Loss Model of Interior Permanent Magnet Synchronous Machine with Series Iron-loss Resistance

Interior permanent magnet synchronous machines (IPMSMs) are widely used, because of the high power density and high efficiency. It is noted that the loss model of IPMSM is essential to analysis, and furtherly suppress the motor loss, especially for the loss-model based maximum efficiency control. The traditional loss model is the one with parallel iron-loss resistance, which has high-order and mixed parameters. Therefore, in order to identify the variable model parameters under the wide variation range of current vectors and speeds, some necessary simplifications or iteration solutions should be adopted, which may lead to the sacrifice of accuracy or time cost. In this paper, a loss model with series iron-loss resistance is introduced. This model is much mathematically simpler than the traditional one and is quite appropriate for parameters identification. Besides, considering the variable currents and speeds, the torque-related and loss-related parameters’ variation is discussed to improve the accuracy of torque and motor loss under different operating conditions. The analysis results are verified on a prototype IPMSM experimentally.