Auxiliary teeth design to reduce short-circuit current in permanent magnet generators

Abstract

In this paper, a new auxiliary teeth structure is proposed for fault-tolerant permanent magnet (PM) generators, which can reduce the short-circuit currents. Firstly, the short-circuit current and the phase to phase isolation of the fault-tolerant generator are analyzed briefly. Secondly, the auxiliary teeth structure is optimized to improve fault-tolerant capability. Then, the PM generators with different stator structures are compared to evaluate the proposed auxiliary teeth structure. Four critical generator parameters are investigated, i.e. back-electromotive forces, short-circuit currents, stator magneto motive force (MMF) harmonics, and torque performances. The results show that the proposed structure has better fault-tolerant capability than the conventional two-layer windings. Moreover, the stator MMF harmonics can be suppressed. Furthermore, the cogging torque and torque ripple can be suppressed by adopting the proposed structure. Finally, the simulated results are given to validate the theoretical analysis. Index Terms-Auxiliary teeth, fault-tolerant generator, magneto motive force, torque, finite-element method, permanent magnet generator.