Analytical Exploration of Harmonics Behavior in Multiphase Machines

This paper explains the reason for harmonics elimination in asymmetrical six-phase machines. The benefits of a 30° shift between two sets of three-phase windings are explored in great detail. A magnetomotive force has been investigated in a manner of harmonics behavior. A transparent explanation has been derived mathematically and interpreted utilizing time-dependent and position-dependent analytical simulations. The paper presents an analysis of the impact of individual harmonic components separately. The procedure shows the exact points where the harmonic components are canceled and clearly states the reasons for their elimination. Six-phase machine with various electrical and mechanical shifts between two sets of three-phase systems has been studied and compared to three-phase machines. The influence of current harmonics on a torque ripple has been examined experimentally on a six-phase permanent magnet synchronous machine.