Numerical analysis of rotation loss of superconducting magnetic bearing

The degradation of levitation force and rotation speed is one of the most significant problems for the practical use of superconducting magnetic bearings (SMB) for flywheel energy storage systems. The rotation loss is caused by the AC magnetic field due to the inhomogeneous distribution of magnetic flux density of the permanent magnet (PM) rotor. A simulation method has been developed by the authors' group to simulate the rotation losses. In this research, this method was improved so that the eddy current flowing in the cryostat around the superconductor was taken into account. The dependency of the rotation losses of radial type SMB with cryostat were evaluated by this new simulation method with respect to the levitating height, the initial rotation speed and the amplitude of inhomogeneous component of PM rotor's field.