An innovative rotor core assembly for high performance 4-pole synchronous reluctance traction motor using grain oriented lamination

One of the major requirements of traction motors is to develop high torque at low speed. This allows the electrified powertrain to perform properly during start-up and acceleration. Hence, maximizing the peak torque of the synchronous reluctance motor is a strong objective when it is designed for automotive applications. This may be possible by amplifying the saliency of the rotor geometry which means high magnetization in the flux carriers and low magnetization through the flux barriers that is high saliency ratio. Recent advantages of high quality anisotropic magnetic materials such as cold rolled grain oriented electrical steels have contributed to new energy efficient, compact, and high performance static electrical machines such as transformers. However, from the rotor core point of view, the circular geometry of the rotor has remained an obstacle for utilizing these high performance magnetic materials in electrical motors core lamination in particular, synchronous reluctance motors with number of poles higher than two. This paper presents an innovative rotor lamination design and assembly using cold rolled grain oriented electrical steels for achieving a higher performance for 4-pole synchronous reluctance motors. The design method and manufacturing process of a prototype is discussed, finite element analyses along with the experimental examinations are carried out to verify and validate the proposed method.