Comparison of Linear Superconducting Magnetic Bearings Using Isotropic and Anisotropic Materials

Critical current density anisotropy is a common property of high-temperature superconducting materials. We clarify here how it could impact the performances of superconducting magnetic bearings by comparing linear bearings using isotropic and anisotropic materials. To be fair, the comparison considers optimized designs. An H-formulation finite element model is used to obtain the levitation and guidance forces of the bearing for a given moving sequence. It is coupled with a stochastic optimization algorithm. For the considered bearing topology (single bulk above PM Halbach array), it was found that for applications requiring only levitation force, both isotropic and anisotropic materials are suitable. But for applications requiring both levitation and guidance forces, isotropic materials are more suitable than anisotropic ones since they can provide a stable guidance force for a given minimal levitation force at the smallest cost. This could serve as general design guidelines for future engineering applications.