In a magnetically suspended rotor (MSR) system, harmonic current mainly caused by mass imbalance and sensor runout would produce harmonic vibration. Repetitive control (RC) is one remarkable approach for eliminating such harmonics. Conventional RC (CRC) attempts to compensate for all frequency components simultaneously. However, in the practical MSR system, it is usual that the current comprises only odd-harmonic components. This paper investigates a modified odd-harmonic RC (MORC) scheme to respond to this issue. The signal generator of arbitrary-order discrete-time periodic signal is established, by which the general forms of CRC and ORC can be obtained. Besides, it is proved that ORC with halved data memory possesses a faster convergence rate, higher repetitive gain, wider frequency bandwidth at the targeted frequency and greater robustness to frequency fluctuation than CRC. The stability criterion for the MORC-controlled MSR system is proved as well. Simulation and experimental results have highlighted the effectiveness of the proposed approach.

中文翻译：

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磁悬浮转子系统奇次谐波电流抑制的改进重复控制


在磁悬浮转子（MSR）系统中，主要由质量不平衡和传感器跳动引起的谐波电流会产生谐波振动。重复控制（RC）是消除此类谐波的一种出色方法。传统的 RC (CRC) 尝试同时补偿所有频率分量。然而，在实际的MSR系统中，电流通常仅包含奇次谐波分量。本文研究了一种改进的奇次谐波 RC (MORC) 方案来解决这个问题。建立了任意阶离散时间周期信号的信号发生器，得到了CRC和ORC的一般形式。此外，事实证明，数据存储器减半的ORC比CRC具有更快的收敛速度、更高的重复增益、更宽的目标频率带宽以及对频率波动的鲁棒性。 MORC控制的MSR系统的稳定性判据也得到了证明。仿真和实验结果凸显了该方法的有效性。