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A Novel Hybrid Technique for Thermal Analysis of Permanent Magnet Synchronous Motor Used in Electric Vehicle Application
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on April 14, 2020 by SAE International in United States
Due to high torque and power density, nowadays permanent magnet synchronous motor has become the most viable candidate as traction motor for electric vehicle application. Moreover, the permanent magnet synchronous motor is also comparatively more advantageous in terms of size and weight due to its compact structure which is a favorable feature for the smooth operation of electric vehicles. However, on the other hand, such high torque and high power density within such a compact motor structure cause a significant temperature rise within the motor while in operation. As a result of such high temperature rise, permanent demagnetization may occur within the motor. Thus, the permanent magnet synchronous motor is susceptible to thermal instability. Therefore, to ensure thermally stable operation condition, thermal analysis is also a mandatory procedure besides electromagnetic analysis during the design phase of the motor. In this paper, a computationally efficient numerical finite element analysis process has been proposed for thermal analysis of the permanent magnet synchronous motor. The proposed method is a hybrid technique which is also utilizing the analytical lumped parameter thermal network and the numerical computational fluid dynamics strategies to address the weaknesses of the finite element analysis process. The main goal of the proposed method is to make the thermal analysis process computationally more efficient for motor temperature prediction by keeping the proper balance between simplification and accuracy of the process. Later, the proposed method has been used to check the thermal performance of the newly designed interior permanent magnet synchronous motor prototype for future electric vehicle application. Finally, the analyzed results from the proposed method have been validated through experiments to show improvements.