Effects of Demagnetization on Torque Ripples in Permanent Magnet Synchronous Machines With Manufacturing Tolerances

Nowadays the compactness, cost effectiveness and low torque ripple are some of the most demanded requirements in electrical machines. Due to these requirements, Fractional Slot Concentrated Windings Permanent Magnet Synchronous Machines are getting more and more popularity. However, this kind of machines are sensible to mass production tolerances, which can increase the ideal low torque ripple. Apart from that, decreasing the volume of magnets and/or selecting magnets with worse thermal properties, the production costs are decreased. Nevertheless, this fact increases the demagnetization risk. Therefore, it is important to take into account the effects of the demagnetization on the torque ripple. This work investigates the demagnetization effects on the torque ripple assuming mass production tolerances by Finite Element Method and with experimental results.