Skewing and notching configurations for torque pulsation minimization in spoke-type interior permanent magnet motors

Interior permanent magnet (IPM) motors become popular and commonly used in industry and domestic applications. One of them is spoke-type IPM. Spoke-type interior permanent magnet (IPM) machines are an attractive topology for high-performance electric motors. In most of the applications, the high strength of permanent magnets causes the undesirable effects of high cogging torque that can aggravate motor performance. Consequently, the reduction of cogging torque becomes an important topic in IPM motor. In this paper, to minimize the effect of cogging torque in IPM motor, two common techniques for cogging torque reduction such as skewing, and notching, has been analyzed in order to compare the cogging torque, back EMF and efficiency effect. 3D finite element analysis (FEA) by JMAG software is carried out for each technique. The results showed the reduction of cogging torque up to 98.6%, followed by 81.84%, 45.24% and 36.79% compared to the initial model design.