Measurement and Calculation Method of the Radial Stiffness of Radial High-Temperature Superconducting Bearings

Stiffness of radial high-temperature superconducting (HTS) bearings is widely researched by experiments (measurement method). These researches include radial stiffness and axial stiffness at different temperatures and rotational speeds, cross stiffness, and so on. The measurement method can obtain the precise value of stiffness, while it takes so much time and cost. Simulation calculation method is suitable to model radial HTS bearings which have different structures, and it is easier to obtain stiffness than the measurement method. The problem is that the calculation precision is sensitive to the parameters in the simulation calculation. The measurement and calculation method of the radial stiffness of radial HTS bearings has the strong points of saving time and cost, and high precision. In this paper, this method is improved. Radial stiffness between HTS bulk and permanent magnet (PM) rotor is analyzed basing on a new mechanical model, and equation for the radial stiffness of radial HTS bearings is deduced. The error of calculation is reduced to 2.86 % according to the measured values. Application of this method for calculating the radial stiffness of radial HTS bearings with different number of HTS stator layers is introduced.