混合磁悬浮系统零功率抗偏载控制方法研究

Research on Zero Power and Resisting Eccentric Load Control Method of Hybrid Magnetic Levitation System

针对混合磁悬浮洁净传送装置无法兼顾零功率和抗偏载悬浮的问题,提出一种磁铁可动式混合磁悬浮系统,并设计了其零功率抗偏载控制策略。该系统中一个磁极固定,其他两个磁铁可绕悬浮圆盘中心轴线转动,通过调节气隙长度和磁铁转动角度克服偏载引起的扰动力和扰动力矩,从而实现零稳态电流和抗偏载悬浮。首先建立系统的线性变参数模型,分析该系统实现零功率水平悬浮需要满足的条件。零功率抗偏载控制策略在比例-微分控制器中引入电流和气隙偏差的积分反馈,并应用质心观测器反求磁体转动角度,求解方法分别采用雅可比逆变换解析求解和查表法内插取值两种方法。试验结果表明,该系统能够在偏载条件下保持零功率水平悬浮,应用雅可比的连续控制策略具有更好的纠偏特性,稳态时电流波动范围小。

To solve coexistent problem of zero-power and resisting eccentric load in the clean transmission system using hybrid magnetic levitation,a novel system structure with the movable magnet unit is proposed and concomitant control strategies are designed.One magnetic pole is fixed,while the other two can rotate around the central axis of the levitated plate.Under levitation with the eccentric load,the zero-power and horizontal levitation could be realized by adjusting air gap to overcome the disturbance force and changing the position of magnet to counteract the moment introduced by eccentric load.Firstly,the linear parameter-varying model is established,and the conditions for the system to achieve zero power horizontal suspension are analyzed.The zero-power control strategies with resisting eccentric load introduces the integral feedback of current and air gap deviation in the proportional-differential controller,and uses the centroid observer to reverse the rotation angle of the magnet.The solving methods are implemented by inverse Jacobian transform matrix and look-up table with interpolation respectively.The experimental results show that the system can maintain zero power horizontal suspension under eccentric load.In terms of rectifying deviation and fluctuation of steady-state current,the continuous control strategy using Jacobi is superior to the discrete look-up table strategy.