针对磁悬浮高速电动机拖动系统中会存在较大的外部不平衡量问题，提出了一种基于最小均方差(Least mean square, LMS)的变步长算法实现工作转速范围内实时自动平衡方法。在自适应LMS算法抑制电流同频量的基础上,提出切换步长因子符号的控制策略实现工作转速范围内自动平衡，同时分析步长因子的选择在不同转速下实现同频电流抑制的效果。在此基础上，改进一种随转子位移信号频率变化而变化的变步长因子实现自动平衡。那么在开环系统截止频率前以及截止频率后能够实时性地让转子绕其惯性轴旋转，保证升降速过程中转子运行状况良好。试验结果表明所提出的方法能够实时并稳定实现转子工作转速范围内的自动平衡。

Because of a large number of external imbalances in the magnetically suspended high-speed motor drive system, an adaptive variable step-size least mean square (LMS) algorithm is proposed to achieve real-time automatic balancing in working speed range. A control strategy based on switching the sign of the step-size factor in adaptive LMS algorithm is proposed to suppress synchronous current in the full speed range. By analyzing the effect of synchronous current suppression in different speeds with different step-size factor, a modified variable step-size factor with changing frequency is improved. So the rotor is in good condition with rotating around its axis of inertial before and after the cutoff frequency of the open-loop system. Experimental results indicate it can stably achieve real-time automatic balancing in the working speed range.