UMP Suppression Strategy for 8-Pole SPMSMs With Rotor Dynamic Eccentricity Faults

This is the authors' abstract. We don't add key points for this paper.

Unbalanced magnetic pull (UMP) inevitably arises in motors with rotor eccentricity faults, leading to mechanical damage. This paper investigates the UMP control capability of 8-pole surface-mounted permanent magnet synchronous motors (SPMSMs) from the perspective of p±1 order magnetomotive force (MMF) synthesis. Analysis of the armature reaction MMF of winding branches suggests that configuring the motor with two sets of three-phase windings with symmetric axes is advantageous. This configuration allows the regulation of p+1 order MMF via negative-sequence current (NSC), thereby enabling active UMP control. Furthermore, a method for determining the optimal NSC for UMP suppression under rotor dynamic eccentricity (DE) conditions is proposed. This method utilizes stator voltage signals instead of inaccessible eccentricity information, making it suitable for practical industrial applications. Finite element analysis (FEA) and experimental results conducted on 48s-8p and 12s-8p SPMSMs with DE faults validate the theoretical analysis and the proposed method. After injecting the optimal NSC, UMP is reduced by over 89% under various operating conditions.