Influence of open-circuit fault on electromagnetic field of high-speed permanent magnet generator with Gramme ring windings

As the core of the distributed generation system, the health status of high-speed permanent magnet generator (HSPMG) has attracted much attention. HSPMG is often used in military, rescue and other fields. When the open-circuit fault of HSPMG stator winding occurs, it will seriously affect the operation stability and power supply reliability. In this study, a 117 kW, 60,000 rpm HSPMG is taken as an example, and a 2D finite element model is established. The accuracy of the model is verified by comparing the calculated results with the experimental data. By the field-circuit coupling method, the magnetic field changes pre-and post-fault is analysed, and the mechanism of magnetic field spatial distribution changes post-fault is revealed. In addition, the changes in eddy current loss pre-and post-fault are analysed. The influence of the harmonic magnetic field and the rotating magnetic field produced by negative sequence current on eddy current loss is studied, and the dominant factors effecting eddy current loss post-fault are investigated. The study provides some useful conclusions for HSPMG fault analysis.