Calculation and Measurement of the Magnetic Field of Nd2Fe14B Magnets for High-Temperature Superconducting Magnetic Bearing Rotor

The external magnetic flux density and distribution of the permanent magnet (PM) rotor of the high-temperature superconducting (HTS) magnetic bearing directly affect the load-carrying properties and stability of the HTS magnetic bearing. In order to facilitate the design of the PM rotor that meets the application requirements, a finite element analysis (FEA) method to calculate the magnetic flux density and distribution of PM rings and PM rotor would be used. A magnetic field measurement system was built as well. By comparing the results of calculation and measurement, the validity of the magnetic field calculation method is verified. And the calculation results are promoted after correcting the calculation parameters of the magnetic ring. Therefore, the correctness and accuracy of the calculation method are verified by experimental measurement. The magnetic field measurement system can be used to measure and select the magnetic rings with uniform and consistent magnetic field to improve the stability of the HTS magnetic bearing. And the performance of the Nd2Fe14B magnets N52 at liquid nitrogen temperature (77 K) was measured, which has been increased by about 9% relative to magnetic field at room temperature (295 K).