Experimental and numerical evaluation of rotation speed degradation of radial type 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 bearing (SMB) for flywheel energy storage system. The degradation are called the rotation losses caused by the AC magnetic field due to the inhomogeneous distribution of magnetic flux density of the permanent magnet (PM) rotor. In this research, our simulation 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 was evaluated by this new simulation method concerning the amplitude of inhomogeneous component of PM rotor's field.