Simulations and Tests of Superconducting Linear Bearings for a MAGLEV Prototype

The complex microstructure of melt grown YBCO bulk material and the non-linear electromagnetic behavior makes it difficult to determine their thermal, electrical and magnetic properties. The knowledge of these parameters is essential to design superconducting magnetic bearings (SMB) for various applications. The main characteristic of a SMB is the levitation force that arises between the superconductor and the magnetic source. The availability of simulation tools can greatly simplify the design of new prototypes. An algorithm based on the critical state model and the Finite Element Method (FEM) was developed. This method is based on the determination of the current density profile within the superconductor due to the penetration of the flux lines. This algorithm showed satisfactory to simulate the levitation force for a rotational magnetic bearing used in a flywheel prototype. In the present paper, this method is used to simulate a linear bearing and to design the optimal geometries for a magnetic rail that is being developed for a MAGLEV vehicle prototype. The linear bearing consists of two parts: a rail assembled with Nd-Fe-B magnets and YBCO bulks mounted inside a cryostat. Some simulated bearings were mounted and tested. The simulation results agree with the measurements.