Abstract
In-wheel direct drive motors are placed inside drive wheels of electric vehicles and have to deliver large torque without any mechanical gear. Most often these machines are of synchronous type with permanent magnets and large pole-pair number. As a consequence of high peak torque, both cogging torque and torque ripple are increased if no measures are taken to decrease them. The vibrations due to cogging torque and torque ripple result in noise and reduced motor durability. In this paper, analytical equations and finite element method are derived, developed and used in order to analyse the dependence of cogging torque on magnet shape and size. A novel magnet shape is found that eliminates cogging torque without reducing the motor torque constant or increasing magnet size. The shape is applicable to any surface mounted permanent magnet motor with high number of pole pairs.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Fazil M, Rajagopal KR (2010) A novel air-gap profile of single-phase permanent-magnet brushless DC motor for starting torque improvement and cogging torque reduction. Magn IEEE Trans 46:3928–3932
Lin Y, Hu Y, Lin T, Lin H, Chang Y, Chen C, Wang S, Ying T (2000) A method to reduce the cogging torque of spindle motors. J Magn Magn Mater 209:180–182
Wang D, Wang X, Kim M, Jung S (2012) Integrated optimization of two design techniques for cogging torque reduction combined with analytical method by a simple gradient descent method. Magn IEEE Trans 48:2265–2276
Ashabani M, Mohamed YA-RI (2011) Multiobjective shape optimization of segmented pole permanent-magnet synchronous machines with improved torque characteristics. Magn IEEE Trans 47:795–804
Wrobel R, Lukaniszyn M, Jagiela M, Latawiec K (2002) A new approach to reduction of the cogging torque in a brushless motor by skewing optimization of permanent magnets. Electr Eng 85:59–69
Goto H, Suzuki Y, Nakamura K, Watanabe T, Guo HJ, Ichinokura O (2005) A multipolar SR motor and its application in EV. J Magn Magn Mater 290–291:1338–1342
Bianchi N, Bolognani S (2002) Design techniques for reducing the cogging torque in surface-mounted PM motors. Ind Appl IEEE Trans 38:1259–1265
Saied SA, Abbaszadeh K (2009) Cogging torque reduction in brushless DC motors using slot-opening shift. Adv Elec Comput Eng 9:28–33
Arof H, Eid AM, Nor KM (2004) Cogging force reduction using special magnet design for tubular permanent magnet linear generators In: Universities power engineering conference, 2004. UPEC 2004. 39th International, vol 1, pp 523–527
Gonzalez DA, Tapia JA, Bettancourt AL (2007) Design consideration to reduce cogging torque in axial flux permanent-magnet machines. Magn IEEE Trans 43:3435–3440
Rahman MF, Zhone L, Lim KW (1996) A DSP based instantaneous torque control strategy for interior permanent magnet synchronous motor drive with wide speed range and reduced torque ripples. In: Industry applications conference, 1996. Thirty-first IAS annual meeting, IAS’96. Conference record of the 1996 IEEE, vol 1, pp 518–524
Fei W, Luk P (2010) A new technique of cogging torque suppression in direct-drive permanent-magnet brushless machines. Ind Appl IEEE Trans 46:1332–1340
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Gotovac, G., Detela, A., Lampič, G. et al. Analytical and FEM approach to reduce the cogging torque in in-wheel motors. Electr Eng 97, 269–275 (2015). https://doi.org/10.1007/s00202-015-0334-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00202-015-0334-5