Analytical model of a fractional slot double‐layer‐winding vernier permanent magnet machine

Abstract

AbstractThis study presents an analytical model (ANA) for predicting magnetic field and performances of a fractional slot (FS) double‐layer‐winding (DLW) vernier permanent magnet (VPM) machine. Magnetic vector potential equations of a FS DLW VPM machine are analytically solved by the technique of variable separation in three subdomains, that is, regions of permanent magnets (PM), air‐gap, and slots in 2‐D polar coordinate system. Field distributions and performances, such as flux linkage, electromotive force (EMF), torque and inductance of a FS DLW VPM machine are developed. Results from ANA of an 18‐slot/2‐stator‐pole‐pair FS DLW VPM machine prototype have been compared with those from finite element analysis (FEA), which indicates that ANA has a huge advantage in the computing speed in addition to a good accuracy. In the end, a prototype is built and its EMF and torque are tested in experiment platforms in which the results verify ANA. The necessity and importance of the research is that the model is an analytical method which provides a close solution of magnetic field and performances of a FS DLW VPM machine and its calculation time is much less than FEA on the base of a good precision.