High performance synchronous reluctance motor with multi-flux barrier for the appliance industry

Advances in power electronics and machining mean that reluctance motors have now become the focus of new studies. Research and development is pursuing two different tracks. One targets what is referred to as a switched reductance motor which uses a pulse signal to drive a salient-pole rotor. The other targets a synchronous reluctance motor (SynRM) which uses a sinusoidal wave to drive a rotor which is constructed with several flux barriers. The stator winding of the latter is of the same specifications as that used in an induction motor or a brushless motor which utilizes permanent magnets. It also carries the merit of effectively utilizing a conventional inverter due to the sinusoidal wave drive. For what regards rotor construction of this type of motor, Lipo, Miller, Boldea, Yagati and others have enthusiastically researched an axially laminated construction which features layers of electromagnetic iron plate in the rotor´s axial direction for the purpose of improving saliency ratio. However, many of these have not clarified the relationship between flux barrier construction and motor efficiency. This paper reports on simulations and experiments using a prototype, in which flux barrier construction and design optimization were investigated in consideration of machining distortion and other factors, as part of studies into making a highly efficient multi-flux barrier SynRM. It is also reported that the prototype model proved to be 6% more efficient than an induction motor with the same inverter drive.