volume | PIER Journals

Abstract

An analytical expression of AC resistance of a single-layer air-core Helmholtz coil is presented. Proximity effects between both bundles and strands of litz-wire as well as skin effect are considered. To obtain an accurate analytical expression of proximity effect on bundle level and strand level, a precise distribution of magnetic field is discussed. The analytical expression of AC resistance and quality factor is verified with the experimental results, and the theoretical predictions are in agreement with the measured results.

1. Van Gossum, A. and M. Ibrahim, "Video capsule endoscopy: What is the future?," Gastroenterol. Clin. North Am., Vol. 39, 807, 2010.
doi:10.1016/j.gtc.2010.08.026 Google Scholar

2. Shiba, K., A. Morimasa, and H. Hirano, "Design and development of low-loss transformer for powering small implantable medical devices," IEEE Trans. Biomed. Circuits Syst., Vol. 4, 77-85, 2010.
doi:10.1109/TBCAS.2009.2034364 Google Scholar

3. Ma, G. Y. and G. Z. Yan, "Wireless powered microrobot for gastrointestinal detection," ICMA'07: nt. Conf. on Mechatronics and Automation, 1085-1089, 2007. Google Scholar

4. Chen, C. J., T. H. Chu, C. L. Lin, et al. "A study of loosely coupled coils for wireless power transfer," IEEE Transactions on Circuits and Systems II: Express Briefs, Vol. 57, No. 7, 536-540, 2010.
doi:10.1109/TCSII.2010.2048403 Google Scholar

5. Chen, L., S. Liu, Y. C. Zhou, et al. "An optimizable circuit structure for high-efficiency wireless power transfer," IEEE Transactions on Industrial Electronics, Vol. 60, No. 1, 339-349, 2013.
doi:10.1109/TIE.2011.2179275 Google Scholar

6. Bartoli, M., N. Noferi, A. Reatti, and M. K. Kazimierczuk, "Modeling litz-wire winding losses in high-frequencies power inductors," Proc. IEEE Power Electronics Specialists Conf., 1960-1966, Baveno, Italy, Jun. 24-27, 1996. Google Scholar

7. Ferreira, J. A., "Analytical computation of AC resistance of round and rectangular litz-wire windings," IEE Proc. B, Electr. Power Appl., Vol. 139, No. 1, 21-25, 1992.
doi:10.1049/ip-b.1992.0003 Google Scholar

8. Tourkhani, F. and P. Viarouge, "Accurate analytical model of winding losses in round litz wire winding," EEE Trans. Magn., Vol. 37, No. 1, 538-543, 2001.
doi:10.1109/20.914375 Google Scholar

9. Nan, X. and C. R. Sullivan, "An equivalent complex permeability model for litz-wire windings," IEEE Trans. Ind. Appl., Vol. 45, No. 2, 854-860, 2009.
doi:10.1109/TIA.2009.2013594 Google Scholar

10. Wojda, R. P. and M. K. Kazimierczuk, "Winding resistance of litz-wire and multi-strand inductors," IET Power Electronics, Vol. 5, No. 2, 257-268, 2012.
doi:10.1049/iet-pel.2010.0359 Google Scholar

11. Wojda, R. P. and M. K. Kazimierczuk, "Analytical optimization of solid{round-wire windings," IEEE Transactions on Industrial Electronics, Vol. 60, No. 3, 1033-1041, 2013.
doi:10.1109/TIE.2012.2189543 Google Scholar

Dr. Weijie Luo

Dr. Quan Ke

Dr. Guozheng Yan

Dr. Kai Yang