Development of Interior Permanent Magnet Motors Reduction of Harmonic Iron Losses by Optimizing Rotor Structures

We developed the rotor structure of interior permanent magnet motors to reduce the harmonic iron losses at high rotational speed under field weakening control. An automatic optimization method combined with the adaptive finite element method is applied to determine the shapes of the magnets and rotor core. The optimized motor is manufactured to verify the validity of the optimization. From both results of the calculation and measurement, it is clarified that the iron loss of the optimized motor is reduced as nearly half compared with the initial motor, without decrease of the maximum torque.

I. Introduction

Interior permanent magnet motors are widely applied to the industry. One of the main advantages of the motor is the wide speed range extended by the flux weakening control [1], [2].