Demosthenous, A

Schormans, M

Valente, V

UCL Discovery

1932-4545 (c) 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TBCAS.2019.2913346, IEEETransactions on Biomedical Circuits and SystemsIEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS, VOL. –, NO. –, – 2019 1Corrections to ‘Practical Inductive Link Design forBiomedical Wireless Power Transfer: A Tutorial’Matthew Schormans, Member, IEEE, Virgilio Valente, Member, IEEE, and Andreas Demosthenous, Fellow, IEEETHE original paper entitled ‘Practical Inductive Link De-sign for Biomedical Wireless Power Transfer: A Tuto-rial’ [1], aimed to provide an accessible review and guide,describing the necessary steps for designing effective biomed-ical inductive links, without the need for FEM software.While the majority of the information in the paper isaccurate and applicable, some errors in formulae have beenbrought to the attention of the authors, which could generateerroneous results if used in calculations. The aim of thismanuscript is to highlight and correct these errors. It shouldbe noted that the accompanying software for performing thesecalculations has also been corrected where necessary, in linewith the corrections presented here [2].The errors largely relate to the equations presented through-out, and are listed below:Firstly, Equation (2) in [1], defining an approximation for Na-gaoka’s coefficient, contains erroneous squares and is missinga term in the fraction of the large denominator. The correctform is presented below:𝜅 = 𝑧𝑘⎛⎜⎜⎜⎜⎝𝑙𝑛 (1 +1𝑧𝑘)1𝑘0 + 𝑘1 (𝑙𝑑) + 𝑘2 (𝑙𝑑)2+ 𝑤1(|𝑤2|+𝑑/𝑙)𝑣⎞⎟⎟⎟⎟⎠,(1)where 𝑧𝑘 = 𝑙/(𝜋𝑟), 𝑘0 = 2.30038, 𝑘1 = 3.437, 𝑘2 = 1.76356,𝑤1 = −0.47, 𝑤2 = 0.755, and 𝑣 = 1.44.Second, Equation (14) in [1] considers the AC losses of aLitz-wire coil. The original form contains errors of coefficientsand signs. The correct formulation is given as follows:𝑅𝐴𝐶 ≈ 𝑅𝐷𝐶𝛾2(𝐴/𝑛𝑠 − 2𝜋𝑛𝑠 (𝜁21 + 𝜁22𝜓2𝜋𝑛𝑠)𝐵) ,𝐴 =𝑏𝑒𝑟(𝛾)𝑏𝑒𝑖′(𝛾) − 𝑏𝑒𝑖(𝛾)𝑏𝑒𝑟′(𝛾)𝑏𝑒𝑟′2(𝛾) + 𝑏𝑒𝑖′2(𝛾),𝐵 =𝑏𝑒𝑟2(𝛾)𝑏𝑒𝑟′(𝛾) − 𝑏𝑒𝑖2(𝛾)𝑏𝑒𝑖′(𝛾)𝑏𝑒𝑟2(𝛾) + 𝑏𝑒𝑖2(𝛾), (2)where 𝑅𝐷𝐶 = (4𝜌𝑙𝑐)/(𝑛𝑠𝜋𝑑2𝑠 ) is the DC loss, 𝛾 = 𝑑𝑠/(𝛿√2),𝜁1 = (𝑑𝑠/𝑝)√𝜋/4 is an external porosity factor, 𝜁2 =Manuscript submitted —; revised —.This research was supported by the Engineering and Physical SciencesResearch Council (EPSRC) under grant EP/K031953/1 and a PhD studentshipawarded by the EPSRC to M. Schormans.M. Schormans, and A. Demosthenous are with the Department of Electronicand Electrical Engineering, University College London, London WC1E 7JE,UK. (e-mail: {matthew.schormans.10,a.demosthenous}@ucl.ac.uk)V. Valente was with the Department of Electronic and Electrical Engineer-ing, University College London, London WC1E 7JE, UK. He is now with theDepartment of Microelectronics, Delft University of Technology, 2628 CDDelft, The Netherlands. (e-mail: v.valente@tudelft.nl)(𝑑𝑠/𝑝𝑠)√𝜋/4 is an internal porosity factor (𝑝𝑠 is the averagestrand pitch, and 𝜓 = (𝑛𝜋𝑑2𝑠 )/(𝜋𝑑20) is a packing factor.Third, Equation (17) in [1] is missing a square. The correctform is as follows:𝐶𝑃 =⎛⎜⎝12𝜋𝑓SRF√𝐿⎞⎟⎠2. (3)Fourth, Equation (26) in [1], that defines ℵang, is missing acos𝛼 from the numerator of the top fraction under the squareroot. The correct form is given below:ℵ𝑎𝑛𝑔 =√√√⎷4𝑎𝑏𝑐𝑜𝑠𝜙𝑐𝑜𝑠𝛼𝑐𝑜𝑠𝜆𝑎2 + 𝑏2 + 𝐷2 − 2𝑏𝐷𝑐𝑜𝑠𝜙𝑠𝑖𝑛𝛼 + 2𝑎𝑏𝑐𝑜𝑠𝜙𝑐𝑜𝑠𝛼𝑐𝑜𝑠𝜆, (4)𝜆 = 𝑡𝑎𝑛−1 (𝑠𝑖𝑛𝜙𝑐𝑜𝑠𝜙𝑐𝑜𝑠𝛼) . (5)Finally, the caption of Fig. 17 in [1] is in error; it currentlyrefers to coupling coefficient, while it shows Q-factor. It shouldread as follows:‘Changing Q-factor as winding pitch is modified, withrespect to frequency.’.AcknowledgmentThe authors would like to thank Dietmar Schroeder, forkindly bringing the first of these errors to our attention.References[1] M. Schormans, V. Valente, and A. Demosthenous, “Practical inductivelink design for biomedical wireless power transfer: A tutorial,” IEEETransactions on Biomedical Circuits and Systems, vol. 12, no. 5, pp.1112–1130, Oct 2018.[2] (2018) CuCCo: The coupled coil configurator. [Online]. Available:https://github.com/schormans/CuCCo

Corrections to 'Practical Inductive Link Design for Biomedical Wireless Power Transfer: A Tutorial'

http://discovery.ucl.ac.uk/10074119/1/08698877.pdf

Corrections to 'Practical Inductive Link Design for Biomedical Wireless Power Transfer: A Tutorial'

Abstract

Similar works

Full text

Available Versions

UCL Discovery