Proposal of a Novel Air-Gap Structure for Magnet-Less 3-Axis Active Control-Type Magnetic Bearing with Cylindrical Rotor: Reducing Axial Length of Turbomachinery System

This paper proposes a novel airgap structure for magnetic bearing (MB) that realizes 70% smaller lower side coil space area than that of a conventional MB for turbomachinery system. The proposed MB contributes to reducing the total axial length of a 3-axis MB by 17.9%. This means that the critical rotation speed can be increased, improving a serious problem for turbomachinery system that requires high-speed rotational speed. This paper shows comparison of suspension force between a conventional and the proposed MB, which is analyzed by 3D-FEA. Finally, superiority of the proposed MB is shown from various perspective.