IPM motors have a structure that embeds the magnet in the rotor. Centrifugal force kicks in during motor drive, so the magnet becomes pressed against the rotor core because it gets peeled off or displaced, making it so that a strong local stress begins to operate. It is necessary to correctly handle the phenomena of a magnet peeling off or becoming displaced in order to accurately obtain the local stress distribution. It is important to account for the adhesion and contact conditions between the magnet and rotor core in an analysis in order to do this.
This Application Note presents examples of cases that obtain changes and stress distribution from the centrifugal force in the rotor.
Fig. 1 shows that the magnet drastically deforms the rotor core with centrifugal force in the radial direction. Also, the Mises stress increases at the bridge part of the rotor core. Mises stress allows the evaluation of the risks of damaged rotor cores and mechanical strength.