(12) United States Patent
`Tseng
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 9,129,741 B2
`Sep. 8, 2015
`
`US009129741B2
`
`(54) METHOD AND APPARATUS FOR WIRELESS
`POWER TRANSMISSION
`Inventor: Ryan Tseng, Longwood, FL (US)
`(75)
`(73) Assignee: Qualcomm Incorporated, San Diego,
`CA (US)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1305 days.
`(21) Appl. No.: 11/901,158
`Sep. 14, 2007
`(22) Filed:
`Prior Publication Data
`(65)
`US 2008/0067874 A1
`Mar. 20, 2008
`Related U.S. Application Data
`(60) Provisional application No. 60/844,478, filed on Sep.
`14, 2006.
`Int. Cl.
`H01F 5/00
`H01F 27/28
`H01F 38/14
`A61C 17/22
`
`( * ) Notice:
`
`(51)
`
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(Continued)
`
`(52) U.S. Cl.
`CPC .............. H01F 38/14 (2013.01); A61C 17/224
`(2013.01); H02J 7/025 (2013.01); H01F
`17/0006 (2013.01)
`
`(58) Field of Classification Search
`CPC ................................... H01F 5/00; H01F 27/28
`USPC .................................................. 336/200, 232
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3,390,337 A *
`6,249,039 B1 *
`6,436,299 B1
`
`6/1968 Beitman, Jr. .................. 455/123
`6/2001 Harvey et al. ................. 257/531
`8/2002 Baarman et al.
`(Continued)
`
`FOREIGN PATENT DOCUMENTS
`
`JP
`JP
`
`2001085230 A * 3/2001
`2003257740 A * 9/2003
`
`OTHER PUBLICATIONS
`
`HotSpotzz Network, “WiFi Market Information and Statistics,” Feb.
`2003. Online: http://www.hotspotzz.com/resource/WiFi—stats.pdf.
`(Continued)
`
`Primary Examiner — Tsz Chan
`(74) Attorney, Agent, or Firm — Knobbe, Martens, Olson &
`Bear, LLP
`
`(57)
`
`ABSTRACT
`
`Embodiments of the invention relate to a method and system
`for transferring power wirelessly to electronic devices. The
`system can utilize magnetic coupling between two coils at
`close proximity to transfer sufficient power to charge an elec-
`tronic device. Embodiments of the invention pertain to an
`array of spiral coils that can be used to transmit power for
`transfer to receiver coils. Potential applications of this tech-
`nology include charging consumer electronic devices (cell
`phones, laptops, PDAs, etc), developing hermetically sealed
`devices for extreme environments, and less invasive transcu-
`taneous energy transfer (TET) systems. Various embodi-
`ments of the subject system can be referred to as PowerPad
`system. Embodiments can incorporate one or more of the
`following: planar inductors, PCB transformers, and very high
`frequency power supplies. Embodiments of the invention also
`pertain to planar inductors having characteristics that allow
`the production of even magnetic field, as well as systems that
`incorporate such planar inductors.
`
`24 Claims, 21 Drawing Sheets
`(17 of 21 Drawing Sheet(s) Filed in Color)
`
`Page 1 of 31
`
`Volkswagen Exhibit 1013
`
`

`

`US 9,129,741 B2
`Page 2
`
`Int. Cl.
`H02J 7/02
`H01F 17/00
`
`(51)
`
`(56)
`
`(2006.01)
`(2006.01)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3/2003 Townsend et al. ............ 340/505
`6,529,127 B2 *
`8/2003 Collins et al. ................. 219/662
`6,608,291 B1 *
`1/2004 Kuennen et al.
`6,673,250 B2
`6/2005 Cheng et al.
`6,906,495 B2
`5/2006 Ka-Lai et al.
`7,042,196 B2
`5/2007 Baarman
`7,212,414 B2
`7/2007 Cheng et al.
`7,239,110 B2
`7/2007 Cheng et al.
`7,248,017 B2
`............ 257/531
`5/2003 Sugiyama et al.
`2003/0098496 A1 *
`7/2003 Ishikawa et al. .............. 333/219
`2003/0137370 A1 *
`2003/0186674 A1 * 10/2003 Keeney et al.
`................ 455/347
`2005/0046538 A1 *
`3/2005 Maruyama .................... 336/232
`2005/0116683 A1
`6/2005 Cheng et al.
`2005/0189910 A1 *
`9/2005 Hui ............................... 320/108
`2005/0275497 A1 * 12/2005 Ramadan et al.
`............. 336/200
`2006/0043927 A1
`3/2006 Beart et al.
`2006/0061323 A1
`3/2006 Cheng et al.
`2006/0205381 A1
`9/2006 Beart et al.
`2007/0171681 A1
`7/2007 Baarman
`OTHER PUBLICATIONS
`
`WiFi Net News, “Laptop Sales Pass Desktop Sales,” Feb. 2006.
`Online: http://wifinetnews.com/archives/006258.html.
`Network World, “Juniper, Foundry size up Router Race,” Jun. 2000.
`http://www.networkworld.com/archive/2000/98086—06-
`Online:
`05-2000.html.
`CBS News, “Microsoft Debuts Wireless Mouse,” Sep. 2003. Online:
`http://www.cbsnews.com/stories/2003/09/22/tech/main574453.
`shtml.
`Bluetooth, “Bluetooth History,” Feb. 2006. Online: http://www.
`bluetooth.com/Bluetooth/SIG/Who/History/.
`
`Bluetooth Technology, “History of Bluetooth,” Jul. 2005. Online:
`http://www.du.edu/∼ccfergus/bluetoothweb/history.htm.
`Farber, D., “Highlight Reel from the D conference,” ZDNet, Jun.
`2006. Online: http://blogs.zdnet.com/BTL/?p=3132.
`Splashpower Inc., “Frequently Asked Questions” Feb. 20, 2005.
`Online: www.splashpower.com.
`Hui, S.Y.R., et al. “A New Generation of Universal Contactless Bat-
`tery Charging Platform for Portable Consumer Electronic Equip-
`ment,” IEEE Transactions on Power Electronics, May 2005, pp.
`620-627, vol. 20, No. 3.
`Tang, S.C., et al. “Evaluation of the Shielding Effects on Printed-
`Circuit-Board Transformers using Ferrite Plates and Copper Sheets,”
`IEEE Transactions on Power Electronics, Nov. 2002, pp. 1080-1088,
`vol. 17, No. 6.
`Tang, S.C., et al. “Characterization of Coreless Printed Circuit Board
`(PCB) Transformers,” IEEE Transactions on Power Electronics,
`Nov. 2000, pp. 1275-1282, vol. 15, No. 6.
`Tang, S.C., et al. “A Low Profile Power Converter Using Printed-
`Circuit-Board (PCB) Power Transformer with Ferrite Polymer Com-
`posite,” IEEE Transactions on Power Electronics, Jul. 2001, pp.
`493-498, vol. 16, No. 4.
`Tang, S.C., et al. “Optimal Operation of Coreless PCB Transformer-
`Isolated Gate Drive Circuits with Wide Switching Frequency Range,”
`IEEE Transactions on Power Electronics, May 1999, vol. 14, No. 3.
`Fairchild Semiconductor, “Induction Heating System Topology
`Review,” Jul. 2000, pp. 1-28.
`Tsai, Huan-Shang et al. “Investigation of Current Crowding Effect of
`Spiral Inductors,” IEEE, 1997, pp. 139-142.
`Hui, Dong, et al. “Research on the Electromagnetic Radiation of a
`PCB Planar Inductor,” IEEE, APMC2005 Proceedings, 2005.
`Li, Faye, et al. “A Low Loss High-Frequency Half Bridge Driver with
`Integrated Power Devices using EZ-HV SOI Technology,” IEEE,
`2002, pp. 1127-1132.
`Peter, M. et al. “Planar Inductors with Subdivided Conductors for
`Reducing Eddy Current Effects,” IEEE, 2003, pp. 104-106.
`
`* cited by examiner
`
`Page 2 of 31
`
`

`

`U.S. Patent
`U.S. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 1 of 21
`Sheet 1 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
` FIG. 1
`
`Page 3 of 31
`
`Page 3 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet2 of 21
`Sheet 2 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`
`
`
`
`
`
` —————SKSe.
`
`
`
`Page 4 of 31
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`Page 4 of 31
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`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet3 of 21
`Sheet 3 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`
`98.49
`
`Unit: dBuV
`
`FIG. 5
`
`Page 5 of 31
`
`Page 5 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet4 of 21
`Sheet 4 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`|
`
`Unit dBA |
`|
`106,02 |
`103.21 |
`100.39 |
`97.57
`
`
`
`FIG. 7
`
`
`
`FIG. 8
`
`Page 6 of 31
`
`Page 6 of 31
`
`

`

`U.S. Patent
`U.S. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 5 of 21
`Sheet 5 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`PowerMate
`
`
`
`
`Electronic
`
`
`
`
`
`Device
`
`PowerPad
`
`=|/ OO
`
`DC Supply
`fo
`
`Diiving Circuit
`——\\
`
`OW
`
`|
`
`J
`
`pl
`
`CcY™NY Ge
`
`high frequency AC
`
`high frequency
`magnetic field
`
`FIG. 9
`
`12V
`
`65V-85V
`
`10luH
`
`"1
`
`83ohm
`
`PowerPad
`
`-Lm— |
`
` S¥ PWM Signal
`
`IN3819
`
`IRF640
`
`FIG. 10
`
`Page 7 of 31
`
`Page 7 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet6 of 21
`Sheet 6 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`FIG.11
`
`Page 8 of 31
`
`Page 8 of 31
`
`

`

`U.S. Patent
`U.S. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 7 of 21
`Sheet 7 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`
`
`FIG.12
`
`PowerPad
`
`PowerMate Coil
`e
`
`FIG. 13
`
`Page 9 of 31
`
`Page 9 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet8 of 21
`Sheet 8 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`Power Received vs. Frequency
`
`Frequency kHz
`
`iS S iS} > by S S
`AS)
`PEE BETS SPP EP OP DP GO
`
`FIG. 14
`
`
`
`Voltage Distribution over Surface
`
`Voltage
`
`m@ 16-18
`0 14-16
`012-14
`
`w 10-12
`@ 8-10
`
`FIG. 15
`
`Page 10 of 31
`
`Page 10 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet9 of 21
`Sheet 9 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`V3
`
`.
`
`|
`
`|
`65-85V
`
`L
`
`PowerPad
`
`|
`
`ei
`
`1|\|
`
`12V
`
`| O.1uF
`|
`PWM_signal_2
`
`+
`}
`PY
`|
`
`a
`
`°
`
`?
`|
`
`e
`| a
`Lt)
`is
`MbreakN t
`PWM_signal_1\¢_‘/
`4
`
`@
`
`FIG. 16
`
`||
`
`Page 11 of 31
`
`D1
`1
`Dbreak
`
`e
`
`|
`
`|
`
`1k
`
`0.1uF
`"
`IR2101
`7
`vee — _
`4 vec
`4HIN
`HO~
`|
`a
`S!LIN vs
`MbreakN t
`in
`~8
`COM
`LU
`
`Page 11 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 10 of 21
`Sheet 10 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`
`
`FIG. 17
`
` af
`
`Maxtmum-impedance
`
`-_—*
`
`as
`
`_:. PlAe
`<
`
`
`
`i
`
`a ao”
`smy
`/
`=*
`ss
`4
`ees
`iB
`aapa nia =
`eness* =
`aos"”
`
`
`
`
`
`
`Frequency / Hz
`
`
`
`0.00600 2.00610694.00E-06 «6.00606«=BOUEL06 «1.006107=120607 1.400 60E-07 1 80R0T 2.006607
`
`FIG. 18
`
`—O- Measurement
`
`—e— MATLABprograrn
`
`—* PSPICE simulation
`
`Voltagegain
`
`Frequency/ Hz
`
`FIG. 19
`
`Page 12 of 31
`
`Page 12 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 11 of 21
`Sheet 11 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`FIG. 20
`
`
`
`
`FIG.21
`
`Page 13 of 31
`
`Page 13 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 12 of 21
`Sheet 12 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`Voltage Distribution over Surface
`
`
`
`SS,
`SORALRTITA
`
`Se
`
`
`<Or
`
`
`Page 14 of 31
`
`Page 14 of 31
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 13 of 21
`Sheet 13 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`DIOOT
`RRRRR RH NHS
`PReeeeee
`x)
`RepairSeSSeS
`
`100.00.
`
`75.00.
`
`50.00
`
`25.00.
`
`OFactor
`
`
`0,00. i= 63.38MiHz
`
`
`
`v1= 97.70
`
`SDDS
` (XXXKXXYYYXXXRYYYS
`
`50.00.
`
`40.00.
`
`30.00.
`
`20,00.
`
`10.00
`
`FIG.24
`
`Page 15 of 31
`
`Page 15 of 31
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`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 14 of 21
`Sheet 14 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`
`
`FIG.25
`
`
`
`naminbeeoee
`
`4ane
`perigee gags Regs bg
`
`
`PSRRSEERG RSA
`AROORR OOK FT FHHNNAS
`
`Page 16 of 31
`
`Page 16 of 31
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`

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`U.S. Patent
`U.S. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 15 of 21
`Sheet 15 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`97*D1d
`
`T@2-*88803
`
`T@e-STSzZg°S
`
`1@e@-*8ZeSzSs
`
`T@Q-SES28"+
`
`Cusv]pieraw
`
`Tee-eTT@sTt
`
`2@@-FEZTSLT@Q-STSZTTt
`
`2@Q-SZE92°€
`
`hOB-F38Th“T
`
`Page 17 of 31
`
`Page 17 of 31
`
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet16 of 21
`Sheet 16 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`aL FIG.27
`
`Page 18 of 31
`
`Page 18 of 31
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`

`

`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet17 of 21
`Sheet 17 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`
`
`FIG. 28
`
`Region1
`
`Region2
`
`Region3
`
`Region4
`
`v1
`
`|=
`
`|
`
`FIG.29
`
`Page 19 of 31
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`Page 19 of 31
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`

`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet18 of 21
`Sheet 18 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`FIG.30
`
`U.S. Patent
`US. Patent
`
`Page 20 of 31
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`Page 20 of 31
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`

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`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 19 of 21
`Sheet 19 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`
`
`FIG. 31
`
`MicrocontrollerR} wiganiesia
`
`
`
`
`Sensor
`
`
`DC Power
`pet
`
`Semiconductor
`peeeate
`
`maa
`
`PowerPad
`
`maa
`
`FIG.32
`
`Page 21 of 31
`
`Page 21 of 31
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`U.S. Patent
`
`Sep. 8, 2015
`
`Sheet 20 of 21
`
`US 9,129,741 B2
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`Page 22 of 31
`
`

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`U.S. Patent
`US. Patent
`
`Sep. 8, 2015
`Sep. 8, 2015
`
`Sheet 21 of 21
`Sheet 21 of 21
`
`US 9,129,741 B2
`US 9,129,741 B2
`
`Voltage[peak
`
`Received Waveform
`LN
`
`3.12Vp-p a-f = 146kHz
`
`g-tum, AWG-10
`
`copperwioshielding
`
`9-turn, AWG-10
`
`13-turn, AWG-10
`coppercoil w/
`shielding
`
`-f = 146kHz
`
`3.44Vp-p
`
`10-turn, AWG-10
`coppercoil w/
`
`2.36Vp-p
`
`i147kHz
`shielding a142kHz
`diameteroctagon|mom|mom-f=are
`7 en=146kHz
`
`
`
`Ferromagnetic 7.5cm
`
`15-turn PCB coil, with
`
`80-turn, AWG-14
`coppercoil w/
`shielding
`
`3.40Vp-p
`
`ei146kHz
`15-turn coil, AWG-24 i146kHz
`
`tot=1A6kHz
`conductorcopper)
`
`-33-turn coil, 22-gauge
`magnet wire (enamel|See graphfor
`covered solid-
`extendedtesting
`
`FIG, 34
`
`Page 23 of 31
`
`Page 23 of 31
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`

`

`US 9,129,741 B2
`
`1
`METHOD AND APPARATUS FOR WIRELESS
`POWER TRANSMISSION
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`
`The present application claims the benefit of U.S. Appli-
`cation Ser. No. 60/844,478, filed Sep. 14, 2006, which is
`hereby incorporated by reference herein in its entirety, includ-
`ing any figures, tables, or drawings.
`
`BACKGROUND OF THE INVENTION
`
`In an increasingly mobile world, consumers have quickly
`embraced wireless technologies such as WiFi and Bluetooth
`to make their workspace less cluttered and more convenient.
`In order to power an ever growing assortment of battery
`operated devices, a consumer must deal with a large collec-
`tion of bulky transformers and an unsightly, frustrating wire
`nest. Mobile users and travelers are often forced to lug a
`tangle of chargers and they often suffer for leaving one
`behind. In front of a cheering audience at the All Things
`Digital conference on Jun. 1, 2006, Martha Stewart brought a
`jumbled mess of power adapters to the microphone and chal-
`lenged the tech community to find a solution [22].
`There have been several attempts to bring a wireless power
`solution to consumers. The most common wireless systems
`charge our electric toothbrushes and razors. Two newer tech-
`nologies, by SplashPower and Dr. Ron Hui of City University
`of Hong Kong, have also been presented.
`Many electric toothbrushes and razors employ a voltage
`reducing transformer with no metallic contact between the
`primary and secondary side. For the efficiency of power trans-
`fer, designers typically incorporate ferromagnetic cores that
`provide a low reluctance path for magnetic fields traveling
`from the primary 100 to the secondary 110 windings, as
`illustrated in FIGS. 2A, 2B, and 2C. However, devices typi-
`cally need to be placed in a very specific position or orienta-
`tion with respect to the base station to be charged efficiently,
`or to be charged at all. In addition, the physical dimensions,
`such as the depth and weight of the components, can often
`make this system unsuitable for today’s lightweight portable
`electronic devices.
`SplashPower, founded by two Cambridge University stu-
`dents in June 2001, has disclosed a system that uses two
`perpendicular coils to create an even magnetic field distribu-
`tion over a planar surface, as shown in FIG. 3. The coils
`alternate switching on and off to create two perpendicular
`magnetic fields, parallel to the base stations surface. When a
`device with a secondary winding having a highly permeable
`core is placed on the base station, magnetic fields will tend to
`travel through the low reluctance core rather than the sur-
`rounding air as shown in FIG. 4. FIG. 4 shows cross sectional
`views of SplashPower base station illustrating magnetic field
`lines (1), where the top figure shows undisturbed (no device
`present) field lines during normal operation and the middle
`figure shows the effect of placing a piece of ferromagnetic
`material (800) in the magnetic fields. The field lines can be
`seen traveling through the core rather than the surrounding
`air. The bottom figure simulates two individual cores in the
`magnetic field. Again, the magnetic fields travel through the
`core material rather than surrounding air. SplashPower indi-
`cates that specially equipped electronic devices can receive
`charge in any position or orientation on top of the base station.
`The SplashPower design has receivers built to include a dense
`ferromagnetic core, which would add undesirable bulk to
`small devices.As the SplashPower base station uses a two coil
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
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`layout, it may waste large amounts of power, especially if a
`user attempts to charge a device in the corner of the pad.
`SplashPower’s base station can be thick and clunky due to the
`inclusion of a dense ferromagnetic core.
`Dr. Ron Hui, Chair Professor of Hong Kong City Univer-
`sity’s Department of Electronic Engineering, has disclosed a
`wireless power system having a transmitter claimed to create
`an even magnetomotive force in the immediate vicinity, by
`using a three layer array of hexagonal inductive coils, as
`shown in FIG. 5. FIG. 6 shows an mmf scan of a single layer,
`while FIG. 7 shows an mmf scan of the three layers. The
`inductive coils are coreless to allow a small, lightweight, low
`cost system. A receiving coil placed on top of the transmitter
`as shown in FIG. 5 can be used to charge an electronic device.
`However, interactions between multiple layers may hinder
`system performance, and the fabrication of multilayer PCB
`boards is considerably more expensive than single layer
`boards.
`There is a need for a method and apparatus to reduce, or
`even eliminate, the need for a myriad of power supplies and
`wires in an efficient mariner.
`
`SUMMARY OF THE INVENTION
`
`Embodiments of the invention relate to a method and sys-
`tem for transferring power wirelessly to electronic devices.
`The system can utilize magnetic coupling between two coils
`at close proximity to transfer sufficient power to charge an
`electronic device. Embodiments of the invention pertain to an
`array of spiral coils that can be used to transmit power for
`transfer to receiver coils. Potential applications of this tech-
`nology include charging consumer electronic devices (cell
`phones, laptops, PDAs, etc), developing hermetically sealed
`devices for extreme environments, and less invasive transcu-
`taneous energy transfer (TET) systems. Various embodi-
`ments of the subject system can be referred to as PowerPad
`system. Embodiments can incorporate one or more of the
`following: planar inductors, PCB transformers, and very high
`frequency power supplies. Embodiments of the invention also
`pertain to planar inductors, and/or arrays of planar inductors,
`having characteristics that allow the production of an even
`magnetic field, as well as systems that incorporate such planar
`inductors.
`An embodiment of the PowerPad system can include two
`primary components: a base station, which can be referred to
`as PowerPad, and one or more receivers, which can be
`referred to as Power Mate. An embodiment of the base station
`is a planar device that provides power to the receiver modules.
`The PowerPad can simultaneously power multiple devices of
`different make, model, and power configuration placed in any
`position or orientation on its surface. The PowerPad can uti-
`lize an array of inductive coils attached to one or more high
`frequency power supplies. The PowerPad can be,
`for
`example, scaled to cover an entire desktop or integrated into
`an airplane tray table. Embodiments of the PowerPad can
`provide sufficient power to operate laptops, flat panel moni-
`tors, PDAs, cell phones, mp3 players, and other consumer
`electronic devices.
`The receiver, which can be referred to as PowerMate, can
`be integrated into the chassis of an electronic device and can
`receive charge from the PowerPad. PowerMate is a relatively
`simple, low-cost receiving device designed to work in con-
`junction with the PowerPad. Devices equipped with a Pow-
`erMate unit receive power by being placed anywhere, directly
`on top of a PowerPad base station. To enable easy integration,
`the PowerMate can be small and lightweight. The device is
`scalable to satisfy the requirements of larger more power
`
`Page 24 of 31
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`US 9,129,741 B2
`
`3
`hungry devices. In an embodiment, a unit 1 mm thick and 36
`mm in diameter is utilized and can receive more than enough
`power to drive a laptop computer or flat panel monitor.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`5
`
`The patent or application file contains at least one drawing
`executed in color. Copies of this patent or patent application
`publication with color drawing(s) will be provided by the
`Office upon request and payment of the neccessary fee.
`FIG. 1 shows an embodiment of Power Pad System.
`FIGS. 2A-2C show wireless technology used in electric
`toothbrushes and razors, where ferromagnetic cores are at the
`center of each winding and magnetic fields created by the
`bottom winding (base) induce current in the top winding
`(device).
`FIG. 3 shows a top down view of the two coils in the
`SplashPower base station where magnetic fields directions
`are shown as large arrows.
`FIG. 4 shows magnetic field patterns for a SplashPower
`base station.
`FIG. 5 shows a structure of three-layer hexagonal array.
`FIG. 6 shows an mmf scan for a single layer design having
`an uneven magnetic field.
`FIG. 7 shows an mmf scan for three layer design, where the
`distribution of magnetic fields improves considerably, com-
`pared to the distribution of FIG. 6.
`FIG. 8 shows an embodiment of a PowerMate module
`driving an LED on top of an embodiment of a Power Pad
`surface.
`FIG. 9 shows a PowerPad system block diagram for a
`specific embodiment in accordance with the subject inven-
`tion.
`FIG. 10 shows a driving circuit used in an embodiment of
`a PowerPad.
`FIG. 11 shows a Magnetic field (H Field) vector and mag-
`nitude plot for a spiral inductor cross-section having an
`uneven field distribution with peak fields in the center and
`minimum fields on the perimeter.
`FIG. 12 shows a Protei layout of a top layer, where the
`location of the bottom layer is drawn in light circles.
`FIG. 13 shows a schematic for an embodiment of a Pow-
`erMate.
`FIG. 14 shows the received power vs. driving circuit fre-
`quency for an embodiment of the subject invention.
`FIG. 15 shows a relative voltage distribution over the sur-
`face of an embodiment of the PowerPad.
`FIG. 16 shows a microprocessor controlled half bridge
`inverter that can be utilized in accordance with an embodi-
`ment of the subject PowerPad.
`FIG. 17 shows a voltage waveform measured across the
`PowerPad terminals before and after insertion of the capacitor
`shown in FIG. 16.
`FIG. 18 shows impedance vs. frequency for a PCB trans-
`former.
`FIG. 19 shows voltage gain vs. frequency for a PCB trans-
`former.
`FIG. 20 shows Ansoft HFSS H field vectors that can be
`seen flowing in opposing directions, where the large arrows
`show a generalization of the net effect.
`FIG. 21 shows a close up of the magnetic field vectors
`along the perimeter of a spiral inductor.
`FIG. 22 shows a voltage distribution over the surface of a
`two layer array that shows coil overlap compared to received
`voltage.
`FIG. 23 shows the magnetic field intensity measured at 0.4
`mm over a square inductive coil.
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`FIG. 24 shows the effect of trace width and spacing on Q
`factor.
`FIG. 25 shows the magnetic field distribution of a typical
`planar inductor, where the field peaks in the center.
`FIG. 26 shows the effect of variable width planar inductor
`on magnetic field.
`FIG. 27 shows the current crowding effect seen on a planar
`inductor.
`FIG. 28 shows an example of a subdivided embodiment of
`a PowerPad.
`FIG. 29 shows an embodiment of a circuit schematic that
`can be utilized to drive the subdivided PowerPad layout
`shown in FIG. 2B.
`FIG. 30 shows the H field magnitude of two spiral induc-
`tors placed side by side.
`FIG. 31 shows a circuit equivalent of a planar, coreless
`PCB transformer.
`FIG. 32 shows a block diagram of an embodiment of a
`PowerPad having six components, in accordance with the
`subject invention.
`FIG. 33 shows an embodiment of a PowerPad spiral induc-
`tor array layout in accordance with the subject invention.
`FIG. 34 shows a received waveform of an embodiment of
`the PowerMate produced under indicated coil and voltage
`conditions.
`
`DETAILED DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Embodiments of the invention relate to a method and sys-
`tem for transferring power wirelessly to electronic devices.
`The system can utilize magnetic coupling between two coils
`at close proximity to transfer sufficient power to charge an
`electronic device. Embodiments of the invention pertain to an
`array of spiral coils that can be used to transmit power for
`transfer to receiver coils. Potential applications of this tech-
`nology include charging consumer electronic devices (cell
`phones, laptops, PDAs, etc), developing hermetically sealed
`devices for extreme environments, and less invasive transcu-
`taneous energy transfer (TET) systems. Various embodi-
`ments of the subject system can be referred to as Power Pad
`system. Embodiments can incorporate one or more of the
`following: planar inductors, PCB transformers, and very high
`frequency power supplies. Embodiments of the invention also
`pertain to planar inductors having characteristics that allow
`the production of even magnetic field, as well as systems that
`incorporate such planar inductors.
`FIG. 1 shows an embodiment of a PowerPad system in
`accordance with the subject invention. An embodiment of the
`PowerPad system can include two primary components: a
`Base Station, which can be referred to as PowerPad, and one
`or more receivers, which can be referred to as PowerMate. An
`embodiment of the base station is a planar device that pro-
`vides power to the receiver modules. The PowerPad can
`simultaneously power multiple devices of different make,
`model, and power configuration placed in any position or
`orientation on its surface. The PowerPad can utilize an array
`of inductive coils attached to one or more high frequency
`power supplies. The PowerPad can be, for example, scaled to
`cover an entire desktop or integrated into an airplane tray
`table. Embodiments of the Power Pad can provide sufficient
`power to operate laptops, flat panel monitors, PDAs, cell
`phones, mp3 players, and other consumer electronic devices.
`M. Peter, H. Hein, F. Oehler, P. Baureis, “Planar Inductors
`with Subdivided Conductors for Reducing Eddy Current
`Effects,” IEEE, 2003 provides an overview of existing tech-
`
`Page 25 of 31
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`US 9,129,741 B2
`
`5
`nologies, discusses operational theory applicable to embodi-
`ments of the Power Pad system, and is hereby incorporated by
`reference in its entirety.
`The receiver, which can be referred to as PowerMate, can
`be integrated into the chassis of an electronic device and can
`receive charge from the PowerPad. The PowerMate is a rela-
`tively simple, low-cost receiving device designed to work in
`conjunction with the PowerPad. Devices equipped with a
`PowerMate unit receive power by being placed anywhere,
`directly on top of a PowerPad base station. To enable easy
`integration, the PowerMate can be small and lightweight. The
`device is scalable to satisfy the requirements of larger more
`power hungry devices. In an embodiment, a unit 1 mm thick
`and 36 mm in diameter is utilized and can receive more than
`enough power to drive a laptop computer or flat panel moni-
`tor.
`In an embodiment, devices can be placed on the pad in any
`orientation. Without the need to carefully position the device
`or fumble with adapters. The PowerPad can eliminate power
`cables for all types of electronic devices, and eliminate the
`associated unsightly wire nests. An embodiment of the Power
`Pad is a versatile device capable of providing power to almost
`any type of electronic device. Power Pad can charge multiple
`devices at once as if they were plugged into their conventional
`adapters. Embodiments of the Power Pad can be integrated
`into desks, tables, and other flat surfaces. Users can take their
`devices to the coffee shop, lecture hall, or an airplane and
`charge their devices on PowerPad enabled surfaces. Elec-
`tronic device manufacturers can integrate the subject technol-
`ogy into their devices.
`Embodiments of the subject system utilize PCB transform-
`ers, which incorporate polychlorinated biphenyls (PCB’s).
`Embodiments of the invention utilize multiple layers of coils
`for generation of magnetic fields. An LED equipped with a
`PowerMate receiver module, in accordance with an embodi-
`ment of the invention, as shown in FIG. 8, reliably illuminated
`when placed in any position or orientation on top of an
`embodiment of the PowerPad’s surface.
`In order to charge devices placed in various locations on its
`surface, and in a specific embodiment anywhere on its sur-
`face, an embodiment of the PowerPad base station generates
`an even high frequency, magnetic field. The PowerMate
`receiver converts this magnetomotive force into electrical
`current and supplies power to, for example, an electronic
`device.
`A specific embodiment of the invention has four primary
`components and will be described with reference to FIG. 9. A
`DC power supply 310 uses three 1A, 13.5/30V RadioShack
`power supplies connected in series to produce a 65V output.
`During steady-state operation the entire system draws a maxi-
`mum of 0.65 amps. A microprocessor controlled driving cir-
`cuit 330 includes two cascaded resistive load switches, as
`shown in FIG. 10. A PIC12F629 8-pin microprocessor
`switches a 2N3819 n-channel MOSFET at 208 kHz. The
`drain terminal of the 2N3819 MOSFET drives the gate of a
`larger IRF640 power MOSFET. The output is a 65 Vpp, 208
`kHz square wave output that feeds into the PowerPad base
`station.
`Magnetic field vector and magnitude field plots of spiral
`inductor cross-sections are shown in FIG. 11, and reveal peak
`intensity at the center of the inductor and minimum intensity
`along the perimeter. To compensate for this phenomenon, a
`second layer of inductors can be arranged, as shown in FIG.
`12, such that the peak magnetic field regions of the bottom
`layer align with minimum magnetic field regions of the top.
`The embodiment of the PowerPad shown in FIG. 12 uses a
`two layer, series connected, array of PCB, spiral inductors to
`
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`create an even magnetic field over its surface. Inductors are
`arranged in series so that current does not bypass the loaded
`region of the Power Pad. The inductors are 15 turn inductors
`with 15 mil trace widths and 25 mil trace gaps.
`The receiving device for this embodiment includes a 33
`turn, 22 gauge magnet wire coil connected to a full bridge
`rectifier. Current flows from the rectifier into a parallel con-
`nected LED and 220 capacitor, as shown in FIG. 13. Table 4.1
`shows the system specifications for a specific embodiment of
`the invention.
`
`TABLE 4.1
`
`System Specifications
`
`Parameter
`
`Description
`
`1 PowerPad Transmission Region
`2 Max Received Power
`3 PowerMate Diameter
`4 PowerMate Weight
`5 Transmission Range
`6 Input Voltage/Current
`7 Voltage Fluctuation above
`Transmission Region
`8 Efficiency
`
`Planar, 19.5 cm*16 cm
`3.7 VDC, and 2.4 mA, ∼10 mW
`6 cm
`14 grams
`<1 cm
`65 VDC, 0.65 A ∼40.3 Watts
`17.5%
`
`.025%
`
`Increasing the DC supply voltage can yield proportional
`gains in received power. With respect to frequencies from 0 to
`200 kHz, a higher frequency can result in more efficient
`coupling, as shown in FIG. 14, which shows received power
`vs. driving circuit frequency.
`Probe measurements above an embodiment of the Power
`Pad reveal peak voltages around the perimeter and lower
`voltages in the center, as shown in FIG. 15, which shows a
`relative voltage distribution over the surface of the PowerPad.
`The low voltage region is likely attributable to destructive
`interference between the top and bottom layer inductor
`arrays.
`With respect to embodiments of the PowerMate, inline
`with theoretical expectations, large coils with many turns
`received the most power. Increasing the spacing between
`conductors significantly reduced the received power. A large
`number of designs were evaluated. The results are shown in
`FIG. 34 which illustrates a table including test results of the
`PowerMate with PowerPad input of: 146 kHz; 130 Vp-p, 50%
`duty cycle, square wave. A specific embodiment of the Pow-
`erMate, listed last in the table of FIG. 34, uses a 33 turn, 22
`gauge magnet wire coil.
`The resistive load configuration of an embodiment of a
`driving circuit dissipated 18.4 watts of power as heat loss and
`delivered 55% of the input power to the PowerPad. The heat
`byproduct can be addressed with several large heat sinks and
`fans to regulate the temperature of the prototype.
`Another embodiment, having a circuit employing a micro-
`processor controlled, halfbridge inverter, as shown in FIG.
`16, is designed without resistive elements and significantly
`reduces the wasted power. Referring to FIG. 16, a micropro-
`cessor transmits two high frequency signals, 180 degrees out
`of phase, to the high and low side inputs of an IR21 01 gate
`driver. The gate driver switches two n-channel MOSFETs that
`create a high frequency, 65V square wave feeding into the
`PowerPad base station. This driving circuit delivered ∼95% of
`the input to the PowerPad and significantly reduced the cool-
`ing requirement.
`The half-bridge inverter design permits the insertion of a
`capacitor between the PowerPad and ground, as shown in
`FIG. 16. This addition can double the peak to peak voltage by
`pumping charge back through the PowerPad as it is switched
`
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`US 9,129,741 B2
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`7
`from 65 volts to ground, as shown in FIG. 17, which shows a
`voltage waveform measured across the PowerPad terminals
`before and after insertion of the capacitor shown in FIG. 16.
`The resonant frequency of typical core less PCB trans-