Document Type : Research Article


Department of Electrical and Computer Engineering, Babol Noshiravani University of Technology, P. O. Box: 47148-71167, Babol, Mazandaran, Iran.


Nowadays, the Permanent Magnet (PM) generator has become an instrumental tool for wind power generation due to its high performance. In this study, an optimal design is established to provide a cost-effective multiphase outer-rotor PM wind generator (OR-PMWG). The cost of the generation system (generator and power converter) as well as the annual energy output must be optimized to ensure cost-effective PM wind generation. In fact, the main novelty of this paper lies in the presentation of an accurate model of OR-PMWG and the investigation of the design variables affecting annual energy output and the generation system cost (GSC). In this respect, a multi-objective framework is presented to make satisfactory agreement among all objectives. At first, the main optimal design objectives namely generation system cost and annual energy output are optimized separately and then, a multi-objective optimization is established, in which all the objectives are considered simultaneously. In order to tackle these optimization problems, Genetic Algorithm (GA) is adopted herein to determine the design variables. It is also shown that simultaneous optimization with 71.39 (MWh) AEO and 2651.51 (US$) GSC leads to a more optimal design for a PM wind generation system. In addition, the effectiveness of the presented optimal design is demonstrated by making a comparison between a prototype outer-rotor PM wind generator and the theoretical counterpart. Finally, a finite element analysis (FEA) is carried out for the validation of the outcomes obtained from the proposed optimal design. 


Main Subjects

  1. Eterafi, S., Gorjian, S. and Amidpour, M., "Effect of covering aperture of conical cavity receiver on thermal performance of parabolic dish collector: Experimental and numerical investigations", Journal of Renewable Energy and Environment (JREE), Vol. 8, No. 4, (2021), 29-41. (
  2. Hosseini, E., Behzadfar, N., Hashemi, M., Moazzami, M. and Dehghani, M., "Control of pitch angle in wind turbine based on doubly fed induction generator using fuzzy logic method", Journal of Renewable Energy and Environment (JREE), Vol. 9, No. 2, (2022), 1-7. (
  3. Global Wind Energy Council, "Global wind report: Annual market update 2021", (2021). (, (Accessed: 11 March 2021).
  4. Jahangiri, M., Karimi Shahmarvandi, F. and Alayi, R., "Renewable energy-based systems on a residential scale in southern coastal areas of Iran: Trigeneration of heat, power, and hydrogen", Journal of Renewable Energy and Environment (JREE), Vol. 8, No. 4, (2021), 67-76. (
  5. Abdoos, A.A., Moazzen, M.E. and Hosseini, S.M., "Optimal design of an exterior-rotor permanent magnet generator for wind ‎power applications", Journal of Operation and Automation in Power Engineering (JOAPE), Vol. 9, No. 3, (2021), 193-202. (
  6. Grauers, A., "Design of direct-driven permanent-magnet generators for wind turbines", Doctoral Thesis at School of Electrical and Computer Engineering, Chalmers University of Technology, (1996), 76-79. (
  7. Hailemariam, Z.M., Leidhold, R. and Tesfamariam, G.T., "Real-time dc-link voltage control of 5-kW PMSG-based wind turbine generator through a test-rig", Electrical Engineering (EE), Vol. 103, (2021), 1869-1880. (
  8. Polinder, H., Pijl, F., Vilder, G. and Tavner, P., "Comparison of direct-drive and geared generator concepts for wind turbines", IEEE Transactions on Energy Conversion (IEEETEC), Vol. 23, No. 3, 725-733, (2006). (
  9. Puri, V., Chauhan, Y.K. and Singh, N., "A comparative design study and analysis of inner and outer rotor permanent magnet synchronous machine for power generation in vertical axis wind turbine using GSA and GSA-PSO", Sustainable Energy Technologies and Assessments (SETA), Vol. 23, (2017), 136-148. (
  10. Tapia, J., Pyrhönen, J., Puranen, J., Lindh, P. and Nyman, S., "Optimal design of large permanent magnet synchronous generators", IEEE Transactions on Magnetics (IEEETM), Vol. 49, No. 1, (2013), 642-650. (
  11. Chen, J., Nayar, C.V. and Xu, L., "Design and finite-element analysis of an outer-rotor permanent-magnet generator for directly coupled wind turbines", IEEE Transactions on Magnetics (IEEETM), Vol. 36, No. 5, (2000), 3802-3809. (
  12. Li, H., Chen, Z. and Polinder, H., "Optimization of multibrid permanent- magnet wind generator systems", IEEE Transactions on Energy Conversion (IEEETEC), Vol. 24, No. 1, (2009), 82-92. (
  13. Lee, S., Kim, Y., Lee, K. and Kim, S., "Multiobjective optimization design of small-scale wind power generator with outer-rotor based on box–behnken design", IEEE Transactions on Applied Superconductivity (IEEETASC), Vol. 26, No. 4, (2016), 605-609. (
  14. Bazzo, T.P.M., Kolzer, J.F., Carlson, R., Wurtz, F. and Gerbaud, L., "Multiphysics design optimization of a permanent magnet synchronous generator", IEEE Transactions on Industrial Electronics (IEEETIE), Vol. 64, No. 12, (2017), 9815-9823. (
  15. McDonald, A. and Bhuiyan, N., "On the optimization of generators for offshore direct drive wind turbines", IEEE Transactions on Energy Conversion (IEEETEC), Vol. 32, No. 1, (2017), 348-358. (
  16. Asef, P., Perpiñà, R.B., Barzegaran, M.R., Lapthorn, A. and Mewes, D., "Multiobjective design optimization using dual-level response surface methodology and booth's algorithm for permanent magnet synchronous generators", IEEE Transactions on Energy Conversion (IEEETEC), Vol. 33, No. 2, (2018), 652-659. (
  17. Potgieter, J.H.J. and Kamper, M.J., "Torque and voltage quality in design optimization of low-cost non-overlap single layer winding permanent magnet wind generator", IEEE Transactions on Industrial Electronics (IEEETIE), Vol. 59, No. 5, (2012), 2147-2156. (
  18. Öztürk, N., Dalcalı, A., Çelik, E. and Sakar, S., "Cogging torque reduction by optimal design of PM synchronous generator for wind turbines", International Journal of Hydrogen Energy (IJHE), Vol. 42, (2017), 17593-17600. (
  19. Sedaghat, A., El Haj Assad, M. and Gaith, M., "Aerodynamics performance of continuously variable speed horizontal axis wind turbine with optimal blades", Energy, Vol. 77, (2014), 752-759. (
  20. Sedaghat, A., Samani, I., Ahmadi-Baloutaki, M., El Haj Assad, M. and Gaith, M., "Computational study on novel circulating aerofoils for use in Magnus wind turbine blades", Energy, Vol. 91, (2015), 393-403. (
  21. Abidoye, L.K., Bani-Hani, E., El Haj Assad, M., AlShabi, M., Soudan, B. and T Oriaje, A., "Effects of environmental and turbine parameters on energy gains from wind farm system: Artificial neural network simulations", Wind Engineering (WE), Vol. 44. No. 2, (2019), 181-195.vv (
  22. Bazzo, T.P.M., Kolzer, J.F., Carlson, R., Wurtz, F. and Gerbaud, L., "Multidisciplinary design optimization of direct-drive PMSG considering the site wind profile", Electric Power Systems Research (EPSR), Vol. 141, (2016), 467-475. (
  23. Li, F. and Zhu, X., "Comparative study of stepwise optimization and global optimization on a nine-phase flux-switching PM generator", Energies, Vol. 14, No. 16, (2021), 4754. (
  24. Singh, G., Kumar, A. and Saini, R., "Performance evaluation of series compensated self-excited six-phase induction generator for stand-alone renewable energy generation", Energy, Vol. 35, No. 1, (2010), 288-297. (
  25. Pyrhönen, J., Jokinen, T. and Hrabovcová, V., Design of rotating electrical machines, Wiley, USA, (2009), 512-519. (
  26. Boldea, I., Variable speed generators, CRC Press, (2005), 420-423. (
  27. Gieras, J.F., Permanent magnet motor technology, design and applications, CRC Press, (2010), 100-102. (
  28. Kurt, E, Gör, H. and Çelik, K., "Optimization of a 3-kW axial flux permanent magnet generator with variable air gap", International Transactions on Electrical Energy Systems (ITEES), Vol. 31, No. 11, (2021), e13074. (
  29. Khan, A. and Pillay, P., "Design of a PM wind, optimized for energy capture over a wide operating range", IEEE International Conference on Electrical Machines and Drives, San Antonio, TX, USA, (2005), 1501-1506. (
  30. Wang, T. and Wang, Q., "Optimization design of a permanent magnet synchronous generator for a potential energy recovery system", IEEE Transactions on Energy Conversion (IEEETEC), Vol. 27, No. 4, (2012), 856-863. (
  31. Eriksson, S. and Bernhoff, B., "Loss evaluation and design optimization for direct driven permanent magnet synchronous generators for wind power", Applied Energy (AE), Vol. 88, No. 1, (2011), 265-271. (
  32. Jagau, H., Khan, M.A. and Barendse, P., "Design of a sustainable wind generator system using redundant material", IEEE Transactions on Industry Applications (IEEETIA), Vol. 23, No. 6, (2012), 1827-1837. (
  33. Iranian Renewable Energy Organization Magazine, (2010) (in Farsi) . (, (Accessed: 15 July 2010).
  34. Abdoos, A.A., Moazzen, M.E. and Ebadi, A., "Optimal design of a radial-flux permanent magnet generator with outer-rotor for direct-drive wind turbines", Computational Intelligence in Electrical Engineering (CIEE), Vol. 11, No. 4, (2020), 51-64. (In Farsi)  (