Sage Journals: Discover world-class research

Abstract

When the interior permanent magnet (PM) machine operates under load condition, the armature current is ahead of the back electromotive force. However, the advanced armature current produces the demagnetizing field, which makes the irreversible demagnetization appeared in PMs easily. In this paper, aiming at the U-type PM structure, the expressions of the flux density components in the corresponding magnetizing directions of PMs at each node of PMs are derived. A calculation model to analyze the demagnetization in PMs is established in the Finite Element software by utilizing the derived expressions. Several improved geometries for rotor are proposed in this paper to strengthen the anti-demagnetization ability of PM. Based on the established calculation model, effects of variables in the improved geometries on the demagnetization in PMs and the rated electromagnetic torque are analyzed in detail. Based on the analysis results, optimized improved rotor geometry is achieved giving consideration to the anti-demagnetization ability of PM and rated electromagnetic torque.

Keywords

U-type PM structure interior PM machine improved rotor geometry irreversible demagnetization

Get full access to this article

View all access options for this article.

References

Rehman

Nino-Baron

T.E.

and Strangas

E.G.

, Iron and magnet losses and torque calculation of interior permanent magnet synchronous machines using magnetic equivalent circuit, IEEE Transactions on Magnetics 46(12) (2010), 4073–4080.

Woo

Lim

and Jung

, Rotor design strategy of interior permanent magnet synchronous motor for fuel cell electric vehicle, International Journal of Applied Electromagnetics and Mechanics 40(1) (2012), 51–66.

Xia

Guo

Zhang

Shi

and Wang

, Optimal designing of permanent magnet cavity to reduce iron loss of interior permanent magnet machine, IEEE Transactions on Magnetics 51(12) (2015), 8115409.

Tang

, Modern Permanent Magnet Machines-Theory and Design, Machinery Industry press Beijing, 1997, pp. 164–174.

Ruoho

Dlala

and Arkkio

, Comparison of demagnetization models for finite-element analysis of permanent-magnet synchronous machines, IEEE Transactions on Magnetics 43(11) (2007), 3964–3968.

Shi

, The Research of Anti-Demagnetization Technology of Permanent Magnet in High Density Permanent Magnet Motor, Shanghai University, 2012.

Lee

Kim

Jin

and Lee

, Local demagnetisation analysis of a permanent magnet motor, IET Electric Power Applications 9(3) (2015), 280–286.

McFarland

J.D.

and Jahns

T.M.

, Investigation of the rotor demagnetization characteristics of interior pm synchronous machines during fault conditions, IEEE Transactions on Industry Applications 50(4) (2014), 2768–2775.

Ruoho

Kolehmainen

Ikäheimo

and Arkkio

, Interdependence of demagnetization, loading, and temperature rise in a permanent-magnet synchronous motor, IEEE Transactions on Magnetics 46(3) (2010), 949–953.

10.

and Sarlioglu

, Partial Irreversible Demagnetization assessment of flux-switching permanent magnet machine using ferrite permanent magnet material, IEEE Transactions on Magnetics 51(7) (2015), 8106209.

11.

Patel

V.I.

Wang

and Nair

S.S.

, Demagnetization assessment of fractional-slot and distributed wound 6-phase permanent magnet machines, IEEE Transactions on Magnetics 51(6) (2015), 8105511.

12.

Ruoho

and Arkkio

, Mixed-grade pole design for permanent magnet synchronous machines, in: International Aegean Conference on Electrical Machines and Power Electronics, 2007, pp. 452–457.

13.

Ruoho

Kolehmainen

Ikäheimo

and Arkkio

, Demagnetization testing for a mixed-grade dovetail permanent-magnet machine, IEEE Transactions on Magnetics 45(9) (2009), 3284–3289.

14.

Kim

and Lee

, Demagnetization analysis of permanent magnets according to rotor types of interior permanent magnet synchronous motor, IEEE Transactions on Magnetics 45(6) (2009), 2799–2802.

15.

Shen

Jin

and Yang

, Investigation and Countermeasures for Demagnetization in Line Start Permanent Magnet Synchronous Motors, IEEE Transactions on Magnetics 49(7) (2013), 4068–4071.

16.

Imamura

Sanada

Morimoto

and Inoue

, Improvement of Characteristics by Flux Barrier Shape and Magnet Thickness of IPMSM with Dy-free Rare-Earth Magnet, in: 15th European Conference on Power Electronics and Applications (EPE), 2013, pp. 1–10.

17.

Sanada

Inoue

and Morimoto

, Rotor structure for reducing demagnetization of magnet in a PMASynRM with ferrite permanent magnet and its characteristics, in: IEEE Energy Conversion Congress and Exposition (ECCE), 2011, pp. 4189–4194.

Improving rotor geometry to strengthen anti-demagnetization ability of PM

Abstract

Keywords

Get full access to this article

References