A design example of an 8-pole radial AMB for flywheel energy storage

High speed flywheel energy storage systems normally use magnetic bearings to reduce friction loss. Bearing load consists of radial forces with or without axial forces according to drive configuration and requirements. The magnetic bearing system may be passive magnetic bearing (PMB), active magnetic bearing (AMB) or superconducting magnetic bearing (SMB) according to the required application. In this paper, a design example for an 8-pole radial AMB used for flywheel energy storage is presented. The design details along with finite element simulations are given to verify the design requirements. Finite element analysis is also used to obtain the bearing parameters. Based on calculated system parameters, a Matlab model is built to simulate the magnetic bearing in different cases.