Thermal Analysis of Modular Fault-Tolerant Permanent Magnet Motor Based on Electromagnetic-Thermal Bi-Directional Coupling

Compared with multi-phase single-module permanent magnet motors, three-phase multi-modularized permanent magnet motors have stronger fault tolerance ability, widely used in aerospace, ship propulsion, and other special fields. Especially in ship direct-drive propulsion, low speed and high torque modular combined stator fault-tolerant permanent magnet motor (MCS-FTPMSM) has high torque density, and fault-tolerant operation conditions may appear in actual operation, so it is essential to analyze the temperature of the fault-tolerant motor accurately. This paper analyzes the temperature of MCS-FTPMSM under different operating conditions and determines the longest operating time of the motor under different fault-tolerant operating conditions based on the 3D electromagnetic-temperature bi-directional coupling method. Among them, the loss of the motor is calculated by the 3D electromagnetic field, which is added to the 3D temperature field as an excitation, and then the material properties in the 3D electromagnetic field are updated according to the calculated temperature distribution. The cyclic iteration method is used to make the calculated temperature deviation less than the given error value. When analyzing the electromagnetic loss of the motor, the field-circuit coupling method is adopted to consider the influence of the current time-harmonics of the controller on the loss of the motor during actual operation. Finally, the 12kw100r/min 3 x 3 modular prototype was tested. By comparing the results of experiments, one-way coupling method (OWCM) and bi-directional coupling method (BDCM), it is found that the electromagnetic-thermal bi-directional coupling can more accurately predict the temperature of the fault-tolerant motor. (c) 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.