KR20130117039A - Method and apparatus for wireless power transmission and apparatus for wireless power reception - Google Patents

Abstract

PURPOSE: A wireless power transmission device, a method thereof, and a wireless power receiving device efficiently receive power from the wireless power transmission device by compensating for the changing size of a load by virtual resistance and maintaining the same size as the size of an initial load. CONSTITUTION: A sensor unit (210) senses the entry of a receiving device wireless receiving power into a charging area. The sensor unit includes a measurement unit (211) measuring the amplitude of a signal oscillated in an array sensor (213) or a source resonator. The array sensor senses the array of the receiving device entering the charging area and a wireless power transmission device. A control unit (220) controls a resonance frequency or impedance of the source resonator to be matched with a load of the receiving device. A communication unit (230) transmits information about a position to be able to receive power from the wireless power transmission device with optimum efficiency to the receiving device. [Reference numerals] (210) Sensor unit; (211) Measurement unit; (213) Array sensor; (220) Control unit; (230) Communication unit

Description

Apparatus and method for wireless power transmission, and apparatus for receiving wireless power {METHOD AND APPARATUS FOR WIRELESS POWER TRANSMISSION AND APPARATUS FOR WIRELESS POWER RECEPTION}

TECHNICAL FIELD The art relates to an apparatus and method for transmitting power wirelessly.

The research on wireless power transmission has begun to overcome the inconvenience of wired power supply due to the explosive increase of various electric devices including electric vehicles and portable devices, and the limitation of existing battery capacity. One of the wireless power transfer technologies utilizes the resonance characteristics of RF devices. The wireless power transfer system using the resonance characteristic may include a source device that supplies power and a target device that is powered.

In one aspect, a wireless power transmitter is a device for wirelessly transmitting power through mutual resonance between a source resonator and a target resonator, wherein the wireless power transmitter wirelessly transmits power from the device based on an amount of change in amplitude of a signal oscillated in the source resonator. And a detector configured to detect an entry into a charging region of a receiving device that receives a signal, and a controller configured to control a resonance frequency or an impedance of the source resonator to match a load of the receiving device.

The detector may detect an entry into the charging region of the receiving device based on whether the amplitude of the oscillating signal is attenuated from an initial amplitude value having an amplitude value of a predetermined magnitude.

After the sensing unit detects an entry into the charging region of the receiving device, if the amplitude of the signal oscillating from the source resonator is detected to be greater than or equal to a predetermined value, the receiving device is aligned with an apparatus for wirelessly transmitting power. It can be judged that.

The sensing unit may include a measuring unit measuring the amplitude of the signal oscillated by the source resonator.

The detector may include an alignment sensor configured to sense whether the receiving device entering the charging region and the device for transmitting power wirelessly are aligned based on an optical triangular scheme.

The controller may adjust the virtual resistance included in the apparatus for transmitting power wirelessly to match the load of the receiving device that varies according to the degree of charging.

The virtual resistor is characterized by consisting of a connection circuit of a plurality of resistors and capacitors and a plurality of transistors.

The controller may control the resonance frequency or the impedance of the source resonator so that the reflected power amount has a minimum value based on the reflected power amount reflected from the receiving device.

In another aspect, the wireless power transmission apparatus may receive power at an optimal efficiency from the wirelessly transmitting device when it is detected that the receiving device and the wirelessly transmitting device are not aligned. The apparatus may further include a communication unit configured to transmit information regarding a location to the receiving device.

If the controller detects that the receiving device and the apparatus for transmitting power wirelessly are not aligned, the control unit may include a virtual resistance included in the apparatus for transmitting power wirelessly to match the load of the receiving device at an unaligned position. I can regulate it.

In one aspect, a wireless power receiver is a device for receiving power wirelessly through mutual resonance between a source resonator and a target resonator, the supply device for supplying power wirelessly based on a waveform of a signal stored in the target resonator A sensing unit for detecting entry into a charging region of the apparatus, a communication unit receiving information on an alignment position of the charging region from the supply device, and an apparatus for wirelessly receiving power to the alignment position such that impedance is matched with the supply device. The control unit for controlling the movement of the.

In another aspect, the wireless power receiver may further include a display unit configured to display an alignment position of the charging region of the supply device when the sensing unit detects an entry into the charging region.

The communication unit receives information on the amount of reflected power from the supply device, and the control unit is based on the information on the amount of reflected power, the load mounted on the device for receiving power wirelessly is a constant resistance regardless of the charging progress situation The size of the virtual resistor connected to the load may be controlled to have a value.

In one aspect, a wireless power transfer method is a device for wirelessly transmitting power through mutual resonance between a source resonator and a target resonator, wherein the power is wirelessly transmitted from the device based on an amount of change in amplitude of a signal oscillated in the source resonator. Detecting an entry into a charging region of a receiving device receiving a signal; and controlling a resonance frequency or an impedance of the source resonator to match a load of the receiving device.

The sensing may detect an entry into a charging region of the receiving device based on whether the amplitude of the oscillating signal is attenuated from an initial amplitude value having an amplitude value of a predetermined magnitude.

The controlling may control the resonance frequency or the impedance of the source resonator such that the reflected power amount has a minimum value based on the reflected power amount reflected from the receiving device.

When the wireless power receiver enters the charging area of the wireless power transmitter, the wireless power transmitter determines whether the wireless power receiver is aligned with a predetermined charging area according to the entry position of the wireless power receiver, and receives the wireless power information for alignment. Can be delivered to the device.

In addition, even when the charging area of the wireless power transmitter and the wireless power receiver are not aligned, the wireless power transmitter may change the resonance frequency or impedance to match the load of the wireless power receiver by adjusting the virtual resistance.

In addition, the wireless power receiver can efficiently receive power from the wireless power transmitter by compensating for the size of the load that changes as the charging progresses, by maintaining the same size as the initial load.

1 illustrates a wireless power transfer system according to an embodiment.
2 is a block diagram of a wireless power transmission apparatus according to an embodiment.
3 is a block diagram of a wireless power receiver according to an embodiment.
4 is a diagram illustrating an alignment method between a source and a target in a wireless power transmission system according to an embodiment.
5 is a diagram illustrating an alignment method between a source and a target in a wireless power transmission system according to another exemplary embodiment.
6 is a graph illustrating an amplitude of a signal oscillating in a wireless power transmission apparatus according to an embodiment.
FIG. 7 is a diagram illustrating a configuration of a detector detecting a change in amplitude of a signal oscillated by a wireless power transmitter according to an embodiment.
8 is a diagram illustrating a virtual resistor used in a wireless power receiver according to an embodiment.
9 is a diagram illustrating a display unit in a wireless power receiver according to an embodiment.
10 illustrates a distribution of a magnetic field in a resonator and a feeder according to an embodiment.
11 is a diagram illustrating a configuration of a resonator and a feeder according to an exemplary embodiment.
12 is a diagram illustrating a distribution of a magnetic field in a resonator according to feeding of a feeding unit, according to an exemplary embodiment.
13 illustrates an electric vehicle charging system according to one embodiment.
14 is a flowchart of a wireless power transmission method according to an embodiment.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

There are in-band communication methods and out-band communication methods for performing communication between a source and a target. The in-band communication method means that the source and the target communicate at the same frequency as the frequency used for the power transmission, and the out-band communication method means that the source and the target communicate using a frequency different from the frequency used for the power transmission do.

1 illustrates a wireless power transfer system according to an embodiment.

Referring to FIG. 1, a wireless power transmission system according to an embodiment includes a source 110 and a target 120. The source 110 refers to a device for supplying wireless power, and the device may include all electronic devices capable of supplying power such as a pad, a terminal, and a TV. The target 120 refers to a device that receives wireless power, and the device may include all electronic devices that require power such as a terminal, a TV, a car, a washing machine, a radio, a lamp, and the like.

The source 110 includes a Variable SMPS 111, a Power Amplifier 112, a matching network 113, a controller 114, and a communicator 115.

Variable Switching Mode Power Supply (SMPS) 111 generates a DC voltage by switching the AC voltage of the tens of Hz band output from the power supply. The variable SMPS 111 may output a DC voltage of a constant level or adjust the output level of the DC voltage according to the control of the Tx Control Logic 114.

The variable switching mode power supply (SMPS) 111 controls the supply voltage according to the output power level of the power amplifier 112 so that the Class-E type power amplifier 112 can always operate in a highly efficient saturation region. Thus, maximum efficiency can be maintained at all output levels.

When using a commercially available SMPS instead of the Variable Switching Mode Power Supply (SMPS) 111, an additional Variable DC / DC should be used. Commercial SMPS and Variable DC / DC control the supply voltage according to the output power level of the Power Amplifier 112 so that the Class-E type Power Amplifier 112 can always operate in the highly efficient saturation region. It is possible to maintain maximum efficiency at the level.

The power detector 116 detects the output current and the voltage of the variable SMPS 111 and transmits information on the detected current and the voltage to the controller 114. In addition, the power detector 116 may detect the input current and voltage of the power amplifier 112.

The power amplifier 112 may generate power by converting a DC voltage of a constant level into an AC voltage by a switching pulse signal of several MHz to several tens of MHz bands. That is, the power amplifier 112 converts the DC voltage supplied to the power amplifier 112 into an AC voltage using the reference resonance frequency F _Ref to generate communication power or charging power used in the plurality of target devices. Can be.

Here, the communication power means a small power of 0.1 to 1 mWatt, and the charging power means a large power of 1 mWatt to 200 Watt consumed in the device load of the target device. In the present specification, the term "charging" may be used to mean powering a unit or an element that charges power. The term "charging" may also be used to mean powering a unit or element that consumes power. Here, the unit or element includes, for example, a battery, a display, a voice output circuit, a main processor, and various sensors.

In the present specification, the "reference resonance frequency" is used as the meaning of the resonance frequency that the source 110 basically uses. In addition, "tracking frequency" is used to mean a resonant frequency adjusted according to a preset scheme.

The control unit 114 detects a reflected wave for “communication power” or “charge power” and detects mismatching between the target resonator 133 and the source resonator 131 based on the detected reflected wave. The control unit 114 can detect the mismatching by detecting the envelope of the reflected wave and detecting the mismatching or detecting the amount of power of the reflected wave.

The matching network 113 may compensate the impedance mismatching between the source resonator 131 and the target resonator 133 with an optimal matching under the control of the controller 114. The matching network 113 may be connected via a switch under the control of the controller 114 to a combination of capacitors or inductors.

The controller 114 calculates a voltage standing wave ratio (VSWR) based on the level of the output voltage of the source resonator 131 or the power amplifier 112 and the voltage level of the reflected wave. If less than the set value, it may be determined that the mismatch is detected.

If the voltage standing wave ratio is smaller than the preset value, the controller 114 calculates the power transmission efficiency for each of the N tracking frequencies and determines the best tracking frequency F _best among the N tracking frequencies And the reference resonance frequency F _Ref can be adjusted to F _Best .

Also, the control unit 114 can adjust the frequency of the switching pulse signal. The frequency of the switching pulse signal can be determined by the control of the controller 114. [ The controller 114 may generate a modulated signal for transmission to the target 120 by controlling the power amplifier 112. That is, the communication unit 115 may transmit various data 140 with the target 120 through in-band communication. In addition, the controller 114 may detect the reflected wave and demodulate a signal received from the target 120 through the envelope of the reflected wave.

The control unit 114 may generate a modulated signal for performing in-band communication through various methods. The control unit 114 can generate a modulation signal by turning on / off the switching pulse signal. In addition, the control unit 114 may perform delta-sigma modulation to generate a modulated signal. The controller 114 may generate a pulse width modulated signal having a constant envelope.

The controller 114 determines initial wireless power to be transmitted to the target 120 in consideration of a temperature change of the source 110, a battery state of the target 120, a change in the amount of received power, or a temperature change of the target 120.

The source 110 may further include a temperature measuring sensor (not shown) for detecting a temperature change. Information about a battery state of the target 120, a change in a received power amount, or a temperature change of the target 120 may be received from the target 120 through communication.

That is, the temperature change of the target 120 may be detected based on the data received from the target 120.

In this case, the controller 114 may adjust the voltage supplied to the power amplifier 112 by using the look-up table in which the amount of adjustment of the voltage supplied to the power amplifier 112 is stored according to the change of the temperature of the source 110. For example, when the temperature of the source 110 rises, the controller 114 may lower the voltage supplied to the power amplifier 112.

Meanwhile, the communication unit 115 may perform out-band communication using a communication channel. The communication unit 115 may include a communication module such as Zigbee or Bluetooth. The communicator 115 may transmit the target 120 and the data 140 through out-band communication.

The source resonator 131 transfers electromagnetic energy 130 to the target resonator 133. The source resonator 131 transfers "communication power" or "charging power" to the target 120 through magnetic coupling with the target resonator 133.

The target 120 includes a matching network 121, a rectifying section 122, a DC / DC converter 123, a communication section 124 and a control section 125.

The target resonator 133 receives electromagnetic energy from the source resonator 131. That is, the target resonator 133 receives "communication power" or "charging power" from the source 110 through magnetic coupling with the source resonator 131. In addition, the target resonator 133 may receive various data 140 from the source 110 through in-band communication.

The target resonator 133 receives the initial wireless power determined in consideration of the temperature change of the source 110, the battery state of the target 120, the change of the received power amount, or the temperature change of the target 120.

The matching network 121 may match the input impedance shown to the source 110 and the output impedance shown to the load. The matching network 121 may be composed of a combination of a capacitor and an inductor.

The rectifying unit 122 rectifies the AC voltage to generate a DC voltage. That is, the rectifying section 122 rectifies the received AC voltage to the target resonator 133.

The DC / DC converter 123 adjusts the level of the DC voltage output from the rectifier 122 according to the capacity required by the load. For example, the DC / DC converter 123 can adjust the level of the DC voltage output from the rectifying unit 122 to 3 to 10 Volts.

The power detector 127 may detect the voltage of the input terminal 126 of the DC / DC converter 123 and the current and voltage of the output terminal. The detected voltage at the input 126 can be used to calculate the transmission efficiency of the power delivered from the source. The detected current and voltage at the output terminal can be used to calculate the power to which the control unit (Rx Control Logic) 125 transfers the load. The controller 114 of the source 110 may determine the power to be transmitted from the source 110 in consideration of the power required for the load and the power transmitted to the load.

When the power of the output terminal calculated by the communication unit 124 is transferred to the source 110, the source 110 may calculate the power to be transmitted.

The communication unit 124 may perform in-band communication for transmitting and receiving data using the resonance frequency. The control unit 125 may detect a signal between the target resonator 133 and the rectifying unit 122 to demodulate the received signal or detect the output signal of the rectifying unit 122 to demodulate the received signal. That is, the controller 125 may demodulate a message received through in-band communication. The control unit 125 can modulate the signal to be transmitted to the source 110 by adjusting the impedance of the target resonator 133 through the matching network 121. [ As a simple example, the control unit 125 may increase the impedance of the target resonator 133 so that the reflected wave is detected at the control unit 114 of the source 110. [ Depending on whether the reflected wave is generated, the controller 114 of the source 110 may detect a binary number "0" or "1".

The communication unit 124 is "type of the product of the target", "manufacturer information of the target", "model name of the target", "battery type of the target", "charging method of the target", "load of the target Impedance value "," information on the target resonator's characteristic of the target "," information on the frequency band used by the target "," power consumption of the target "," unique identifier of the target "and" The response message including the "version or specification information of the product of the target" may be transmitted to the communication unit 115 of the source 110.

Meanwhile, the communication unit 124 may perform out-band communication using a communication channel. The communication unit 124 may include a communication module such as Zigbee or Bluetooth. The communication unit 124 may transmit and receive the source 110 and the data 140 through out-band communication.

The communicator 124 receives the wake-up request message from the source 110, the power detector 127 detects the amount of power received by the target resonator 133, and the communicator 124 transmits the target resonator 133. Information about the amount of power received at may be transmitted to the source 110. The information on the amount of power received by the target resonator 133 may be information on the input voltage value and the current value of the rectifying section 122 or the output voltage value and current value of the rectifying section 122 or the DC / Output voltage value and current value of the converter 123 ".

2 is a block diagram of a wireless power transmission apparatus according to an embodiment.

2, the apparatus for transmitting power wirelessly includes a detector 210, a controller 220, and a communicator 230. The wireless power transmitter may wirelessly transmit power through mutual resonance with a target resonator mounted in the wireless power receiver by using the mounted source resonator.

The wireless power receiver may be represented as a receiving device in the following description. In addition, the wireless power receiver may be an electric vehicle (EV), and the wireless power transmitter may be implemented in the form of charging the electric vehicle in the lower or upper portion of the electric vehicle.

The detector 210 detects an entry into a charging region of a receiving device that receives power wirelessly based on an amount of change in the amplitude of the signal oscillated by the source resonator. When the receiving device approaches the high frequency magnetic field generated by the source resonator, power is transmitted to the receiving device through mutual resonance, and energy stored in the wireless power transmitter is lost. Due to the lost energy, the amplitude of the signal oscillating in the source resonator is attenuated or stopped. The detector 210 may detect an entry into the charging region of the receiving device through attenuation of the amplitude of the oscillation signal or stop of the amplitude.

The detector 210 may transmit an oscillation signal having a constant amplitude through the source resonator to detect an entry into the charging region of the receiving device.

The charging region may mean a predetermined region of the wireless power transmission apparatus implemented as a pad type. In addition, the charging region may be defined as a region where mutual resonance may occur.

When the sensing unit 210 detects that the receiving device enters the charging region, the control unit 220 controls the resonance frequency or impedance of the source resonator to match the load of the receiving device. The control unit 220 may adjust the resonant frequency of the source resonator according to which position or amount of the charging device has entered. The controller 220 may adjust the resonance frequency of the source resonator so that the amount of reflected power is minimized in the region where the receiving device is located.

In addition, the controller 220 may adjust the impedance of the source resonator. The impedance of the source resonator can be adjusted through the connection of additional resistors or capacitors.

The detector 210 may detect an entry into the charging region of the receiving device based on whether the amplitude of the oscillating signal is attenuated from an initial amplitude value having an amplitude value of a predetermined magnitude. When the receiving device enters the charging region, the amplitude value is attenuated or has a constant value smaller than the initial amplitude value as a result of the attenuation, so that the sensing unit 210 detects a change in the amplitude value and thus moves to the charging region of the receiving device. It is possible to determine the entry of.

The sensing unit 210 may be implemented as a proximity sensor. In the case of the proximity sensor, when the power is turned on, a signal having a constant amplitude is generated within about 60 ms, and as a result, an electromagnetic field may be formed.

After detecting the entry of the receiving device into the charging region, the sensing unit 210 senses that the amplitude of the signal oscillating from the source resonator is greater than a predetermined value, the receiving device is aligned with the apparatus for transmitting power wirelessly. You can judge. Depending on where the receiving device is in the charging region, the amplitude of the oscillation signal can be large and small. When the receiving device is correctly matched to the charging region, the sensing unit 210 may detect the value of the amplitude of the oscillation signal more than a predetermined value.

The controller 220 may adjust the virtual resistance included in the wireless power transmitter to match the load of the receiving device that changes according to the degree of charge. The virtual resistor may be composed of a plurality of resistors and capacitors and a connection circuit of the plurality of transistors. Each resistor and transistor can be connected, and depending on the operation of the transistor, each resistor can be connected to a source resonator, which can be used to change the impedance of the source resonator. That is, the controller 220 may control the operation of the transistor to adjust the size of the virtual resistor.

As the load of the receiving device is charged, the magnitude of the load decreases. Therefore, in order to efficiently transfer wireless power, the impedance of the wireless power transmitter needs to be adjusted to match the size of the decreasing load.

The controller 220 may control the resonance frequency or the impedance of the source resonator so that the reflected power amount has a minimum value based on the reflected power amount reflected from the receiving device.

If it is detected that the receiving device and the wireless power transmitter are not aligned, the controller 220 may adjust the size of the virtual resistor to match the load of the receiving device at the unaligned position. Alignment here means that the receiving device is correctly positioned in the predetermined charging region.

If it is detected that the receiving device and the wireless power transmitter are not aligned, the communicator 230 may transmit information about a location at which power can be received from the wireless power transmitter to the receiving device with optimal efficiency. The communicator 230 may transmit direction information and distance information to which the receiving device should move so that the receiving device is located in the charging area.

The sensing unit 210 may include a measuring unit 211 or an alignment sensor 213. The measurement unit 211 may measure the amplitude of the signal oscillated by the source resonator. The measurement unit 211 may measure the voltage value of the voltage signal oscillated by the source resonator.

The alignment sensor 213 may sense whether the reception device and the wireless power transmitter that enter the charging area are aligned based on the optical triangulation. The optical triangulation method is a method of calculating a distance value to an object by triangulation method from the position information of the laser beam projected on the optical sensor after imaging the laser beam used for the measurement object to the optical sensor. The alignment sensor 213 may be located in the charging region of the wireless power transmitter, calculate a distance between the receiving device and the alignment sensor 213, and determine that the alignment is aligned when the calculated distance is within a predetermined error range.

The controller 220 may be in charge of overall control of the wireless power transmitter and perform the functions of the detector 210 and the communicator 230. In the embodiment of FIG. 2, this configuration is illustrated separately to describe each function. Therefore, when a product is actually implemented, all of them may be processed by the control unit 220, or only a part of them may be processed by the control unit 220.

3 is a block diagram of a wireless power receiver according to an embodiment.

Referring to FIG. 3, the wireless power receiver includes a detector 310, a controller 320, a communication unit 330, and a display unit 340. The wireless power transmitter may wirelessly transmit power through mutual resonance with a target resonator mounted in the wireless power receiver by using the mounted source resonator. The wireless power transfer apparatus may be represented as a supply device in the following description.

The detector 310 may detect an entry into a charging region of a supply device that wirelessly supplies power based on a waveform of a signal stored in the target resonator. Upon entering the charging region, power can be received from the supply device through mutual resonance. Power is stored in the target resonator by mutual resonance between the target resonator and the source resonator of the supply device. When the waveform of the signal stored in the target resonator changes, the detector 310 may determine that the wireless power receiver has entered the charging region.

The communication unit 330 may receive information about the alignment position of the charging region from the supply device. The communication unit 330 may receive the information on the alignment position in an in band method or an out band method.

The controller 320 may move the wireless power receiver to an alignment position such that the impedance of the supply device matches the impedance.

The communication unit 330 receives information on the amount of reflected power from the supply device, and the control unit 320 based on the information on the amount of reflected power, the load mounted on the wireless power receiver receives a constant resistance value regardless of the charging progress. The size of the virtual resistor connected to the load can be controlled.

As charging progresses, the amount of reflected power reflected by the wireless power receiver may change. The change in the reflected power amount is because the impedance of the load changes according to the degree of charging, and the controller 320 may adjust the size of the virtual resistor so that the impedance of the load at the time of charging start is continuously maintained.

If the sensing unit 310 detects that the wireless power receiver enters the charging area, the display unit 340 may display an alignment position of the charging area of the supply device on the screen. Since the information about the alignment position is obtained by the communication unit 330, the display unit 340 may display the alignment position on the screen mounted on the wireless power receiver. In this case, the display unit 340 may display the alignment position on the image photographed by the camera.

The controller 320 is responsible for overall control of the wireless power receiver, and may perform the functions of the detector 310 and the communicator 330. In the embodiment of FIG. 3, these are separately configured and described to distinguish the respective functions. Therefore, when realizing a product, all of them may be processed by the control unit 320, or only a part of them may be processed by the control unit 320. [

4 is a diagram illustrating an alignment method between a source and a target in a wireless power transmission system according to an embodiment.

Referring to FIG. 4, a source corresponds to a wireless power transmitter and a target corresponds to a wireless power receiver. For example, the target may be an electric vehicle and the source may be a device for charging the electric vehicle.

The alignment position can be set in the charging region of the source. The alignment position may be set according to the type of target to be charged. In the case of FIG. 4, positions 441, 443, 445, and 447 correspond to alignment positions of the charging region. When the target enters the charging region and reaches the positions 431, 433, 435, 437, it can be said that the source and the target are aligned. That is, if the target is located in the vertical direction of the positions 441, 443, 445, and 447, it may be determined that the source is aligned.

In this case, the source may determine the position of the target through the sensor 420, and the target may determine which position on the charging region through the sensor 410. Alternatively, the target may acquire information on the distance and direction to the positions 441, 443, 445, and 447 of the charging region through the sensor 410. The sensor 410 may obtain information regarding the locations 441, 443, 445, and 447 from the sensor 420.

5 is a diagram illustrating an alignment method between a source and a target in a wireless power transmission system according to another exemplary embodiment.

Referring to FIG. 5, a source corresponds to a wireless power transmitter and a target corresponds to a wireless power receiver. For example, the target may be an electric vehicle and the source may be a device for charging the electric vehicle.

The source may determine the position of the target through the Tx System 510, and the target may determine which position on the charging region through the Rx System 530. The source may transmit information on the alignment position on the charging area through the wireless communication unit 520. The target may receive information about the alignment position on the charging area through the wireless communication unit 540. The target may receive information about the alignment position and move the target to the alignment position through the Rx System 530.

6 is a graph illustrating an amplitude of a signal oscillating in a wireless power transmission apparatus according to an embodiment.

Referring to FIG. 6, a section in which the magnitude of the oscillation voltage decreases or increases in the direction of the arrow occurs. The period in which the magnitude of the oscillation voltage decreases means that the wireless power receiver approaches or enters the charging region of the wireless power transmitter. In the section in which the magnitude of the oscillation voltage increases, the wireless power receiver is charged by the wireless power transmitter. It means moving away from the area.

It may be determined that the wireless power receiver enters the charging region in a section where the oscillation voltage is constant.

FIG. 7 is a diagram illustrating a configuration of a detector detecting a change in amplitude of a signal oscillated by a wireless power transmitter according to an embodiment.

The sensing unit may be implemented using a proximity sensor, and FIG. 7 illustrates a configuration of the proximity sensor. When power is supplied to the proximity sensor, a signal having a constant amplitude is formed in the oscillation circuit 730 within about 60 ms. An electromagnetic field is formed around the detection surface 710 from the formed signal. When the wireless power receiver approaches the detection surface 710, the induced current increases on the surface of the detection surface 710, so that the amplitude of the formed signal is reduced. When the wireless power receiver is fully detected, the amplitude of the voltage is close to 0V.

The source resonator 720 may be positioned below the detection surface 710. At least one source resonator 720 may be mounted in the proximity sensor according to the size of the detection surface 710.

The detector 740 detects the amplitude of the signal formed in the oscillator circuit 730. Integrator 750 integrates the detected amplitude value over time, and amplifier 760 amplifies the amount of change in amplitude. The output unit 770 outputs an operation signal for operating the operation indicator 780 when the amount of change in amplitude is greater than or equal to a predetermined value. The operation indicator 780 may blink or display a specific color when the wireless power receiver enters.

8 is a diagram illustrating a virtual resistor used in a wireless power receiver according to an embodiment.

Referring to FIG. 8, in the wireless power receiver, the virtual resistor 810 is used to keep the impedance of the wireless power receiver constant regardless of the degree of charge of the battery 820. The virtual resistor 810 may be composed of resistors R1, R2, R3, R4, R5, and R6, a capacitor C1, and transistors M1, M2, M3, M4, M5, M6, and M7. The controller 830 controls the operation of the transistors M1, M2, M3, M4, M5, M6, and M7 so that any one of the resistors R1, R2, R3, R4, R5, and R6 and the capacitor C1 may be controlled. One may be connected to the battery 820. The resistors R1, R2, R3, R4, R5, and R6 may have different resistance values or may have the same resistance value.

Through the control of the controller 830, the resistors R1, R2, R3, R4, R5, R6 and the capacitor C1 are adaptively connected to the battery 820, whereby the battery 820 is charged to reduce impedance. Even in this case, the impedance can be kept constant.

9 is a diagram illustrating a display unit in a wireless power receiver according to an embodiment.

When the wireless power receiver is an electric vehicle, the charging area of the wireless power transmitter may be displayed on the screen 920 located on the dashboard 910 of the electric vehicle. When the electric vehicle is positioned in the charging area and aligned with the wireless power transmitter, charging may be started or terminated through the charging button 930. Alternatively, even when not aligned, if the electric vehicle enters the charging region, charging may be started or terminated through the charging button 930.

10 to 12, a "resonator" includes a source resonator and a target resonator.

The resonator of FIGS. 10 to 12 may be applied to the resonator described in FIGS. 1 to 9.

10 illustrates a distribution of a magnetic field in a resonator and a feeder according to an embodiment.

When the resonator is powered by a separate feeder, a magnetic field is generated in the feeder, and a magnetic field is generated in the resonator.

Referring to FIG. 10A, as the input current flows in the feeder 1010, the magnetic field 1030 is generated. The direction 1031 of the magnetic field inside the feeder 1010 and the direction 1033 of the magnetic field externally have opposite phases. Induced current is generated in the resonator 1020 by the magnetic field 1030 generated in the feeder 1010. At this time, the direction of the induced current is opposite to the direction of the input current.

The magnetic field 1040 is generated in the resonator 1020 by the induced current. The direction of the magnetic field has the same direction inside the resonator 1020. Accordingly, the direction 1041 of the magnetic field generated inside the feeder 1010 by the resonator 1020 and the direction 1043 of the magnetic field generated outside the feeder 1010 have the same phase.

As a result, when the magnetic field generated by the feeder 1010 and the magnetic field generated by the resonator 1020 are synthesized, the strength of the magnetic field is weakened inside the feeder 1010, and the strength of the magnetic field is strengthened outside the feeder 1010. do. Accordingly, when power is supplied to the resonator 1020 through the feeder 1010 having the structure as shown in FIG. 10, the strength of the magnetic field is weak at the center of the resonator 1020, and the strength of the magnetic field is strong at the outside. When the distribution of the magnetic field on the resonator 1020 is not uniform, it is difficult to perform impedance matching because the input impedance changes from time to time. In addition, since the wireless power transmission is good at the strong magnetic field and the wireless power transmission is not good at the weak magnetic field, the power transmission efficiency is reduced on average.

(b) shows the structure of the wireless power transmission apparatus in which the resonator 1050 and the feeder 1060 have a common ground. The resonator 1050 may include a capacitor 1051. The feeder 1060 may receive an RF signal through the port 1061. An RF signal may be input to the feeder 1060 to generate an input current. An input current flowing through the feeder 1060 generates a magnetic field, from which an induced current is induced in the resonator 1050. In addition, a magnetic field is generated from the induced current flowing through the resonator 1050. At this time, the direction of the input current flowing through the feeder 1060 and the direction of the induced current flowing through the resonator 1050 have opposite phases. Therefore, in the region between the resonator 1050 and the feeder 1060, the direction 1071 of the magnetic field generated by the input current and the direction 1073 of the magnetic field generated by the induced current have the same phase, so that Century is strengthened. On the other hand, inside the feeder 1060, the direction 1081 of the magnetic field generated by the input current and the direction 1083 of the magnetic field generated by the induced current have opposite phases, so that the strength of the magnetic field is weakened. As a result, the strength of the magnetic field may be weakened at the center of the resonator 1050, and the strength of the magnetic field may be enhanced at the outside of the resonator 1050.

The feeder 1060 may determine an input impedance by adjusting an area inside the feeder 1060. Here, the input impedance refers to the impedance seen when looking at the resonator 1050 in the feeder 1060. As the area inside the feeder 1060 increases, the input impedance increases. As the area inside the feeder 1060 decreases, the input impedance decreases. However, even when the input impedance decreases, since the magnetic field distribution inside the resonator 1050 is not constant, the input impedance value is not constant according to the position of the target device. Therefore, a separate matching network is required for matching the output impedance of the power amplifier with the input impedance. If the input impedance increases, a separate matching network may be needed to match the large input impedance to the small output impedance.

11 is a diagram illustrating a configuration of a resonator and a feeder according to an exemplary embodiment.

Referring to FIG. 11A, the resonator 1110 may include a capacitor 1111. The feeding unit 1120 may be electrically connected to both ends of the capacitor 1111.

(b) shows the structure of (a) in more detail. In this case, the resonator 1110 may include a first transmission line, a first conductor 1141, a second conductor 1142, and at least one first capacitor 1150.

The first capacitor 1150 is inserted in series at a position between the first signal conductor portion 1131 and the second signal conductor portion 1132 on the first transmission line, so that the electric field is connected to the first capacitor (1 capacitor). 1150). Generally, the transmission line includes at least one conductor at the top and at least one conductor at the bottom, where current flows through the conductor at the top and the conductor at the bottom is electrically grounded. In the present specification, a conductor in an upper portion of the first transmission line is divided into a first signal conductor portion 1131 and a second signal conductor portion 1132, and a conductor in a lower portion of the first transmission line is referred to as a first ground conductor portion ( 1133).

As shown in (b), the resonator has the form of a two-dimensional structure. The first transmission line includes a first signal conductor portion 1131 and a second signal conductor portion 1132 at the top and a first ground conductor portion 1133 at the bottom. The first signal conductor portion 1131, the second signal conductor portion 1132 and the first ground conductor portion 1133 are disposed to face each other. Current flows through the first signal conductor portion 1131 and the second signal conductor portion 1132.

In addition, as shown in (b), one end of the first signal conductor portion 1131 is grounded with the first conductor 1141 and the other end is connected with the first capacitor 1150. One end of the second signal conductor portion 1132 is grounded with the second conductor 1142, and the other end thereof is connected with the first capacitor 1150. As a result, the first signal conductor portion 1131, the second signal conductor portion 1132, the first ground conductor portion 1133, and the conductors 1141 and 1142 are connected to each other, whereby the resonator has an electrically closed loop structure. Have Here, the 'loop structure' includes a circular structure, a polygonal structure such as a square, and the like, and 'having a loop structure' means that the electrical structure is closed.

The first capacitor 1150 is inserted in the interruption of the transmission line. More specifically, the first capacitor 1150 is inserted between the first signal conductor portion 1131 and the second signal conductor portion 1132. In this case, the first capacitor 1150 may have a form such as a lumped element and a distributed element. In particular, a distributed capacitor in the form of a dispersing element may comprise zigzag-shaped conductor lines and a dielectric having a high dielectric constant between the conductor lines.

As the first capacitor 1150 is inserted into the transmission line, the source resonator may have a metamaterial characteristic. Here, the metamaterial is a material having special electrical properties that cannot be found in nature, and has an artificially designed structure. The electromagnetic properties of all materials in nature have inherent permittivity or permeability, and most materials have positive permittivity and positive permeability.

In most materials, the right-hand rule applies to electric fields, magnetic fields and pointing vectors, so these materials are called RHM (Right Handed Material). However, meta-materials are materials that have a permittivity or permeability that does not exist in nature, and according to the sign of permittivity or permeability, ENG (epsilon negative) material, MNG (mu negative) material, DNG (double negative) material, NRI (negative refractive) index) substances, LH (left-handed) substances and the like.

At this time, when the capacitance of the first capacitor 1150 inserted as the concentrating element is appropriately determined, the source resonator may have characteristics of metamaterials. In particular, by appropriately adjusting the capacitance of the first capacitor 1150, the source resonator may have a negative permeability, so that the source resonator may be referred to as an MNG resonator. Criteria for determining the capacitance of the first capacitor 1150 may vary. The criterion that allows the source resonator to have the properties of metamaterial, the premise that the source resonator has a negative permeability at the target frequency, or the zero-resonance characteristic of the source resonator at the target frequency. There may be a premise so as to have, and the capacitance of the first capacitor 1150 may be determined under at least one of the above-described premise.

The MNG resonator may have a zeroth-order resonance characteristic with a resonant frequency at a frequency of zero propagation constant. Since the MNG resonator may have a zero resonance characteristic, the resonance frequency may be independent of the physical size of the MNG resonator. That is, as will be described again below, in order to change the resonant frequency in the MNG resonator, it is sufficient to properly design the first capacitor 1150, so that the physical size of the MNG resonator may not be changed.

In addition, in the near field, the electric field is concentrated on the first capacitor 1150 inserted into the transmission line, so that the magnetic field is dominant in the near field due to the first capacitor 1150. In addition, since the MNG resonator may have a high Q-factor using the first capacitor 1150 of the lumped device, the efficiency of power transmission may be improved. For reference, the queue-factor represents the ratio of the reactance to the degree of resistance or ohmic loss in the wireless power transmission, the larger the queue-factor, the greater the efficiency of the wireless power transmission .

In addition, although not shown in (b), a magnetic core penetrating the MNG resonator may be further included. Such a magnetic core can perform a function of increasing a power transmission distance.

Referring to (b), the feeding unit 1120 may include a second transmission line, a third conductor 1171, a fourth conductor 1172, a fifth conductor 1181, and a sixth conductor 1182. .

The second transmission line includes a third signal conductor portion 1161 and a fourth signal conductor portion 1162 at the top, and a second ground conductor portion 1163 at the bottom. The third signal conductor portion 1161 and the fourth signal conductor portion 1162 and the second ground conductor portion 1163 are disposed to face each other. Current flows through third signal conductor portion 1161 and fourth signal conductor portion 1162.

Also, as shown in (b), one end of the third signal conductor portion 1161 is grounded to the third conductor 1171, and the other end thereof is connected to the fifth conductor 1181. One end of the fourth signal conductor portion 1162 is grounded to the fourth conductor 1172, and the other end thereof is connected to the sixth conductor 1182. The fifth conductor 1181 is connected with the first signal conductor portion 1131, and the sixth conductor 1182 is connected with the second signal conductor portion 1132. The fifth conductor 1181 and the sixth conductor 1182 are connected in parallel to both ends of the first capacitor 1150. In this case, the fifth conductor 1181 and the sixth conductor 1182 may be used as input ports for receiving an RF signal.

As a result, the third signal conductor portion 1161, the fourth signal conductor portion 1162 and the second ground conductor portion 1163, the third conductor 1171, the fourth conductor 1172, the fifth conductor 1181, Since the sixth conductor 1182 and the resonator 1110 are connected to each other, the resonator 1110 and the feeding unit 1120 have a closed loop structure. Here, the 'loop structure' includes a circular structure, a polygonal structure such as a square, and the like. When the RF signal is input through the fifth conductor 1181 or the sixth conductor 1182, the input current flows to the feeding unit 1120 and the resonator 1110, and the resonator (resonance) is generated by a magnetic field generated by the input current. Induction current is induced at 1110. Since the direction of the input current flowing through the feeding unit 1120 and the direction of the induced current flowing through the resonator 1110 are formed in the same manner, the strength of the magnetic field is strengthened at the center of the resonator 1110, and the magnetic field at the outside of the resonator 1110. The strength of is weakened.

Since the input impedance may be determined by the area of the region between the resonator 1110 and the feeding unit 1120, a separate matching network is not required to perform matching of the output impedance of the power amplifier and the input impedance. Even when a matching network is used, the structure of the matching network can be simplified because the input impedance can be determined by adjusting the size of the feeding unit 1120. A simple matching network structure minimizes the matching loss of the matching network.

The second transmission line, the third conductor 1171, the fourth conductor 1172, the fifth conductor 1181, and the sixth conductor 1182 may have the same structure as the resonator 1110. That is, when the resonator 1110 has a loop structure, the feeding unit 1120 may also have a loop structure. In addition, when the resonator 1110 has a circular structure, the feeding unit 1120 may also have a circular structure.

12 is a diagram illustrating a distribution of a magnetic field in a resonator according to feeding of a feeding unit, according to an exemplary embodiment.

Feeding in wireless power transfer means supplying power to the source resonator. In addition, in the wireless power transmission, feeding may mean supplying AC power to the rectifier. (a) shows the direction of the input current flowing in the feeding part and the direction of the induced current induced in the source resonator. In addition, (a) shows the direction of the magnetic field generated by the input current of the feeding part and the direction of the magnetic field generated by the induced current of the source resonator. (a) is a simplified diagram of the resonator 1210 and the feeding unit 1220 of FIG. (b) shows an equivalent circuit of the feeding part and the resonator.

Referring to (a), the fifth or sixth conductor of the feeding part may be used as the input port 1210. The input port 1210 receives an RF signal. The RF signal may be output from the power amplifier. The power amplifier can increase or decrease the amplitude of the RF signal as needed by the target device. The RF signal input from the input port 1210 may be displayed in the form of input current flowing through the feeding unit. The input current flowing through the feeding part flows clockwise along the transmission line of the feeding part. However, the fifth conductor of the feeding part is electrically connected to the resonator. More specifically, the fifth conductor is connected with the first signal conductor portion of the resonator. Therefore, the input current flows not only in the feeding part but also in the resonator. In the resonator, the input current flows counterclockwise. The magnetic field is generated by the input current flowing through the resonator, and the induced current is generated by the magnetic field. Induced current flows clockwise in the resonator. In this case, the induced current may transfer energy to the capacitor of the resonator. In addition, a magnetic field is generated by the induced current. In (a), the input current flowing through the feeding part and the resonator is indicated by a solid line, and the induced current flowing through the resonator is indicated by a dotted line.

The direction of the magnetic field generated by the current can be known from the right-screw law. Inside the feeding portion, the direction 1221 of the magnetic field generated by the input current flowing through the feeding portion and the direction 1223 of the magnetic field generated by the induced current flowing through the resonator are the same. Thus, the strength of the magnetic field is enhanced inside the feeding portion.

Further, in the region between the feeding part and the resonator, the direction 1233 of the magnetic field generated by the input current flowing through the feeding part and the direction 1231 of the magnetic field generated by the induced current flowing through the source resonator are opposite phases. Thus, in the region between the feeding part and the resonator, the strength of the magnetic field is weakened.

In the loop type resonator, the strength of the magnetic field is generally weak at the center of the resonator, and the strength of the magnetic field is strong at the outer portion of the resonator. However, referring to (a), the feeding part is electrically connected to both ends of the capacitor of the resonator so that the direction of the induced current of the resonator and the direction of the input current of the feeding part are the same. Since the direction of the induced current of the resonator and the direction of the input current of the feeding part are the same, the strength of the magnetic field is enhanced inside the feeding part, and the strength of the magnetic field is weakened outside the feeding part. As a result, the strength of the magnetic field may be enhanced by the feeding part at the center of the loop type resonator, and the strength of the magnetic field may be weakened at the outer portion of the resonator. Therefore, the strength of the magnetic field as a whole can be uniform inside the resonator.

Meanwhile, since the efficiency of power transmission from the source resonator to the target resonator is proportional to the strength of the magnetic field generated in the source resonator, the power transmission efficiency may also increase as the strength of the magnetic field is enhanced at the center of the source resonator.

Referring to (b), the feeding unit 1240 and the resonator 1250 may be represented by an equivalent circuit. The input impedance Zin seen when looking at the resonator side from the feeding unit 1240 may be calculated by the following equation.

Here, M means mutual inductance between the feeding unit 1240 and the resonator 1250, ω means the resonant frequency between the feeding unit 1240 and the resonator 1250, Z is the target device in the resonator 1250 The impedance seen when looking to the side. Zin is proportional to the mutual inductance M. Therefore, Zin may be controlled by adjusting mutual inductance between the feeding unit 1240 and the resonator 1250. The mutual inductance M may be adjusted according to the area of the region between the feeding unit 1240 and the resonator 1250. The area of the region between the feeding unit 1240 and the resonator 1250 may be adjusted according to the size of the feeding unit 1240. Since Zin may be determined according to the size of the feeding unit 1240, a separate matching network is not required to perform impedance matching with the output impedance of the power amplifier.

The target resonator and the feeding unit included in the wireless power receiver may also have a distribution of magnetic fields as described above. The target resonator receives wireless power through the magnetic coupling from the source resonator. In this case, an induced current may be generated in the target resonator through the received wireless power. The magnetic field generated by the induced current in the target resonator may generate the induced current again in the feeding unit. At this time, when the target resonator and the feeding unit are connected as in the structure of (a), the direction of the current flowing through the target resonator and the direction of the current flowing through the feeding unit become the same. Therefore, the strength of the magnetic field may be enhanced inside the feeding part, and the strength of the magnetic field may be weakened in the region between the feeding part and the target resonator.

13 illustrates an electric vehicle charging system according to one embodiment.

Referring to FIG. 13, the electric vehicle charging system 1300 includes a source system 1310, a source resonator 1320, a target resonator 1330, a target system 1340, and a battery 1350 for an electric vehicle.

The electric vehicle charging system 1300 has a structure similar to the wireless power transfer system of FIG. 1. That is, the electric vehicle charging system 1300 includes a source composed of a source system 1310 and a source resonator 1320. The electric vehicle charging system 1300 also includes a target composed of a target resonator 1330 and a target system 1340.

In this case, the source system 1310 may include a variable SMPS, a power amplifier, a matching network, a controller, and a communication unit, as in the source 110 of FIG. 1. In this case, like the target 120 of FIG. 1, the target system 1340 may include a matching network, a rectifier, a DC / DC converter, a communication unit, and a controller.

The electric vehicle battery 1350 may be charged by the target system 1340.

The electric vehicle charging system 1300 may use resonant frequencies of several KHz to several tens of MHz.

The source system 1310 may generate power according to the type of the charging vehicle, the capacity of the battery, and the state of charge of the battery, and supply the generated power to the target system 1340.

The source system 1310 may perform control to align the alignment of the source resonator 1320 and the target resonator 1330. For example, if the alignment between the source resonator 1320 and the target resonator 1330 is not aligned, the controller of the source system 1310 may control the alignment by transmitting a message to the target system 1340.

In this case, the misalignment may be a case where the position of the target resonator 1330 is not at a position for the maximum magnetic resonance. That is, when the vehicle is not correctly stopped, the source system 1310 may induce adjustment of the position of the vehicle, thereby inducing the alignment of the source resonator 1320 and the target resonator 1330 to match.

The source system 1310 and the target system 1340 may transmit and receive an identifier of a vehicle and communicate various messages through communication.

2 to 12 may be applied to the electric vehicle charging system 1300. However, the electric vehicle charging system 1300 uses a resonant frequency of several KHz to several tens of MHz, and may perform power transmission of several tens of watts or more to charge the battery 1350 for the electric vehicle.

14 is a flowchart of a wireless power transmission method according to an embodiment.

In operation 1410, the wireless power transmitter detects an entry into a charging region of a receiving device that receives power wirelessly from the wireless power transmitter based on the amount of change in the amplitude of the signal oscillated by the source resonator.

In operation 1420, the wireless power transmitter controls the resonant frequency or impedance of the source resonator to match the load of the receiving device.

The wireless power transmitter may detect entry into the charging region of the receiving device based on whether the amplitude of the oscillating signal attenuates from an initial amplitude value having an amplitude value of a constant magnitude.

The wireless power transmitter may control the resonance frequency or the impedance of the source resonator so that the reflected power amount has a minimum value based on the reflected power amount reflected from the receiving device.

The methods according to embodiments of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Claims (16)

An apparatus for wirelessly transmitting power through mutual resonance between a source resonator and a target resonator,
A detector configured to detect entry into a charging region of a receiving device that receives power wirelessly from the apparatus based on an amount of change in amplitude of a signal oscillated by the source resonator; And
A control unit controlling a resonant frequency or impedance of the source resonator to match the load of the receiving device
And a wireless power transmission device. The method of claim 1,
The sensing unit
Detecting entry into the charging region of the receiving device based on whether the amplitude of the oscillating signal attenuates from an initial amplitude value having an amplitude value of a constant magnitude;
Wireless power transmission device. The method of claim 1,
The sensing unit
After detecting the entry of the receiving device into the charging region, if the amplitude of the signal oscillating from the source resonator is detected to be greater than a predetermined value, it is determined that the receiving device is aligned with the device for transmitting power wirelessly
Wireless power transmission device. The method of claim 1,
The sensing unit
Measuring unit for measuring the amplitude of the signal oscillating from the source resonator
And a wireless power transmission device. The method of claim 1,
The sensing unit
An alignment sensor sensing whether or not the receiving device entering the charging area and the device for transmitting power wirelessly are aligned based on an optical triangular method.
And a wireless power transmission device. The method of claim 1,
The control unit
Adjusting the virtual resistance included in the apparatus for transmitting power wirelessly to match the load of the receiving device that varies depending on the degree of charge
Wireless power transmission device. The method according to claim 6,
The virtual resistance is
Wireless power transmission device comprising a plurality of resistors and capacitors and a connection circuit of a plurality of transistors. The method of claim 1,
The control unit
Controlling the resonant frequency or impedance of the source resonator such that the reflected power amount has a minimum value based on the reflected power amount reflected from the receiving device;
Wireless power transmission device. The method of claim 5,
If it is detected that the receiving device and the apparatus for transmitting power wirelessly are not aligned, transmitting information to the receiving device about a position at which power can be received with optimal efficiency from the apparatus for transmitting power wirelessly. Communication
Wireless power transmission device further comprising. The method of claim 5,
The control unit
If it is detected that the receiving device and the apparatus for transmitting power wirelessly are not aligned, adjusting the virtual resistance included in the apparatus for transmitting power wirelessly to match the load of the receiving device in an unaligned position.
Wireless power transmission device. An apparatus for wirelessly receiving power through mutual resonance between a source resonator and a target resonator,
A detector for detecting entry into a charging region of a supply device that wirelessly supplies power based on a waveform of a signal stored in the target resonator;
A communication unit for receiving information on the alignment position of the charging region from the supply device; And
A controller for controlling movement of the apparatus for receiving power wirelessly to the alignment position such that the impedance of the supply device is matched
And the wireless power receiving device. 12. The method of claim 11,
A display unit displaying an alignment position of a charging region of the supply device when the sensing unit detects an entry into the charging region;
Wireless power receiving device further comprising. 12. The method of claim 11,
The communication unit receives information on the amount of reflected power from the supply device,
The controller is configured to control the size of the virtual resistor connected to the load such that the load mounted on the wirelessly-receiving device has a constant resistance value based on the information on the reflected power amount regardless of the charging progress situation.
Wireless power receiving device further comprising. An apparatus for wirelessly transmitting power through mutual resonance between a source resonator and a target resonator,
Detecting entry into a charging region of a receiving device that receives power wirelessly from the apparatus based on an amount of change in amplitude of a signal oscillating in the source resonator; And
Controlling the resonant frequency or impedance of the source resonator to match the load of the receiving device
Wireless power transmission method comprising a. 15. The method of claim 14,
The sensing step
Detecting entry into the charging region of the receiving device based on whether the amplitude of the oscillating signal attenuates from an initial amplitude value having an amplitude value of a constant magnitude;
Wireless power transmission method. 15. The method of claim 14,
The step of controlling
Controlling the resonant frequency or impedance of the source resonator such that the reflected power amount has a minimum value based on the reflected power amount reflected from the receiving device;
Wireless power transmission method.

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