Synchronous Reluctance Motor Iron Losses: Analytical Model and Optimization

Abstract

The complex rotor structure of synchronous reluctance machines causes a high harmonic content in the air-gap flux density and then flux density fluctuations in different iron parts. The importance of determining accurately the total iron losses in the whole motor structure is crucial even during the first design stage. An analytical model is presented to predict the total iron losses as well as the average torque and ripple. Then, an optimization approach is applied to such a model to improve the motor performance. In addition, in several applications a field weakening is required to extend the speed range of the motors. Therefore, it is important to design and optimize the machine not only considering the base speed working point, but also the field weakening operation. An optimization process is applied to two different operating conditions, simultaneously, applying the fast analytical synthesis. The validation of the model accuracy is assessed by means of finite element analysis.