WO2013165165A1

WO2013165165A1 - Wireless power transmission device, wireless power relay device, and wireless power transmission system

Info

Publication number: WO2013165165A1
Application number: PCT/KR2013/003751
Authority: WO
Inventors: Min Seok Han; Young Sun Kim; Jeong Man WHANG; Un Kyu Park; Ji Hyung Lee
Original assignee: Ls Cable & System Ltd.
Priority date: 2012-05-04
Filing date: 2013-04-30
Publication date: 2013-11-07
Also published as: KR20130123842A

Abstract

The present invention relates to a wireless power transmission device, a wireless power relay device, and a wireless power transmission system using the same. The wireless power relay device includes a relay coil configured to receive power from the resonant coil of a wireless power transmission device by way of magnetic resonance and transmit the received power to another adjacent wireless power relay device by way of magnetic resonance and a communication unit configured to transmit and receive pieces of information about power transfer states through communication with the wireless power transmission device or other wireless power relay devices, wherein the wireless power relay device forms a mesh structure along with one or more adjacent wireless power relay devices and provides a power transmission path from the wireless power transmission device to a wireless power reception device through the formed mesh structure.

Description

WIRELESS POWER TRANSMISSION DEVICE, WIRELESS POWER RELAY DEVICE, AND WIRELESS POWER TRANSMISSION SYSTEM

Aspects of embodiments of the present invention relates to a wireless power transmission system using a plurality of electronic devices including relay coils.

Recently, there is a growing interest in energy-Information Technology (IT) convergence technology. Energy-IT convergence technology refers to the convergence of rapidly developing IT technology with conventional energy technology. As one field of this energy-IT convergence technology, there is Wireless Power Transfer (WPT) technology. WPT refers to technology in which power is wirelessly supplied to home appliances or electric vehicles instead of a conventional wired power line. Active researches related to WPT are being carried out because of an advantage that home appliances, etc. can be wirelessly charged even without connecting a wired power cable from a power receptacle to home appliances or a charging device in order to charge home appliances, etc.

WPT technology now being commercialized and researches can be chiefly classified into four methods. One of the four methods is a high output microwave radiation method. This method enables long distance transmission because high output transmission is possible using a frequency of several GHz bands, but this method is not commercialized due to problems, such as harmfulness to the human body and a linear property. Another method is a short distance transmission method of a radiative method. This method relates to RFID service using Radio Frequency Identification (RFID) of a Ultra High Frequency (UHFP) band/Ubiquitous Sensor Network (USN) frequency band or a 2.4 GHz Industrial Scientific Medical (ISM) band. This method has been commercialized in some fields, such as distribution and logistic fields, and this method is disadvantageous in that only power transmission of a maximum of several tens of mW is possible due to a radiation loss. Furthermore, there is very short range wireless communication technology extended from an RFID standard, such as Near Field Communication (NFC).

Meanwhile, a contact type transmission method using inductive coupling is a method of transmitting power of several W by using a contact method at a distance of several mm ~ several cm. This method employs a frequency of 125 kHz or 135 kHz, and this method is used in a traffic card, a wireless razor, an electric toothbrush, etc. Meanwhile, a non-radiated magnetic resonance method is based on a resonant coupling method. Resonant coupling refers to a phenomenon in which in the case of magnetic resonance, when two media resonate in the same frequency, electromagnetic waves move from one medium to the other medium through a short-distance magnetic field. This method is advantageous in that high power transmission of several tens of W is possible within a distance of several meters. However, for actual implementations, it is necessary to maintain the Q (quality factor) value of a resonator high.

Meanwhile, in a wireless power transmission system using a magnetic resonance method, if a distance between a wireless power transmission device and a wireless power reception device is wide, a relay coil is disposed between the two devices so that a power signal can be transmitted from the wireless power transmission device to the wireless power reception device through the relay coil. However, a conventional relay coil needs to have a corresponding diameter in order to satisfy a desired relay distance. For this reason, there is a need for wireless power transmission technology capable of satisfying a desired relay distance while reducing the diameter of a relay coil in a wireless power transmission system using a magnetic resonance method.

For reference, an example of the wireless power transmission system is disclosed in Korean Patent Application Publication No. 2009-0115407 entitled "Wireless resonance power charging system."

Aspects of embodiments of the present invention have been made in view of the above problems, and it is an object of embodiments of the present invention to provide a wireless power relay device capable of securing a power transmission path by disposing a plurality of electronic devices including a relay coil between a wireless power transmission device and a wireless power reception device and a wireless power transmission system using the same.

Objects of the present invention are not limited to the above-described object and other objects not described above can be readily understood from the following description.

According to an embodiment of the present invention, a wireless power relay device includes: a relay coil configured to receive power from a resonant coil of a wireless power transmission device by way of magnetic resonance and transmit the received power to another adjacent wireless power relay device by way of magnetic resonance; and a communication unit configured to transmit and receive pieces of information about power transfer states through communication with the wireless power transmission device or other wireless power relay devices, wherein the wireless power relay device forms a mesh structure along with one or more adjacent wireless power relay devices and provides a power transmission path from the wireless power transmission device to a wireless power reception device through the formed mesh structure.

The wireless power relay device may further include a charging unit configured to charge a battery by using the received power, wherein the charging unit may check a charged amount of the battery and transmits information about the charged amount of the battery to the wireless power transmission device through the communication unit.

The wireless power relay device further includes: a switch formed at an end of the relay coil, and a control unit configured to block the relay coil by controlling the switch in response to a coil block signal received from the wireless power transmission device.

If a battery included in the wireless power relay device may be charged to a reference value or higher or an adjacent wireless power relay device for receiving the power by way of magnetic resonance with the relay coil is not present, the coil block signal generated from the wireless power transmission device is received through the communication unit.

The information about the power transfer state may include one or more of an identification code of the wireless power relay device and a number of hops from the wireless power transmission device to the wireless power relay device.

According to another embodiment of the present invention, a wireless power transmission device includes: a transmission antenna unit configured to wirelessly transmit power to a wireless power relay device by way of magnetic resonance; a communication unit configured to receive information about a power transfer state from the wireless power relay device; and a control unit configured to transmit a coil block signal to the wireless power relay device based on the information about the power transfer state, wherein the wireless power transmission device provides a power transmission path to a wireless power reception device by controlling one or more wireless power relay devices, forming a mesh structure, in response to the coil block signal.

The information about the power transfer state may include information about a charged amount of a battery of the wireless power relay device.

If the battery is charged to a reference value or higher or a transfer of power between the wireless power relay device and another adjacent wireless power relay device is not present, the control unit may generate the coil block signal and transmits the generated coil block signal to the wireless power relay device.

The control unit may manage a list of the one or more wireless power relay devices based on the received information about the power transfer state.

If a change in a state of a wireless power relay device forming the mesh structure is detected or a new wireless power relay device is added, the control unit may transmit a coil connection signal to all the wireless power relay devices forming the mesh structure.

According to another embodiment of the present invention, a wireless power transmission system for supplying power to a wireless power reception device includes: a wireless power transmission device configured to wirelessly send external power by way of magnetic resonance at a resonant frequency; and one or more wireless power relay devices configured to receive the power and relay the received power externally by way of magnetic resonance at the resonant frequency, wherein each of the wireless power relay devices may transmit the received power to another wireless power relay device or the wireless power reception device, may include a relay coil configured to receive the power from a resonant coil of the wireless power transmission device by way of magnetic resonance and transmit the received power to another adjacent wireless power relay device by way of magnetic resonance, form a mesh structure along with one or more adjacent wireless power relay devices, and provide a power transmission path from the wireless power transmission device to the wireless power reception device through the formed mesh structure.

The wireless power relay device further may include a communication unit configured to transmit and receive pieces of information about power transfer states through communication with the wireless power transmission device or other wireless power relay devices and a charging unit configured to charge a battery by using the received power, and the charging unit may check a charged amount of the battery and transmits information about the charged amount of the battery to the wireless power transmission device through the communication unit.

The wireless power relay device further includes a control unit configured to block the relay coil by controlling a switch, formed at an end of the relay coil, in response to a coil block signal received from the wireless power transmission device.

The wireless power relay device may transmit information about a power transfer state to the wireless power transmission device if a battery included in the wireless power relay device is charged to a reference value or higher or an adjacent wireless power relay device for receiving the power by way of magnetic resonance with the relay coil is not present, and the wireless power transmission device may block the relay coils of the one or more wireless power relay devices, forming the mesh structure, based on the information about the power transfer state.

According to another embodiment of the present invention, a wireless power transmission system for supplying power to a wireless power reception device includes: a wireless power transmission device configured to wirelessly send external power by way of magnetic resonance at a resonant frequency; and one or more wireless power relay devices configured to receive the power and relay the received power externally by way of magnetic resonance at the resonant frequency, wherein each of the wireless power relay devices may transmit the received power to another wireless power relay device or the wireless power reception device, and the wireless power transmission device includes: a transmission antenna unit configured to wirelessly transmit the power to the wireless power relay device by way of magnetic resonance, a communication unit configured to receive information about a power transfer state from the wireless power relay device, and a control unit configured to transmit a coil block signal to the wireless power relay device based on the information about the power transfer state, wherein the wireless power transmission device may provide a power transmission path to the wireless power reception device by controlling the one or more wireless power relay devices, forming a mesh structure, in response to the coil block signal.

If a battery included in the wireless power relay device is charged to a reference value or higher or a transfer of power between the wireless power relay device and another adjacent wireless power relay device is not present, the control unit of the wireless power transmission device may generate the coil block signal and transmit the generated coil block signal to the wireless power relay device.

If a change in a state of a wireless power relay device forming the mesh structure is detected or a new wireless power relay device is added, the control unit of the wireless power transmission device may transmit a coil connection signal to all the wireless power relay devices forming the mesh structure.

If a battery included in the wireless power relay device is charged to a reference value or higher or another adjacent wireless power relay device for receiving the power by way of magnetic resonance with a relay coil is not present, the wireless power transmission device may transmit the information about the power transfer state to the wireless power transmission device, and the wireless power transmission device may block the relay coils of the one or more wireless power relay devices, forming the mesh structure, based on the information about the power transfer state.

According to aspects of embodiments of the present invention, power can be transmitted to a wireless power reception device located at a distance longer than a power transfer limit distance by disposing a plurality of electronic devices including a relay coil between a wireless power transmission device and the wireless power reception device.

Furthermore, according to an embodiments of the present invention, the size of a resonant coil necessary to wirelessly transmit power up to the same distance can be reduced.

FIG. 1 is an outline diagram showing a wireless power transmission system using a plurality of wireless power relay devices including a relay coil in accordance with an embodiment of the present invention.

FIG. 2 is a diagram showing the construction of the wireless power transmission system using a wireless power relay device in accordance with an embodiment of the present invention.

FIG. 3 is a diagram showing a wireless power method employing magnetic resonance in the wireless power transmission system using a wireless power relay device in accordance with an embodiment of the present invention.

FIG. 4 is a diagram showing the construction of a wireless power transmission device in accordance with an embodiment of the present invention.

FIG. 5 is a diagram showing the construction of a wireless power relay device in accordance with an embodiment of the present invention.

FIG. 6 is a diagram illustrating a power transmission method using a plurality of wireless power relay devices in accordance with an embodiment of the present invention.

FIG. 7 is another diagram illustrating a power transmission method using a plurality of wireless power relay devices in accordance with an embodiment of the present invention.

FIG. 8 is yet another diagram illustrating a power transmission method using a plurality of wireless power relay devices in accordance with an embodiment of the present invention.

The present invention may be modified in various ways and may be implemented to have several embodiments. Specific embodiments of the present invention are illustrated in the drawings and are described in detail in the detailed description. It is however to be noted that the present invention is not intended to be limited to the specific embodiments, but is intended to include all modifications, equivalents, or substitutions which fall within the spirit and technical scope of the present invention.

Furthermore, in describing the present invention, a detailed description of known functions related to the present invention will be omitted if it is deemed to make the gist of the present invention unnecessarily vague. Numbers (for example, the first and the second) used in a process of describing the present invention are merely identification symbols for distinguishing one element from the other element.

Furthermore, a detailed description of the known functions and constructions will be omitted if it is deemed to make the gist of the present invention unnecessarily vague. Furthermore, numbers (for example, the first and the second) used in a process of describing this specification are merely identification symbols for distinguishing one element from the other element.

Furthermore, in this specification, when there is reference to one element described as being “connected to” or “coupled with” the other element, the one element may be directly connected to the other element or may be directly coupled with the other element, but it should be understood that a third element may be placed between the two elements unless described otherwise.

In this specification, a wireless power relay device is a device including a resonant coil for relaying a power signal and can be a mobile terminal, such as a handheld phone, a smart phone, a laptop computer, a terminal for digital broadcasting, a Personal Digital Assistant (PDA), a Portable Multimedia Player (PMP), and a navigator. Furthermore, the mobile terminal can be home appliances used in common homes or offices, such as wall TV, a lighting stand, electronic picture frames, and a vacuum cleaner.

Detailed contents for implementing the present invention are described below with reference to the accompanying drawings.

As shown in FIG. 1, the wireless power transmission system of the present invention may include a wireless power transmission device 100, a wireless power reception device 300, and a plurality of wireless power relay devices 200.

The wireless power relay device 200 may relay power transmitted between the wireless power transmission device 100 and the wireless power reception device 300. Here, power may be transmitted between the wireless power transmission device 100, the wireless power relay device 200, and the wireless power reception device 300 in accordance with a magnetic resonance method. For reference, wireless power transmission technology using the magnetic resonance method corresponds to non-radiative power transfer. The wireless power transmission technology using the magnetic resonance method may be based on evanescent wave coupling in which when two media resonate in the same frequency, electromagnetic waves may move from one medium to the other medium through a short distance magnetic field.

The wireless power relay device 200 may include a plurality of electronic devices installed indoors, such as a home or an office. For example, the wireless power relay device 200 may include a Personal Computer (PC) 200-1, TV 200-2, a desk lamp 200-3, an audio device 200-4, a telephone 200-5, a laptop computer 200-6, etc. The wireless power relay device 200 may perform a power relay function. To this end, the wireless power relay device 200 may include a relay-side resonant coil (hereinafter called a relay coil).

The wireless power transmission system of the present invention may transfer power at a power transfer limit distance or higher by using the wireless power relay device 200, that is, electronic devices including relay coils having the same resonant frequency, even when the wireless power transmission device 100 and the wireless power reception device 300 may be spaced apart from each other by a power transfer limit distance or higher. If the wireless power transmission device 100 and the wireless power reception device 300 may be located within a power transfer limit distance, power may be directly transferred to the wireless power reception device 300 without the wireless power relay device 200.

A method of the wireless power transmission system transferring power is described below with reference to FIGS. 2 and 3.

FIG. 2 is a diagram showing the construction of the wireless power transmission system using a wireless power relay device in accordance with an embodiment of the present invention, and FIG. 3 is a diagram showing a power transmission relation between the power transmission antenna unit 110 of the wireless power transmission device 100, the relay coil 210 of the wireless power relay device 200, and the power reception antenna unit 310 of the wireless power reception device 300 in the wireless power transmission system.

Referring to FIGS. 2 and 3, the wireless power transmission device 100 and the wireless power reception device 300 may transmit and receive power by using a power transmission antenna unit 110 and a power reception antenna unit 310, respectively. The power transmission antenna unit 110 may include a power feeding coil 112 and a power transmission-side resonant coil 114, and the power reception antenna unit 310 may include a power reception coil 312 and a power reception-side resonant coil 314.

One or more wireless power relay devices 200 may be disposed between the wireless power transmission device 100 and the wireless power reception device 300. Here, the relay coil 210 of the wireless power relay device 200 may have the same resonant frequency as or a similar resonant frequency to the power transmission-side resonant coil 114 of the wireless power transmission device 100 and the power reception-side resonant coil 314 of the wireless power reception device 300. In a resonant state in which the resonant frequencies may be matched with each other, power is transmitted between the power transmission antenna unit 110 and the relay coil 210 or between the relay coil 210 and the power reception antenna unit 310 at optimum efficiency.

Here, an energy transfer channel may be formed between the power transmission-side resonant coil 114 and the relay coil 210 or between the relay coil 210 and the power reception-side resonant coil 314 by way of resonant coupling. A power signal emitted from the power transmission-side resonant coil 114 may be transmitted to the relay coil 210 through the energy transfer channel. The power signal transmitted to the relay coil 210 may be transferred to the power reception-side resonant coil 314 through the energy transfer channel between the relay coil 210 and the power reception-side resonant coil 314. Here, the power signal may be transferred through the one or more wireless power relay devices 200.

As described above, in one embodiment, one mesh network may be formed by the one or more wireless power relay devices 200 disposed between the wireless power transmission device 100 and the wireless power reception device 300. Accordingly, a power transfer distance can be extended to a power transfer limit distance or higher by way of magnetic resonance, and power transfer efficiency in the wireless power reception device 300 located at a long distance may be improved.

Detailed constructions of the wireless power transmission device 100 and the wireless power relay device 200 of the present invention are described below.

FIG. 4 is a diagram showing the construction of the wireless power transmission device 100 in accordance with an embodiment of the present invention.

The wireless power transmission device 100 may rectify AC power, received from an external input power source, into DC power and then generates a high frequency power signal for wireless power transmission. The generated high frequency power signal may be transmitted externally through the power transmission antenna unit 110. Here, energy not transferred to the power reception antenna unit 310 or the relay coil 210, from the power signal emitted from the power transmission antenna unit 110, may be absorbed by the power transmission antenna unit 110.

Referring to FIG. 4, the wireless power transmission device 100 may include the power transmission antenna unit 110, a power feeding unit 120, a communication unit 130, and a control unit 140.

The power transmission antenna unit 110 may include a pair of the power feeding coil 112 and the power transmission-side resonant coil 114 and transmit a high frequency power signal externally. The power feeding coil 112 of the power transmission antenna unit 110 may receive the power signal from the power feeding unit 120. The transferred power signal may be transferred to the power transmission-side resonant coil 114 by means of magnetic induction between the power feeding coil 112 and the power transmission-side resonant coil 114. Next, the power signal may be transmitted to the wireless power relay device 200 through an energy transfer channel formed by magnetic resonance between the power transmission-side resonant coil 114 and the relay coil 210 of the wireless power relay device 200.

The power transmission-side resonant coil 114 may have a loop form and may have a helical coil structure or a spiral coil structure, for example.

The power feeding unit 120 may generate a frequency signal by using power supplied from AC power and generate a high frequency power signal by amplifying the frequency signal. To this end, the power feeding unit 120 may include a phase synchronization circuit (not shown) for generating a high frequency signal in response to a clock, a high frequency filter circuit (not shown) for receiving the output of the phase synchronization circuit and performing high band filtering on the received output, an amplification circuit (not shown) for amplifying the output signal of the phase synchronization circuit, an impedance matching circuit (not shown) for matching the impedance of the power transmission antenna unit 110.

Meanwhile, the communication unit 130 may transmit and receive information about the power transfer states of corresponding devices through communication with the wireless power relay device 200 or the wireless power reception device 300. Here, some of the devices may charge their batteries by using power received from the wireless power transmission device 100 or use the received power as their driving power. In this case, information about the power transfer state may include information about the charged amount of the battery of a corresponding device.

The control unit 140 may select a wireless power relay device 200 whose relay function will be stopped, from among a plurality of the wireless power relay devices 200, based on the information about a power transfer state received from the communication unit 130. The control unit 140 may control the wireless power relay device 200 whose relay function will be stopped by transmitting a coil block signal to the wireless power relay device 200 through the communication unit 130.

A case where the relay function of the wireless power relay device 200 is stopped by transmitting the coil block signal to the wireless power relay device 200 in order to block the relay coil 210 of the wireless power relay device 200 may correspond to, for example, a case where the battery of the wireless power relay device 200 may have been charged to a reference value or higher or a case where another adjacent wireless power relay device for receiving power through the wireless power relay device 200 is not present.

Furthermore, the information about a power transfer state may include the identification code of the wireless power relay device 200 or the number of hops from the wireless power transmission device 100 to the corresponding wireless power relay device 200. The control unit 140 may determine an optimized power transmission path from the wireless power transmission device 100 to the wireless power reception device 300 and select the wireless power relay device 200 whose relay function will be stopped on the basis of the information.

Meanwhile, the control unit 140 may check the wireless power relay devices 200, forming a mesh network, based on the received information about a power transfer state and can generate and manage a list of the wireless power relay devices 200. Furthermore, if the states of some of the wireless power relay devices 200 forming a mesh structure are changed or a new wireless power relay device 200 is added to the mesh structure, the control unit 140 may detect a change of the states or the new wireless power relay device 200 on the basis of information about a power transfer state and update the list of the wireless power relay devices 200. In this case, the control unit 140 may transmit a coil connection signal to all the wireless power relay devices 200 that are being managed by the control unit 140 in order to update information about the existing power transmission path on the mesh structure. In response to the coil connection signal, the wireless power relay device 200 may connect the broken relay coil to the wireless power transmission device 100 and perform a relay function. Next, the control unit 140 may determine a new power transmission path in the updated mesh structure.

A detailed construction of the wireless power relay device 200 is described below.

FIG. 5 is a diagram showing a detailed construction of the wireless power relay device 200 in accordance with an embodiment of the present invention.

The wireless power relay device 200 may relay a power signal, received from the wireless power transmission device 100, to another adjacent wireless power relay device or the wireless power reception device 300. To this end, a plurality of the wireless power relay devices 200 may form a mesh structure. A power transmission path from the wireless power transmission device 100 to the wireless power reception device 300 may be provided through the plurality of wireless power relay devices 200 that form the mesh structure.

Meanwhile, the wireless power relay device 200 may include a battery and can use power, received from the wireless power transmission device 100, as its driving power or charge the battery with the received power. In this case, the wireless power relay device 200 may have the same construction as the wireless power reception device 300. In this specification, an example in which the wireless power relay device 200 may have the same construction as the wireless power reception device 300 is described. In some embodiments, the wireless power relay device 200 may have a construction including only the relay coil 210 so that it can perform only a function of relaying power.

Referring to FIG. 5, the wireless power relay device 200 includes the relay coil 210. The relay coil 210 may receive power by way of magnetic resonance and relay the received power to another relay coil or the power reception antenna unit 310 of the wireless power reception device 300.

Here, the relay coil 210 may have the same construction as the power transmission-side resonant coil 114 and the power reception-side resonant coil 314. In other words, the relay coil 210 may be made of almost the same material as the power transmission-side resonant coil 114 and the power reception-side resonant coil 314 and may be formed of a conducting wire having almost the same thickness as the power transmission-side resonant coil 114 and the power reception-side resonant coil 314. The relay coil 210 may be formed to have the same number of windings as the power transmission-side resonant coil 114 and the power reception-side resonant coil 314 on the same circumference. In this case, the three relay coils may have almost the same inductance L and capacitance C. Accordingly, the relay coil 210, the power transmission-side resonant coil 114, and the power reception-side resonant coil 314 may have almost the same resonant frequency.

In some embodiments, the wireless power relay device 200 may include a battery 240. In this case, the relay coil 210 may further include a power reception coil 214 in addition to a relay resonant coil 212.

A power signal received through the relay resonant coil 212 may be transmitted to the power reception coil 214 by way of magnetic induction and then inputted to a power reception unit 220. The power reception unit 220 may include a rectification circuit (not shown) for rectifying the received power signal, a voltage control circuit (not shown) for filtering the rectified DC power and converting the DC power into available voltage, etc.

A charging unit 230 may use the converted output power to charge the battery 240. Here, the charging unit 230 may check the charged amount of the battery 240 and transmit information about the charged amount of the battery to the wireless power transmission device 100 through a communication unit 260.

A control unit 250 may detect a change in the amount of transmission power in the relay coil 210 or the power reception unit 220, generate information about a power transfer state based on the detected change, and transmit the generated information about a power transfer state to the wireless power transmission device 100 through the communication unit 260.

Furthermore, the control unit 250 may block or connect the relay coil 210 from or to the wireless power transmission device 100 in response to a coil block signal or a coil connection signal received from the wireless power transmission device 100. To this end, a switch 216 may be disposed at the end of the relay coil 210. In response to a coil block signal, the control unit 250 blocks the relay coil 210 from the wireless power transmission device 100 by controlling the switch 216 of the relay coil 210. Furthermore, in response to a coil connection signal, the control unit 250 may connect the relay coil 210 to the wireless power transmission device 100 by controlling the switch 216.

Through the above construction, the wireless power transmission system of the present invention may prevent unnecessary power consumption and improve power transfer efficiency by blocking the relay coil 210 of a wireless power relay device 200 that does not form a power transmission path between the wireless power transmission device 100 and the wireless power reception device 300, from among a plurality of wireless power relay devices 200 that form a mesh network.

Method of configuring a power transmission path in the wireless power transmission system is described below with reference to FIGS. 6 to 8.

FIGS. 6 to 8 show methods of configuring a power transmission path in the wireless power transmission system in accordance with embodiments of the present invention.

Referring to FIG. 6, power transmission paths between the wireless power transmission device 100 and the wireless power reception device 300 may be sequentially formed by the four wireless power relay devices 200-1, 200-2, 200-3, and 200-4. Meanwhile, power may also be transmitted from the wireless power relay device 200-1 to the wireless power relay device 200-5. In this case, since another adjacent device for receiving power from the wireless power relay device 200-5 is not present, the wireless power transmission device 100 may block the relay coil of the wireless power relay device 200-5 by transmitting a coil block signal to the wireless power relay device 200-5. Likewise, the relay coil of the wireless power relay device 200-6 may be blocked.

Referring to FIG. 7, the wireless power relay devices 200-1~200-6 or/and the wireless power reception device 300 may transmit pieces of information about power transfer states to the wireless power transmission device 100. Here, the transmitted information about a power transfer state may include the number of relay hops from the wireless power transmission device 100 to each wireless power relay device. Each of the wireless power relay devices 200 may add information about the number of hops to a power signal or change information about the number of hops or can provide the information about the number of hops to adjacent devices through each communication unit.

The wireless power transmission device 100 may determine an optimum power transmission path by using the information about the number of hops. For example, referring to FIG. 8, a wireless power relay device 200-6 can receive power from a wireless power relay device 200-5 and a wireless power relay device 200-4 at the same time because it is close to the wireless power relay device 200-5 and the wireless power relay device 200-4. Here, the wireless power transmission device 100 may compare the number of hops of the wireless power relay device 200-4 with the number of hops of the wireless power relay device 200-5. The wireless power transmission device 100 may activate the relay coil of the wireless power relay device 200-5 having a relatively small number of hops and deactivate the relay coil of the wireless power relay device 200-4 having a relatively large number of hops based on a result of the comparison.

In this case, a power transmission path formed by the wireless power relay devices 200-1, 200-5, and 200-6 may be activated, and the relay coils of the remaining wireless power relay devices 200-2, 200-3, and 200-4 may be deactivated.

In accordance with the present invention, the wireless power transmission system having the above construction is advantageous in that it can effectively set up a power transmission path for the transmission of power to the wireless power reception device 300 and improve transfer efficiency.

While some exemplary embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may change and modify the present invention in various ways without departing from the essential characteristic of the present invention.

Accordingly, the disclosed embodiments should not be construed as limiting the technical spirit of the present invention, but should be construed as illustrating the technical spirit of the present invention.

The scope of the technical spirit of the present invention is not restricted by the embodiments, and the scope of the present invention should be interpreted based on the following appended claims. Accordingly, the present invention should be construed as covering all modifications or variations derived from the meaning and scope of the appended claims and their equivalents.

Claims

A wireless power relay device, comprising:

a relay coil configured to receive power from a resonant coil of a wireless power transmission device by way of magnetic resonance and transmit the received power to another adjacent wireless power relay device by way of magnetic resonance; and

a communication unit configured to transmit and receive pieces of information about power transfer states through communication with the wireless power transmission device or other wireless power relay devices,

wherein the wireless power relay device forms a mesh structure along with one or more adjacent wireless power relay devices and provides a power transmission path from the wireless power transmission device to a wireless power reception device through the formed mesh structure.
The wireless power relay device of claim 1, wherein:

some of the received power is used as driving power of the wireless power relay device, and

a remainder of the received power is transmitted to another adjacent wireless power relay device.
The wireless power relay device of claim 1, further comprising a charging unit configured to charge a battery by using the received power, wherein the charging unit checks a charged amount of the battery and transmits information about the charged amount of the battery to the wireless power transmission device through the communication unit.
The wireless power relay device of claim 1, further comprising:

a switch formed at an end of the relay coil, and

a control unit configured to block the relay coil by controlling the switch in response to a coil block signal received from the wireless power transmission device.
The wireless power relay device of claim 4, wherein if a battery included in the wireless power relay device is charged to a reference value or higher or an adjacent wireless power relay device for receiving the power by way of magnetic resonance with the relay coil is not present, the coil block signal generated from the wireless power transmission device is received through the communication unit.
The wireless power relay device of claim 1, wherein the information about the power transfer state comprises one or more of an identification code of the wireless power relay device and a number of hops from the wireless power transmission device to the wireless power relay device.
A wireless power transmission device, comprising:

a transmission antenna unit configured to wirelessly transmit power to a wireless power relay device by way of magnetic resonance;

a communication unit configured to receive information about a power transfer state from the wireless power relay device; and

a control unit configured to transmit a coil block signal to the wireless power relay device based on the information about the power transfer state,

wherein the wireless power transmission device provides a power transmission path to a wireless power reception device by controlling one or more wireless power relay devices, forming a mesh structure, in response to the coil block signal.
The wireless power transmission device of claim 7, wherein the information about the power transfer state comprises information about a charged amount of a battery of the wireless power relay device.
The wireless power transmission device of claim 8, wherein if the battery is charged to a reference value or higher or a transfer of power between the wireless power relay device and another adjacent wireless power relay device is not present, the control unit generates the coil block signal and transmits the generated coil block signal to the wireless power relay device.
The wireless power transmission device of claim 7, wherein the information about the power transfer state comprises one or more of an identification code of the wireless power relay device and a number of hops from the wireless power transmission device to the wireless power relay device.
The wireless power transmission device of claim 7, wherein the control unit manages a list of the one or more wireless power relay devices based on the received information about the power transfer state.
The wireless power transmission device of claim 11, wherein if a change in a state of a wireless power relay device forming the mesh structure is detected or a new wireless power relay device is added, the control unit transmits a coil connection signal to all the wireless power relay devices forming the mesh structure.
A wireless power transmission system for supplying power to a wireless power reception device, the system comprising:

a wireless power transmission device configured to wirelessly send external power by way of magnetic resonance at a resonant frequency; and

one or more wireless power relay devices configured to receive the power and relay the received power externally by way of magnetic resonance at the resonant frequency,

wherein each of the wireless power relay devices transmits the received power to another wireless power relay device or the wireless power reception device, comprises a relay coil configured to receive the power from a resonant coil of the wireless power transmission device by way of magnetic resonance and transmit the received power to another adjacent wireless power relay device by way of magnetic resonance, forms a mesh structure along with one or more adjacent wireless power relay devices, and provides a power transmission path from the wireless power transmission device to the wireless power reception device through the formed mesh structure.
The wireless power transmission system of claim 13, wherein:

the wireless power relay device further comprises a communication unit configured to transmit and receive pieces of information about power transfer states through communication with the wireless power transmission device or other wireless power relay devices and a charging unit configured to charge a battery by using the received power, and

the charging unit checks a charged amount of the battery and transmits information about the charged amount of the battery to the wireless power transmission device through the communication unit.
The wireless power transmission system of claim 13, wherein the wireless power relay device further comprises a control unit configured to block the relay coil by controlling a switch, formed at an end of the relay coil, in response to a coil block signal received from the wireless power transmission device.
The wireless power transmission system of claim 15, wherein:

the wireless power relay device transmits information about a power transfer state to the wireless power transmission device if a battery included in the wireless power relay device is charged to a reference value or higher or an adjacent wireless power relay device for receiving the power by way of magnetic resonance with the relay coil is not present, and

the wireless power transmission device blocks the relay coils of the one or more wireless power relay devices, forming the mesh structure, based on the information about the power transfer state.
A wireless power transmission system for supplying power to a wireless power reception device, the system comprising:

a wireless power transmission device configured to wirelessly send external power by way of magnetic resonance at a resonant frequency; and

one or more wireless power relay devices configured to receive the power and relay the received power externally by way of magnetic resonance at the resonant frequency,

wherein each of the wireless power relay devices transmits the received power to another wireless power relay device or the wireless power reception device, and

the wireless power transmission device comprises:

a transmission antenna unit configured to wirelessly transmit the power to the wireless power relay device by way of magnetic resonance,

a communication unit configured to receive information about a power transfer state from the wireless power relay device, and

a control unit configured to transmit a coil block signal to the wireless power relay device based on the information about the power transfer state,

wherein the wireless power transmission device provides a power transmission path to the wireless power reception device by controlling the one or more wireless power relay devices, forming a mesh structure, in response to the coil block signal.
The wireless power transmission system of claim 17, wherein if a battery included in the wireless power relay device is charged to a reference value or higher or a transfer of power between the wireless power relay device and another adjacent wireless power relay device is not present, the control unit of the wireless power transmission device generates the coil block signal and transmits the generated coil block signal to the wireless power relay device.
The wireless power transmission system of claim 17, wherein the information about the power transfer state comprises one or more of an identification code of the wireless power relay device and a number of hops from the wireless power transmission device to the wireless power relay device.
The wireless power transmission system of claim 19, wherein if a change in a state of a wireless power relay device forming the mesh structure is detected or a new wireless power relay device is added, the control unit of the wireless power transmission device transmits a coil connection signal to all the wireless power relay devices forming the mesh structure.
The wireless power transmission system of claim 17, wherein:

if a battery included in the wireless power relay device is charged to a reference value or higher or another adjacent wireless power relay device for receiving the power by way of magnetic resonance with a relay coil is not present, the wireless power transmission device transmits the information about the power transfer state to the wireless power transmission device, and

the wireless power transmission device blocks the relay coils of the one or more wireless power relay devices, forming the mesh structure, based on the information about the power transfer state.