要结论.(1)仅考虑气隙边缘效应时,对电磁力模型的精度影响较大.(2)漏磁通对模型的影响较小,同时考虑3种因素影响时的曲线和不考虑漏磁通效应影响时的曲线非常相近.但这并不说明磁路中漏磁通量很少.(3)随着悬浮气隙的增大,按理想磁路理论建立的简化电磁力表达式计算的磁动势,与同时考虑气隙边缘效应、铁芯磁阻和漏磁通时的表达式计算结果之间的误差也不断增大,会对系统的控制产生较大的影响.

In order to get accurate modeling of the electromagnetic force in the magnetic suspension system, the rationale of magnetic circuit is used to analyze the impact of the fringing effect of air gap, the magneto resistive effect of iron core and magnetic circuit magnetic flux leakage on electromagnetic force model. The expressions of electromagnetic force model are derived under different conditions, and the corresponding error curves are plotted. Then 3 conclusions can be drawn, as following： firstly, the accuracy of the electromagnetic force model is influenced greatly if only the air-gap fringing effect is considered; secondly, because of small influence of the magnetic flux leakage on the accuracy of the electromagnetic force model, there is little difference between the curve for the electromagnetic force model under the condition of considering the 3 kinds of factors mentioned above and that without considering the magnetic flux leakage, but it can not be concluded that there exists few magnetic flux leakage; thirdly, with the increase of the air-gap, the errors also increase between the results of the magnetic momentum calculated by the simplified expression of the electromagnetic force model according to the ideal magnetic circuit theory and those calculated by expression when the air-gap fringing effect, the magneto resistive effect of iron core and magnetic flux leakage are taken into account together, which will have a great impact on the control of the suspension system.