KR102051270B1 - Wireless power transmission system for improving degree of freedom of receiver - Google Patents

Abstract

The present invention relates to a wireless power transmission system for improving receiver freedom. The wireless power transmission apparatus according to an embodiment includes a power divider for distributing power supplied from a power source, and an amplifying power of the distributed first phase. A first amplifier adjusts the power of the distributed first phase to a second phase, and adjusts the power to the second phase by using a first variable capacitor connected in series with the inductor and a second variable capacitor connected in parallel with the capacitor. A shifter, a second amplifier for amplifying the power amplified to the second phase, and controlling to transmit the power of the amplified first phase and the power of the amplified second phase to a receiving side through different resonance coils. It may include a control unit.

Description

Wireless power transmission system for improved receiver freedom {WIRELESS POWER TRANSMISSION SYSTEM FOR IMPROVING DEGREE OF FREEDOM OF RECEIVER}

The present invention relates to wireless power transmission, and more particularly, to a system capable of wireless power transmission that reduces the sensitivity to the misalignment of the axis while solving the problem for each misalignment.

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 transmitting unit using a plurality of rectenna in the receiving unit 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 a beacon positioning technique in a three-dimensional space.

In the case of the magnetic induction method, which is widely available as a commercial product, there is a limitation in charging a portable terminal while using the portable terminal because it is an ultra short-range contact wireless power transmission method. In the case of the self-resonant wireless power transmission, the dependence of distance is improved to a certain extent. However, in the case of having a single transmitter / receiver, the dead zone cannot receive power because the coupling coefficient becomes 0 according to the position and angle of the receiver. And the reception power decreases relatively rapidly even in the vicinity.

For example, when a receiver is moved, a dead zone occurs when the coupling coefficient changes from a positive value to a negative value. Also, dead zone occurs when the angle made by the transmitter / receiver becomes right angle.

This misalignment of dead zones cannot be solved with a single transmitter / receiver. Therefore, there is a need to use multiple transmitters to solve this problem.

According to this need, the sensitivity to misalignment of the axes is reduced when using multiple transmitters. However, this method alone cannot solve the problem of each misalignment.

Korean Laid-Open Patent Publication No. 2017-0083886, "Wireless Power Receiver, Wireless Power Transmission System Including The Same, and Method for Automatically Controlling Effective Load Resistance Conversion Ratio of Receiver." Korean Laid-Open Patent No. 2016-0047560, "Wireless Power Transmitter and Wireless Power Receiver Using Phase Amplitude Control Algorithm"

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, the present invention is to provide a system capable of wireless power transmission that can solve the problem for each misalignment while reducing the sensitivity to the misalignment of the axis.

In one embodiment, a wireless power transmitter includes: a power divider for distributing power supplied from a power source; a first amplifier configured to amplify the divided first phase power; and the distributed first phase power as a second phase. A phase shifter for adjusting to the second phase by using a first variable capacitor connected in series with an inductor and a second variable capacitor connected in parallel with the inductor, and a second amplifying power amplified with the second phase. And a control unit for controlling the power of the amplified first phase and the power of the amplified second phase to be transmitted to a receiving side through different resonance coils.

In an exemplary embodiment, the wireless power transmitter may amplify the distributed power in different sizes.

The control unit may receive received power information based on the received power and the load resistance from the receiving side controller, and control the phase and the magnitude of power based on the received received power information.

The phase shifter according to an embodiment may adjust the power of the distributed first phase to a second phase, but adjust the second phase between 0 degrees and 360 degrees.

The control unit according to an embodiment requests the receiving side to control the load resistance of the receiving side in consideration of the optimum load resistance to receive the maximum power, and the receiving side simultaneously controls the inductor and the capacitor by using a variable capacitor The load resistance can be adjusted or the load resistance can be adjusted through the selected matching circuit.

In one embodiment, a method of operating a wireless power transmitter includes: distributing power supplied from a power source in a power divider; amplifying power of the divided first phase in a first amplifier; and in a phase shifter Adjusting the power of the distributed first phase to a second phase, using the first variable capacitor connected in series to the inductor and the second variable capacitor connected in parallel to the second phase; Amplifying the power amplified by the second phase in the amplifying unit, and controlling, by the control unit, transmitting power of the amplified first phase and power of the amplified second phase to a receiving side through different resonance coils It may include the step.

In a method of operating a wireless power transmitter according to an embodiment, the first amplifier and the second amplifier may amplify the distributed power to different magnitudes.

According to an exemplary embodiment, the controlling may include receiving received power information based on received power and load resistance from a receiving controller, and controlling phase and power based on the received received power information. It may include.

The adjusting of the second phase according to an embodiment may include adjusting, in the phase shifter, the power of the distributed first phase to a second phase, wherein the second phase is adjusted between 0 degrees and 360 degrees. It may include the step.

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

According to the present invention, it is possible to provide a system capable of wireless power transmission that can solve the problem of each misalignment while reducing the sensitivity to misalignment of the axis.

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 example of an operation of a wireless charging pad when the device to be charged 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 is a diagram illustrating an embodiment of a phase shifter in a configuration of a near field power transmitter according to an exemplary embodiment.
13 is a diagram illustrating the efficiency of controlling only the magnitude of the input voltage when the reception loop rotates.
14 is a diagram illustrating the efficiency of controlling only the phase of the input voltage when the reception loop rotates.

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, far field wireless power transform may be used to cover short distance and long distance 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. In this case, the distributed power is a first phase, and the first amplifier 820 may amplify the distributed power of the first phase.

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.

More specifically, the phase shifter 840 may adjust the power of the distributed first phase to the second phase. For example, the phase shifter 840 may adjust to the second phase by using a first variable capacitor connected in series with the inductor and a second variable capacitor connected in parallel with the capacitor.

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.

The first amplifier 820 and the second amplifier 830 may amplify the power distributed in different sizes. That is, the power of the first phase and the power of the second phase may be divided into different magnitudes and different phases.

Through this transmission scheme, the size and phase of the two transmitters can be arbitrarily adjusted. The control unit on the receiving side checks the received power and adjusts the load resistance, passes the received power information through communication with the control unit on the transmitting side, and the control unit on the transmitting side controls the phase and the magnitude of power based on the information. do.

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,..., ElementN.

The array antenna unit 930 may adjust the radiation characteristics by controlling the phase and the magnitude of 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 transfer efficiency of microwave wireless power transfer 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 array factor 1122 by the inverse of the radiation pattern by the radiation pattern 1121. 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.

Hereinafter, another embodiment of the near field power transmitter 220 of FIG. 2 will be described with reference to FIGS. 12 to 14.

12 is a diagram illustrating an embodiment of a phase shifter 1200 in a configuration of a near field power transmitter according to an exemplary embodiment.

In the wireless power transmission system according to the present invention, after dividing a signal of a transmitter into two powers through a power divider, a phase shifter 1200 may be attached to only one side to control a phase difference between two transmitters.

The phase shifter 1200 for adjusting the phase difference has a low frequency band to be configured in a general manner using the length of the line, which makes it difficult to increase the size. Therefore, the structure shown in FIG. 12 may be used to solve this problem.

The wireless power transmitter according to the present invention may distribute the power supplied from the power source and amplify the power of the first phase distributed through the first amplifier. In addition, after adjusting the power of the first phase distributed through the phase shifter to the second phase, the second amplification unit amplifies the power of the second phase, the power of the amplified first phase and the power of the amplified second phase. May be controlled to be transmitted to the receiving side through different resonant coils.

As shown in FIG. 12, the phase shifter 1200 may use variable capacitors to adjust the power of the first phase to the second phase.

Specifically, the phase shifter 1200 is the reference numeral as shown in 1201, an inductor (L _0/2) and the first variable capacitor (2C _v1) being connected in series, the capacitor 2 is connected in parallel (C ₀₎ Capacitor 2C _v2 may be included.

In addition, the power of the first phase distributed using the first variable capacitor and the second variable capacitor may be phase adjusted to the second phase.

That is, the phase shifter 1200 is a phase shift device designed using a Lumped element to operate even at a low frequency. In addition, by connecting the variable capacitors in series and in parallel, it is a phase shifting device having a wider phase shift width through a method of simultaneously controlling a series connected inductor and a parallel connected capacitor.

The shifted phase and the power output from the power divider can be made of different power through two power amplifiers and then supplied to the transmitter.

For example, the size and phase of the two transmitters can be arbitrarily adjusted through this transmission scheme. The controller of the receiver checks the received power and adjusts the load resistance, passes the received power information through communication with the controller of the transmitter, and the controller of the transmitter controls the phase and the magnitude of power based on the information. have.

The wireless power transmitter according to the present invention may adjust the load resistance of the receiver.

Transmitting and Receiving Period For example, assuming that MCU (Micro Controller Unit) communication is performed, the alignment between the transmitters and receivers may be misaligned so that the efficiency may fall below a certain value. In this case, the phase difference can be changed and additionally, in this state, the receiver load resistance can be varied to find a state where the maximum efficiency is achieved.

The control unit according to an embodiment may request the receiving side to control the load resistance of the receiving side in consideration of the optimum load resistance to receive the maximum power. In this case, the receiving side may adjust the load resistance by controlling the inductor and the capacitor simultaneously using the variable capacitor, or adjust the load resistance through the selected matching circuit.

As another example, the controller may request to adjust the load resistance of the receiving side at regular intervals so as to visit the state of maximum efficiency.

As another example, the controller may adjust the load resistance of the receiver in consideration of both efficiency between the transmission and reception and a predetermined period.

According to one embodiment, the coupling coefficient between the transmitter and the receiver changes according to the attitude of the receiver (the angle between the receiver and the transmitter), and the distance between the transmitter and the receiver, which changes the optimum load resistance for receiving the maximum power. Therefore, in addition to controlling the phase difference and the magnitude of power between the transmissions, it is necessary to control the load resistance on the receiving side. Therefore, whenever the load resistance of the receiver is changed, the size and phase of the transmitter should be changed and the state of maximum efficiency should be found.

The load resistance on the receiving side can be realized by adjusting the input impedance through the LC matching circuit. For example, at the receiving side, as in the phase shifter, a method of simultaneously controlling the LC using a variable capacitor is possible. In addition, the receiving side may select and implement some matching circuits, and may also be implemented in a form of selecting a matching circuit through a switch.

FIG. 13 is a graph 1300 illustrating efficiency of controlling only the magnitude of the input voltage when the reception loop rotates, and FIG. 14 is a graph 1400 illustrating efficiency of controlling only the phase of the input voltage when the reception loop rotates.

As shown in FIGS. 13 and 14, it is possible to prevent the phenomenon of decreasing efficiency through the phase control of the input voltage, the current, or the power, and to keep it constant.

As a result, when using the phase shifter according to the present invention, it is possible to contribute to the related industry expansion by providing convenience to the user because it guarantees a high degree of freedom of the receiver as compared to the conventional magnetic resonance wireless power transmission system.

Through this, it can be used as a magnetic resonance type wireless power transmission system for charging smart phones, wearable devices, tablets, IoT sensors and the like. In detail, the present invention is expected to be commercialized in the field of charging a portable terminal in a limited space such as a magnetic resonance type wireless power transmission system and a vehicle interior, a coffee shop, and the like.

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 include, 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.

810: coil unit 815: power divider
820: first amplifier 830: second amplifier
840: phase shifter 850: control unit

Claims (12)

Monitor the environment in the three-dimensional space to transmit power through at least one of the wireless charging pad unit, the near field power transmitter, and the microwave power transmitter based on the monitoring result and the characteristics of the power receiver,
The wireless charging pad unit transmits power to the three-dimensional space by a magnetic induction method or a magnetic resonance method,
The near field power transmitter transmits power to the three-dimensional space in a self-resonant manner.
The microwave power transmitter transmits power to the three-dimensional space by a microwave power transfer method.
The wireless charging pad unit,
Drive control each of the plurality of small power transmission coil independently,
Generating a first control signal to apply a first driving voltage having a first phase to the driving target power transmission coils corresponding to the position where the charging target device is located among the plurality of small power transmission coils, A second control signal is generated to apply a second driving voltage having a phase different from the first phase to peripheral power transmission coils among the power transmission coils except for the driving target power transmission coil, and the first driving voltage and the Apply a second driving voltage to the wireless charging pad,
The near field power transmitter,
A power divider for distributing power supplied from the power source;
A first amplifier configured to amplify the distributed first phase power;
A phase shifter that adjusts the power of the distributed first phase to a second phase, and adjusts the power of the first phase to the second phase by using a first variable capacitor connected in series with the inductor and a second variable capacitor connected in parallel with the capacitor;
A second amplifier configured to amplify the power amplified in the second phase; And
Control unit for controlling to transmit the power of the amplified first phase and the power of the amplified second phase to the receiving side through a different resonant coil
Wireless power transmission device comprising a. The method of claim 1,
And a first amplifying unit and a second amplifying unit amplify the distributed power to different sizes. The method of claim 1,
The control unit,
And receiving received power information based on the received power and the load resistance from the receiving controller, and controlling a phase and a magnitude of power based on the received received power information. The method of claim 1,
The phase shifter,
And adjusting the power of the distributed first phase to a second phase, wherein the second phase is adjusted between 0 degrees and 360 degrees. The method of claim 1,
The control unit,
Requesting the receiver to control the load resistance of the receiver in consideration of the optimum load resistance to receive the maximum power,
On the receiving side,
A wireless power transmission device using a variable capacitor to control the inductor and the capacitor at the same time to adjust the load resistance, or through the selected matching circuit to adjust the load resistance. delete delete delete delete The method of claim 1,
The wireless charging pad unit,
A wireless charging pad disposed in a plurality of small power transmission coil structures;
A scanning control unit scanning the wireless charging pad to detect a device to be charged on the wireless charging pad;
Identifying the driving target power transmission coils positioned below the charging target device among the plurality of small power transmission coils, and identifying the peripheral power transmission coils surrounding the driving target power transmission coils among the plurality of small power transmission coils. Coil determination unit; And
A first control signal is generated to apply a first driving voltage having a first phase to the driving target power transmission coils, and a second driving voltage having a phase different from the first phase is applied to the peripheral power transmission coils. A driving control unit generating a second control signal
Wireless power transmission device comprising a. The method of claim 1,
The microwave power transmitter,
Comprising an array antenna unit including a plurality of antenna elements (element1, element2, ... elementN), the average (R _mean ) of the distance between the plurality of antenna elements and the receiving antenna is calculated by the following equation, To calculate the power transmission efficiency based on R _mean ,
[Equation]

Where R ₁ , R ₂ ,... R _N is the distance between the receiving antenna and each antenna element,
Wireless power transmission device. The method of claim 1,
The microwave power transmitter,
Using an array antenna to control multiple beam formation,
And calculating an electric field pattern of the array antenna by multiplying an array factor by the inverse of the radiation pattern and multiplying the array factor by the inverse of the radiation pattern.

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