Gain-scheduled control of a magnetic bearing with low bias flux
Gain-scheduled control of a magnetic bearing with low bias flux
复制标题
低偏置磁通磁轴承的增益调度控制
DOI：
10.1109/cdc.1997.650659
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Charles Yang
中科院分区：
文献类型：
--
作者：
C. Knospe;Charles Yang
传统的主动磁轴承(AMB)使用偏置电流(或磁通)来实现更大的线性度和动态能力。然而，偏置会导致不希望的旋转损失和随之而来的转子发热。研究了低偏置磁悬浮轴承的增益调度控制问题。研究了由一个质量和两个相对的电磁铁组成的单自由度系统。通过对二次型和控制输入饱和非线性进行线性化，将非线性系统表示为准LPV(线性参数变)系统。增益调度控制器保证在一定的输入饱和范围内的性能。然后将闭环系统变换为具有共享线性时变(LTV)不确定性和非共享线性乘性时不变(LTI)不确定性的线性分数变换(LFT)形式。稳健分析包括通过迭代求取两个极小值的上界，即a/spl u/分析问题和比例L/SUB 2/Gain问题。所开发的技术也可以应用于许多其他应用，其中包括具有控制输入限制的相反的二次型致动器。
Conventional active magnetic bearings (AMB) use a bias current (or flux) to achieve greater linearity and dynamic capability. Bias, however, results in undesirable rotating losses and consequent rotor heating. Gain-scheduled control of a magnetic bearing with low bias is investigated. A single degree-of-freedom system consisting of a mass and two opposing electromagnets is considered. The nonlinear system is formulated as a quasi-LPV (linear parameter varying) system by linearizing the quadratic and the control input saturation nonlinearities. The gain-scheduled controller guarantees performance over a certain range of input saturation. The closed loop system is then transformed into linear fractional transformation (LFT) form with shared linear time varying (LTV) uncertainties and unshared multiplicative linear time invariant (LTI) uncertainty. The robust analysis consists of finding an upper bound via iteration between two minimizations, namely, a /spl mu/ analysis problem and a scaled L/sub 2/ gain problem. The techniques developed may also be applied to many other applications which contain opposing quadratic actuators with limits on control input.