磁浮軸承轉子偏心力之估測與補償研究

Abstract

本論文旨在建立一數位式的力量估測系統，藉由轉子位移量和定子線圈電流的訊息，將轉子轉速同頻率的偏心力估算出來，並以前饋補償的技巧加以消泯，以降低轉子因內部質量不平衡旋轉所帶來震動及驅動器飽和等不良的影響。於控制器設計方面，利用類比轉數位的雙線性轉換配合相位補償，再加上根軌跡法完成整個數位控制器的設計。 一般磁浮軸承的控制原理是：將所承載轉子的幾何中心軸控制在旋轉中心軸上來旋轉，以達到轉子與磁浮軸承定子間的氣隙為定值，而在轉子質量不平衡的狀況下，對於高轉速應用的磁浮軸承則會帶來許多負面的影響，故本論文建構了傳統的Luenberger以及滑動模式Utkin兩種不同的數位式偏心力補償器，並使用德州儀器C240 Evaluation Control Board加以實現，將不平衡轉子在定轉速狀況下所造成之偏心力干擾予以抑制。

The thesis develops two different digital force observation systems of Magnetic Bearing using the displacement of rotor and the current of coil to estimate the eccentric force. These estimators use feed-forward skill to avoid vibration and driver saturation coming from rotor imbalance. As for digital controller design, bilinear transform with compensation of phase and root locus method is developed in this thesis. The design procedure confirmed by simulation results is concise and flexible. General principle of controlling magnetic bearing is to maintain rotor rotating on its geometric center. But for high-speed application of magnetic bearings, even small scale of imbalance would excite many side effects. Two digital observers, i.e., traditional Luenberger observer and sliding mode Utkin observer, are implemented in this thesis by C240 evaluation control board, suppressing the eccentric force disturbance under constant operation speed.