Vibration Suppression in Four-Unit Permanent Magnet Synchronous Motor under Open-Circuit Fault Tolerance Based on Similarity Measure

Open-circuit fault, as a common type of winding faults, can lead to severe vibration in permanent magnet synchronous motors. However, the reason of this phenomenon is not well understood yet. Hence, this article proposes a similarity measure method for suppressing vibration of the four-unit permanent magnet synchronous motor under the open-circuit fault operation. Firstly, the shortcoming of the traditional fault tolerance method is studied, and the analysis indicates that the electromagnetic forces and moment are distributed asymmetrically along the air gap circumference. Then, it is found that the vibration intensification is induced by the asymmetric armature reaction magnetic field. By the proposed similarity measure method, the fault tolerance currents are derived and the armature reaction magnetic field is redesigned. The results show that the vibration performance is greatly improved by applying the proposed fault tolerance method. Finally, the prototype of an 8pole-12slot four-unit permanent magnet synchronous motor is manufactured. Several numerical simulations and prototype experiments are carried out to verify the effectiveness of the proposed fault tolerance method.