A Bearingless Motor With Passive Electrodynamic Suspension in Axial Direction

Experimental Verification of Passive Axial Electrodynamic Suspension in a Bearingless Motor

“…Among these passive suspension techniques, electrodynamic suspension was chosen for this project, because the motor coils that generate torque are also used for passive stabilization, they provide stronger stiffness than that of room temperature diamagnetic levitation, and they do not require superconductors with a dedicated cooling system. The electrodynamic suspension principle was already employed in several electrodynamic bearings [14], [15], [16], [17], [18], [19], [20], [21], [22] and bearingless motors [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35]. Full passive suspension was confirmed in a bearingless motor that combines axial electrodynamic suspension and radial permanent magnet bearings [29], [30], [31].…”

“…However, the rotor remains in axial touchdown position until a certain minimum rotational speed is surpassed. In case full suspension is required for all rotational speeds, it is possible to operate these bearingless motors as a single-drive 1DOF machine up to the threshold speed of axial suspension [30], [35].…”

“…This article presents a surface-mounted permanent magnet bearingless motor with axial electrodynamic suspension [32], [33], [34], [35]. The radial directions and tilting angles are stabilized by radial permanent magnet bearings.…”

“…This principle was previously adapted for bearingless motors [23], [28], but, owing to the lack of superconducting electromagnets, flux density and electrodynamic forces are considerably lower than that of the maglev train for high-speed transportation. The machine covered in this article has a double rotor structure with three layers of permanent magnets [33], [34], [35] for improved radial flux density and passive axial electrodynamic force. This radial air-gap rotor shape offers the possibility of axial suspension with 1DOF control at low rotational speed.…”

Vibration Analysis and Active Control of Rotor Shaft in Magnetically Suspended Air-Blower

“…Compared to normal rotary machines supported by mechanical bearing, the magnetically suspended rotary machine with stable suspension of active magnetic bearing (AMB) [1,2] has advantages of contactless suspension, free-lubrication, micro-vibration and active controllability. Therefore, to improve the dynamic performance and service period of rotary machines, the AMB has been widely used in many kinds of rotary machines, such as the momentum flywheel for satellite altitude control [3,4], the flywheel energy storage system (FESS) [5,6] and the high energy density motor [7,8].…”