Design Considerations for Enhanced Coupling Coefficient and Misalignment tolerance Using Asymmetrical Circular Coils for WPT System
- 47 Downloads
In case of misalignment, variation in the coupling coefficient between transmitting and receiving coils employed for wireless power transfer is obvious. During the design process of coil system, assurance of least affected coupling coefficient during misalignment is an important issue and can be addressed through appropriate coil structure. Asymmetrical circular spiral coils with unequal outer diameter and fixed self-inductance exhibits better tolerance to misalignment with the limitation of smaller averaged coupling coefficient. The present paper considers the analytical model of asymmetrical circular spiral coils to investigate the dependency of the coil system dimensions on mutual inductance and coupling coefficient with equal outer diameter. Based on the observations from analytical expressions, simulations are performed through finite element method approach using ANSYS MAXWELL. Outcome of the investigations has been used for the design consideration of coil system, which is less sensitive to the misalignment. Based on the proposed design considerations, experimental setup is developed and tested for the case study of E-Rickshaw with 400 mm outer diameter and 120-mm air gap.
KeywordsAsymmetrical circular spiral coils Coupling coefficient Misalignment Mutual inductance Wireless power transfer
Unable to display preview. Download preview PDF.
Authors are grateful to Department of Science and Technology SERB and Ministry of Electronics and Information Technology, Government of India for financial support under projects DST/ECR/2016/002029 and MLA/MUM/GA/10(37)B respectively.
- 6.Vilathgamuwa, D.; Sampath, J.: Wireless power transfer (WPT) for electric vehicles (EVs) present and future trends. In: Plug in Electric Vehicles in Smart Grids, chap 2. Springer, Berlin, pp. 3360 (2015)Google Scholar
- 9.Kim, H.; et al.: Coil design and measurements of automotive magnetic resonant wireless charging system for high-efficiency and low magnetic field leakage. IEEE Trans. Microw. Theory Tech. 64(2), 383–400 (2016)Google Scholar
- 13.Ravikiran, V.; Keshri, R.K.; Santos, M.M.: Inductive characteristics of asymmetrical coils for wireless power transfer. In: Eighteenth annual IEEE international conference on industrial technology, ICIT, Toronto, ON, pp. 538–542 (2017)Google Scholar
- 20.Zhao, F.; Wei, G.; Zhu, C.; Song, K.: Design and optimizations of asymmetric solenoid type magnetic coupler in wireless charging system for electric vehicles. In: IEEE PELS Workshop on Emerging Technologies: Wireless Power Transfer (WoW), Chongqing, pp. 157–162 (2017)Google Scholar
- 21.Fujita, T.; Yasuda, T.; Akagi, H.: A moving wireless power transfer system applicable to a stationary system. In: IEEE Energy Conversion Congress and Exposition (ECCE), Montreal, QC, pp. 4943–4950 (2015)Google Scholar
- 22.Boys, J.T.; Covic, G.A.: Inductive power transfer systems (IPT) fact sheet: No. 1 basic concepts. In: Qualcomm (2012)Google Scholar
- 29.Bosshard, R.; Kolar, J.W.; Wunsch, B.: Accurate finite-element modeling and experimental verification of inductive power transfer coil design. In: IEEE Applied Power Electronics Conference and Exposition, APEC, Fort Worth, TX, pp. 1648–1653 (2014)Google Scholar
- 31.Esteban, B.; Stojakovic, N.; Sid-Ahmed, M.; Kar, N.C.: Development of mutual inductance formula for misaligned planar circular spiral coils. In: IEEE Energy Conversion Congress and Exposition (ECCE), Montreal, QC, pp. 1306–1313 (2015)Google Scholar
- 36.Wheeler, H.A.: Simple inductance formulas for radio coils. Proc. Inst. Radio Eng. 16(10), 13981400 (1928)Google Scholar
- 38.SAE TIR J2954 Wireless Power Transfer for Light-Duty Plug-In/Electric Vehicles (2016)Google Scholar
- 39.Chopra, S.; Bauer, P.: Analysis and design considerations for a contactless power transfer system. In: IEEE 33rd International Telecommunications Energy Conference (INTELEC), Amsterdam, pp. 1–6 (2011)Google Scholar