Affiliations: [a] Ningbo Institute of Technology, Zhejiang University,
Ningbo, China | [b] School of Electrical and Electronic Engineering,
Nanyang Technological University, Singapore
Correspondence:
[*]
Corresponding author: Dr. Chi Zhang, PhD, No. 1 the Southern
Road of Qianhu, High Education Park, School of Information Science and
Engineering, Ningbo Institute of Technology, Zhejiang University, Ningbo City,
315100, China. Tel.: +86 15168586753; Fax: +86 574 88229505; E-mail:
[email protected]
Abstract: A compact flywheel energy storage system assisted by axial-flux
partially-self-bearing permanent magnet motor has been proposed by the authors.
The proposed machine combines axial magnetic bearing and motoring functionality
into a single magnetic actuator, which not only spins the rotor-flywheel but
also generates a levitation force to overcome the gravity. The mathematical
model of the levitation force and stiffness of the active magnetic bearing are
developed. The relationships between the stiffness and the key motor parameters
are studied. High stiffness can be achieved for the special motor design. The
derived force model is validated by finite element analysis. The control system
of the levitation force is designed and experimental setup is built. The test
results prove the correctness of the mathematical analysis and feasibility of
the designed control system.
Keywords: Stiffness analysis, active magnetic bearing, levitation force control, flywheel energy storage system, partially-self-bearing motor
