In-wheel Motor Design for an Electric Scooter

  • Lee, Ji-Young (Electric Motor Research Center, Korea Electrotechnology Research Institute) ;
  • Woo, Byung-Chul (Electric Motor Research Center, Korea Electrotechnology Research Institute) ;
  • Kim, Jong-Moo (Electric Motor Research Center, Korea Electrotechnology Research Institute) ;
  • Oh, Hong-Seok (Star Group Industry Company (SGI))
  • Received : 2017.05.15
  • Accepted : 2017.08.16
  • Published : 2017.11.01


The aim of this paper is to provide an optimal design of in-wheel motor for an electric scooter (E-scooter) considering economical production. The preliminary development in-wheel motor, which has a direct-driven outer rotor type attached to the E-scooter's rear wheel without any gear, is introduced first. The objective of the optimal design of this in-wheel motor is to improve the output characteristics of the motor and to have a stator form to facilitate automatic winding. Response surface methodology was used for the optimal design and 2-dimensional finite element method was used for electro-magnetic field analysis. Experimental results showed that the designed and fabricated in-wheel motor could satisfy the required specifications in terms of speed, power, efficiency, and cogging torque.


Supported by : NST


  1. K. Sone, M. Takemoto, S. Ogasawara, K. Takezaki, and H. Akiyama, "A ferrite PM in-wheel motor without raer earth materials for electric city commuters," IEEE Trans. Magn., vol. 48, no. 11, pp. 2961-2964, Nov. 2012.
  2. S. Chung, S. Moon, D. Kim, and J. Kim, "Development of a 20-pole-24-slot SPMSM with consequent pole rotor for in-wheel direct drive," IEEE Trans. Ind. Electron., vol. 63, no. 1, pp. 302-309, 2016.
  3. C. J. Ifedi, B. C. Mecrow, S. T. M. Brockway, B. S. Boast, G. J. Atkinson, and D. K. Perovic, "Faulttolerant in-wheel motor topologies for highperformance electric vehicle," IEEE Trans. Ind. Appl., vol. 49, no. 3, pp. 1249-1257, May/June 2013.
  4. Y. P. Yang, H. C. Lin, F. C. Tsai, C. T. Lu, and K. H. Tu, "Design and integration of dual power wheels with rim motors for a powered wheelchair," IET Electr. Power Appl., vol. 6, no. 7, pp. 419-428, 2012.
  5. Y. P. Yang, W. C. Huang, and C. W. Lai, "Optimal design of rim motor for electric powered wheelchair," IET Electr. Power Appl., vol. 1, no. 5, pp. 825-832, 2007
  6. Y. P. Yang, F. X. Ding, "Driving-scenario oriented design of an axial-flux permanent-magnet synchronous motor for a pedal electric cycle," IET Electr. Power Appl., vol. 9, no. 6, pp. 420-428, 2015
  7. T. F. Chan, L. T. Yan, and S.Y. Fang, "In-wheel permanent-magnet brushless dc motor drive for an electric bicycle," IEEE Trans. Energy conversion, vol. 17, no. 2, pp. 229-233, June 2002.
  8. A. Muetze and Y. C. Tan, "Electric bicycles - a performance evaluation," IEEE Ind. Appl. Magazine, pp. 12-21, 2007.
  9. Z. Q. Zhu and D. Howe, "Electrical machines and drives for electric, hybrid, and fuel cell vehicles," Proceedings of the IEEE, vol. 95, no. 4, pp. 746-765, April 2007.
  11. T. Kim, O. Vodyakho, and J. Yang, "Fuel cell hybrid electric scooter," IEEE Ind. Appl. Magazine, pp. 25-31, Mar/Apr. 2011.
  12. D. Fodorean, L. Idoumghar, and L. Szabo, "Motorization for an electric scooter by using permanentmagnet machines optimized based on a hybrid metaheuristic Algorithm," IEEE Trans. Vehicular Technology, vol. 62, no. 1, pp. 39-49, January 2013.
  13. Y. Yang, C. Lee, and P. Hung, "Multi-objective optimal design of an axial-flux permanent-magnet wheel motor for electric scooters," IET Electr. Power Appl., vol. 8, iss. 1, pp. 1-12, 2014.
  14. I. Husan, Electric and Hybric Vehicles Design Fundamentals 2nd Edition, CRC Press, 2011.
  15. YM. Ehsani, Y. Gao, S. E. Gay, and A. Emadi, Modern Electric, Hybrid Electric, and Fuel Cell Vehicle, CRC Press, 2004.
  16. L. Guzzella and A. Sciarretta, Vehicle Propulsion Systems- Introduction to Modeling and Optimization 2nd Edition, Springer, 2007.
  17. Y. Chen, X. Li, C. Wiet, and J. Wang, "Energy management and driving strategy for in-wheel motor electric ground vehicles with terrain profile preview," IEEE Trans. Industrial Informatics, vol. 10, no. 3, pp. 1938-1947, 2014.
  18. J. Larminie and J. Lowry, Electric Vehicle Technology- Explained, Wiley, 2003.
  19. J. Lee, J. Kim, and B. Woo, "Optimal design of inwheel motor for an E-bike," in Proc. 2016 IEEE Transportation Electrification Conference and Expo (ITEC Asia-pacific), pp.441-443, 2016.
  20. D. Hong, J. Lee, B. Woo, D. Park, and B. Nam, "Investigating a direct-drive PM type synchronous machine for turret application using optimization," IEEE Trans. Magn., vol. 48, no. 11, pp. 4491-4494, November 2012.
  21. Maxwell online help, Ansys Corporation, Maxwell 16.0
  26. R. H. Myers and D. C. Montgomery, Response Surface Methodology: Process and Product Optimization Using Designed Experments, Nework, NY, USA: Wiley, 2002.
  27. S. Lee, J. Hong, S. Hwang, W. Lee, J. Lee, and Y. Kim, "Optimal design for noise reduction in interior permanent-magnet motor," IEEE Trnas. Ind. Appl., vol. 45, no. 6, pp. 1954-1960, Nov. 2009.
  28. J. Lee, B. Park, and B. Woo, "Design and comparison of multistage axial flux permanent magnet machines for portable generating application," Journal of Magnetics, vol. 20, no. 4, pp. 1-8, 2015.
  29. J. Xie, D. Kang, B. Woo, J. Lee, Z. Sha, and S. Zhao, "Optimal design of transverse flux machine for high contribution of permanent magnet to torque using response surface methology," JEET, vol. 7, no. 5, pp. 745-752, 2012.
  30. S. Chung, and J. Kim, "Double-sided iron-core PMLSM mover teeth arrangement design for reduction of detent force and speed ripple," IEEE Trans. Ind. Electron., vol. 63, no. 5, pp. 3000-3008, May 2016.
  31. D. Wang, X. Wang, and S. Jung, "Cogging torque minimization and torque ripple suppression in surface-mounted permanent magnet synchronous machines using different magnet widths," IEEE Trans. Magn., vol. 49, no. 5, pp. 2295-2298, May 2013.