Calculation Of The Electromagnetic Field And Temperature Field Of The High-speed Permanent Magnetic Generator Dirved By Micro-gas Turbine

The high speed generator, due to its small volume, high efficiency and great power density, is one of the great concerns in electrical engineering. Two main features: the high rotating speed of the rotor and the high frequency of the winding current and the stator core flux, determine the unique technology of the high speed generator. In this thesis, the main contents which due to the problems of the high-speed permanent magnetic synchronous generator (PMSG) are listed as follows:Firstly, the mathematic and physical models with generator eccentric of the PMSG are established and presented two different methods to calculate the magnetic field distribution and unilateral magnetic force (UMF) in the whole calculating region. And then analysis of influences of the eccentricity, load current and harmonics on the UMF have been undertaken. Finally, variation of UMF with the eccentricity is presented.Secondly, the temperature is very high for greater loss per volume and the smaller cooling areas of the high-speed machine when the generator running, so the cooling problem seems to be serious. In this paper, two modified modes are presented by modifying the structure of stator winding of the high-speed PMSG. One is made by widening the stator slot which increases the cooling areas, it is called wide slot. The other one is stator ring winding. The lower layers of the stator winding are fixed in the inner slot of the core, and the upper layers are fixed in the outer slots of the stator yoke. The ring windings increase not only the cooling areas but also the cooling efficiency for the cooling oil go through the windings'surfaces directly. More important, the axial end of the ring winding is much shorter than that of the traditional 2-pole windings, which reduces the rotor stiffness greatly. Based on the three different stator structures, physical models of the high-speed machine are established and the surface losses of generator'screen are calculated with the field-circuit coupled method, and then analysis their load performances.Finally, the stator losses of the three modes are calculated and compared. On this basis, 2-D temperature calculation modes are established and the stationary temperature rise of the high-speed machine is calculated using finite element method.