Torque ripple reduction by multi-layering technique in an interior permanent magnet motor used in hybrid electric vehicle

In this paper, a new method in terms of reducing the torque ripple in interior permanent magnet motors is presented. Permanent magnet motor used in Toyota Prius 2004 is assumed as the basic design. After illustrating the significant output torque ripple in this machine, a reforming procedure will be conducted to decline the rate of ripple. Inner magnets will be arranged in multi-layer formation and to some extent the thickness of magnets will reduce. Owing to the fact that making the magnets thinner will escalate the chance of irreversible demagnetization, magnets will become tangential to radial direction. (The structure is known as spoke type magnet.) After implementing the new structure, a linear sweep parametric analysis will be carried out to exploit the optimized location for magnets. Besides, price comparison between proposed motor and base interior permanent magnet motor will be illustrated. In addition, there is a possibility of collapse in structural durability, as magnets become thinner compared to primary design. Hence, a structural review of machine will also be held at ultimate speed of 6000 rpm to demonstrate the final stress in controversial edges of the rotor.