Research of Inherent Relationship between Contribution Proportion of Harmonic and Gear Ratio in FSCWPMSM

The magnetic field modulation effect in fractional slot permanent magnet synchronous motors(FSCW PMSM) has received widespread academic attention in recent years, and the selection of the pole-slot combination will have a decisive impact on the performance of the motor. The Gear Ratio is a function closely related to the motor pole-slot combination, while the existing method of measuring the electromagnetic performance of motors based on the Gear Ratio has failed to accurately calculate contribution proportions of different harmonic field, since the existing theory does not conduct in-depth research on the distribution of harmonics in the modulated magnetic field, and cannot accurately calculate the proportion of each harmonic component. This article provides a more detailed elaboration and explanation of the relationship between the pole slot combination and the Gear Ratio in the FSCW PMSM after an in-depth analysis of the magnetic field modulation effect. Subsequently, the contribution proportion of different harmonics to torque has been accurately and quantitatively calculated based on different pole-slot combination. Then detailed analysis of the characteristic changes of magnetic field modulation effects in FSCW PMSM, thereby comparing the electromagnetic properties of the motors. The work of this paper is to analyze the electromagnetic performance of the motor from the perspective of magnetic field modulation, which is a supplement and expansion of the magnetic field modulation theory.