适合变速转子的不平衡质径积搜索电磁轴承振动抑制

Vibration Suppression by Seeking Unbalance Mass-radius Product in Active Magnetic Bearing-rotor System with Varying Speed Condition

转子不可避免地存在质量不平衡是转子运行产生同步振动的主要原因。一种适合在变速条件的电磁轴承转子不平衡控制方法被提出。该方法能够自适应地搜索转子不平衡质径积的大小和方位,并以此为依据产生控制信号,抑制转子振动,强迫转子绕其几何中心旋转,提高转子的旋转精度。不平衡质径积是转子的固有特性,与转速无关。与基于不平衡力的控制方法相比较,在跟踪变速引起的不平衡力剧烈变化时,基于不平衡质径积的控制方法不需要频繁更新控制参数,只需要为克服系统非线性而调整控制参数。同时,该方法能根据振动抑制误差调节搜索步长,调和了搜索速度和控制精度的矛盾。试验表明,所述方法能够有效抑制转子的不平衡振动,并且在变转速条件下,大幅降低控制器的计算负荷,提高在快速变速、转子过临界等转子振动随转速变化较快应用场合的控制性能。

The undesired synchronous vibration due to rotor mass imbalance is a main disturbance source in all rotating machinery. In this research, a novel unbalance compensation method is proposed for the active magnetic bearings-rigid rotor system. It can force the rotor to spin around its geometric axis for the better rotary precision by means of producing the control signal according to seeking the unbalance mass-radius product of the rotor, which is suitable especially for the varying speed condition. The control methods based on the unbalance force must continually update its control to track the varying unbalance force due to the varying speed. In contrast, the unbalance mass-radius product is the inherent property of the rotor and independent of the rotor speed. The method based on the mass-radius product updates its control only for overcoming the system nonlinearity. Additionally, the seeking step size in the proposed method is variable to reconcile the contradiction between the seeking efficiency and the control precision. The experiments indicate that the proposed method achieves the good effectiveness to suppress the rotor vibration. It has the lower computational cost and suitable for the condition of crossing the critical speed and fast varying-speed.