A Study on Winding MMF Harmonic and Vibration of Polyphase Motor

This paper mainly discusses the magnetic motive force (MMF) distribution and its harmonic amplitude related to vibration of polyphase stator winding, According to a series of formulation derived, it is obvious that some MMF harmonic amplitude is much more related to stator radial force, then for different type of stator winding on the number of phases, based on the same input stator current value, it can be designed for three types of surface permanent magnet motor with different output torque density, which is also the outstanding advantage of polyphase machines compared to other type of permanent magnet (PM) motors. Then, this paper design three type motors for a 12-slot 10-pole three-phase PM motor, a 10-slot 12-pole five-phase PM motor and a 12-slot 10-pole six-phase PM motor respectively. Additionally, through the several contrast with stator inner edge core radial magnetic force, this paper analyzes its distribution wave and Fourier decomposition, develop the rule about how the MMF harmonic and magnetic density in air gap effect the radial force and cause the deformation of stator core and housing, and how to avoid this type vibration by weakening the MMF harmonic amplitude on related order and improve the magnetic density wave in other ways.