Suspension Force Error Source Analysis and Multidimensional Dynamic Model for a Centripetal Force Type-Magnetic Bearing

The traditional modeling methods on suspension force of magnetic bearings are mainly based on static fields analysis, and lack of consideration for the effect of real-time temperature and rotation speed. However, the action area of Maxwell force and the air gap size in the calculation formula of the suspension force dynamically change with temperature rise and rotation speed. Therefore, the accuracy of model results on suspension force is compromised. In this article, taking the centripetal force type-magnetic bearing as an example, the error sources that affect the accuracy of the suspension force are analyzed meticulously. Then, based on the suspension force error sources results, a dynamic model involving multiple dimensional variables is proposed, which includes control current, displacement, temperature, and rotational speed. Superior to the traditional static models, the temperature and rotation speed are integrated into the proposed multidimensional model besides the traditional current and displacement. To prove the validity of suspension force error sources analysis and the accuracy of the proposed model, the dynamic stiffness experiments are carried out. The experiment results show that the multidimensional model is more practical and has higher precision than the traditional static model.