Preisach 모델을 이용한 영구자석 전동기의 히스테리시스 토크 해석

Abstract

Generally, hysteresis phenomena occur under numerous physical conditions. In particular, such phenomena lead to hysteresis loss in iron and thus to unnecessary energy loss from the perspective of electrical machines using magnetic energy. Such energy creates hysteresis torque in the direction opposite to the driving direction of the motor and cause problems in securing the linearity of control in driven power steering. Hence, there is a need for an analysis method to evaluate the hysteresis torque within the motor. The recent trend in the analysis of hysteresis loss has been to compute it by applying a hysteresis model to nonlinear model of iron cores. In particular, a hysteresis model is added to a nonlinear magnetizing curve to apply the finite element method repeatedly, using pseudo permeability and the definition of association with permeability of each movement condition along with the previous analysis results. Based on the Preisach hysteresis model, the present paper constructs a hysteresis model that can utilize the measurements. Furthermore, it introduces the resulting hysteresis model in the post-process of the finite element analysis. By determining the direction and size of the input magnetic field for each element in the post-process, the mark and size are granted to the strength of the magnetic field. Moreover, a suggestion is made for the method to enable the method to derive the hysteresis torque easily by substituting the Preisach density with the Everett density. The proposed analysis method combines the hysteresis model with the post- process of the finite element analysis, to secure the hysteresis curve and calculate the hysteresis torque without major changes in the existing algorithm. In particular, given the impossibility of directly measuring the hysteresis torque of the equipment to verify the method comparisons are achieved by experimenting with motors in which hysteresis torque phenomena occur most frequently. The suggested calculating method is very simple and does not apply disguised permeability to shorten the analysis time. Hence, it is likely to be helpful in calculating hysteresis torque and losses in future studies.