TY - JOUR
T1 - The circuit theory behind coupled-mode magnetic resonance-based wireless power transmission
AU - Kiani, Mehdi
AU - Ghovanloo, Maysam
N1 - Funding Information:
Manuscript received July 14, 2011; revised October 20, 2011; accepted November 21, 2011. Date of publication January 24, 2012; date of current version August 24, 2012. This work was supported in part by the National Institutes of Health, NIBIB, under Grant 1R21EB009437-01A1, and in part by the National Science Foundation under Award ECCS-824199. This paper was recommended by Associate Editor E. Alarcon The authors are with the GT-Bionics Lab, School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30308 USA (e-mail: [email protected]).
PY - 2012
Y1 - 2012
N2 - Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor (Q) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory.
AB - Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor (Q) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory.
UR - https://www.scopus.com/pages/publications/84864232377
UR - https://www.scopus.com/pages/publications/84864232377#tab=citedBy
U2 - 10.1109/TCSI.2011.2180446
DO - 10.1109/TCSI.2011.2180446
M3 - Article
C2 - 24683368
AN - SCOPUS:84864232377
SN - 1549-8328
VL - 59
SP - 2065
EP - 2074
JO - IEEE Transactions on Circuits and Systems I: Regular Papers
JF - IEEE Transactions on Circuits and Systems I: Regular Papers
IS - 9
M1 - 6138883
ER -