Efficiency modeling and comparison of surface and interior permanent magnet machines for electric vehicle

This paper presents the analysis and comparisons between the Surface Permanent Magnet (SPM) and Interior Permanent Magnet (IPM) Machines about their loss and efficiency characteristics. To calculate the airgap flux density and torque, an analytic model is created. The loss functions are derived using the key design parameters which have a great influence on the loss characteristic. As a result, the efficiency can be calculated. The relationship between the design parameters and efficiency characteristic is investigated adopting the proposed method. The efficiency of different driving cycles is also calculated and compared. Finally, some principles are obtained to help the initial design to fit the actual loading requirement. The analytic results are compared with those by Finite Elements Analysis (FEA), and a prototype is made and tested to validate the proposed method and analysis. (c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This paper presents an analysis and comparison of the loss and efficiency characteristics between Surface Permanent Magnet (SPM) and Interior Permanent Magnet (IPM) Machines. An analytic model is created to calculate the airgap flux density and torque, and the loss functions are derived based on key design parameters. The relationship between the design parameters and efficiency characteristic is investigated, and the efficiency under different driving cycles is calculated and compared. The proposed method and analysis are validated through a comparison with Finite Elements Analysis (FEA) and testing on a prototype.