KR102042116B1 - Method and apparatus for controlling of power in wireless power transmission system - Google Patents

Abstract

Disclosed are a power control apparatus and method in a wireless power transmission system. A power transmission apparatus of a wireless power transmission system includes a first power transmitter for transmitting power to a receiver in a magnetic coupling method at a fixed position, and second power for transmitting power to the receiver at a position different from the first power transmitter. A control unit which monitors power reception efficiency of a transmitter, a power supply unit that independently supplies power to the first power transmitter and the second power transmitter, and the receiver and controls the power supply unit based on the power reception efficiency It includes.

Description

TECHNICAL AND APPARATUS FOR CONTROLLING OF POWER IN WIRELESS POWER TRANSMISSION SYSTEM

TECHNICAL FIELD The present invention relates to wireless power transmission, and more particularly, to power control of a wireless power transmission system having a multiple transmission structure.

The wireless power transmission system includes a wireless power transmitter for wirelessly transmitting electrical energy and a wireless power receiver for receiving electrical energy from the wireless power transmitter.

Using a wireless power transfer system, it is possible to charge the battery of a mobile phone, for example by simply placing the mobile phone on a charging pad without connecting a separate charging connector.

The wireless energy transfer method may be classified into a magnetic induction method, a magnetic resonance method, and an electromagnetic wave method according to a principle of transmitting electrical energy.

Magnetic induction is a method of transmitting electrical energy by using a phenomenon in which electricity is induced between a transmitter coil and a receiver coil.

The magnetic resonance method is a method in which energy is intensively transferred to a receiver coil designed to have the same resonance frequency by generating a magnetic field oscillating at a resonance frequency in a transmitter coil.

Electromagnetic wave or microwave method is a method of receiving the electromagnetic wave generated by the transmitter using a plurality of rectenna at the receiver to convert the electromagnetic wave into electrical energy.

On the other hand, the wireless power transmission technology is a flexible coupled wireless power transfer technology (flexibly coupled technology) according to the type or strength of the magnetic resonant coupling of the transmitter coil and the receiver coil. And may be classified into a tightly coupled wireless power transfer technology (hereinafter, 'tightly coupled technology').

In this case, in the case of 'flexibly coupled technology', since a magnetic resonance coupling may be formed between one transmitter resonator and a plurality of receiver resonators, simultaneous multiple charging may be possible.

In this case, 'tightly coupled technology' may be a technology capable of only one-to-one power transmission between one transmitter coil and one receiver coil.

Wireless power transfer systems can be applied in complex wireless channel environments such as homes, offices, airports and trains.

In addition, the wireless power transmission system may be applied to an environment for charging a wireless device / IoT device / wearable device by synthesizing a three-dimensional beam pattern of an array antenna based on beacon positioning technology in a three-dimensional space.

The present invention is to provide a wireless power transmission system that can be applied in a complex wireless channel environment, such as in the home, office, airport, train.

In addition, an object of the present invention is to provide an apparatus and method for performing efficient power transmission through power control in a wireless power transmission system having a multiple transmission structure.

In one embodiment, a power transmitter of a wireless power transmission system includes a first power transmitter for transmitting power to a receiver in a self-coupled manner from a fixed position, and power to the receiver at a position different from the first power transmitter. A second power transmitter for transmitting, a power supply unit for independently supplying power to the first power transmitter and the second power transmitter, and a power reception efficiency of the receiver and monitoring the power reception efficiency based on the power reception efficiency And a control unit for controlling the supply unit.

According to the present invention, it is possible to efficiently provide selective wireless power transmission for three-dimensional space in visible and non-visible environments.

 According to the present invention, it is possible to perform efficient power transmission through power control in a wireless power transmission system having a multiple transmission structure.

1 is an exemplary diagram for describing an environment to which a wireless power transmission system is applied.
FIG. 2 is a diagram for describing a wireless power transmitter capable of transmitting power in various ways in the environment as shown in FIG. 1.
3 is a view for explaining an example of the configuration of the wireless charging pad unit in FIG.
4 is a view for explaining an example of the configuration of a wireless charging pad of the wireless charging pad unit according to an embodiment.
FIG. 5 is a diagram for describing an operation example of a wireless charging pad when a charging target device is placed on the wireless charging pad illustrated in FIG. 4.
FIG. 6 is a diagram illustrating an exemplary configuration of the drive control unit and the coil drive unit shown in FIG. 3.
7 is a diagram illustrating an example of a configuration of a coil driver and a connection relationship between a small power transmission coil and a coil driver according to an exemplary embodiment.
FIG. 8 is a diagram for describing an example of a configuration of a near field power transmitter in FIG. 2.
9 is a view for explaining the configuration and operating environment of the microwave power transmitter in FIG.
FIG. 10 is a diagram for describing another configuration example of the microwave power transmitter in FIG. 2.
FIG. 11 is a diagram for describing a beamforming method of the microwave power transmitter of FIG. 10.
12 illustrates a power transmission apparatus of a wireless power transmission system including multiple power transmitters according to an embodiment.
FIG. 13 is a diagram for describing an operation example when the second power transmitter moves in FIG. 12.
14 is a diagram for describing an example of operation according to power reception efficiency in the environment of FIG. 13.
FIG. 15 is a diagram for describing an operation example when the second power transmitter is fixed and the receiver moves in FIG. 12.
FIG. 16 is a diagram for describing an operation example according to power reception efficiency in the environment shown in FIG. 15.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited to the embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions.

As used herein, “an embodiment”, “an example”, “side”, “an example”, etc., should be construed that any aspect or design described is better or advantageous than other aspects or designs. It is not.

In addition, the term 'or' means inclusive or 'inclusive or' rather than 'exclusive or'. In other words, unless stated otherwise or unclear from the context, the expression 'x uses a or b' means any one of natural inclusive permutations.

Also, the singular forms “a” or “an”, as used in this specification and in the claims, generally refer to “one or more” unless the context clearly dictates otherwise or in reference to a singular form. Should be interpreted as

In addition, terms such as first and second used in the present specification and claims may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. In addition, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are specifically defined clearly.

On the other hand, in describing the present invention, when it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terminology used herein is a term used to properly express an embodiment of the present invention, which may vary according to a user, an operator's intention, or a custom in the field to which the present invention belongs. Therefore, the definitions of the terms should be made based on the contents throughout the specification.

1 is an exemplary diagram for describing an environment to which a wireless power transmission system is applied.

As shown in FIG. 1, the wireless power transmission environment may be a three-dimensional space such as a living room, a room, an office, an airport, and a train in a home.

Power transmission in the three-dimensional space may use a near field wireless power transform of the magnetic induction or magnetic resonance method. In addition, a far field wireless power transform may be used to cover short and long distances according to the location or type of the power receiver.

Meanwhile, the power receiving apparatus may be a communication device, or an RF harvesting device that may collect energy from electromagnetic waves in a three-dimensional space.

FIG. 2 is a diagram for describing a wireless power transmitter capable of transmitting power in various ways in the environment as shown in FIG. 1.

Referring to FIG. 1, the power transmission apparatus may include at least one of the wireless charging pad unit 210, the near field power transmitter 220, and the microwave power transmitter 230.

In other words, although the wireless charging pad unit 210, the near field power transmitter 220, and the microwave power transmitter 230 are all illustrated in FIG. 2, any one power transmission scheme may be used according to a three-dimensional space environment. Only a power transmission device may be provided.

Therefore, in the following description, the wireless power transmitter or the power transmitter should be understood to include at least one of the wireless charging pad unit 210, the near field power transmitter 220, and the microwave power transmitter 230.

The controller 240 may control an operation of at least one of the wireless charging pad unit 210, the near field power transmitter 220, and the microwave power transmitter 230.

The controller 240 may monitor an environment of a three-dimensional space and operate at least one of the wireless charging pad unit 210, the near field power transmitter 220, and the microwave power transmitter 230 based on the monitoring result. Can be controlled.

For example, the controller 240 operates the wireless charging pad unit 210 and the near field power transmitter 220 when the long distance transmission is not necessary, and the microwave power transmitter 230 performs a control function so as not to operate. can do.

The wireless charging pad unit 210 may transmit power in a magnetic induction method or a magnetic resonance method.

The near field power transmitter 220 may transmit power in a three-dimensional space in a self-resonant manner.

The microwave power transmitter 230 may transmit power in a three-dimensional space using a microwave power transmission method.

Meanwhile, a far field may be defined as a case where a distance between a transmitter and a receiver is greater than or equal to '2x (antenna length) ² / wavelength'.

3 is a view for explaining an example of the configuration of the wireless charging pad unit in FIG.

The device illustrated in FIG. 3 may include a wireless charging pad (not shown) and a wireless charging pad driving device 210. In this case, the wireless charging pad may be configured as shown in FIG. 4.

The wireless charging pad driver includes a driving controller 315 and a coil driver 317. The wireless charging pad driving device may further include a coil determiner 313 and a scanning controller 311.

The wireless charging pad driving apparatus according to an embodiment may include a driving controller 315 and a driving controller 315 which independently drive control each of the small power transmission coils of the wireless charging pad including a plurality of small power transmission coils. It may be composed of a plurality of driving modules for driving each of the plurality of small power transmission coils in accordance with the first control signal or the second control signal.

The scanning controller 311 scans the wireless charging pad to detect a device to be charged on the wireless charging pad including a plurality of small power transmission coils.

The scanning controller 311 may detect whether the device to be charged is placed on the small power transmission coil by using at least one of impedance change and pressure change of each of the small power transmission coils.

The coil determination unit 313 identifies the driving target power transmission coils positioned below the charging target device among the plurality of small power transmission coils, and surrounds the driving target power transmission coils among the plurality of small power transmission coils. Check the surrounding power transmission coils.

The driving controller 315 generates a first control signal to apply a first driving voltage having a first phase to the driving target power transmission coils, and has a phase different from the first phase to the peripheral power transmission coils. The second control signal may be generated to apply the second driving voltage.

In this case, the driving target power transmission coil may be a small power transmission coil matched to the charging target device. 'Matched to the device to be charged' may mean located below the device to be charged or in the vicinity of the device to be charged to transmit power to the device to be charged.

In this case, the first control signal controls the coil driver 317 to select the 'A' signal from the signal indicated by 'A' in FIG. 6 and FIG. It may be a 'Select' signal.

Also, the second control signal controls the coil driver 317 to select the 'B' signal among the signal indicated by 'A' in FIG. 6 and FIG. It may be a 'Select' signal.

The coil driver 317 applies the first driving signal and the second driving signal to the wireless charging pad.

4 is a view for explaining an example of the configuration of a wireless charging pad of the wireless charging pad unit according to an embodiment.

Referring to FIG. 4, the plurality of small power transmission coils 410 may be arranged in a tessellation structure, which is a structure that does not overlap on the wireless charging pad.

5 illustrates an example in which a device to be charged, 'DEVICE', is placed on a wireless charging pad.

In this case, only the small power transmission coils inside the hexagonal thick line where the 'DEVICE' is located among the small power transmission coils may be controlled to operate.

FIG. 5 is a diagram for describing an operation example of a wireless charging pad when a charging target device is placed on the wireless charging pad illustrated in FIG. 4.

3 and 5, the scanning controller 311 may detect whether the device to be charged is placed on the small power transmission coil by using at least one of impedance change and pressure change of each of the small power transmission coils. have.

For example, in the case of scanning by using the impedance change, in the case of the coil in which the charging target device is placed, when the impedance change is out of the preset range, it may be determined that the charging target device is placed on the coil.

In addition, when each small power transmission coil is provided with a pressure sensor, the pressure sensor on which the charging target device is placed may detect the device through a pressure change.

The scanning control unit 311 may scan the wireless charging pad to detect that the charging target device is positioned on the 10, 11, 12, 13, 17, 18, 19, 20, 21, 25, 26, 27, 28 coils. Can be.

As a result of scanning by the scanning control unit 311, coils provided under the position where the charging target device is placed are 10, 11, 12, 13, 17, 18, 19, 20, 21, 25, 26, 27, 28 When detected as coils, the coil determination unit 313 determines that each of the 10, 11, 12, 13, 17, 18, 19, 20, 21, 25, 26, 27, and 28 coils is a driving target power transmission coils. You can check it.

In addition, the coil determination unit 313 may include 10, 11, 12, 13, 17, 18, 19, 20, 21, 25, 26, 27, and 28 coils which are the driving target power transmission coils among the plurality of small power transmission coils. 2, 3, 4, 5, 6, 9, 14, 16, 22, 24, 29, 32, 33, 34, 35, 36 coils surrounding them can be seen that the surrounding power transmission coils.

In the example shown in FIG. 5, the clockwise arrow means the first phase and the counterclockwise arrow means the second phase.

The coil driver 317 may output the first driving signal to the corresponding small power transmission coil when the first control signal is input, and output the second driving signal to the corresponding small power transmission coil when the second control signal is received. have.

For example, the coil driver 317 may apply a first driving signal to each of the 10, 11, 12, 13, 17, 18, 19, 20, 21, 25, 26, 27, and 28 coils, which are driving target power transmission coils. Output a second drive signal to each of the peripheral power transmission coils 2, 3, 4, 5, 6, 9, 14, 16, 22, 24, 29, 32, 33, 34, 35, and 36 coils. Can be.

As such, the electric power is transmitted to the device to be charged by operating the coils placed at the place where the device to be charged is located, and the coils around the coils at which the device to be charged are operated to have opposite phases, so that the magnetic force lines directed to the device to be charged are The magnetic force lines that increase and spread out can be reduced.

Therefore, even when the power to be transmitted to the device to be charged is increased, the power transmission efficiency can be maintained and the influence of the magnetic field lines on the outside can be reduced.

FIG. 6 is a diagram illustrating an exemplary configuration of the drive control unit and the coil drive unit shown in FIG. 3.

6 illustrates an example in which one driving control unit (first driving control unit 631) controls four driving modules 642, 643, 645, and 647.

In other words, although not shown in FIG. 9, the driving control unit may include a plurality of second driving control units and third driving control units in addition to the first driving control unit 931.

In this case, the first driving controller 931 may be a shift register having eight output signal terminals 601 to 908.

Therefore, when cascading the first driving control unit 931 such as the shift register, the circuit for individually driving the small power transmission coils may be linearly expanded.

Each of the driving modules 642, 643, 645, and 647 may be connected to a small power transmission coil.

For example, the first drive module 642 is connected to the first small power transfer coil, the second drive module 643 is connected to the second small power transfer coil, and the third drive module 645 is connected to the third drive. The fourth power supply module 647 may be connected to the fourth small power transmission coil.

Therefore, when the 36 small power transmission coils are provided in the wireless charging pad, the wireless charging driving device may include 36 driving modules and 9 driving controllers.

Therefore, the apparatus for driving a wireless charging pad according to an embodiment may include a first driving control unit and a plurality of small power transmission units, each of which independently drives and controls each of the small power transmission coils of the first wireless charging module including the plurality of small power transmission coils. It may include a second driving control unit for independently driving control each of the small power transmission coils of the second wireless charging module composed of a coil.

In this case, one end of the second driving control unit may be connected to the first driving control unit, and the other end of the second driving control unit may be connected to the third driving control unit to support expansion of the wireless charging module.

Referring back to FIG. 9, the coil driver includes a plurality of driving modules 642, 643, 645, and 647 connected to each of the plurality of small power transmission coils.

In addition, the coil driver may apply a first switching signal A having a first phase and a second switching signal B having the second phase to each of the plurality of driving modules 642, 643, 645, and 647. It may include two bus lines.

The first driving controller 631 applies an enable signal and a first control signal or a second control signal to control the operation of the corresponding driving module to each driving module.

The first driving controller 631 applies an enable signal to the driving target power transmission coils and the driving modules connected to each of the peripheral power transmission coils, and applies the first control signal or the second control signal. The enable signal may be applied to driving modules to which the enable signal is applied.

For example, when the first driving module 642 is a driving module connected to the driving target power transmission coil, the enable signal may be output to the terminal 601 and the first control signal may be output to the terminal 602. .

For example, when the fourth driving module 647 is a driving module connected to the peripheral power transmission coil, an enable signal may be output to the terminal 607, and a second control signal may be output to the terminal 608.

7 is a diagram illustrating an example of a configuration of a coil driver and a connection relationship between a small power transmission coil and a coil driver according to an exemplary embodiment.

Referring to FIG. 7, reference numeral 710 denotes an equivalent circuit of one small power transmission coil.

One end of the small power transmission coil 710 may be connected to the driving voltage Vcc and the other end may be connected to the switching element 720 provided in the coil driver.

In this case, the coil driver may include a switching device 720, a multiplexer 750, and an and gate device 760 connected to the small power transmission coil 710.

The coil driver may receive the enable signal through the reference numeral 730 and the control signal through the reference numeral 740.

In this case, the multiplexer 750 outputs an A signal, which is a first switching signal, when the control signal input through the 740 terminal is the first control signal, and outputs a second control signal when the control signal input through the 740 terminal is the second control signal. The B signal, which is a switching signal, may be output.

The AND gate element 760 may control the switching element 720 by receiving the enable signal input through the 730 terminal and the output signal of the multiplexer 750.

For example, when the small power transmission coil 710 is a driving target power transmission coil, the first control signal is input to the terminal 740, and the switching element 720 is switched by a switching signal such as the A signal shown in FIG. It may be turned on / off.

As the driving voltage Vcc is applied to the small power transmission coil 710 according to the on / off of the switching element 720, the small power transmission coil 710 operates with the first driving voltage having the first phase. Done.

For example, when the switching element 720 is an NMOS transistor, the capacitor of the small power transfer coil 710 is charged in the time interval when the NMOS transistor is on, and the time interval when the NMOS transistor is off. In the capacitor of the small power transmission coil 710 is discharged, the magnetic field of the inductor can be controlled through the repetition of the charging and discharging.

FIG. 8 is a diagram for describing an example of a configuration of a near field power transmitter in FIG. 2.

Referring to FIG. 8, the near field power transmitter includes a coil unit 810 including a plurality of power transmission coils, a power divider 815, a first amplifier 820, a second amplifier 830, and a phase shifter ( 840 and the controller 850.

The coil unit 810 transmits wireless power to the receiving coil in a self-resonant manner.

For example, the coil unit 810 may include two magnetic resonance coils 811 and 813.

The first self-resonant coil 811 and the second self-resonant coil 813 may respectively transmit power wirelessly by forming a magnetic coupling with a single receiving coil.

As such, an environment composed of a plurality of transmitting coils and a single receiving coil may be referred to as a multi-input single output (MISO) system.

Meanwhile, an environment composed of a single transmitting coil or a single transmitter and a single receiving device may be referred to as a single input single output (SISO) system.

The MISO system may transmit power more efficiently than the SISO system, and may have superior performance compared to the SISO system even in an environment in which the power receiver is moved.

However, in the MISO system, magnetic coupling may be greatly affected by the alignment of the transmitting coil and the receiving coil.

When the phases of the currents supplied to the first self resonant coil 811 and the second self resonant coil 813 are controlled differently, magnetic coupling may be formed without being greatly influenced by the alignment state of the transmitting coil and the receiving coil. .

The power divider 815 may distribute the power supplied from the power source, and output the distributed power to the first amplifier 820 and the phase shifter 840.

The phase shifter 840 may change the phase of the input power.

The phase shifter 840 may adjust the phase of the current supplied to the second amplifier 830 by adjusting the phase of the input current.

Therefore, the phases of the currents supplied to the first self resonant coil 811 and the second self resonant coil 813 may be adjusted differently.

For example, the phase difference between the currents supplied to the first magnetic resonance coil 811 and the second magnetic resonance coil 813 may be set to 0 to 180 degrees.

This phase control can solve the problem of efficiency degradation caused by the movement of the receiver in the MISO system.

9 is a view for explaining the configuration and operating environment of the microwave power transmitter in FIG.

Referring to FIG. 9, the microwave power transmitter may include an array antenna unit 930 including a plurality of antenna elements element1, element2, and elementN.

The array antenna unit 930 may adjust the radiation characteristics by controlling the magnitude of the phase and the distribution current for each of the plurality of antenna elements.

At this time, by adjusting the feed phase of each radiating element, the electric field is added in phase at the position of the receiving antenna to maximize the received power.

In general, it is assumed that the distance between the array antenna and the receiving antenna is very far. Therefore, the power transmission efficiency between the antennas can be calculated by applying the Friis formula of Equation 1 after assuming that the distance between each antenna element of the array antenna from the receiving antenna is the same.

[Equation 1]

In Equation 1, P _r is the reception power, P _t is the transmission power, R is the distance between the transmitting antenna and the receiving antenna, G _t is the gain of the transmitting antenna, G _r is the gain of the receiving antenna.

However, since the distance between each antenna element of the array antenna and the receiving antenna in the environment for wireless power transmission is different, the general Friis formula cannot be applied.

Therefore, in calculating the power transmission efficiency, the controller 240 or the microwave power transmitter 230 of FIG. 2 calculates the power transmission efficiency in consideration of an environment for actual wireless power transmission.

The controller 240 or the microwave power transmitter 230 of FIG. 2 may receive information on the received power through communication with the power receiver, and calculate the power transmission efficiency based on Equation 2 below.

That is, the magnitude of the input power in each transmitting radiating element is P ₁ , P ₂ ,... , P _N and the distance between the receiving antenna and each radiating element is R ₁ , R ₂ ,. , R _N and each radiating element has the same gain G _t0 , and the power transmission efficiency to the receiving antenna whose antenna gain is G _r can be expressed as in Equation 2.

[Equation 2]

In Equation 2, an average of distances between the radiating element of the transmitting end and the receiving antenna may be defined as in Equation 3, and the power transmission efficiency calculation scheme according to an embodiment may be expressed as in Equation 4.

[Equation 3]

[Equation 4]

FIG. 10 is a diagram for describing another configuration example of the microwave power transmitter in FIG. 2.

The microwave power transmitter shown in FIG. 10 may control multiple beam formation using an array antenna (not shown).

The identification unit 1010 confirms information on the radiation pattern of the array antenna through full-wave simulation. For example, the radio wave simulation may use a high frequency structure simulator (HFSS).

The identification unit 1010 confirms the radiation pattern of each single antenna constituting the array antenna. The radiation pattern may be a radiation pattern modified by interference between the array position of the array antenna and the surrounding single antenna.

The identification unit 1010 generates information on the radiation pattern of the array antenna by calculating an average value of the radiation patterns of the single antennas constituting the identified array antenna.

The identification unit 1010 may check only at least one radiation pattern of the single antenna constituting the array antenna.

The information on the radiation pattern of the array antenna may be the value of the radiation pattern of any single antenna constituting the array antenna, may be an average value of at least two or more of the single antennas constituting the array antenna, and all of the single antennas constituting the array antenna It may also be an average value of.

The identification unit 1010 may check the information on the radiation characteristics of the array antenna before checking the information on the radiation pattern of the array antenna.

The information on the radiation characteristics may include information on the number of main beams, beam width, null section, steering angle, steering range, spacing between single antennas, and the like.

For example, when the user needs three main beams, the information on the three main beams may be included.

The identification unit 1010 may receive information on the radiation characteristic from a user through an input device connected to the multi-beam forming control device according to an embodiment of the present invention.

The identification unit 1010 may check the radiation pattern of the single antennas through radio wave simulation based on the information on the radiation characteristics of the array antennas.

The determiner 1020 determines an array factor AF based on the information AEP of the radiation pattern.

The array factor AF can be determined to have optimal gain and steering performance.

The array factor AF takes the form of the inverse of the information about the radiation pattern AEP.

The array factor AF may be expressed by Equation 5 below when the array antenna consists of N single antennas.

[Equation 5]

는 조향 각도, d는 단일 안테나 간 간격,

는 전파 상수,

는 인접한 단일 안테나 사이의 위상차를 나타낸다. Where A _n is the amplitude of the n-th single antenna, AEP is information on the radiation pattern,

Is the steering angle, d is the spacing between single antennas,

Is the propagation constant,

Denotes the phase difference between adjacent single antennas.

The power calculator 1030 may calculate the amplitude and phase of each single antenna constituting the array antenna based on the array factor.

)과 위상(

)의 계산은 하기 수학식 6으로 표현될 수 있다.Amplitude of each of the single antennas that make up the array antenna (

) And phase (

) Can be expressed by Equation 6 below.

[Equation 6]

는 조향 각도, n은 단일 안테나의 인덱스, d는 단일 안테나 간 간격,

는 전파 상수,

는 n 번째 단일 안테나의 진폭,

는 n 번째 단일 안테나의 위상,

는 인접한 단일 안테나 사이의 위상차를 나타낸다. Where AF is an array factor, AEP is information about a radiation pattern,

Is the steering angle, n is the index of a single antenna, d is the spacing between single antennas,

Is the propagation constant,

Is the amplitude of the n th single antenna,

Is the phase of the n th single antenna,

Denotes the phase difference between adjacent single antennas.

)과 위상(

)에 기초하여 단일 안테나 각각을 제어한다.The controller 1040 calculates each calculated amplitude (

) And phase (

Control each single antenna based on

)과 위상(

)이 입력되도록 단일 안테나 각각을 제어한다.The control unit 1040 is a calculated amplitude (each of a single antenna)

) And phase (

Control each of the single antennas to be input.

Accordingly, the apparatus for controlling multiple beamforming according to an embodiment of the present invention minimizes errors by calculating and controlling the amplitude and phase of each single antenna using an array factor (AF) in which information on the radiation pattern (AEP) is considered. Therefore, various beam shapes can be formed more precisely.

It is also possible to improve gain in steering and multi-beam formation, which directly affects power transmission efficiency in microwave wireless power transmission.

This not only improves the power transmission efficiency of microwave wireless power transmission, but also improves the simultaneous charging and avoiding technology of multiple devices.

FIG. 11 is a diagram for describing a beamforming method of the microwave power transmitter of FIG. 10.

In FIG. 11, (a) illustrates a beam forming method according to the prior art, and FIG. 11 (b) illustrates a beam forming method according to an embodiment of the present invention.

Referring to FIG. 11, a radiation pattern of an array antenna is represented as a product of the information on the radiation pattern AEP and the array factor AF.

Here, the radiation pattern refers to the radiation pattern of the entire array antenna to which the radiation pattern of each single antenna is combined.

The prior art calculates a radiation pattern 1113 by multiplying the radiation pattern 1111 and the array factor 1112. In this case, since the radiation pattern modified by the arrangement position of the array antenna and the interference with the surrounding single antenna is not considered, gain reduction and an error in the beam steering angle may occur.

However, the method according to the embodiment of the present invention multiplies the array factor AF by the inverse of the radiation pattern AEP and multiplies the radiation factor 1121 by the array factor 1122 multiplied by the inverse of the radiation pattern. Calculate the Radiation Pattern (1123).

,

)에서 모두 같은 크기 값을 가지며 다중 빔을 형성함을 확인할 수 있다.In this case, the two steering angles (

,

), All have the same size value and form multiple beams.

As such, multiple beams having improved gain can be formed at a desired steering angle.

12 illustrates a power transmission apparatus of a wireless power transmission system including multiple power transmitters according to an embodiment.

12, a power transmission apparatus of a wireless power transmission system including a heavy power transmitter according to an embodiment may include a first power transmitter 1210, a second power transmitter 1220, a power supply 1230, and a power transmitter. The controller 1240 is included.

The first power transmitter 1210 transmits power to the receiver in a magnetically coupled manner at a fixed position.

The first power transmitter 1210 may include a power amplifier and a magnetic resonance coil as shown in FIG. 8.

The second power transmitter 1220 transmits power to a receiver (not shown) at a location different from the first power transmitter 1210.

The second power transmitter 1220 may include a magnetic resonance coil.

The power supply unit 1230 may independently supply power to the first power transmitter 1210 and the second power transmitter 1220.

In this case, the power supply unit 1230 may include the same configuration as the power divider 815 illustrated in FIG. 8, and may be configured to the first power transmitter 1210 and the second power transmitter 1220 through power distribution. Can be powered independently

The controller 1240 may monitor power reception efficiency of the receiver through communication with the receiver and control the power supply unit based on the power reception efficiency. For example, the controller 1240 may receive information about the received power amount of the receiver, and calculate the power reception efficiency based on the information about the received power amount of the receiver and the total power transmitted by the power transmission device.

Meanwhile, the second power transmitter 1220 may periodically move in a direction parallel to the first power transmitter 1210 between the first power transmitter 1210 and the receiver. As the second power transmitter 1220 moves, power transmission coverage may be extended.

At this time, the control unit 1240 is the power supply unit 1230 so that the magnitude of the voltage supplied to the first power transmitter 1210 and the voltage supplied to the second power transmitter 1220 have different values. Can be controlled.

The magnitude V1 of the voltage supplied to the first power transmitter 1210 and the magnitude V2 of the voltage supplied to the second power transmitter 1220 may be values determined by an experimental value.

In addition, after the system is booted, a process for testing the power reception efficiency may be performed before sensing the receiver and starting the power transmission.

For example, the process for testing the power reception efficiency may be a process for determining the size ratio of V1 and V2.

Control unit 1240 to perform the process for testing a much smaller voltage power receiving efficiency based on the (e. G. _{0.1 ~ 0.2mV, V1t est, V2} test) than the size of the V1 and V2 when transmitting the actual power have.

Control 1240 V1t _est value of the fixed and V1t _est and V2 of when and while gradually increasing until it is doubled to 3 of the V2 _test V1t _est value monitor the power receiving efficiency, the power receiving efficiency is maximized with this _test The ratio of can be determined. However, if the efficiency is reduced to increase V2 _test when the fixed monitor, and this power receiving efficiency is optimized by the power receiving efficiency while gradually reduced until the times of 0.1 of the V2 _test V1t _est value of the V1t _est value V1t _est And the ratio of the V2 _test .

Control unit 1240 may determine the percentage of equal to V1 and V2 to the ratio of V1t _{est test} and V2, and controls the power supply 1230 based on the determined ratio of V1 and V2.

The controller 1240 may have a value different from that of the voltage supplied to the first power transmitter 1210 and the voltage supplied to the second power transmitter 1220 when the power reception efficiency is lower than the reference value. The power supply may be controlled to have a. In this case, different values may be determined at the same ratio as the ratio of V1t _est and V2 _test .

The controller 1240 may generate a phase shift control signal of the current supplied to the second power transmitter when the power reception efficiency is measured to be equal to or less than a preset value. have.

Therefore, the power transmission apparatus including the multiple power transmitter may perform the phase shift as well as the power control as shown in FIG. 8.

FIG. 13 is a diagram for describing an operation example when the second power transmitter moves in FIG. 12.

Referring to FIG. 13, the first power transmitter 1320 is fixed and the second power transmitter 1311 moves in a position parallel to the first power transmitter 1320.

The second power transmitter 1311 may perform power transfer at the power position indicated by reference numeral 1313 while moving in the direction of the dotted arrow.

That is, in FIG. 13, the second power transmitter 1311 may transmit power to the receiver 1301 while moving along the x axis.

14 is a diagram for describing an example of operation according to power reception efficiency in the environment of FIG. 13.

In FIG. 14, Tx1 only represents an example in which power reception efficiency is measured in an environment in which only a single power transmitter is provided, and a solid line represents a case where the ratio of V1 and V2 is 1: 1, and a line including a triangular mark represents the The size is set to an experimental value or an optimized value through a test process, and the measured efficiency graph is shown, and the line with thick dots shows the power reception efficiency graph when power control and phase control are performed together.

Referring to FIG. 14, it can be seen that power transmission efficiency is improved compared to an environment in which only a single transmitter is provided (Tx1 only) when a multi transmitter is provided.

However, when the second power transmitter 1311 is moved about 12 to 14 cm on the x-axis, the efficiency decreases.

In this case, it can be seen that the efficiency is improved when the size of V2 is set differently from V1 through power control.

FIG. 15 is a diagram for describing an operation example when the second power transmitter is fixed and the receiver moves in FIG. 12.

Referring to FIG. 15, the receiver 1501 moves in the direction of reference numeral 1503.

In this case, the first power transmitter 1510 and the second power transmitter 1520 are provided at positions parallel to each other. That is, the first power transmitter 1510 and the second power transmitter 1520 may have the same coordinates on the z-axis and the y-axis, and the x-axis may be represented by opposite signs and the same value.

In this case, the controller 1240 of FIG. 12 determines that the location of the receiver 1501 is located in a power transmission dead zone of the first power transmitter 1510 and the second power transmitter 1520. The power supply unit may be controlled to have a different value between the voltage supplied to the first power transmitter 1510 and the voltage supplied to the second power transmitter 1520.

In this case, different values may be determined based on a ratio determined by an experiment or a ratio determined through a power reception efficiency test process.

FIG. 16 is a diagram for describing an example of operation according to power reception efficiency in the environment shown in FIG. 15.

In FIG. 16, Tx1 only represents an example in which power reception efficiency is measured in an environment in which only a single power transmitter is provided, and a solid line represents a case where the ratio of V1 and V2 is 1: 1, and a line including a triangular mark is represented by V2. The size is set to an experimental value or an optimized value through a test process, and the measured efficiency graph is shown, and the line with thick dots shows the power reception efficiency graph when power control and phase control are performed together.

Referring to FIG. 16, when the location of the receiver 1501 is located in a vicinity where power reception efficiency is degraded in the vicinity of an x-axis coordinate of 0, it may be determined that the receiver 1501 is located in a power transmission dead zone.

At this time, the controller may determine that the position of the receiver 1501 is located in the dead zone when the power transmission efficiency is less than or equal to a specific value. When the receiver 1501 is located in the dead zone, power transmission may be stopped, power control may be performed, or phase control may be performed together with power control.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the devices and components described in the embodiments may be, for example, processors, controllers, arithmetic logic units (ALUs), digital signal processors, microcomputers, field programmable arrays (FPAs), It may be implemented using one or more general purpose or special purpose computers, such as a programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to the execution of the software. For convenience of explanation, one processing device may be described as being used, but one of ordinary skill in the art will appreciate that the processing device includes a plurality of processing elements and / or a plurality of types of processing elements. It can be seen that it may include. For example, the processing device may include a plurality of processors or one processor and one controller. In addition, other processing configurations are possible, such as parallel processors.

The software may include a computer program, code, instructions, or a combination of one or more of the above, and configure the processing device to operate as desired, or process it independently or collectively. You can command the device. Software and / or data may be any type of machine, component, physical device, virtual equipment, computer storage medium or device in order to be interpreted by or to provide instructions or data to the processing device. Or may be permanently or temporarily embodied in a signal wave to be transmitted. The software may be distributed over networked computer systems so that they may be stored or executed in a distributed manner. Software and data may be stored on one or more computer readable recording media.

The method according to the embodiment may be embodied in the form of program instructions that can be executed by 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 media may be those specially designed and constructed for the purposes of the embodiments, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or even if replaced or substituted by equivalents, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims (6)

A first power transmitter for transmitting power to the receiver in a magnetically coupled manner at a fixed position;
A second power transmitter for transmitting power to the receiver at a location different from the first power transmitter;
A power supply unit supplying power independently to the first power transmitter and the second power transmitter; And
A control unit for monitoring the power reception efficiency of the receiver and controlling the power supply unit based on the power reception efficiency;
The second power transmitter is provided to periodically move between the first power transmitter and the receiver in a direction parallel to the first power transmitter,
The control unit controls the power supply unit so that the magnitude of the voltage supplied to the first power transmitter and the magnitude of the voltage supplied to the second power transmitter have different values.
Power transmission device of a wireless power transmission system comprising a multi-power transmitter. delete The method of claim 1,
The control unit controls the power supply unit so that the magnitude of the voltage supplied to the first power transmitter and the magnitude of the voltage supplied to the second power transmitter have different values when the power reception efficiency is lower than a reference value.
Power transmission device of a wireless power transmission system comprising a multi-power transmitter. The method of claim 1,
The controller generates a phase shift control signal of the current supplied to the second power transmitter when the power reception efficiency is measured to be equal to or less than a predetermined value measured by the single power transmitter.
Power transmission device of a wireless power transmission system comprising a multi-power transmitter. The method of claim 1,
The second power transmitter is provided at a position parallel to the first power transmitter,
If it is determined that the position of the receiver is located in a power transmission dead zone of the first power transmitter and the second power transmitter, the control unit may determine the magnitude of the voltage supplied to the first power transmitter and the second power transmitter. To control the power supply so that the magnitude of the voltage supplied to the power transmitter has a different value
Power transmission device of a wireless power transmission system comprising a multi-power transmitter. The method of claim 5,
The controller generates a phase shift control signal of the current supplied to the second power transmitter when the power reception efficiency is measured to be equal to or less than a predetermined value measured by the single power transmitter.
Power transmission device of a wireless power transmission system comprising a multi-power transmitter.

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