Study Of Unequal Span Windings Based On Unit Modular Combined Stator

The feature of a low-speed high-power AC motor is large, which brings a series ofquestions to the manufacture, transportation, installation, commissioning and maintenance.A kind of unequal span and reverse inserted form was proposed based on multi-branch tomake the motor stator modularized. The flexibility was improved by the independent ofeach stator unit. That the size of stator unit is relatively small is easy to the manufactureand transportation, while a faulty unit could be easily replaced. The large span coil bringsthe asymmetrical structure of three-phase windings. Unequal span winding reverselyembedding makes the magnetic field distribution of the motor end complex, then theelectromagnetic force of windings ends should be calculated. The main work is as follows:Relationship between the number of stator unit and the number of poles and thenumber of slots could be summed up according to the presentation and analysis ofstructural features of modular combined stator motor. According to the relationshipbetween the number of stator unit and the number of poles and the number of slots,combined with design principles of conventional low-speed high-power AC PMSM, a12kW,3modules,100r/min three-phase permanent magnet synchronous motor wasdesigned.Self inductance and mutual inductance of large span coil and small span coil werecalculated with analytical method. Phase inductance in a unit motor could be obtained byincremental inductance. The asymmetry of three-phase winding caused by unequal spancoil was analyzed and judged by comparison with phase inductances with include largespan coil and not.The magnetic field of prototype end model was analyzed and calculated by FEMsoftware. The time and position of the maximum electromagnetic force of each phasewindings ends were achieved by analysis and calculation of windings ends force in onemotor unit. Then stress and strain distributions of the coils were gained by electromagneticand structural coupled field. Finally, the performance parameters of unit module combined stator PMSM weretested by the prototype experimental analysis and research. The experimental value anddesign value and the simulation values were basically identical. And the self and mutualinductances of each phase winding were measured with static measurement method. Thevalues and the results of method of incremental inductance calculated are basicallyidentical. The incremental inductance method was proved correctly. The conclusion of thispaper has a certain reference value in further study of module combination stator motor.