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Convex optimization of coil spacing in cascaded multi-coil wireless power transfer

Published online by Cambridge University Press:  19 February 2020

Connor Badowich ,
Jacques Rousseau  and
Loïc Markley Open the ORCID record for Loïc Markley [Opens in a new window]
Connor Badowich
Affiliation:
School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada
Jacques Rousseau
Affiliation:
School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada
Loïc Markley*
Affiliation:
School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada
*
Author for correspondence: Loïc Markley, School of Engineering, University of British Columbia, Kelowna, BC, V1V 1V7, Canada. E-mail: [email protected]
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Abstract

In this paper, we use convex optimization to maximize power efficiency through cascaded multi-coil wireless power transfer systems and investigate the resulting characteristic spacing. We show that although the efficiency is generally a non-convex function of the coil spacing, it can be approximated by a convex function when the effects of higher-order couplings are small. We present a method to optimize the spacing of cascaded coils for maximum efficiency by perturbing the solution of the convex approximation to account for higher-order interactions. The method relies on two consecutive applications of a local optimization algorithm in order to enable fast convergence to the global optimum. We present the optimal configurations of coil systems containing up to 20 identical coils that transfer power over distances up to 4.0 m. We show that when spacing alone is optimized, there exist an optimal number of coils that maximize transfer efficiency across a given distance. We also demonstrate the use of this method in optimizing the placement of a select number of high-Q coils within a system of low-Q relay coils, with the highest efficiencies occurring when the high-Q coils are placed on either side of the largest gaps within the relay coil chain.

Keywords

Cascaded resonatorsconvex optimizationmagnetic resonance couplingmaximum efficiencymulti-coil system
Type
Research Article
Information
Wireless Power Transfer , Volume 7 , Issue 1 , March 2020 , pp. 42 - 50
Copyright
Copyright © The Author(s), 2020. Published by Cambridge University Press

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References

Park, J, Kim, D, Hwang, K, Park, HH, Kwak, SI, Kwon, JH and Ahn, S (2017) A resonant reactive shielding for planar wireless power transfer system in smartphone application. IEEE Transactions on Electromagnetic Compatibility 59, 695–703.CrossRefGoogle Scholar
Yang, Y, El Baghdadi, M, Lan, Y, Benomar, Y, Van Mierlo, J and Hegazy, O (2018) Design methodology, modeling, and comparative study of wireless power transfer systems for electric vehicles. Energies 11, 1716.CrossRefGoogle Scholar
Reza Khan, S and Choi, G (2016) Optimization of planar strongly coupled wireless power transfer system for biomedical applications. Microwave and Optical Technology Letters 58, 1861–1866.CrossRefGoogle Scholar
Huang, C, Kawajiri, T and Ishikuro, H (2018) A 13.56-mhz wireless power transfer system with enhanced load-transient response and efficiency by fully integrated wireless constant-idle-time control for biomedical implants. IEEE Journal of Solid-State Circuits 53, 538–551.CrossRefGoogle Scholar
Kurs, A, Karalis, A, Moffatt, R, Joannopoulos, JD, Fisher, P and Soljačić, M (2007) Wireless power transfer via strongly coupled magnetic resonances. Science 317, 83–86.CrossRefGoogle ScholarPubMed
Imura, T and Hori, Y (2017) Unified theory of electromagnetic induction and magnetic resonant coupling. Electrical Engineering in Japan 199, 58–80.CrossRefGoogle Scholar
Mi, CC, Buja, G, Choi, SY and Rim, CT (2016) Modern advances in wireless power transfer systems for roadway powered electric vehicles. IEEE Transactions on Industrial Electronics 63, 6533–6545.CrossRefGoogle Scholar
Lee, K, Pantic, Z and Lukic, SM (2014) Reflexive field containment in dynamic inductive power transfer systems. IEEE Transactions on Power Electronics 29, 4592–4602.CrossRefGoogle Scholar
Zhang, Y, Lu, T, Zhao, Z, Chen, K, He, F and Yuan, L (2015) Wireless power transfer to multiple loads over various distances using relay resonators. IEEE Microwave and Wireless Components Letters 25, 337–339.CrossRefGoogle Scholar
Zhong, W, Lee, CK and Hui, SR (2013) General analysis on the use of tesla's resonators in domino forms for wireless power transfer. IEEE Transactions on Industrial Electronics 60, 261–270.CrossRefGoogle Scholar
Zhang, X, Ho, S and Fu, W (2012) Quantitative design and analysis of relay resonators in wireless power transfer system. IEEE Transactions on Magnetics 48, 4026–4029.CrossRefGoogle Scholar
Zhang, F, Hackworth, SA, Fu, W, Li, C, Mao, Z and Sun, M (2011) Relay effect of wireless power transfer using strongly coupled magnetic resonances. IEEE Transactions on Magnetics 47, 1478–1481.CrossRefGoogle Scholar
Zhong, WX, Lee, CK and Hui, S (2012) Wireless power domino-resonator systems with noncoaxial axes and circular structures. IEEE Transactions on Power Electronics 27, 4750–4762.CrossRefGoogle Scholar
Lee, K and Chae, SH (2018) Power transfer efficiency analysis of intermediate-resonator for wireless power transfer. IEEE Transactions on Power Electronics 33, 2484–2493.CrossRefGoogle Scholar
Lee, CK, Zhong, WX and Hui, SYR (2012) Effects of magnetic coupling of nonadjacent resonators on wireless power domino-resonator systems. IEEE Transactions on Power Electronics 27, 1905–1916.CrossRefGoogle Scholar
Lang, HD, Ludwig, A and Sarris, CD (2014) Convex optimization of wireless power transfer systems with multiple transmitters. IEEE Transactions on Antennas and Propagation 62, 4623–4636.CrossRefGoogle Scholar
Lang, HD and Sarris, CD (2017) Optimization of wireless power transfer systems enhanced by passive elements and metasurfaces. IEEE Transactions on Antennas and Propagation 65, 5462–5474.CrossRefGoogle Scholar
Boyd, SP and Vandenberghe, L (2004) Convex Optimization. Cambridge, UK: Cambridge University Press.CrossRefGoogle Scholar
Muir, T (1882) A Treatise on the Theory of Determinants: With Graduated Sets of Exercises for Use in Colleges and Schools. London, UK: MacMillan and Co.Google Scholar
Byrd, RH, Hribar, ME and Nocedal, J (1999) An interior point algorithm for large-scale nonlinear programming. SIAM Journal on Optimization 9, 877–900.CrossRefGoogle Scholar
Jackson, JD (1999) Classical Electrodynamics, 3rd Edn, Hoboken, NJ: John Wiley and Sons, Inc.Google Scholar
Tilston, MA and Balmain, KG (1990) A multiradius, reciprocal implementation of the thin-wire moment method. IEEE Transactions on Antennas and Propagation 38, 1636–1644.CrossRefGoogle Scholar
Balanis, CA (2016) Antenna Theory: Analysis and Design. New Jersey, US: John Wiley & sons.Google Scholar
Badowich, C and Markley, L (2018) Idle power loss suppression in magnetic resonance coupling wireless power transfer. IEEE Transactions on Industrial Electronics 65, 8605–8612.CrossRefGoogle Scholar