Analysis of Higher Harmonic Components in Magnetic Fields on Three Phase Squirrel-Cage Induction Motors Considering Higher Harmonics in the Secondary Current.

Abstract

Reduction of machine size increases the number of harmonic components which appear in the magnetic fields on induction motors. For practical design, it is necessary to estimate these harmonic components. This paper describes a method to analyze harmonic fields on induction motors, considering higher harmonics in the secondary current. The method consists of two parts. One is the magnetic field calculating part done by a 2D-finite element method considering rotor rotation, and the other is the harmonics analyzing part done by considering space and time harmonic components using the former results.Dependence of periodicity in the magnetic fields on driving conditions is discussed. Then the relationship between the analysis period, the method of mesh division, and the periodicity is clarified for calculating magnetic fields. From the comparison between calculated and experimental results, the proposed method is shown to be appropriate and useful for quantitative estimation of harmonic components on induction motors.