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Date of Award
Thesis - Campus Access Only
Master of Science (MS)
This thesis is motivated in part by the lack of published research pertaining to
active magnetic thrust bearings (AMTB), as compared to active magnetic radial bearings
(AMRB). This thesis presents one method in implementing AMTBs to provide a near
frictionless support to a rotor contained in a vacuum environment, mitigating the
concerns of viscous drag and chemical reaction as a result of the exposure to lubricants.
An analytical model was first developed to linearize the AMTB against a predefined
operating point. A finite element simulation was subsequently conducted to verify the
analytical model. The analytical and finite element methods both indicated that the
steady state power consumption of the AMTB was approximately 12 W, and there was
no occurrence of magnetic saturation within the material. The stress analysis showed that
the stresses experienced by the rotor part of the AMTB as it rotated at the maximum
rotation speed were well below the yield stress of the material. Lastly, a closed loop
feedback network with proportional-integral-derivative (PID) controllers was designed
and implemented as the control scheme for keeping the flywheel rotor at a predefined
axial position, while the rotor underwent axial position variations due to the external
disturbance, thermal expansion, or Poisson contraction effects. The resulting simulations
showed that the PID controller was able to stabilize the flywheel rotor 0.3 s after it was
disturbed by an external force equaling 10% of its weight.
Lam, Siu Kiong, "Design and Optimization of an Active Magnetic Thrust Bearing for Flywheel Energy Storage Systems" (2011). Master's Theses. Paper 4057.