Reduction of Magnet Eddy-Current Loss in Interior Permanent-Magnet Motors With Concentrated Windings

We designed and analyzed an interior permanent magnet synchronous motor (IPMSM) to prevent irreversible demagnetization of the permanent magnets (PMs). Irreversible demagnetization of NdFeB PMs mainly occurs due to high temperature, which should thus be minimized. Therefore, it is necessary to reduce the eddy current loss in the PM through optimal design. The shape of the rotor core was optimized using finite element analysis (FEA) and response surface methodology. Three-dimensional (3-D) FEA is required for accurate computation of the eddy current loss, but there is huge time, effort, and cost consumption. Therefore, a method is proposed for indirectly calculating the eddy current loss of PMs using 2-D FEA. A thermal equivalent circuit analysis was used to calculate the PM temperature of the optimized model. For the thermal analysis, the copper loss, core loss, and eddy current loss in PMs were estimated and applied as a heat source. Based on the results, we confirmed the stability of the optimum model in terms of the PM demagnetization.

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Analytical Modeling and Experimental Validation of Rotor Harmonic Eddy-Current Loss in High-Speed Surface-Mounted Permanent Magnet Motors

IEEE Transactions on Magnetics ◽

10.1109/tmag.2018.2882514 ◽

2019 ◽

Vol 55 (2) ◽

pp. 1-11 ◽

Cited By ~ 5

Author(s):

Zhongming Zhang ◽

Zhiquan Deng ◽

Quangui Sun ◽

Cong Peng ◽

Yu Gu ◽

...

Keyword(s):

Permanent Magnet ◽

Eddy Current ◽

High Speed ◽

Analytical Modeling ◽

Experimental Validation ◽

Eddy Current Loss ◽

Permanent Magnet Motors ◽

Current Loss

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Development of spoke-type IPM magnetic gear

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209389 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 771-778

Author(s):

Yuma Mizuana ◽

Kenji Nakamura ◽

Yuma Suzuki ◽

Yuhei Oishi ◽

Yuichi Tachiya ◽

...

Keyword(s):

Permanent Magnet ◽

Eddy Current ◽

Permanent Magnets ◽

Acoustic Noise ◽

Eddy Current Loss ◽

Current Loss ◽

Torque Density ◽

Output Torque ◽

Interior Permanent Magnet ◽

Magnetic Gear

Magnetic gears can change output-torque and -speed without any mechanical contacts. Therefore, they have a low acoustic noise and vibration, and their maintainability and reliability are high. Especially, a flux-modulated type magnetic gear is expected to be put into practical use because its torque density is higher than that of other magnetic gears. For the practical use, further improvement of torque and losses is important, especially, reduction of eddy current loss in permanent magnets (PMs) due to asynchronous harmonic magnetic fluxes is necessary. This paper investigates an interior permanent magnet (IPM) structure to improve the efficiency by reducing the eddy current loss in PMs. In addition, this paper presents a method for increasing torque of the IPM magnetic gear by changing a position of magnetic-bridge.

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