Numerical Calculation On The Electromagnetic And Heat Transfer In Mw-level Half-direct Driven Permanent Magnet Wind Generator

Half-direct driven permanent magnet wind generator (HD PMWG) is the right balance between doubly-fed and direct driven wind generator. It combines the advantages of both styles as well as some appending problems. The phenomenon of demagnetization would take place easily since the short-circuit current of half-direct driven wind generator becoming larger. These generators have high request to the ability of heat and cooling because of the larger power density compared with the direct driven ones. So it is significant to calculate and research on electromagnetic field and temperature field of HD PMWG.Firstly, this thesis presents the current research situation of the direct driven and half-direct driven wind generator as well as the structural characteristics of HD PMWG. It carries out a structural scheme of 1.5MW HD PMWG by calculating the effect of pole number and slot number on cogging torque and meeting the requirement of generator designation.Second , it analyzes the magnetic field distribution, the output performances, the voltage regulation factor and the leakage flux coefficients at no-load by establishing the 2-D finite element analysis model for the generator. It also proposes the coefficient of pole ununiformity( hb ) as well as studying the influence law of hb on magnetic field distribution and output performances. According to the operation characteristics of HD PMWG, we could calculate the transient short-circuit current and analyze demagnetization phenomenon on the permanent magnet. By the comparison of the analysis results on a small prototype, the test data results are consistent with the analysis of the theory.Finally, the theory of fluid heat transfer and 3-D finite volume method are used to calculate the temperature field of the half-direct driven wind generator. It calculates the model of the test prototype machine after establishing the 3-D fluid and temperature coupling analysis with the given the calculation methods for heat source. It is verified the correctness of the calculation model by comparing with the experimental data. Then it calculates the 3-D temperature field of the 1.5MW HD PMWG. Further more,based on the operational features of large power permanent magnet wind generator, the temperature distribution of generator for wind turbine is simulated and calculated at different wind conditions., and this could help to develop generator cooling design.