Asymmetric electromagnetic analysis and design of a permagnet biased axial magnetic bearings

摘要

In this paper, an asymmetric permagnet biased axial magnetic bearing has developed. The PM rings can not only produce bias flux, but also provide a large axial force to reduce the burden of axial bearing. As a result, the proposed PBAMB can lower the current, lower the power loss and make an easier control. Firstly, structure and operation principle are introduced. Then, the mathematical models are built based on traditional equivalent magnetic circuit. The analytical and design results are verified by finite element method (FEM). The loss is also analyzed by comparing with usual AMBs and symmetric PBAMB. The result shows the copper loss is reduced to 22% of usual AMBs and 56% of symmetric PBAMB. Finally, the design principle has been introduced in detail. The proposed PBAMB has an important reference value for magnetic bearings applied in the device when the load forces in two axial directions are different.