CN103887896A - Method for designing wireless charging coil allowing charging device to be placed freely - Google Patents
Method for designing wireless charging coil allowing charging device to be placed freely Download PDFInfo
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- CN103887896A CN103887896A CN201410068777.1A CN201410068777A CN103887896A CN 103887896 A CN103887896 A CN 103887896A CN 201410068777 A CN201410068777 A CN 201410068777A CN 103887896 A CN103887896 A CN 103887896A
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Abstract
The invention discloses a method for designing a wireless charging coil allowing a charging device to be placed freely. The wireless charging coil allowing the charging device to be placed freely is composed of N round single-circle coils which are connected in parallel, two capacitors are connected to each coil in series, and the current ratio between the round single-circle coils is the capacitance ratio between the capacitors connected to the round single-circle coils in series; even magnetic fields can be generated on the surface of a sending coil by reasonably setting the capacitance ratio. According to the method for designing the wireless charging coil allowing the charging device to be placed freely, due to the fact that the parallel connection form is adopted, even magnetic fields can be generated, and requirements for even magnetic fields at different heights of the sending coil can be met by conveniently adjusting the capacitors connected to the coils in series.
Description
Technical field
The invention belongs to wireless charging field, be specifically related to the design of Wireless charging coil, can make charging device freely place within the specific limits.
Background technology
Wireless charging technology has broad application prospects in consumer electronics, medical electronics, industrial electronic.Electromagnetic induction coupling is most popular technology near radio charging, and it is by sending the electromagnetic induction electric energy transmitting between coil and these two coupling coils of receiving coil.
Coupling coefficient between efficiency and two coupling coils of electromagnetic induction coupling delivery of electrical energy is closely related.Conventionally, coupling coefficient is larger, and delivery of electrical energy efficiency is higher.Coupling coefficient is determined by shape, size, the relative position of coil.In many application scenarios, as mobile phone wireless charger, shape, the size of coil are fixed, and the position sending between coil and receiving coil changes.Because the uncertain coupling coefficient causing of relative position is uncertain, will make charging system can not reach optimum efficiency efficiency of transmission, even likely the damage system due to the fluctuation of receiver voltage.Although under a certain fixed coupling coefficient, design by rational compensating circuit, and make circuit working under resonance condition, can make efficiency of transmission reach maximum, but the uncertain compensating circuit that will make of coupling coefficient lost efficacy, unless compensating circuit can be adjusted according to the variation of coupling coefficient, this has strengthened the difficulty of circuit design greatly, even becomes and can not realize.
In the region of receiving coil work, produce uniform magnetic field if can make to send coil, the coupling coefficient of receiving coil in this region and between transmission coil also will be fixed, and can address the above problem.
Summary of the invention
For solving in electromagnetic induction coupling wireless charging device, can not reach the optimum even problem of system cisco unity malfunction owing to sending the uncertain system efficiency of transmission that makes of relative position between coil and receiving coil, the present invention has designed a kind of transmission coil that can produce uniform magnetic field.
The technical solution adopted in the present invention is: send coil and can adopt printed circuit board (PCB) or coiling to realize, composed in parallel by the circular coil of N individual pen.The radius r of each circular coil
nfor nR/N, wherein R is outermost coil radius, n=1,2 ... N.Two electric capacity of connecting on each coil, the selection of the value of electric capacity is required to meet following condition: under coil operating frequency, condensance is much larger than the impedance of coil.Now, the electric current on each coil mainly determines by electric capacity, and because this N coil is in parallel, the voltage at coil two ends all equates, therefore the current ratio between each coil is exactly the ratio of each coil capacitance of connecting.Can produce uniform magnetic field for meeting transmission coil surface, the ratio between each coil obtains in the following way.
Due to the symmetry of circular coil, the magnetic field on from distance of center circle from the circle that equates to locate equates, therefore only needs to select the point at different radii place to analyze.Be h place from sending coil surface height, choose radius p
ibe respectively N point (i=1,2 of (i-0.5) R/N ... N), when sending electric current in n coil in coil and being unitary current size, the big or small available a in the magnetic field perpendicular to sending coil plane that above-mentioned i point produced
nirepresent a
niexpression formula be 0.5 × 10
-7(m/r
n/ p
i)
0.5/ p
i{ p
ik-[r
nm-(2-m) p
i] E/ (2-2m), wherein K and E are respectively the first kind and the complete elliptic integral of the second kind taking m as modulus, the expression formula of m is 4r
np
i/ [(r
n+ p
i)
2+ h
2].The relation perpendicular to sending between magnetic field and N the coil current of coil plane of selected N point can obtain, and can be expressed as [B]=[A] [J] with matrix.In the time that the magnetic field perpendicular to sending coil plane of selected N point is uniform magnetic field, when element all equates in [B], can obtain the current matrix [J] of N coil, [J]=[A]-
1[B], wherein [A]-
1the contrary of [A].
Tool of the present invention has the following advantages:
(1) can produce uniform magnetic field at transmission coil surface coil, can make receiving coil send placement arbitrarily within the scope of coil dimension, it is stable that both coupling coefficients keep, and is beneficial to the global design of system.
(2) coil design approaches of generation uniform magnetic field is simple.In traditional transmission coil, between each coil, adopt and be connected in series, therefore the electric current that each coil flows through equates, need to produce uniform magnetic field by the radius that designs each coil, there are two shortcomings: the method complexity of determining on the one hand each coil radius size, the magnetic field homogeneity obtaining is poor, especially send coil edge place and decline rapidly for preventing magnetic field, need to place multiple or lattice coil in edge; If after the transmission coil form designs such as printed circuit board that design are on the other hand fixing, cannot finely tune.As, in the time that receiving coil changes from the distance that sends coil, cannot regulate and make it produce more uniform magnetic field at receiving coil place At The Height the radius of each coil in transmission coil.The form that is connected in parallel that the present invention adopts not only can produce more uniform magnetic field, and can be comparatively easily by the electric capacity of connecting on regulating winding, meets from the requirement that sends coil differing heights place uniform magnetic field.
Brief description of the drawings
Fig. 1 is transmission coil design schematic diagram of the present invention, comprises the linear coil that increases and be connected in parallel of multiple radiuses, two electric capacity of connecting on each coil.
Fig. 2 be coil to add upper frequency be 100kHz, when voltage that amplitude is 10V, the amplitude figure of the magnetic field intensity of generation.
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described.
Embodiment 1: as shown in Figure 1, a transmission coil for mobile phone charging platform, is made up of 10 small coils in parallel altogether, and the radius of each coil is respectively 0.01m, 0.02m from inside to outside, 0.03m, 0.04m, 0.05m, 0.06m, 0.07m, 0.08m, 0.09m, 0.1m, the live width of each coil is 2mm.For apart from coil height being a uniform magnetic field of 5mm place generation, the electric capacity (C on each coil
a, C
b) be respectively from inside to outside (1nF, 18nF), (2.2nF, 15nF), (3.3nF, 27nF), (4.7nF, 33nF), (5.6nF, 100nF), (10nF, 22nF), (10nF, 82nF), (18nF, 33nF), (15nF, 470nF), (56nF, 0nF), on outermost coil, only need an electric capacity, the capacitance short-circuit that need be only 0 by capacitance here.Be 100kHz when coil adds upper frequency, when voltage that amplitude is 10V, the amplitude of the magnetic field intensity of generation as shown in Figure 2.From accompanying drawing 2, in coil radius 0.0968m (account for send coil region 96.8%), the maximum of magnetic field intensity and minimum value are respectively 0.5292A/m and 0.4509A/m, and mean value is 0.4886A/m, and rate of change is 16%.In the time that receiving coil is placed on this transmission coil surface, because receiving coil covers larger area, the uniformity of the total magnetic intensity (magnetic flux density) that therefore receiving coil covers in the time of diverse location will significantly improve.
Claims (1)
1. the Wireless charging coil method for designing that charging device can be placed arbitrarily, is characterized in that: sends coil and adopts printed circuit board (PCB) or coiling to realize, by
nthe circular coil of individual individual pen composes in parallel; The radius of each circular coil
r n for
nR/
n, wherein
rfor outermost coil radius,
n=1,2 ... N; Two electric capacity of connecting on each coil, the selection of the value of electric capacity is required to meet following condition: under coil operating frequency, condensance is much larger than the impedance of coil; Now, the electric current on each coil is mainly determined by electric capacity, due to this
nindividual coil is in parallel, and the voltage at coil two ends all equates, therefore the current ratio between each coil is exactly the ratio of each coil capacitance of connecting; Can produce uniform magnetic field for meeting transmission coil surface, the current ratio between each coil obtains in the following way:
From sending coil surface height be
hplace, chooses radius
p i be respectively (
i-0.5)
r/
n's
nindividual point;
i=1,2 ... N, sends in coil
nelectric current in individual coil is unitary current when size, to above-mentioned the
ithe magnetic field perpendicular to sending coil plane that individual point produces is used
a ni represent,
a ni expression formula be 0.5 × 10
7(
m/
r n /
p i )
0.5/
p i {
p i k[
r n m(2
m)
p i ]
e/ (2 2
m), wherein
kwith
ebe respectively with
mfor the first kind and the complete elliptic integral of the second kind of modulus,
mexpression formula be 4
r n p i / [(
r n +
p i )
2+
h 2]; Selected
nindividual point perpendicular to send coil plane magnetic field with
nrelation between individual coil current can obtain, with matrix can be expressed as [
b]=[
a] [
j]; When selected
nwhen the magnetic field perpendicular to sending coil plane of individual point is uniform magnetic field, [
b] in element while all equating, can obtain N coil current matrix [
j], [
j]=[
a]
1[
b], wherein [
a]
1be [
a] contrary.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410068777.1A CN103887896B (en) | 2014-02-27 | 2014-02-27 | The Wireless charging coil method for designing that a kind of charging device can be placed arbitrarily |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410068777.1A CN103887896B (en) | 2014-02-27 | 2014-02-27 | The Wireless charging coil method for designing that a kind of charging device can be placed arbitrarily |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103887896A true CN103887896A (en) | 2014-06-25 |
| CN103887896B CN103887896B (en) | 2016-04-06 |
Family
ID=50956654
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410068777.1A Active CN103887896B (en) | 2014-02-27 | 2014-02-27 | The Wireless charging coil method for designing that a kind of charging device can be placed arbitrarily |
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|---|---|
| CN (1) | CN103887896B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106026414A (en) * | 2016-08-01 | 2016-10-12 | 福建工程学院 | Dynamic coupling coil magnetic field adjusting method and device for wireless power transmission |
| CN106464032A (en) * | 2016-09-20 | 2017-02-22 | 香港应用科技研究院有限公司 | A charging device having a small loop transmission coil and used for wirelessly charging a target device |
| CN106532981A (en) * | 2016-12-22 | 2017-03-22 | 电子科技大学 | Design method of PCB coil used for magnetic coupling resonant wireless power transmission system |
| CN108123551A (en) * | 2017-12-29 | 2018-06-05 | 维沃移动通信有限公司 | A kind of Wireless charging coil, wireless charging receiving module and terminal device |
| US10097031B2 (en) | 2016-09-20 | 2018-10-09 | Hong Kong Applied Science And Technology Research Insittute Company Limited | Charging device having small loop transmission coils for wireless charging a target device |
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| EP2037465A1 (en) * | 2007-09-17 | 2009-03-18 | Seiko Epson Corporation | Double LC-tank structure |
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| US20130144588A1 (en) * | 2011-12-01 | 2013-06-06 | Bingnan Wang | System and Method for Analyzing Spiral Resonators |
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2014
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| EP2037465A1 (en) * | 2007-09-17 | 2009-03-18 | Seiko Epson Corporation | Double LC-tank structure |
| US20100213770A1 (en) * | 2007-09-17 | 2010-08-26 | Hideo Kikuchi | Induced power transmission circuit |
| CN101971452A (en) * | 2008-03-13 | 2011-02-09 | 捷通国际有限公司 | Inductive power supply system with multiple coil primary |
| US20130144588A1 (en) * | 2011-12-01 | 2013-06-06 | Bingnan Wang | System and Method for Analyzing Spiral Resonators |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106026414A (en) * | 2016-08-01 | 2016-10-12 | 福建工程学院 | Dynamic coupling coil magnetic field adjusting method and device for wireless power transmission |
| CN106026414B (en) * | 2016-08-01 | 2018-05-18 | 福建工程学院 | The coupling coil magnetic field dynamic adjusting method and device of wireless power transmission |
| CN106464032A (en) * | 2016-09-20 | 2017-02-22 | 香港应用科技研究院有限公司 | A charging device having a small loop transmission coil and used for wirelessly charging a target device |
| US10097031B2 (en) | 2016-09-20 | 2018-10-09 | Hong Kong Applied Science And Technology Research Insittute Company Limited | Charging device having small loop transmission coils for wireless charging a target device |
| CN106464032B (en) * | 2016-09-20 | 2019-03-01 | 香港应用科技研究院有限公司 | A kind of pair of target device carries out the charging unit with small ring transmission coil of wireless charging |
| CN106532981A (en) * | 2016-12-22 | 2017-03-22 | 电子科技大学 | Design method of PCB coil used for magnetic coupling resonant wireless power transmission system |
| CN106532981B (en) * | 2016-12-22 | 2019-05-10 | 电子科技大学 | The design method of PCB coil for magnetic coupling resonance wireless power transmission systems |
| CN108123551A (en) * | 2017-12-29 | 2018-06-05 | 维沃移动通信有限公司 | A kind of Wireless charging coil, wireless charging receiving module and terminal device |
| CN108123551B (en) * | 2017-12-29 | 2020-04-21 | 维沃移动通信有限公司 | Wireless charging coil, wireless charging receiving module and terminal equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103887896B (en) | 2016-04-06 |
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Effective date of registration: 20171218 Address after: 315000 Ningbo Province, Zhenhai District, camel street, long Luo Road, No. 181 Patentee after: Zhejiang Morgan Intelligent Technology Co., Ltd. Address before: Hangzhou City, Zhejiang province 310018 Xiasha Higher Education Park No. 2 street Patentee before: Hangzhou Electronic Science and Technology Univ |
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