A novel tooth concentrated winding with low space harmonic contents

The fractional slots tooth concentrated windings are characterized with high space MMF harmonics which results to undesirable effects on electric machine. A novel and high efficiency method is presented in this paper to reduce simultaneously the suband high MMF harmonics of these winding types. Using this technique, a new 18-teeth/10-poles PM machine for traction applications is designed and their characteristics are compared with the convectional 12-teeth/10poles PM machine. The both machines are designed and investigated under the same electrical and geometrical constrains and the obtained results show high performances for the new machine design compared with the conventional machine. With the new winding type the radial force modes of low order (mode-2) are reduced for about 70%, the stator and rotor iron losses are reduced 30%, however, the magnet losses are reduced 80%.