Finite Element Analysis And Structure Optimization Of Electromagnetic Field At The End Of 700MW Dual Internal Water Cooled Generator

With the rapid growth of national economy,people’s demand for electricity is increasing.With the continuous improvement of materials and manufacturing technology,the single unit capacity of large generators is growing.Usually,two methods are used to improve the capacity of generator,increase the linear size of generator and increase the electromagnetic load.The first method is difficult to implement because the rotor deflection and stator transport size will have a great impact on the capacity.Therefore,the second method is mainly used in engineering application,but with the increase of end magnetic flux leakage and eddy current loss,it will bring a lot of heat.The problem of heat dissipation of generator restricts the improvement of generator capacity.To deal with the problem of heat dissipation of generator can greatly improve the efficiency of generator.In this paper,the double water internal cooling generator is taken as the research object,and the eddy current loss at the end of the generator and the optimization of the magnetic shielding thickness to reduce the cost are mainly studied.Firstly,the mathematical model of the electromagnetic field at the end of the generator is established.The mathematical principle of the eddy current field at the end of the generator is deduced and analyzed in detail.Combined with the actual structure of the end of the generator,a three-dimensional solid model of the end is established,including the side core,the toothed pressing plate,the pressing ring,the magnetic shield,the stator bar,the rotor body,and the rotor coil;Secondly,a new calculation method of eddy current loss is proposed.The steady-state time harmonic simulation is used to replace the traditional transient simulation,which saves a lot of time.At the same time,the block modeling of the coil is carried out,and the block loss value of each part of the coil is extracted.The influence of different coil materials on the eddy current loss of the generator end is studied,and the coil temperature measurement of the field motor is carried out The lateral analysis of aircraft simulation verifies the feasibility and accuracy of the time harmonic simulation method,which provides a reference for engineering design;Finally,the influence of the change of the magnetic shield thickness on the end loss is explored.In order to reduce the manufacturing cost of the magnetic shield,the parametric modeling method is proposed to realize the rapid modeling.The loss of each component under different magnetic shield thickness is studied.Combined with the economic index,the appropriate magnetic shield thickness is selected,which provides a certain reference for the motor to reduce the cost,and has a strong engineering application value Use value.