Design of Wave Winding with Bar Wires for Six-Phase Interior Permanent Magnet Traction Machines

This article aims to analyze different six-phase winding configurations with rectangular bar wires to be used in an interior permanent magnet machine for an electrified vehicle application. Rectangular bar wires allow a higher slot fill factor compared to conventional round wires, and they are currently utilized in wave windings in the traction motors of commercial electrified vehicles. Combining bar wire winding with a six-phase configuration can lead to achieving a higher power density and more reliable operation in a traction motor. However, applying bar wires for a six-phase operation may raise further complications in the winding design, which requires special care to prevent complexities and potential failure points. In this article, the full-pitch wave winding pattern is discussed and then utilized for the implementation of pure six-phase and dual three-phase windings. The potential implementation process and the type of connections between different winding segments have also been considered. Finally, a comparison between the two winding arrangements has been presented in terms of complexities in the mechanical design and implementation. In order to find the optimal winding design, a MATLAB script has been provided, which enables investigating all possible winding configurations for both pure six-phase and dual three-phase windings.