撓性轉子磁浮軸承系統之研究與控制

Abstract

在使用磁浮軸承系統的渦輪分子真空幫浦轉子中，幫浦轉子在低速旋轉下可視為剛性。實際上渦輪分子真空幫浦之工作轉速高達上萬轉，此時幫浦轉子轉速已經接近第一自然振動頻率，甚至達到第二自然振動頻率。幫浦轉子因共振而產生的撓性變形，以及轉子質心不在幾何中心上，偏心力也會激發主軸撓性振動，對於外界干擾的影響下，甚至會激發幫浦轉子高頻振動。 本篇論文旨在用兩種控制理論（Observer-Based Control，Integral control），將其應用在主動型磁浮軸承支撐之撓性轉子系統上，使磁浮撓性轉子系統動態穩定，利用控制器加以回授補償，使主軸在旋轉時能更穩定以及避免轉子在突破臨界轉速時因產生撓性共振而與磁浮軸承相互碰撞。且以Matlab之函式庫Simulink模擬磁浮軸承系統遭遇偏心力、重力影響及硬體設備限制，使受控之撓性轉子磁浮軸承系統能抵抗上述之影響而穩定達到原先所預期的響應之內。

In low rotating speed, the rotor of magnetic bearing system is assumed to be a rigid body. In fact, the turbomolecular pump is rotating in very high speed. If we assumed the rotor is rigid, the system will be unstable when the rotating speed increases over the resonant frequency of the bending mode. Additionally, the unbalance force and environmental disturbance will cause the high frequency resonant. The main purpose of this thesis is to design an inner loop controller by using “Observer-Based Control” and an outer loop using “Integral Control” theory. Then, these two controllers are applied to make our magnetic bearing system with flexible rotor stable and reach expectant response under unbalance force, gravitation, when rotating speed increases over the first flexible mode. Finally, we simulate response of the magnetic bearing with toolbox, “Simulink” of the Matlab considering the limitation of real hardware.