3-D Electromagnetic Field Analysis Combined With Mechanical Stress Analysis for Interior Permanent Magnet Synchronous Motors

The method of 3-D electromagnetic field analysis combined with mechanical stress analysis has been developed for loss calculation of interior permanent magnet motors. Both the stator compressive stress caused by shrink fitting and the rotor tensile stress caused by centrifugal force are considered in the stress analysis. The 3-D flux density vector is calculated by the electromagnetic field analysis, including the core end regions. The variation in the stress effect with the angle between stress and flux vectors is considered using the equivalent stress. The calculated loss is compared with the experimental loss in order to confirm the validity of the analysis. It is clarified that the accuracy of loss calculation is significantly improved as compared with the conventional method that neglects the angles between the stress and flux density vector.