End Electromagnetic Field Analysis And Calculation Of Large Generator-motor In Multiple Load Cases

Generator-motor is the key equipment of pumped storage unit. End windingmotor and electromagnetic properties are improved and the difficulty of design isincreased when the unit more frequent change running condition. An accuratecalculation of the unit magnetic field and the end structure loss is theprecondition of end winding and the structure design, also be the basis of unit canstable operation. According to the difficult situation of numerical analysis withcomplete pumped storage units power motor machine, time step finite elementmethod (FEM) with2d and3d coupling, electromagnetic and movement couplingis used in this paper, and the pumped storage machine is taken as an example, theend magnetic field loss and the structural are analyzed and calculated.Firstly, the2D numerical analysis model of generator-motor is built. Themethod of endpoint iteration combined with finite element analysis is used fordetermining rated field current under three typical running operating conditionsabout on load operation, generator rated operation, motor rated operation.Secondly, the3D numerical model of the generator-motor in the end region isgiven. Time step finite element method (FEM) with2d and3d coupling,electromagnetic and movement coupling is used for analysis and calculation onmagnetic field and structure loss in end region of generator-motor under no loadoperation, generator rated operation and motor rated operation. Meanwhile, theinfluence factors of the rotor core relative to the stator core extending length, thestructure of stator end fingers and whether considering the structure betweenstator end fingers and stator press plate nor not to the structure loss in end regionof generator-motor are analyzed.Finally, the method of co-simulation bewteen simulink and finite element calculation software is used in this paper, to calculate stator current, statorvoltage and motor speed when generator-motor under variable frequency start atthe condition of constant proportion of voltage to frequency. On this basismagnetic field and structure loss in end region of generator-motor under variablefrequency start are analyzed in time step finite element method (FEM) with2dand3d coupling, electromagnetic and movement coupling, and the calculationresults is compared with motor rated operation. The feasibility of generator-motoradopt with variable frequency start is proved.