Rotor position estimation in a large airgap Active Magnetic Bearing

In recent years, Active Magnetic Bears (AMBs) becoming attractive for several reason such as frictionless rotation, high reliability and high speed operation. Moreover, AMBs are today an interesting alternative to standard bearing due to power electronics and control hardware price reduction, but the main disadvantage of AMBs is that they are design to have a small airgap and a high stiffness. This paper presents a new large airgap magnetic bearing that allows to add dumping features thanks to a dedicated control. A simplified analytical model has been introduced, a study of the airgap estimation has been presented and some experimental results are provided to validate the approach.