Bolting or sleeve are applied to permanent magnet synchronous generators (PMSGs) to prevent shattering permanent magnet (PM)-generated defects1,2. Of these, bolting is more useful than a sleeve during manufacturing. However, as the magnetic flux is reduced due to the material characteristics of the bolting, overhang structure is often used for PM machines to compensate for the flux reduction2. Therefore, the axial length of the rotor must be considered during the overhang structure-based 3D analysis2. However, the analysis of a 3D model with diverse and complex design variables is time-intensive2. In this study, we analyzed a PMSG considering the bolting and overhang structure based on an analytical method. Preferably, the initial design process must consider several variables, and the analysis time of a PMSG with a complex structure must be reduced2. Characteristic analyses using a semi-3D method have been employed previously. However, there is a limit to the variation of 2D design variables to ensure that they are not saturated when considering a 3D shape. Therefore, we propose analytical methods using electromagnetic transfer relations3. It was used to analytical method considering the operating point of the PM calculated through magnetic energy analyses of the overhang and 3D models 2–4. These were applied to the region of PMs with the overhang1,2. Performance analysis of the separated overhang and bolting regions was conducted based on the superposition principle1,2. A circuit parameter was derived based on the predicted results and applied to the equivalent circuit of the generator2. The performance results were compared with the 3D model and experimental results. Figs. 1(a)–(c) and 2(a) illustrate the manufactured and analysis models, respectively. Fig. 2(b) depicts the variation in the operating point of the PM. Figs. 2(c) and (d) illustrate the results obtained from the comparison of 3D, analytical, and experiment models. The results appear to be in near agreement.

References:

1 K.H Shin, J.Y. Choi, "Electromagnetic Analysis of Permanent Magnet Synchronous Generator Considering Permanent Magnet Bolting" KOSMEE, pp. 154-154, 2018.
2 J.S. Hong, K.H. Shin, J.Y. Choi.,"Semi-3D Analysis of a Permanent Magnet Synchronous Generator Considering Bolting and Overhang Structure." Energies 15, no. 12: 4374.2022.
3 S. Jang, M. Koo, J. Choi, "Characteristic Analysis of Permanent Magnet Synchronous Machines Under Different Construction Conditions of Rotor Magnetic Circuits by Using
Electromagnetic Transfer Relations," in IEEE Transactions on Magnetics, vol. 47, no. 10, pp. 3665-3668, Oct. 2011.
4 J. Song, J. H. Lee, S. Jung, "Computational Method of Effective Remanence Flux Density to Consider PM Overhang Effect for Spoke-Type PM Motor With 2-D Analysis Using
Magnetic Energy," in IEEE Transactions on Magnetics, vol. 52, no. 3, pp. 1-4, March 2016.