Radial displacement tolerance detection of bearingless permanent magnet slice motors under adjacent double Hall faults

The eddy current sensor is used in the traditional bearingless permanent magnet slice motor to sample displacement information, which is difficult to meet the requirements of miniaturization of artificial heart pump. The angle and displacement information of bearingless permanent magnet slice motor based on Hall measurement are derived from Hall signal, which can greatly reduce the volume of the system, however the suspension performance of the system is limited by Hall output signal. When the adjacent double Hall sensors fail, the influence of the non-eccentric basic flux on the displacement solution of the displacement solution can not be eliminated directly, which leads to the slice motor lose its suspension performance. In order to improve the fault tolerance of bearingless permanent magnet slice motor based on Hall displacement measurement, an non-eccentric basic flux elimination algorithm based on harmonic compensation is proposed in this paper. Firstly, the third harmonic of the remaining non-fault Hall is compensated; secondly, the non-fault Halls are used to solve the non-eccentric basic flux coefficient, and then the influence of the non-eccentric foundation flux on the displacement solution is eliminated, and the displacement feedback table under Hall fault is constructed to extract the displacement. Finally, the correctness of the algorithm is verified by simulation and experiments.