Cogging Torque Minimization Using Skewed and Separated Magnet Geometries

Year 2020, Volume: 23 Issue: 1, 223 - 230, 01.03.2020

Adem Dalcalı , Erol Kurt , Emre Çelik , Nihat Öztürk

https://doi.org/10.2339/politeknik.552273

Cited By: 8

Abstract

In the study, analytical design, analysis and
optimization of a 2.5 kW 14-pole, 84-slot permanent magnet synchronous
generator (PMSG) have been performed. The performance characteristics of this
PMSG such as efficiency, torque, cogging torque and magnetic flux density are
assessed. Then, 3D model of the respective generator is acquired to examine the
effect of magnet geometry on the cogging torque produced. In that context, the
effects of splitted and skewed magnet structures are examined. In the first design,
the magnet is modelled with one piece and the rms value of the cogging torque
is found as 436.75 mNm. In the second case, a certain skewed slit is made
alongside the magnet and that yields a slightly reduced cogging torque of
434.58 mNm. In the other design, the magnet of the first design is divided into
two sub-parts, which are then combined together in a skewed fashion. Thus, the
value of cogging torque is found as 159.60 mNm. Eventually, by making two
certain slits on the last model, cogging torque is further depressed down to
89.95mNm. It is concluded from the obtained results that the last design
contributes an improvement in the value of cogging torque up to 80% compared to
the initial design.

Keywords

cogging torque, skewing, PMSG, finite element analysis

References

• [1] Dalcalı A. and Akbaba M., “Optimum pole arc offset in permanent magnet synchronous generators for obtaining lowest voltage harmonics”, Scientia Iranica. Transaction D: Computer Science &Amp; Engineering and Electrical Engineering, 24: 3223-3230, (2017).
• [2] Naciri M., Aggour M. and Ahmed W.A., “Wind energy storage by pumped hydro station”, Journal of Energy Systems, 1: 32-42, (2017).
• [3] Uğurlu A., “An overview of Turkey's renewable energy trend”, Journal of Energy Systems, 1: 148-158, (2017).
• [4] International Energy Agency, “World Energy Outlook 2014”, Paris, France, (2014).
• [5] General Director of Renewable Energy, “2017 Unit Activity Report”, Ankara, Turkey, (2018.)
• [6] Çakır M.T., “Wind Energy potential of turkey and its place in EU countries”, Journal of Polytechnic, 13: 287-293, (2010).
• [7] Altın N. and Eyimaya S.E., “A combined energy management algorithm for wind turbine/ battery hybrid system”, Journal of Electronic Materials, 47: 4430-4436, (2018).
• [8] Sharma M., “Wind energy driven passive solar tracking system”, Int. J. of Renewable Energy Technology, 7: 240-245, (2016).
• [9] Yoo J.H., Park C.S. and Jung T.U., “Permanent magnet structure optimization for cogging torque reduction of outer rotor type radial flux permanent magnet generator”, IEEE International Electric Machines and Drives Conference, Miami, FL, USA, (2017).
• [10] 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, 42: 17593-17600, (2017).
• [11] Dai J.C., Hu Y.P., Liu D.S. and Wei J., “Modelling and analysis of direct-driven permanent magnet synchronous generator wind turbine based on wind-rotor neural network model”, Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 226: 62-72, (2011).
• [12] Lyan O., Jankunas V., Guseınoviene E., Pasilis A., Senulis A., Knolis A. and Kurt E., “Exploration of a permanent magnet synchronous generator with compensated reactance windings in parallel rod configuration”, Journal of Electronic Materials, 47: 1-7, (2018).
• [13] Duan J., Fan S., Wu F., Sun L. and Wang G., “Instantaneous power control of a high speed permanent magnet synchronous generator based on a sliding mode observer and a phase locked loop”, International Journal of Electronics, 105: 923-940, (2017).
• [14] Zhu X., Hua W., Wu Z., Huang W., Zhang H. and Cheng M., “Analytical approach for cogging torque reduction in flux-switching permanent magnet machines based on magnetomotive force-permeance model”, IEEE Transactions on Industrial Electronics, 65: 1965-1979, (2018).
• [15] Ping J., Shuhua F. and Ho. S.L., “Distribution characteristic and combined optimization of maximum cogging torque of surface-mounted permanent-magnet machines”, IEEE Transactions on Magnetics, 54(3), (2018).
• [16] Chu, W.Q. and Zhu Z.Q., “Investigation of torque ripples in permanent magnet synchronous machines with skewing”, IEEE Transaction on Magnetics, 49: 1211-1220, (2013).
• [17] Goryca Z., Paduszynski K and Pakosz A., “Model of the multipolar engine with decreased cogging torque by asymmetrical distribution of the magnets”, Open Physics, 16: 42-45, (2018).
• [18] Jia H., Cheng M., Hua W., Yang Z. and Zhang Y., “Compensation of cogging torque for flux-switching permanent magnet motor based on current harmonics injection”, IEEE International Electric Machines and Drives Conference, Miami, FL, USA, 286-291, (2009).
• [19] Hasanien H.M., “Torque ripple minimization of permanent magnet synchronous motor using digital observer controller”, Energy Conversion and Management, 51: 98–104, 2010.
• [20] Güemes J.A., Iraolagoitia A.M., Del Hoyo J.I and Fernandez P., “Torque analysis in permanent-magnet synchronous motors: a comparative study”, IEEE Transaction on Energy Conversion, 26: 55- 63, (2011).
• [21] Herlina, Setiabudy R. and Rahardjo A., “Cogging torque reduction by modifying stator teeth and permanent magnet shape on a surface mounted PMSG”, International Seminar on Intelligent Technology and Its Application, Indonesia, 227-232, (2017).
• [22] Tseng W.T. and Chen W.S., “Design parameters optimization of a permanent magnet synchronous wind generator”. 19th International Conference on Electrical Machines and Systems, Japan, (2016).
• [23] Liu G., Zeng Y., Zhao W. and Ji J., “Permanent magnet shape using analytical feedback function for torque improvement”, IEEE Transactions on Industrial Electronics, 65: 4619- 4630, (2018).
• [24] Qiu H., Hu K., Yu W. and Yang C., “Influence of the magnetic pole shape on the cogging torque of permanent magnet synchronous motor”, Australian Journal of Electrical and Electronics Engineering, 14:64-70, (2017).
• [25] Duan Y. “Method for design and optimization of surface mount permanent magnet machines and induction machines”, PhD diss., Georgia Institute of Technology, 2010.
• [26] Zala B.O. and Pugachov V., “Methods to Reduce cogging torque of permanent magnet synchronous generator used in wind power Plants”, Elektronika Ir Elektrotechnika, 23: 43-48, (2017).
• [27] Ou J., Liu Y., Qu R. and Doppelbauer M., “Experimental and theoretical research on cogging torque of PM synchronous motors considering manufacturing tolerances”, IEEE Transactions on Industrial Electronics, 65: 3772-3783, (2018).
• [28] Dosiek L. and Pillay R., “Cogging torque reduction in permanent magnet machines”, IEEE Transactions on Industry Applications, 43: 1565-1570 (2007).[29] Ho S.-L. and Fu W.N., “Review and future application of finite element methods in induction motors”, Electric Machines & Power Systems, 26: 111–125, (1998).
• [30] Bouloukza I., Mordjaoui Mm, Kurt E., Bal G. and Ökmen Ç., “Electromagnetic design of a new radial flux permanent magnet motor”, Journal of Energy Systems, 2: 13-27, (2018).
• [31] Faiz J., Ebrahimi B.M. and Sharifian M.B.B., “Finite Element transient analysis of an on-load three-phase squirrel-cage induction motor with static eccentricity”, Electromagnetics, 27: 207-227, (2007).
• [32] Kurt E., Gör H. and Döner U., “Electromagnetic design of a new axial and radial flux generator with the rotor back-irons”, International Journal of Hydrogen Energy, 41: 7019-7026, (2016).
• [33] Lin H., Wang D., Liu D. and Chen J., “Influence of magnet shape on torque behavior in surface-mounted permanent magnet motor”, 17th International Conference on Electrical Machines and Systems, China, (2014).
• [34] Dalcalı A. and Akbaba, M., “Comparison of 2D and 3D magnetic field analysis of single-phase shaded pole induction motors”, Engineering Science and Technology, An International Journal, 19:1-7, (2016).