Low costs and high-efficiency electric machines

This paper present a novel method for reducing or complete canceling some space harmonics of low order in the air-gap flux density of electric machines with fractional slots, tooth-concentrated winding using magnetic flux barriers in the stator teeth region. Furthermore, the new method increase simultaneously the efficiency of the working harmonic and with this the power density of the electric machine. The presented technique is applied to a PM machine with 12-teeth/14-poles single layer concentrated winding during designing of an electric machine for automotive application. Compared with the conventional design it show enormous improvements on the machine performances; the new PM machine design is characterized with high efficiency and high power density.