U.S. patent application number 14/139677 was filed with the patent office on 2014-04-24 for wireless power transmission/reception apparatus and method.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. The applicant listed for this patent is SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Eung Ju KIM, Jeong Hoon KIM, Kyung Uk KIM, Kwang Du LEE.
Application Number | 20140111031 14/139677 |
Document ID | / |
Family ID | 43822652 |
Filed Date | 2014-04-24 |
United States Patent
Application |
20140111031 |
Kind Code |
A1 |
LEE; Kwang Du ; et
al. |
April 24, 2014 |
WIRELESS POWER TRANSMISSION/RECEPTION APPARATUS AND METHOD
Abstract
Disclosed herein is a wireless power transmission/reception
apparatus. The wireless power transmission/reception apparatus
includes a wireless power transmission unit and a wireless power
reception unit. The wireless power transmission unit receives
power, generates a wireless power signal to be wirelessly
transmitted, wirelessly transmits the generated wireless power
signal in a magnetic resonance manner, receives a returned wireless
power signal and detects the number of power consumption devices,
and wirelessly transmits a wireless power signal using resonance
frequency appropriate for the number of power consumption
devices.
Inventors: |
LEE; Kwang Du;
(Jeollanam-do, KR) ; KIM; Kyung Uk; (Seoul,
KR) ; KIM; Jeong Hoon; (Seoul, KR) ; KIM; Eung
Ju; (Suwon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRO-MECHANICS CO., LTD. |
Suwon |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Suwon
KR
|
Family ID: |
43822652 |
Appl. No.: |
14/139677 |
Filed: |
December 23, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12630348 |
Dec 3, 2009 |
8633615 |
|
|
14139677 |
|
|
|
|
Current U.S.
Class: |
307/149 |
Current CPC
Class: |
H02J 50/80 20160201;
H01F 38/14 20130101; H02J 50/40 20160201; H02J 5/005 20130101; H02J
50/90 20160201; H02J 50/12 20160201 |
Class at
Publication: |
307/149 |
International
Class: |
H02J 17/00 20060101
H02J017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 7, 2009 |
KR |
10-2009-0095284 |
Claims
1.-6. (canceled)
7. The wireless power transmission/reception apparatus as set forth
in claim 1, wherein the wireless power reception unit comprises: a
second resonance antenna comprised of an inductor and a capacitor,
and configured to receive the wireless power signal from the
wireless power transmission unit using resonance frequency
depending on the inductor and the capacitor in a magnetic resonance
manner and return the remaining wireless power signal to the
wireless power transmission unit; a power signal converter
connected to each of a plurality of power consumption devices,
configured to convert the wireless power signal received through
the second resonance antenna into a power signal appropriate for a
power supply method and supply the resulting power signal to the
power consumption device; a power detector for detecting and
outputting power intensity of the wireless power signal received
through the second resonance antenna; and a controller for
performing control so that the wireless power signal is received
using the second resonance antenna and power is supplied to the
power consumption device and so that the remaining wireless power
signal is returned to the wireless power transmission unit.
8. The wireless power transmission/reception apparatus as set forth
in claim 7, wherein the controller of the wireless power reception
unit searches for a maximum inflection point of the power intensity
detected by the power detector while tuning the resonance frequency
of the first resonance antenna and sets the resonance frequency of
the second resonance antenna to a resonance frequency corresponding
to the found maximum inflection point.
9. The wireless power transmission/reception apparatus as set forth
in claim 7, wherein: the wireless power reception unit further
comprises an impedance matcher between the second resonance antenna
and the power signal converter; and the controller searches for a
maximum inflection point of the power intensity detected by the
power detector while adjusting impedance of the impedance matcher
and sets the impedance of the impedance matcher to an impedance
corresponding to the found maximum inflection point.
10. The wireless power transmission/reception apparatus as set
forth in claim 7, wherein: the wireless power reception unit
further comprises a switch disposed between the second resonance
antenna and the power signal converter and configured to block
transmission of the power received by the second resonance antenna;
and the controller, when connection of the power consumption device
is released, controls the switch so that transmission of the power
received by the second resonance antenna is blocked.
11.-16. (canceled)
17. A wireless power reception unit, comprising: a second resonance
antenna installed in a power consumption device, comprised of an
inductor and a capacitor, and configured to receive a wireless
power signal from a wireless power transmission unit using
resonance frequency depending on the inductor and the capacitor in
a magnetic resonance manner and return a remaining wireless power
signal to the wireless power transmission unit; a power signal
converter for converting the wireless power signal received through
the second resonance antenna into a power signal appropriate for a
power supply method and supplying the resulting power signal to the
power consumption device; a power detector for detecting and
outputting power intensity of the wireless power signal received
through the second resonance antenna; and a controller for
performing control so that the wireless power signal is received
through the second resonance antenna and power is supplied to the
power consumption device and so that the remaining wireless power
signal is returned to the wireless power transmission unit.
18. The wireless power reception unit as set forth in claim 17,
wherein the power signal converter comprises: an Alternating
Current (AC) converter for converting the received wireless power
signal into an AC signal; and an AC-Direct Current (DC) converter
for converting the received wireless power signal into a DC
signal.
19. The wireless power reception unit as set forth in claim 17,
wherein the controller searches for a maximum inflection point of
power intensity detected by the power detector while adjusting the
resonance frequency of the second resonance antenna and sets the
resonance frequency of the second resonance antenna to resonance
frequency corresponding to the found maximum inflection point.
20. The wireless power reception unit as set forth in claim 17,
further comprises an impedance matcher between the second resonance
antenna and the power signal converter; and the controller searches
for a maximum inflection point of the power intensity detected by
the power detector while adjusting impedance of the impedance
matcher and sets the impedance of the impedance matcher to
impedance corresponding to the found maximum inflection point.
21. The wireless power reception unit as set forth in claim 17,
further comprises a switch disposed between the second resonance
antenna and the power signal converter and configured to block
transmission of the power received by the second resonance antenna;
and the controller, then connection of the power consumption device
is released, controls the switch so that transmission of the power
received by the second resonance antenna is blocked.
22.-26. (canceled)
27. A wireless power reception method, comprising: when a wireless
power reception unit receives a wireless power signal from a
wireless power transmission unit, a power consumption device in
which the wireless power reception unit has been installed
receiving the transmitted wireless power signal and returning a
remaining wireless power signal; and when connection of power
consumption device in which the wireless power reception unit has
been installed is released, stopping receiving a wireless power
signal from the wireless power transmission unit.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2009-0095284, filed on Oct. 7, 2009, entitled
"Wireless Power Transmission Apparatus and Method thereof," which
is hereby incorporated by reference in its entirety into this
application.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates generally to a wireless power
transmission/reception apparatus and method, and, more
particularly, to a wireless power transmission/reception apparatus
and method which enable the active detection of the reception
environment of the wireless power transmission/reception apparatus
without using a separate wireless communication device.
[0004] 2. Description of the Related Art
[0005] With the development of wireless communication technology,
ubiquitous information environments enabling anyone to exchange
desired information anytime and anywhere have been implemented.
However, most communication information devices still depend on
batteries and are supplied with power through power cords, and thus
the use of communication information devices is limited. Therefore,
the environment of a wireless information network cannot be
actually freed from this limitation until the problem of terminal
power is solved.
[0006] In order to solve this problem, various types of
technologies for transmitting power in a wireless manner have been
developed.
[0007] First, representative technologies may include radio
reception technology using microwaves, magnetic induction
technology using a magnetic field, and magnetic resonance
technology using energy conversion between a magnetic field and an
electric field.
[0008] Radio reception technology is advantageous because
microwaves are radiated into the air through an antenna, and thus
long-distance power transmission is made possible. However, radio
reception technology has high radiation loss due to the consumption
of power by the air, and thus the efficiency of power transmission
is limited.
[0009] Furthermore, magnetic induction technology is a technology
based on magnetic energy coupling using the primary coil of a
transmitting end and the secondary coil of a receiving end, and is
advantageous in that the efficiency of power transmission is high.
However, magnetic induction technology is disadvantageous in that
the primary coil of the transmitting end and the secondary coil of
the receiving end must be located adjacent to each other within a
short distance of about several mm so as to transmit power, in that
the efficiency of power transmission rapidly changes according to
the alignment of the primary coil of the transmitting end and the
secondary coil of the receiving end, and in that the amount of heat
generated is large.
[0010] Therefore, magnetic resonance technology that is similar to
magnetic induction technology has recently been developed, but it
is configured to concentrate energy on a specific resonant
frequency determined by an inductor L and a capacitor C, and thus
to transmit power in the form of magnetic energy. This is
advantageous because a relatively large amount of power can be
transmitted even a distance of several meters, but requires high
resonance characteristics (a high quality factor).
[0011] That is, magnetic induction technology is disadvantageous
because the efficiency of power transmission rapidly changes
depending on whether impedance matching has been achieved or
whether the resonant frequencies of the LC circuits of the
transmitting and receiving ends are identical to each other.
[0012] Conventional magnetic induction technology deals with the
above problems via communication between the transmitting end and
the receiving end by installing transceivers both on the
transmitting and receiving ends. However, when the transceivers are
installed separately, problems arise in that the cost of wireless
power transmission and reception units increases and the
construction of the apparatus is complicated.
SUMMARY OF THE INVENTION
[0013] Accordingly, the present invention has been made keeping in
mind the above problems occurring in the prior art, and the present
invention is intended to provide a wireless power
transmission/reception apparatus which is not provided with
separate transceiver modules for performing communication between
transmitting and receiving ends and can perform wireless power
transmission using only a wireless power transmission unit and a
wireless power reception unit, and a wireless power
transmission/reception method.
[0014] In order to accomplish the above object, the present
invention provides a wireless power transmission/reception
apparatus, including a wireless power transmission unit for
receiving power from an outside, generating a wireless power signal
to be wirelessly transmitted, wirelessly transmitting the generated
wireless power signal in a magnetic resonance manner, receiving a
returned wireless power signal and detecting a number of power
consumption devices, and wirelessly transmitting a wireless power
signal using resonance frequency appropriate for the number of
power consumption devices, thereby transmitting the wireless power
signals so that power can be supplied to the power consumption
devices; and a wireless power reception unit installed in each of
the power consumption devices, and configured to receive the
wireless power signal from the wireless power transmission unit in
a magnetic resonance manner, provide the wireless power signal to
at least one connected power consumption device, and return a
remaining wireless power signal, not consumed by at least one
unconnected power consumption device, to the wireless power
transmission unit.
[0015] The wireless power transmission unit includes a power signal
generator for receiving the power from the outside, and generating
and outputting the wireless power signal, that is, power to be
wirelessly transmitted; a first resonance antenna comprised of an
inductor and a capacitor, and configured to transmit the wireless
power signal in a magnetic resonance manner using resonance
frequency depending on the inductor and the capacitor, and receive
and output the returned wireless power signal output from the
wireless power reception unit; a directional power coupler having
directionality so that the wireless power signal input from the
power signal generator through a first port thereof is output to
the first resonance antenna through a second port thereof and the
returned wireless power signal input from the first resonance
antenna through the second port is output through a third port
thereof; a power detector for detecting and outputting power of the
returned wireless power signal output through the third port of the
directional power coupler; and a controller for detecting the
number of power consumption devices based on intensity of the power
of the returned wireless power signal detected by the power
detector, and controlling the first resonance antenna so that the
wireless power signal is transmitted using resonance frequency and
power intensity appropriate for the detected number of power
consumption devices.
[0016] The wireless power reception unit includes a second
resonance antenna comprised of an inductor and a capacitor, and
configured to receive the wireless power signal from the wireless
power transmission unit using resonance frequency depending on the
inductor and the capacitor in a magnetic resonance manner and
return the remaining wireless power signal to the wireless power
transmission unit; a power signal converter connected to each of a
plurality of power consumption devices, configured to convert the
wireless power signal received through the second resonance antenna
into a power signal appropriate for a power supply method and
supply the resulting power signal to the power consumption device;
a power detector for detecting and outputting power intensity of
the wireless power signal received through the second resonance
antenna; and a controller for performing control so that the
wireless power signal is received using the second resonance
antenna and power is supplied to the power consumption device and
so that the remaining wireless power signal is returned to the
wireless power transmission unit.
[0017] According to another aspect of the present invention, there
is provided a wireless power transmission/reception method
including a wireless power transmission unit transmitting a
wireless power signal to a wireless power reception unit in a
magnetic resonance manner, being returned a remaining wireless
power signal of the wireless power signal to be provided to a power
consumption device in which the wireless power reception unit has
been installed, and determining whether at least one power
consumption device has been connected; and the wireless power
transmission unit, if at least one power consumption device is
determined to have been connected, searching for a resonance
frequency at which maximum power transmission is performed,
detecting a number of power consumption devices using the found
resonance frequency, and transmitting a wireless power signal at a
power intensity appropriate for the detected number of power
consumption devices.
[0018] According to another aspect of the present invention, there
is provided a wireless power transmission method, including a
wireless power transmission unit transmitting a wireless power
signal to a wireless power reception unit in a magnetic resonance
manner; the wireless power transmission unit receiving a returned
wireless power signal from a wireless power reception unit,
detecting a power intensity, and determining whether at least one
power consumption device has been connected; and the wireless power
transmission unit, if at least one power consumption device is
determined to have been connected, searching for a resonance
frequency at which maximum power transmission is performed,
detecting a number of power consumption devices using the found
resonance frequency, and transmitting a wireless power signal at a
power intensity appropriate for the detected number of power
consumption devices.
[0019] According to another aspect of the present invention, there
is provided a wireless power reception method, including, when a
wireless power reception unit receives a wireless power signal from
a wireless power transmission unit, a power consumption device in
which the wireless power reception unit has been installed
receiving the transmitted wireless power signal and returning a
remaining wireless power signal; and, when connection of power
consumption device in which the wireless power reception unit has
been installed is released, stopping receiving a wireless power
signal from the wireless power transmission unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The above and other objects, features and advantages of the
present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0021] FIG. 1 is a schematic block diagram illustrating the
construction of a wireless power transmission/reception apparatus
according to a preferred embodiment of the present invention;
[0022] FIG. 2 is a detailed block diagram illustrating the
construction of the wireless power transmission/reception apparatus
according to the preferred embodiment of the present invention;
[0023] FIG. 3 is a graph of reflected power gain P.sub.reflect
against frequency;
[0024] FIG. 4 is a graph of reflected power gain P.sub.reflect
against impedance;
[0025] FIG. 5 is a graph of transmission power gain P.sub.couple
against frequency;
[0026] FIG. 6 is a graph of transmission power gain P.sub.couple
against impedance;
[0027] FIG. 7A is a graph showing variations in transmission power
gain P.sub.couple and resonance frequency depending on the number
of power consumption devices;
[0028] FIG. 7B is a graph showing variations in resonance frequency
depending on the number of power consumption devices;
[0029] FIG. 8 is a flowchart showing a method of operating the
wireless power transmission unit of FIG. 1;
[0030] FIG. 9 is a flowchart showing a method of operating the
wireless power reception unit of FIG. 1; and
[0031] FIG. 10 is a diagram showing a method in which a single
wireless power transmission unit sequentially supplies power to a
plurality of wireless power reception units.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Reference now should be made to the drawings, in which the
same reference numerals are used throughout the different drawings
to designate the same or similar components.
[0033] Preferred embodiments of the present invention will be
described in detail below with reference to the accompanying
drawings.
[0034] FIG. 1 is a schematic block diagram illustrating the
construction of a wireless power transmission/reception apparatus
according to a preferred embodiment of the present invention.
[0035] Referring to FIG. 1, the wireless power
transmission/reception apparatus includes a wireless power
transmission unit 100, and a plurality of wireless power reception
units 200-1, 200-2 and 200-3 respectively installed in a plurality
of power consumption devices 400-1, 400-2 and 400-3.
[0036] Wireless power received by the wireless power reception
units 200-1, 200-2 and 200-3 installed in the power consumption
devices 400-1, 400-2 and 400-3 is stored in power source units
300-1, 300-2 and 300-3.
[0037] Here, the power source units 300-1, 300-2 and 300-3 may use
different power supply methods depending on the power consumption
devices 400-1, 400-2 and 400-3.
[0038] The wireless power transmission unit 100 includes a
capacitor C1 and an inductor L1, and each of the wireless power
reception units 200 (200-1, 200-2 and 200-3) includes a capacitor
C2-1, C2-2 or C2-3 and an inductor L2-1, L2-2 or L2-3. Accordingly,
the wireless power transmission unit 100 and the wireless power
reception units 200-1, 200-2 and 200-3 transmit and receive power
using magnetic resonance.
[0039] Here, the wireless power transmission unit 100 sets an
initial resonance frequency, and transmits a wireless signal
(hereinafter referred to as `a wireless power signal`) to the
wireless power reception units 200-1, 200-2 and 200-3 using the
initial resonance frequency. Furthermore, the wireless power
transmission unit 100 receives a wireless signal (hereinafter
referred to as `a returned wireless power signal`) returned from
the wireless power reception units 200-1, 200-2 and 200-3, and then
detects the number of power consumption devices 400-1, 400-2 and
400-3 in which wireless power reception units 200-1, 200-2 and
200-3 in the state of receiving wireless power signals have been
respectively installed.
[0040] The wireless power transmission unit 100 transmits a
wireless power signal at a resonance frequency appropriate for the
detected number of power consumption devices 400 in which wireless
power reception units 200 in a signal receiving state have been
respectively installed.
[0041] For ease of description, only wireless power transmission
between a single wireless power transmission unit 100 and a single
wireless power reception unit 200 will be described below.
[0042] FIG. 2 is a detailed block diagram illustrating the
construction of the wireless power transmission/reception apparatus
according to the preferred embodiment of the present invention.
Referring to FIG. 2, the wireless power transmission/reception
apparatus includes a wireless power transmission unit 100, and a
wireless power reception unit 200 installed in a power consumption
device 400.
[0043] Energy transmission between the wireless power transmission
unit 100 and the wireless power reception unit 200 using magnetic
resonance will now be described in detail. The wireless power
transmission unit 100 generates a wireless power signal first, and
then the wireless power signal is converted into magnetic energy by
a first resonance antenna 150, including an inductor L and a
capacitor C, through LC resonance. Then, the resulting magnetic
energy is magnetically coupled to the second resonance antenna 210
which includes an inductor L and a capacitor C and belongs to the
wireless power reception unit 200.
[0044] In this case, magnetic energy coupling can be maximized by
tuning which is achieved by making the LC resonance frequency of
the first resonance antenna 150 and the LC resonance frequency of
the second resonance antenna 210 consistent with each other. That
is, since the transmission efficiency rapidly increases depending
on the similarity between the resonance frequencies, the
calibration of resonance frequencies for making the resonance
frequencies of the first resonance antenna 150 and the second
resonance antenna 210 identical to each other is required.
[0045] Furthermore, in order to increase or adjust the intensity of
power, a power amplifier 120 is used in the wireless power
transmission unit 100. Here, the load impedance required to drive
the power amplifier 120 is several tens of ohms, while the
impedance of the actual LC coil of the first resonance antenna 150
required to increase the Q-factor is merely several ohms Since the
transmission efficiency is considerably decreased by a mismatch
between the impedances of the power amplifier 120 and the first
resonance antenna 150, the calibration of an impedance match is
essential.
[0046] Meanwhile, with regard to a magnetic field based on the
magnetic coupling, Maxwell's Fourth Equation regarding
electromagnetic waves states that "a magnetic field always forms a
closed loop."
[0047] Accordingly, unlike an electric field having the
characteristic of propagating far like water waves, a magnetic
field can conserve its energy thanks to the characteristic of
returning along a circle unless there is loss due to a medium.
[0048] When this characteristic is employed, the wireless power
transmission unit 100 can detect the environment of the wireless
power reception unit 200 in a situation in which communication is
not being performed between the wireless power transmission unit
100 and the wireless power reception unit 200.
[0049] That is, when the wireless power transmission unit 100 is
turned on and the power consumption device 400 in which the
wireless power reception unit 200 has been installed does not exist
or is not turned on, the wireless power transmission unit 100 may
determine the power consumption device 400 in which the wireless
power reception unit 200 has been installed not to exist in a
wireless power transmission environment because there is no energy
loss from the viewpoint of the wireless power transmission unit
100. In contrast, when the power consumption device 400 in which
the wireless power reception unit 200 has been installed exists,
the power consumption device 400 in which the wireless power
reception unit 200 has been installed may be determined to exist
because energy loss occurs from the viewpoint of the wireless power
transmission unit 100. When a plurality of power consumption
devices 400 in which a plurality of wireless power reception units
200 has respectively been installed exists, the energy loss
increases, and the resonance frequency varies with the number of
power consumption devices in which the wireless power reception
units 200 have been respectively installed due to the mutual
inductance between the wireless power transmission unit 100 and the
power consumption devices in which the wireless power reception
units 200 have been respectively installed.
[0050] Accordingly, it is possible to determine whether a power
consumption device 400 in which a wireless power reception unit 200
has been installed exists by measuring power returned after power
was transmitted by the wireless power transmission unit 100, to
detect the number of power consumption devices 400 in which
wireless power reception units 200 have been respectively installed
when the wireless power reception units 200 exist, and to transmit
power in an optimal state through the above-described frequency and
impedance adjustment, thereby improving the power transmission
efficiency.
[0051] Here, the power consumption device 400 is a device which
receives a wireless power signal from the wireless power
transmission unit 100 through the second resonance antenna 210 of
the wireless power reception unit 200 and charges the power source
unit 300 of the power consumption device 400 with power or supplies
domestic power, thereby consuming the power with which the power
source unit 300 was charged or which was supplied thereto. The
power consumption device 400 may be, for example, a battery charger
or an electronic/household device, such as a television or a
computer.
[0052] The construction and operation of the wireless power
transmission unit 100 and wireless power reception unit 200 of the
wireless power transmission/reception apparatus according to the
embodiment of the present invention will be described in detail
below.
[0053] The wireless power transmission unit 100 according to the
embodiment of the present invention, as shown in FIG. 2, includes
an oscillator 110, a power amplifier 120, an impedance matcher 130,
a directional power coupler 140, a first resonance antenna 150, a
power detector PD 160, and a controller 170.
[0054] The oscillator 110 converts external power into a wireless
power signal. Here, the wireless power signal is an Alternating
Current (AC) signal. Since an input external AC signal may have an
AC signal form which is not appropriate for wireless power
transmission, the oscillator 110 converts external power into an AC
signal appropriate for wireless transmission and outputs the
resulting AC signal.
[0055] The oscillation frequency of a wireless power signal
generated by the oscillator 110 is lower than the resonance
frequency based on the values of the inductor L and capacitor C of
the first resonance antenna 150, and is equal to the resonance
frequency calculated by adding a mutual inductance value ranging
from the first resonance antenna 150 to a receiving end.
[0056] In order to increase the efficiency of wireless power
transmission, the power amplifier 120 amplifies the wireless power
signal so as to increase or adjust the intensity thereof, and
outputs the resulting signal.
[0057] The directional power coupler 140 includes a plurality of
terminals, and changes the direction of an input signal by causing
a signal input through one terminal to be output only through one
of the remaining contacts and preventing the signal from being
output through some other terminal.
[0058] The wireless power signal is transmitted to the first
resonance antenna 150 through the directional power coupler 140,
and a wireless power signal (hereinafter referred to as a `returned
wireless power signal`) is input from the magnetic coupling energy
forming a closed loop through the first resonance antenna 150 and
is then output.
[0059] The directional power coupler 140 includes a plurality of
input/output terminals, and functions to transmit an input wireless
power signal only to a terminal connected to the first resonance
antenna 150 and transmit a returned wireless power signal only to a
terminal connected to the power detector 160.
[0060] Here, it is preferred that the directional power coupler 140
be formed of a circulator having a plurality of terminals. The
circulator includes a plurality of terminals, but transmits an
input signal in a single direction regardless of the terminal
through which the signal is input.
[0061] The power detector PD 160 detects a returned wireless power
signal output from the directional power coupler 140. The reflected
power P.sub.reflect depending on signal intensity may be detected
from the returned wireless power signal detected by the power
detector PD 160.
[0062] Meanwhile, a battery charger (not shown) for performing
charging using reflected power P.sub.reflect detected by the power
detector PD 160 may be further included. The power used by the
battery charger (not shown) may be used as power for the wireless
power transmission unit 100, so that the waste of power can be
prevented.
[0063] The first resonance antenna 150 includes an inductor L and a
capacitor C. When the wireless power signal is input, it is
converted into magnetic energy through LC resonance, so that a
closed loop is formed.
[0064] In order to transmit power in an optimal state as described
above, the impedance matcher 130 performs impedance matching
between the power amplifier 120 and the first resonance antenna
150.
[0065] The controller 170 generally controls the wireless power
transmission unit 100.
[0066] In greater detail, the controller 170 performs control so
that an initial resonance frequency is set, a wireless power signal
is generated and amplified using the set initial resonance
frequency through the first resonance antenna 150, the amplified
wireless power signal is converted into magnetic energy which forms
a closed loop using the LC resonance of the inductor L and
capacitor C of the first resonance antenna 150, and a returned
wireless power signal is received and detected from magnetic
coupling energy resulting from magnetic coupling to the wireless
power reception units 200 installed in the power consumption
devices 400 through the first resonance antenna 150. In this case,
reflected power P.sub.reflect can be detected from the returned
wireless power signal, the resonance frequency between the wireless
power transmission unit 100 and the power consumption devices 400
in which the wireless power reception units 200 have been installed
is detected based on the variation in reflected power, and the
number of power consumption devices 400 in which the wireless power
reception units 200 have been installed is detected based on the
detected resonance frequency.
[0067] Thereafter, the controller 170 increases the power of the
wireless power signal so as to achieve power intensity appropriate
for the detected number of power consumption devices 400, and
causes the wireless power signal to be transmitted in a state in
which the power has been increased.
[0068] In this case, the controller 170 adjusts the resonance
frequency by controlling the first resonance antenna 150 so that
the maximum power transmission occurs, and adjusts impedance by
controlling the impedance matcher 140.
[0069] The processes of adjusting frequency and impedance will be
described as follows:
[0070] The controller 170 performs control so that reflected power
P.sub.reflect can be detected from the returned wireless power
signal depending on frequency adjustment (frequency tuning)
performed by varying the inductance L and capacitance C of the
first resonance antenna 150. Through this process, a graph of
reflected power gain (P.sub.reflect,S(1,1)) [dB] against frequency
[MHz] can be obtained, and an example of such a graph is
illustrated in FIG. 2.
[0071] From FIG. 3, it can be seen that a minimum inflection point
exists in a reflected power gain curve and the reflected power gain
P.sub.reflect is minimum at a frequency corresponding to the
minimum inflection point. This means that resonance has occurred at
the frequency corresponding to the minimum inflection point.
[0072] The controller 170 performs control so that reflected power
P.sub.reflect can be detected from the returned wireless power
signal depending on impedance adjustment (impedance tuning)
performed by varying the impedance of the impedance matcher 130.
Through this process, a graph of reflected power gain
(P.sub.reflect,S(1,1))[dB] against impedance [ohm] can be obtained,
and an example of such a graph is shown in FIG. 4.
[0073] From FIG. 4, it can be seen that a minimum inflection point
exists in a reflected power gain curve and the reflected power gain
P.sub.reflect is minimum at the impedance corresponding to the
minimum inflection point. This means that resonance has occurred at
the impedance corresponding to the minimum inflection point.
[0074] Meanwhile, the wireless power reception unit 200 provided in
the power consumption device 400 according to the embodiment of the
present invention comprises a second resonance antenna 210, a
switch 220, an impedance matcher 230, a power signal converter 240,
a power detector PD 250, and a controller 260.
[0075] The second resonance antenna 210 includes an inductor L and
a capacitor C. Magnetic energy which forms a closed loop through
the LC resonance of the inductor L and the capacitor C is obtained,
and is magnetically coupled with magnetic energy generated from the
wireless power transmission unit 100. Since the magnetic coupling
energy also forms a closed loop, a wireless power signal into which
the magnetic coupling energy was converted is received.
[0076] The switch 220 performs switching so that the second
resonance antenna 210 selectively performs and blocks magnetic
coupling with the wireless power transmission unit 100. In other
words, the switch 220 determines the reception waiting or reception
termination of the wireless power reception unit 200.
[0077] When the switch 220 is turned on, the wireless power
reception unit 200 receives a wireless power signal. In contrast,
when the switch 220 is turned off, the wireless power reception
unit 200 stops receiving a wireless power signal.
[0078] For example, when the power consumption device 400 in which
the wireless power reception unit 200 has been installed does not
require power any more (for example, when the charging of a battery
is completed or an electronic/household device such as a television
or a computer is turned off), the switch 220 terminates magnetic
coupling with the wireless power transmission unit 100. In
contrast, when the power consumption device 400 in which the
wireless power reception unit 200 has been installed requires power
(for example, the charging of a battery is started or an
electronic/household device such as a television or a computer is
turned on), the switch 220 performs switching so that magnetic
coupling with the wireless power transmission unit 100 is
started.
[0079] In order to increase the transmission power gain of a
wireless power signal received through the second resonance antenna
210, the impedance matcher 230 performs impedance matching between
the second resonance antenna 210 and a power signal converter 240
(which will be described later).
[0080] The power signal converter 240 converts the received
wireless power signal into an appropriate DC or AC signal so as to
charge the power source unit 300 of the power consumption device
400 with power or supply domestic power.
[0081] For example, when the power source unit 300 of the power
consumption device 400 is of a type in which a specific capacity is
stored by performing charging for a predetermined period of time
like a battery charger, the power signal converter 240 converts the
received wireless power signal into an appropriate DC signal so as
to charge the power source unit 300 of the power consumption device
400 with power.
[0082] In this case, the wireless power reception unit 200
installed in the power consumption device 400 further includes a
battery capacity detector (not shown) capable of detecting the
capacity of the battery charger, and transmits a signal detected by
the battery capacity detector (not shown) to the controller 260 of
the wireless power reception unit 200.
[0083] Furthermore, when the power source unit 300 of the power
consumption device 400 is of a type in which power is continuously
supplied, like an electronic/household device, the power signal
converter 240 converts the received wireless power signal into an
appropriate AC signal so as to supply domestic power to the power
source unit 300 of the power consumption device 400.
[0084] Accordingly, the power signal converter 240 may include an
AC-AC converter (not shown) for converting the received wireless
power signal into an appropriate AC signal and an AC-DC converter
(not shown) for converting the received wireless power signal into
an appropriate DC signal.
[0085] The power detector 250 detects the wireless power signal
converted by the power signal converter 240. On the basis of the
intensity of the detected wireless power signal, transmission power
gain P.sub.couple transmitted from the wireless power transmission
unit 100 is detected.
[0086] The controller 260 performs control so that a wireless power
signal is received and converted into an appropriate wireless power
signal according to a power supply method, power is supplied, the
resulting wireless power signal is detected, and transmission power
gain P.sub.couple is detected from the detected wireless power
signal.
[0087] Furthermore, the controller 260 performs control so that the
switch 220 is selectively turned on and off based on information
about the battery capacity transmitted by the battery capacity
detector (not shown).
[0088] Furthermore, the controller 260 performs control so that
transmission power gain P.sub.couple can be detected from the
received wireless power signal depending on frequency adjustment
(frequency tuning) by varying the inductance L and capacitance C of
the second resonance antenna 210. Through this process, a graph of
transmission power gain (P.sub.couple,S(2,1)) [dB] against
frequency [MHz], and an example of such a graph is illustrated in
FIG. 5.
[0089] From FIG. 5, it can be seen that a maximum inflection point
exists in a transmission power gain curve and the transmission
power gain P.sub.couple is at a maximum at a frequency
corresponding to the maximum inflection point. This means that
resonance has occurred at the frequency corresponding to the
maximum inflection point.
[0090] Furthermore, the controller 260 performs control so that
transmission power gain P.sub.couple can be detected from the
returned wireless power signal depending on impedance adjustment
(impedance tuning) performed by varying the impedance of the
impedance matcher 230. Through this process, a graph of
transmission power gain (P.sub.couple,S(2,1)) [dB] against
impedance [ohm] can be obtained, and an example of such a graph is
illustrated in FIG. 6.
[0091] From FIG. 6, it can be seen that a minimum inflection point
exists in a reflected power gain curve and it can be seen that a
maximum inflection point exists in a transmission power gain curve
and the transmission power gain P.sub.couple is at a maximum at the
impedance corresponding to the maximum inflection point. This means
that resonance has occurred at the impedance corresponding to the
maximum inflection point.
[0092] FIG. 7A is a graph showing variations in transmission power
gain P.sub.couple and resonance frequency depending on the number
of power consumption devices 400 in which the wireless power
reception units 200 have been respectively installed, and FIG. 7B
is a graph showing variations in resonance frequency depending on
the number of power consumption devices 400 in which the wireless
power reception units 200 have been respectively installed.
[0093] From FIGS. 7A and 7B, it can be seen that as the number of
power consumption devices 400 increases, the resonance frequency
decreases and the transmission gain characteristic P.sub.couple
decreases.
[0094] Accordingly, the wireless power transmission unit 100 can
determine the number of power consumption devices 400 to detect the
reception environment when the reflected power P.sub.reflect and
the resonance frequency are known.
[0095] FIG. 8 is a flowchart showing a method of operating the
wireless power transmission unit 100 in the wireless power
transmission/reception apparatus according to the embodiment of the
present invention.
[0096] Referring to FIG. 8, the operation of the wireless power
transmission unit 100 will now be described. The controller 170 of
the wireless power transmission unit 100 carries out power
consumption device presence determination mode S810, calibration
mode S820, and wireless power transmission mode S830.
[0097] In power consumption device presence determination mode
S810, when the wireless power transmission unit 100 is turned on,
an initial resonance frequency is set at step S811. Thereafter, the
reflected power P.sub.reflect of wireless power transmitted at the
set initial resonance frequency through the first resonance antenna
150 of the wireless power transmission unit 100 is detected and
then whether the reflected power P.sub.reflect is less than the set
value 1 is determined at step S812.
[0098] Here, the set value 1 is set as follows:
[0099] For example, in the case where the wireless power reception
unit 200 installed in the power consumption device 400 does not
exist or is turned off, assuming that the wireless power
transmission unit 100 has a reflection loss of about 5% and the
power transmitted by the wireless power transmission unit 100 is
`1`, set value 1 is set to a value slightly less than the reflected
power P.sub.reflect of 0.95 of the transmitted power of `1`, for
example, 0.9.
[0100] Then, at step S812, if the reflected power P.sub.reflect is
less than 0.9, it is determined that there is power loss. If the
reflected power P.sub.reflect is equal to or greater than 0.9, it
is determined that there is no power loss. In other words, if the
reflected power P.sub.reflect is less than set value 1, this means
that the wireless power reception unit 200 installed in the power
consumption device 400 exists or is turned on, so that it is
determined that the wireless power reception unit 200 installed in
the power consumption device 400 exists.
[0101] After whether the power consumption device 400 in which the
wireless power reception unit 200 has been installed exists or not
has been determined as described above, calibration mode for
establishing an optimal wireless power transmission state through
frequency adjustment and impedance adjustment is carried out.
[0102] In calibration mode S820, in order to find the resonance
frequency for the optimal wireless power transmission between the
wireless power transmission unit 100 and the wireless power
reception unit 200, reflected power P.sub.reflect depending on the
variation in frequency is detected while the frequency is adjusted
(frequency tuning is performed) by varying the inductance L and
capacitance C of the first resonance antenna 150 at step S821.
Thereafter, the minimum inflection point is determined to be the
optimal resonance frequency by determining whether the reflected
power P.sub.reflect exists at a minimum inflection point at step
S822. The reflected power P.sub.reflect can be detected from the
resonance frequency, and the number of power consumption devices
400 in which the wireless power reception units 200 have been
respectively installed can be detected based on the variations in
resonance frequency and reflected power P.sub.reflect. Accordingly,
the magnitude of transmitted power depending on the number of power
consumption devices 400 in which wireless power reception units 200
have been respectively installed is determined at step S823.
Thereafter, impedance matching is performed to achieve the optimal
wireless power between the wireless power transmission unit 100 and
the wireless power reception unit 200. Such impedance matching is
performed by measuring reflected power P.sub.reflect based on
variation in impedance while adjusting impedance (performing
impedance tuning) by varying the impedance, like the frequency
adjustment, at step S824. Thereafter, the minimum inflection point
is determined to be optimal impedance by determining whether the
reflected power P.sub.reflect exists at a minimum inflection point
at step S825. As a result, by the frequency and impedance
calibration steps for performing optimal wireless power
transmission, wireless power can be transmitted in an optimal
transmission state.
[0103] In wireless power transmission mode S830, wireless power is
transmitted in the optimal transmission state after calibration
mode S820 at step S831. Thereafter, the variation
.DELTA.P.sub.reflect between currently reflected power
P.sub.p.sub.--.sub.ref and initial reflected power
P.sub.o.sub.--.sub.ref is measured at step S832. Thereafter,
whether the reflected power variation .DELTA.P.sub.reflect is
greater than the set value 2 is determined at step S833. If the
reflected power variation .DELTA.P.sub.reflect is equal to or less
than the set value 2, it is determined that charging has not been
completed or power supply has not been stopped for any one of a
plurality of power consumption devices in which the wireless power
reception units 200 have been respectively installed, calibration
mode S820 is carried out, and then wireless power is transmitted in
an optimal transmission state. If the reflected power variation
.DELTA.P.sub.reflect is greater than the set value 2, it is
determined that charging has been completed or power supply has
been stopped for at least one of the plurality of power consumption
devices in which the wireless power reception units 200 have been
respectively installed and whether to stop wireless power
transmission is determined at step S834. If wireless power
transmission is determined to be stopped, wireless power
transmission is stopped. In contrast, if wireless power
transmission is determined not to be stopped, calibration mode S820
is carried out again, and wireless power is transmitted in an
optimal transmission state.
[0104] Here, assuming that the reflected power variation
.DELTA.P.sub.reflect obtained when charging has been completed or
power supply has been stopped for all of the plurality of power
consumption devices in which the wireless power reception units 200
have been respectively installed is `1` and the plurality of power
consumption devices in which the wireless power reception units 200
have been respectively installed has the same reflected power
P.sub.reflect, the set value 2 is set to a value slightly less than
1/N (where N is the number of power consumption devices 400 in
which the wireless power reception units 200 have been respectively
installed). For example, when four reception units exist, the set
value 2 is set to 0.20. If the reflected power variation
.DELTA.P.sub.reflect is greater than 0.20, it is determined that
charging has been completed or power supply has been stopped for at
least one of the power consumption devices 400. If the reflected
power variation .DELTA.P.sub.reflect is less than 0.20, it is
determined that charging has not been completed or power supply has
not been stopped for any one of the power consumption devices
400.
[0105] Meanwhile, the controller 150 of the wireless power
transmission unit 100 may further perform, between steps S811 and
S812 in power consumption device presence determination mode S810,
the step of detecting reflected power P.sub.reflect depending on
the variation in frequency while adjusting the frequency
(performing frequency tuning) by varying the inductance L and
capacitance C of the first resonance antenna 150 so as to find the
resonance frequency for the optimal wireless power transmission
between the wireless power transmission unit 100 and the wireless
power reception unit 200, and the step of finding a minimum
inflection point by determining whether the reflected power
P.sub.reflect exists at a minimum inflection point. Here, the
frequency tuning step is not a fine tuning step like that in
calibration mode S820, but is performed using frequency variation
widths. When these steps are further performed, the time required
to find the resonance frequency can be reduced.
[0106] FIG. 9 is a flowchart illustrating a method of operating the
wireless power reception unit 200 in the wireless power
transmission/reception apparatus according to an embodiment of the
present invention.
[0107] Referring to FIG. 9, the operation of the wireless power
reception unit 200 will now be described. The controller 260 of the
wireless power reception unit 200 carries out calibration mode S910
and power supply mode S920.
[0108] Calibration mode S910 may be configured to perform
transmission frequency tuning or impedance matching by varying the
inductance L and capacitance C of the second resonance antenna 210
of the wireless power transmission unit 200 so as to receive
maximum transmitted power. The steps thereof are as follows:
[0109] In calibration mode S910, in order to receive maximum
transmitted power, the transmitted power P.sub.couple based on the
variation in frequency is detected while the frequency is adjusted
(frequency tuning is performed) by varying the inductance L and
capacitance C of the second resonance antenna 210 so as to achieve
tuning to the transmission frequency at step S911. Thereafter,
whether the transmitted power P.sub.couple exists at a maximum
inflection point is determined and the maximum inflection point is
determined to be the optimal resonance frequency at step S912. At
the resonance frequency, the maximum transmitted power P.sub.couple
is received. Thereafter, as in the frequency adjustment, in order
to receive maximum transmitted power, transmitted power
P.sub.couple based on the variation in impedance is measured while
impedance is adjusted (impedance tuning is performed) by varying
the impedance so as to achieve impedance matching at step S913.
Thereafter, whether the transmitted power P.sub.couple exists at a
maximum inflection point is determined and the maximum inflection
point is determined to be optimal impedance at step S914. As a
result, by the frequency and impedance calibration steps for
performing optimal wireless power transmission, wireless power can
be transmitted in an optimal transmission state. The wireless power
received as described above is used to charge the power source unit
300 of the power consumption device 400 requiring wireless power or
is used to carry out power supply mode S920 for supplying
power.
[0110] In power supply mode S920, the power source unit 300 of the
power consumption device 400 may perform a method of storing a
specific capacity by performing charging for a predetermined period
of time like a battery charger and/or a method of continuously
supplying power like an electronic/household device.
[0111] First, in the case of the power source unit 300 of the power
consumption device 400 such as a battery charger, the power source
unit 300 starts to be charged S921, the current capacity of a
battery charged at the power source unit 300 is detected using a
battery capacity detector (not shown), whether the detected battery
capacity is equal to or greater than the set value 3 is
successively determined at step S922, and the switch 220 of the
wireless power reception unit 200 is turned off if the current
battery capacity is equal to or greater than set value 3 at step
S923. Here, set value 3 is set to a value which is obtained when
the power source unit 300 is all charged.
[0112] Furthermore, in this case, before calibration mode S910,
battery capacity determination mode (not shown) may be carried
out.
[0113] The battery capacity determination mode is carried out in a
state in which the switch 220 of the wireless power reception unit
200 installed in the power consumption device 400 has been turned
off. The battery capacity determination mode is configured to
successively determine whether the capacity of a battery charged at
the power source unit 300 is less than the set value 4 and to turn
the switch 220 of the wireless power reception unit 200 installed
in the power consumption device 400 on if the battery capacity is
less than the set value 4, thereby causing the wireless power
reception unit 200 to enter into the state of being capable of
receiving wireless power. Here, the set value 4 is set to a value
which is obtained when the capacity of the battery charged at the
power source unit 300 is all consumed.
[0114] Meanwhile, in the case of the power source unit 300 of the
power consumption device 400 such as an electronic/household
device, appropriate domestic power is supplied to the power source
unit 300 at step S924, whether an off signal for turning off the
power consumption device 400 has been received from the outside is
successively determined S925, and, if an off signal has been
received, the switch 220 of the wireless power reception unit 200
is turned off so as to cut off the power supply to the power
consumption device 400 at step S926.
[0115] As described above, with regard to the wireless power
transmission/reception apparatus according to the embodiment of the
present invention, when a single wireless power transmission unit
and a plurality of wireless power reception units respectively
installed in a plurality of power consumption device exist, the
wireless power transmission unit and the plurality of wireless
power reception units are all maintained at the same resonance
frequency by the mutual calibration mode between the wireless power
transmission unit and the plurality of wireless power reception
units, thereby enabling simultaneous power transmission.
[0116] Furthermore, as shown in FIG. 10, when a single wireless
power transmission unit and a plurality of wireless power reception
units respectively installed in a plurality of power consumption
devices exist, respective resonance frequencies of the plurality of
wireless power reception units may be set to different resonance
frequencies, so that the wireless power transmission unit and the
wireless power reception units are associated in a one-to-one
correspondence, thereby enabling sequential wireless power
transmission. This is similar to the method of assigning unique
Identifiers (IDs) to a plurality of wireless power reception units,
in which case wireless power can be sequentially provided to the
plurality of wireless power reception units by tuning the
transmission frequency of the wireless power transmission unit to
respective resonance frequencies of the plurality of wireless power
reception units.
[0117] In other words, as shown in FIG. 10, when wireless power
transmission to wireless power reception unit 1 of the plurality of
wireless power reception units is completed, wireless power
reception unit 1 automatically turns off the switch thereof,
thereby cutting off magnetic energy coupling with the wireless
power transmission unit. Then, the wireless power transmission unit
becomes aware that the charging of the wireless power reception
unit 1 has been completed or power supply has been stopped, and
tunes the oscillation frequency and the resonance frequency to each
other for subsequent wireless power reception unit 2. Using this
method, control is performed so that wireless power can be
sequentially supplied to the plurality of wireless power reception
units.
[0118] According to the wireless power transmission/reception
apparatus and method of the present invention, a transmission unit
can detect a reception environment without using a separate
communication device or system, so that the cost of the wireless
power transmission/reception apparatus is reduced and the
construction and control of the apparatus are simplified.
[0119] Furthermore, according to wireless power
transmission/reception apparatus of the present invention,
calibration is performed by frequency adjustment and impedance
matching, so that the very narrow-band resonance characteristic
between a transmission unit and reception units can be
improved.
[0120] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *