Analysis and Research on Local Irreversible Demagnetization of Inverter-Powered PM Motor
Xian Li, Xiuhe Wang, Zezhi Xing
Abstract
Irreversible demagnetization (ID) is one of the essential indicators that must be considered in the motor design stage. To address the problem that the existing magnetic circuit method can only determine the average operating point of the permanent magnet (PM), based on the PM subdivision model and the subdomain method, a novel calculation method for local ID (LID) of the motor is established in this article, which realizes the fast and accurate positioning and calculation of LID of the PM. The accuracy of the proposed method is verified by finite-element simulation and prototype test. To accurately simulate the multiphysical field coupling of electric–magnetic–machine–thermal–control in inverter-PM motor system, a dynamic model integrated with the drive control scheme is proposed, in which the ID cumulative effect and magnetic saturation effect are considered. The ID process of each PM unit and the motion behavior during dynamic process can be precisely simulated, and the LID state can be retained to evaluate its effects on motor performance. Finally, a fast temperature calculation method based on multiple regression analysis is presented, and the interaction between temperature rise, load, and ID, as well as the LID performance under sudden load and flux-weakening control are investigated.