Parameter identification of magnetic bearing based on rotor unbalance responses

The force parameters of magnetic bearing obtained by theoretical design method were usually inaccurate. To solve this problem, an identification method based on rotor unbalance responses was proposed. Making the rotor rotate at high speed, the eccentric effect of the rotor imbalance can be used. The force parameters of magnetic bearing were calculated by measuring the synchronous currents when the rotor was in the null-displacement control mode and the synchronous displacements when the rotor was in the null-current control mode. The null-current controller and the null-displacement controller were designed based on the generalized notch filter theory, and the T matrix was set up to ensure the close loop was stable. The experimental results indicate that the difference rate between experiment identification result and the theoretical design result is within 20%. And it proves that the method is correct and effective to improve the identification precision for the force parameters of the magnetic bearing.