Calculation And Analysis Of Electromagnetic And Temperature Fields In Axial-Radial Flux Type Superconducting Synchronous Motor

With the development of high temperature superconducting materials andtechnology, high temperature superconducting motor becomes one of the hotresearches in the electro-technical field, due to its large power density, smallvolume and nearly no stator windage loss. Compared with the conventionalelectrical machine, the race-track type superconducting coils are used in thestator of superconducting synchronous motor. The eddy current losses appearingin rotor will be dissipated in the heat form, which will be increased the motortemperature and influence the motor on the reliability and stability. So it is verynecessary to do some researches about the electromagnetic and temperature fieldsin axial-radial flux type fully superconducting synchronous motor (ARFTFSSM)using finite element method.First of all, considering the operating principle and the configurationcharacteristic of ARFTFSSM, the3-D analysis model of transientelectromagnetic field is established. The3-D flux density distribution of theARFTFSSM and the influence of the stator structure on air-gap density arestudied. The eddy current losses in the rotor are calculated, and then the eddycurrents of the generator in the starting process and the stable operation areanalyzed comparativelySecondly, the2-D mathematical model of temperature field is establishedaccording to the structure and working condition of the ARFTFSSM prototype.The losses in each component of the motor are given and the heat transfercoefficients of stator surfaces were proposed using the convergent iterationmethod. The temperature distribution of the prototype is obtain through thenumerical calculation, and compared with the test data. Based on the above analysis, the temperature distributions in superconductor motor and conventionalmotor are studied comparatively, and the influence of copper loss on thetemperature is discussed.Finally, the transient electromagnetic field of the ARFTFSSM with differentaxial magnetic EMF is calculated using the finite element method. The non-loadelectromotive force is studied while the motor is operating at different axialmagnetic EMF, and the electromagnetic field of the motor with axial magneticEMF of different directions is analyzed. The results show that the ARFTFSSMhave the ability of excitation control, comparing with the test data of non-loadelectromotive force.