Design of New Dual-Stator Field Modulation Machines

This article proposes a general design method for dual-stator field modulation machines (DSFMMs) that can be separated into two field modulation machine (FMM) portions sharing the key components with each other. The existing permanent-magnet synchronous machines and FMMs can be categorized into R/S types, where R denotes the part that can generate the rotating magnetic field, and S represents the stationary modulator. R and S can be used to derive various DSFMM topologies that take advantage of the high toque density. The combined machines employ the multilayer topology that provides space for multi-PM-excitation and multimodulation. The general design principle, simplest R/S-type machine, and the coupled armature winding configuration are discussed, and the modulated air-gap working harmonic components are investigated. Four representative dual-stator machines are developed based on the proposed method. The proposed hybrid-magnet DSFMM (HM-DSFMM) has the merits of high power factor, low cogging torque, and low torque ripple. The prototype of the HM-DSFMM is manufactured and tested. The result comparisons of the finite-element-analysis prediction and measurement verify the electromagnetic design.