电磁驱动微器件动态吸合特性分析

Dynamic pull-in of magnetostatic micro-devices

电磁驱动微型器件的吸合特性一般是基于准静态假设进行分析,所建立的模型与实际开关工作过程有偏差,因此建立更接近其实际工作情况的动态吸合模型,有助于指导开关器件的设计与控制.在忽略阻尼且考虑磁芯磁阻的情况下,以能量法为基础分析了阶跃磁动势驱动时两种器件的动态吸合特性.结果表明:竖直式结构的动态临界吸合位移值是准静态值的1.5倍,其产生动态吸合现象所需的阶跃磁动势幅值为准静态模型的91.9%;旋转式结构的动态临界吸合角度值比准静态模型值大29%到46%(随磁芯磁阻减小而增大),所需的临界阶跃磁动势幅值为准静态模型的91.2%.

The analysis of the pull-in of magnetostatic micro-devices （MMD） has been done using quasistatic assumptions traditionally. The models established are not exact enough because of the dynamic characteristics of the devices. So it is necessary to establish the dynamic models, which will be more suitable to the normal and could help the design and control of the micro-devices. Based on the energy balance equations, the dynamic pull-in characteristics of two MMD with the step input magneto motive force are analyzed, with the reluctance of the magnetic core m considered and the effect of system damping neglected. The results indicate that as to the parallel-plate device, the critical dynamic pull-in displacement of the mobile part is 1.5 times that when quasi-static pull-in occurs;as to the torsional device, the critical dynamic pull-in angle increases with the decrease of m, and changes from 1.29 to 1.46 times that when quasi-static pull-in occurs. The critical step inputs MMF of the two MMD are about 91.9 % and 91.2 % the quasi-staticallv predicted pull-in MMF of each MMD respectivelv.