Early slight inter-turn short circuit fault diagnosis of axial flux stator coreless permanent magnet motor based on phase difference

Abstract

Aiming at the problem of early inter-turn short circuit fault of axial flux stator coreless motor, a method for early inter-turn short circuit fault diagnosis and positioning of axial flux stator coreless motor based on the phase difference of zero sequence component and stator current component was proposed. Firstly, according to the characteristics of extremely small stator winding inductance, a mathematical model of inter-turn short circuit fault was established. Secondly, Fourier analysis of the short-circuit current, phase current and zero-sequence component before and after the fault was carried out, and the inter-turn short-circuit fault was identified by the change of the amplitude of the zero-sequence voltage fundamental wave.Finally, the fault phase was located by comparing the initial phase difference between the zero-sequence voltage fundamental wave and the stator three-phase current. The results show that the absolute value of the difference between initial phase of the phase current fundamental wave and the initial phase of the zero sequence voltage fundamental wave of the inter-turn short-circuit fault phase is approximately 180°, while the phase difference of the healthy phase is quite different from 180°. Based on the phase difference, the diagnosis and positioning of the early inter-turn short circuit fault of axial flux ironless motor can be realized, which provides some reference for the diagnosis of inter-turn short circuit fault of permanent magnet motor.

Keywords

• electrical machinery; inter-turn short circuit; coreless motor; fault diagnosis; zero-order component; fourier analysis