KR101587546B1 - Wireless Power Transmission Apparatus and Method - Google Patents

Abstract

A wireless power transmission apparatus and a method thereof are provided. According to an aspect, a wireless power transmission apparatus may alternately transmit wireless power using a time division scheme to a first target receiver and a second target receiver.

Description

TECHNICAL FIELD [0001] The present invention relates to a wireless power transmission apparatus,

The present invention relates to a wireless power transmission apparatus and method thereof, and more particularly, to a wireless power transmission apparatus and method for transmitting wireless power to a plurality of target receivers using a time division method.

Due to the characteristics of portable electronic products, battery performance is becoming an important issue. Generally, a portable electronic device receives power using a power line. On the other hand, when Wireless Power Transmission is applied to portable electronic products, portable electronic products can be powered without power lines while on the move. A transmitter that transmits wireless power may provide wireless power to portable electronic products that are allowed to receive wireless power. However, if there are a plurality of portable electronic devices around the transmitter, the transmitter must simultaneously set a plurality of matching parameters to transmit the wireless power.

In one aspect, there is provided a wireless communication system comprising: a source portion for transmitting wireless power to a first target receiver; And receiving a request for transmission of the radio power from a second target receiver transmitting radio power to the first target receiver, wherein the first target receiver and the second target receiver use the resonant frequency and time- And a control unit for controlling the source unit to transmit the wireless power to the target receiver.

A measurement unit measuring a frequency-dependent transmission efficiency of the second target receiver ; And the control unit may determine the time division scheme for alternately transmitting the radio power to the first target receiver and the second target receiver based on the measured transmission efficiency.

The control unit may determine the resonant frequency required to transmit the wireless power to the second target receiver based on the measured transmission efficiency.

And a communication unit for receiving from the second target receiver information on a transmission capacity and a charging speed of the radio power requested by the second target receiver, And determine the resonant frequency required to transmit the wireless power to the second target receiver based on the measured transmission efficiency.

Wherein the control unit further comprises a measurement unit for measuring a transmission efficiency with respect to a value of a matching matching parameter when the resonance frequency and the time division scheme are determined and based on the measured transmission efficiency, The value of the optimal matching parameter for transmitting the power can be determined.

Wherein the control unit alternately changes values of optimal matching parameters of the first target receiver and the second target receiver to transmit the radio power when the first target receiver and the second target receiver have the same resonance frequency The source unit can be controlled.

According to another aspect, there is provided a method comprising: transmitting wireless power to a first target receiver; Receiving a request for transmission of the wireless power from a second target receiver transmitting wireless power to the first target receiver; And transmitting the wireless power to the first target receiver and the second target receiver using the resonant frequency and time-sharing scheme of the second target receiver.

Measuring a transmission efficiency for each frequency of the second target receiver; And determining the time division scheme for alternately transmitting the radio power to the first target receiver and the second target receiver based on the measured transmission efficiency.

And determining the resonant frequency required to transmit the wireless power to the second target receiver based on the measured transmission efficiency.

Receiving information on a transmission capacity and a charging rate of the wireless power requested by the second target receiver from the second target receiver; And determining the resonant frequency required to transmit the radio power to the second target receiver based on the time-divisional scheme and the second target receiver, based on the charging rate requested by the second target receiver and the measured transmission efficiency .

Measuring transmission efficiency with respect to a value of a matching matching parameter when the resonance frequency and the time division method are determined; And determining a value of an optimal matching parameter for transmitting the radio power to the second target receiver based on the measured transmission efficiency.

Wherein the transmitting step alternately changes the value of an optimal matching parameter between the first target receiver and the second target receiver so that the wireless power is changed when the first target receiver and the second target receiver have the same resonance frequency Lt; / RTI >

If the time division scheme is not used, the WP transmitter may set the frequency at which the result of adding the transmission efficiencies of the first target receiver and the second target receiver becomes the maximum to the resonant frequencies of the first target receiver and the second target receiver .

Alternatively, when the time division scheme is not used, the WP transmitter calculates the transmission rate of the second target receiver based on the charging rate requested by the first target receiver, the charging rate requested by the second target receiver, 1 < / RTI > target receiver and the second target receiver.

According to the wireless power transmission apparatus and method thereof, the wireless power transmission apparatus can alternately transmit wireless power using a time division scheme to a plurality of target receivers. This allows wireless power to be efficiently transmitted without performing frequency synchronization and impedance matching with a plurality of target receivers at the same time.

1 shows a wireless power transmission system according to an exemplary embodiment.
2 illustrates a meta-structured resonator according to one embodiment.
3 is a view showing an equivalent circuit of the resonator shown in Fig.
FIG. 4 illustrates a meta-structured resonator according to another embodiment.
5 is a view showing in detail the insertion position of the capacitor of FIG.
6 is a diagram illustrating a system for wireless power transmission and reception according to an example.
7 is a block diagram illustrating an example of a WP transmitter shown in FIG.
8 is a graph showing a relationship between transmission efficiency and frequency.
9 is a diagram showing a resonance frequency and a transmission efficiency that vary according to a time division method.
10 is a graph showing the relationship between the transmission efficiency and the matching parameter.
11 is a flowchart for explaining an example of a wireless power transmission method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, a wireless power transmission technique used in a wireless power transmission system will be described. Wireless power transmission technology can be classified into three types, electromagnetic induction type, radio reception type, and resonance type of electric field or magnetic field.

First, in the electromagnetic induction method, a magnetic flux is generated when alternating current flows in one coil after approaching two different coils close to each other, and an electromotive force is generated in one of the other coils. In the electromagnetic induction method, the efficiency of electric power utilization is about 60% to 98%, and the most efficient and practical use is proceeding the most.

Second, the radio wave reception method uses electric wave energy received by an antenna and converts the AC wave into a direct current through a rectifying circuit to obtain electric power. The radio reception system is capable of wireless power transmission over the longest distance (several meters or more).

Third, the resonance method uses resonance of electric field or magnetic field and resonates at the same frequency between devices to transmit energy. When the resonance of a magnetic field is used, a magnetic resonance coupling using an LC resonator structure is used to generate electric power. The magnetic field resonance method is a technique that utilizes a near field effect of a short distance compared to the wavelength of the used frequency. It is a non-radiative energy transmission unlike the radio wave receiving method. The resonance frequency of the transmitting / Lt; / RTI > The power transmission efficiency is increased to about 50 ~ 60% by the magnetic field resonance method, and this efficiency is considerably higher than the propagation type through the radio wave radiation. The distance between the transmitter and the receiver is about several meters. Although the technique is used in close proximity rather than the radio reception method, it is possible to transmit power even at a very long distance than the electromagnetic induction method within a few millimeters.

1 shows a wireless power transmission system according to an exemplary embodiment.

In the example of FIG. 1, it is assumed that the wireless power transmitted through the wireless power transmission system is a resonance power.

Referring to FIG. 1, a wireless power transmission system is a source-target structure consisting of a source and a target. That is, the wireless power transmission system includes a resonant power transmission device 110 corresponding to a source and a resonant power receiving device 120 corresponding to a target.

The resonant power transmission device 110 includes a source portion 111 and a source resonator 115 that receive energy from an external voltage supply to generate resonant power. The resonant power transmission apparatus 110 may further include a matching controller 113 for performing a resonant frequency or impedance matching.

The source portion 111 receives energy from an external voltage supply to generate resonance power. An AC-AC converter for adjusting a signal level of an AC signal input from an external device to a desired level, an AC-AC converter for outputting a DC voltage of a certain level by rectifying an AC signal output from the AC- DC converter that generates AC signals of several MHz to several tens MHz by switching the DC voltage output from the DC-DC converter and the AC-DC converter at high speed.

The matching controller 113 sets the resonance bandwidth of the source resonator 115 or the impedance matching frequency of the source resonator 115. The matching control 113 includes at least one of a source resonance bandwidth setting unit (not shown) or a source matching frequency setting unit (not shown). The source resonance bandwidth setting unit sets a resonance bandwidth of the source resonator 115. The source matching frequency setting unit sets the impedance matching frequency of the source resonator 115. At this time, the Q-factor of the source resonator 115 can be determined according to the resonance bandwidth of the source resonator or the impedance matching frequency setting of the source resonator.

The source resonator 115 transfers the electromagnetic energy to the target resonator. That is, the source resonator 115 transmits the resonant power to the target device 120 through the magnetic coupling 41 with the target resonator 121. At this time, the source resonator 115 resonates within the set resonance bandwidth.

The resonance power receiving apparatus 120 includes a target resonator 121, a matching control unit 123 for performing resonance frequency or impedance matching, and a target unit 125 for transmitting the received resonance power to a load.

The target resonator 121 receives electromagnetic energy from the source resonator 115. At this time, the target resonator 121 resonates within the set resonance bandwidth.

The matching control unit 123 sets at least one of a resonance bandwidth of the target resonator 121 and an impedance matching frequency of the target resonator 121. The matching control unit 123 includes at least one of a target resonant bandwidth setting unit (not shown) or a target matching frequency setting unit (not shown). The target resonant bandwidth setting unit sets the resonant bandwidth of the target resonator 121. [ The target matching frequency setting unit sets the impedance matching frequency of the target resonator 121. At this time, the Q-factor of the target resonator 121 can be determined according to the resonance bandwidth of the target resonator 121 or the impedance matching frequency setting of the target resonator 121.

The target portion 125 delivers the received resonance power to the load. At this time, the target portion 125 includes an AC-DC converter for rectifying the AC signal received from the source resonator 115 to the target resonator 121 to generate a DC signal, and a DC-DC converter for supplying the DC voltage to a device or a load.

The source resonator 115 and the target resonator 121 may be composed of a resonator of a helix coil structure or a resonator of a spiral coil structure, or a meta-structured resonator.

1, the process of controlling the cue-effector includes setting the resonance bandwidth of the source resonator 115 and the resonant bandwidth of the target resonator 121 and setting the resonant bandwidth of the source resonator 115 and the target resonator 121, And transferring electromagnetic energy from the source resonator 115 to the target resonator 121 through a magnetic coupling between the source resonator 115 and the target resonator 121. At this time, the resonant bandwidth of the source resonator 115 may be set to be wider or narrower than the resonant bandwidth of the target resonator 121. That is, since the resonant bandwidth of the source resonator 115 is set to be wider or narrower than the resonant bandwidth of the target resonator 121, the unbalance relation between the BW-factor of the source resonator and the BW-factor of the target resonator is maintained .

In resonant wireless power transmission, resonant bandwidth is an important factor. Qt is a Q-factor that takes into consideration both a change in distance between the source resonator 115 and the target resonator 121, a change in resonance impedance, impedance mismatching, and a reflection signal, Qt is Qt, Inverse relationship.

[Equation 1]

는 대역폭,

는 공진기 사이의 반사 손실, BW_S는 소스 공진기(115)의 공진 대역폭, BW_D는 타겟 공진기(121)의 공진 대역폭을 나타낸다. 본 명세서에서 BW-factor는 1/ BW_S 또는 1/BW_D를 의미한다.In Equation (1), f ₀ is the center frequency,

Bandwidth,

BW _S is the resonant bandwidth of the source resonator 115, and BW _D is the resonant bandwidth of the target resonator 121. [ In this specification, the BW-factor means 1 / BW _S or 1 / BW _D.

On the other hand, impedance mismatching occurs between the source resonator 115 and the target resonator 121 due to external influences such as a difference between the distance between the source resonator 115 and the target resonator 121, . Impedance mismatching can be a direct cause of reducing the efficiency of power transfer. The matching controller 113 determines that impedance mismatching has occurred by detecting a reflected wave that is reflected by a part of the transmission signal and performs impedance matching. In addition, the matching controller 113 can change the resonance frequency by detecting the resonance point through waveform analysis of the reflected wave. Here, the matching controller 113 can determine the resonance frequency as the frequency with the minimum amplitude in the waveform of the reflected wave.

2 illustrates a meta-structured resonator according to one embodiment.

Referring to FIG. 2, the meta-structured resonator includes a transmission line 210 and a capacitor 220. Here, the capacitor 220 is inserted in series at a specific position of the transmission line 210, and the electric field is confined in the capacitor.

Also, as shown in FIG. 2, the meta-structured resonator has a three-dimensional structure. 2, the resonator can be implemented in a two-dimensional structure in which the transmission line is disposed in the x, z plane.

The capacitor 220 is inserted into the transmission line 210 in the form of a lumped element and a distributed element such as an interdigital capacitor or a gap capacitor centered on a substrate having a high dielectric constant. 220 are inserted into the transmission line 210, the resonator may have a metamaterial characteristic.

Here, a metamaterial is a material having a special electrical property that can not be found in nature, and has an artificially designed structure. The electromagnetic properties of all materials present in nature have inherent permittivity or permeability, and most materials have a positive permittivity and a positive permeability. In most materials, the right-hand rule applies to electric fields, magnetic fields and pointing vectors, so these materials are called RHM (Right Handed Material). However, the meta-material is a material having a permittivity or permeability of less than 1, and may be an epsilon-negative (ENG) material, a mu negative material, a double negative material, a negative refractive index (NRI) Materials, and left-handed (LH) materials.

At this time, when the capacitance of the capacitor inserted as a lumped element is appropriately determined, the resonator can have the property of the metamaterial. In particular, by properly adjusting the capacitance of the capacitor, the resonator can have a negative magnetic permeability, so that the resonator according to an embodiment of the present invention can be referred to as an MNG resonator.

The MNG resonator may have a zeroth-order resonance characteristic with a resonance frequency at a frequency when the propagation constant is zero. Since the MNG resonator may have a zero resonance characteristic, the resonance frequency may be independent of the physical size of the MNG resonator. That is, as will be described later, it is sufficient to appropriately design a capacitor in order to change the resonance frequency in the MNG resonator, so that the physical size of the MNG resonator can be changed.

Also, since the electric field in the near field is concentrated in the series capacitor 220 inserted in the transmission line 210, the magnetic field is dominant in the near field due to the series capacitor 220.

In addition, since the MNG resonator can have a high Q-factor by using the capacitor 220 to the lumped element, the efficiency of power transmission can be improved.

In addition, the MNG resonator may include a matching unit 230 for impedance matching. At this time, the matching unit 230 can appropriately adjust the intensity of the magnetic field for coupling with the MNG resonator, and the impedance of the MNG resonator is adjusted by the matching unit 230. Then, the current flows into the MNG resonator through the connector 240 or out of the MNG resonator.

Further, although not explicitly shown in Fig. 2, a magnetic core passing through the MNG resonator may be further included. Such a magnetic core can perform a function of increasing a power transmission distance.

The characteristics of the MNG resonator of the present invention are described in detail below.

3 is a view showing an equivalent circuit of the resonator shown in Fig.

The resonator shown in Fig. 2 can be modeled by the equivalent circuit shown in Fig. In the equivalent circuit of Fig. 3, C _L represents a capacitor inserted in the form of a lumped element in the middle of the transmission line of Fig.

를 공진 주파수로 갖는다고 가정한다. 이 때, 공진 주파수

는 하기 수학식 1과 같이 표현될 수 있다. 여기서, MZR은 Mu Zero Resonator를 의미한다.At this time, the resonator for the radio power transmission shown in Fig. 2 has the zero-th resonance characteristic. That is, when the propagation constant is zero, the resonator for wireless power transmission

Is assumed to have a resonant frequency. At this time,

Can be expressed by the following equation (1). Here, MZR means Mu Zero Resonator.

는

에 의해 결정될 수 있고, 공진 주파수

와 공진기의 물리적인 사이즈는 서로 독립적일 수 있음을 알 수 있다. 따라서, 공진 주파수

와 공진기의 물리적인 사이즈가 서로 독립적이므로, 공진기의 물리적인 사이즈는 충분히 작아질 수 있다.Referring to Equation 1, the resonance frequency of the resonator

The

And the resonance frequency < RTI ID = 0.0 >

And the physical size of the resonator can be independent of each other. Therefore,

And the physical size of the resonator are independent of each other, the physical size of the resonator can be sufficiently small.

4 is a diagram illustrating a meta-structured resonator according to another embodiment.

Referring to FIG. 4, the meta-structured resonator includes a transmission line portion 410 and a capacitor 420. In addition, the resonator according to an embodiment of the present invention may further include a feeding unit 430.

In the transmission line unit 410, a plurality of transmission line sheets are arranged in parallel. A configuration in which a plurality of transmission line sheets are arranged in parallel will be described in more detail with reference to FIG.

The capacitor 420 is inserted at a specific position of the transmission line portion 410. At this time, the capacitor 420 may be inserted in series to the interruption of the transmission line unit 410. At this time, the electric field generated in the resonator is confined in the capacitor 420.

The capacitor 420 may be inserted into the transmission line portion 410 in the form of a lumped element and a distributed element such as an interdigital capacitor or a gap capacitor centered on a substrate having a high dielectric constant As the capacitor 420 is inserted into the transmission line portion 410, the resonator may have the characteristics of a metamaterial.

The feeding unit 430 may perform a function of feeding a current to the MNG resonator. At this time, the feeder 430 can be designed to evenly distribute the current supplied to the resonator to a plurality of transmission line sheets.

5 is a view showing in detail the insertion position of the capacitor 420 of FIG.

Referring to FIG. 5, the capacitor 420 is inserted into the intermediate portion of the transmission line portion 410. At this time, the intermediate portion of the transmission line unit 410 may be opened so that the capacitor 420 can be inserted, and each of the transmission line sheets 410-1, 410-2, and 410-n And can be configured in parallel with each other at the stop.

6 is a diagram illustrating a system for wireless power transmission and reception according to an example.

Referring to FIG. 6, a system for wireless power transmission / reception includes a wireless power (WP) transmitter 600, a first target receiver 700, and a second target receiver 800.

The WP transmitter 600, the first target receiver 700 and the second target receiver 800 may be used in the wireless power transmission system described with reference to FIG. For example, the resonant power transmission device 110 of FIG. 1 is a source portion 610 of a WP transmitter 600, and the resonant power receiving device 120 of FIG. 1 includes a first target receiver 700 or a second target Receiver 800. < / RTI > The first target receiver 700 and the second target receiver 800 are all devices capable of wireless power charging.

The WP transmitter 600 generates wireless power over the resonant frequency using the wireless power transmission technique described with reference to Figs. 1-5. In addition, the WP transmitter 600 may transmit wireless power to a plurality of target receivers simultaneously or in a time-division manner.

The first target receiver 700 receives wireless power from the WP transmitter 600 to immediately use the power or charge the battery.

FIG. 7 is a block diagram illustrating an example of a WP transmitter 600 shown in FIG.

7, the WP transmitter 600 includes a source unit 610, a communication unit 620, a measurement unit 630, a control unit 640, and a storage unit 650.

The source unit 610 synchronizes the resonance frequency with the first target receiver 700 using the mutually defined frequency, and performs impedance matching. The resonance frequency synchronized with the first target receiver 700 is referred to as a first resonance frequency f ₁ . The source unit 610 transmits the wireless power to the first target receiver 700. [ The source portion 610 may be the resonant power transmission device 110 of FIG. Therefore, detailed description of the source portion 610 is omitted.

The communication unit 620 can perform wire / wireless communication with the first target receiver 700 or the second target receiver 800. [ The communication unit 620 receives from the first target receiver 700 information on the transmission capacity and charging rate of the radio power required by the first target receiver 700. [

In addition, the communication unit 620 may receive a message requesting transmission of radio power from the second target receiver 800. [ The message includes information on the transmission capacity and charging speed of the radio power required by the second target receiver 800. [ The transmission capacity refers to the total capacity of the radio power required by the second target receiver 800, that is, energy. Examples of units of transmission capacity include mWh, mAh, and the like. The charging rate refers to the instantaneous transmission capacity of the wireless power, that is, the power, in units of mW and mA.

The measurement unit 630 measures the transmission efficiency of the first target receiver 700 or the second target receiver 800 by frequency. The measuring unit 630 measures the transmission efficiency of the value of the matching parameter of the first target receiver 700 or the second target receiver 800. [ The measured transmission efficiency is the transmission efficiency of the wireless power.

The control unit 640 receives the request for transmission of the radio power from the second target receiver 800 while transmitting the radio power to the first target receiver 700. The control unit 640 uses the resonant frequency of the second target receiver 800 and the time- And controls the source unit 610 to transmit the wireless power to the first target receiver 700 and the second target receiver 800. [

In order to determine the most efficient frequency when transmitting the radio power to the second target receiver 800, the controller 640 controls the first target receiver 800 to transmit the radio power to the second target receiver 800 while changing the frequency. (610). The control unit 640 controls the measurement unit 630 to measure the transmission efficiency for each changed frequency. The frequency-dependent transmission efficiency of the first target receiver 700 may be measured and stored in the storage unit 650 or may be newly measured in the measurement unit 630.

8 is a graph showing a relationship between transmission efficiency and frequency. Referring to FIG. 8, e ₁ (f) is the transmission efficiency of the first target receiver 700, e ₂ (f) is the transmission efficiency of the second target receiver 800, and f is the frequency. f ₂ may be a frequency determined by the second resonance frequency. The second resonant frequency is the optimal frequency needed to transmit the wireless power to the second target receiver 800. [

The control unit 640 controls the time division method and the second resonance frequency for alternately transmitting the radio power to the first target receiver 700 and the second target receiver 800 based on the measured transmission efficiency, You can choose one.

The controller 640 can calculate the time-division method and the second resonance frequency using Equation (2).

_{However, t 1 + t 2 = 1} , 0≤t 1, 0≤t 2

Referring to Equation (2), WP _MAX is the maximum value of e ₁ (f ₁ ) · t ₁ + e ₂ (f 2) · t ₂ ', f 1 is the first resonant frequency, . ≪ / RTI > f2 is the frequency assigned to the second target receiver 800 at the second resonant frequency. t ₁ and t ₂ are times assigned to the first target receiver 700 and the second target receiver 800, respectively, by time sharing. Controller 640 calculates or determines the f1, f2, t1 and t2 that _{'e 1 (f1) · t} 1 + e 2 (f2) · t 2' to have a maximum value. t ₁ and t ₂ may be a switching period for alternately transmitting wireless power in the first target receiver 700 and the second target receiver 800. Switching cycle, so by the overhead may degrade the transmission efficiency of the wireless power, the controller 640 by considering the overhead due to the switching of the resonant frequency to determine the f1, f2, t ₁ and t _2. At this time, the value f1 may be used as it is for the energy transmission with the first target receiver 700. [

Alternatively, the control unit 640 may determine the charging rate requested by the first target receiver 700, the charging rate requested by the second target receiver 800, and the transmission efficiency of the measured second target receiver 800, The first resonance frequency, and the second resonance frequency. This expression is expressed by Equation (3).

_{However, t 1 + t 2 = 1} , 0≤t 1, 0≤t 2

Referring to Equation (3), WP _MAX is the maximum value of 's _{1 ·} e ₁ (f ₁ ) · t ₁ + s _{2 ·} e ₂ (f 2) · t ₂ ', f 1 is the first resonance frequency, 1 < / RTI > f2 is the frequency assigned to the second target receiver 800 at the second resonant frequency. t ₁ and t ₂ are times assigned to the first target receiver 700 and the second target receiver 800, respectively, by time sharing. S ₁ is the charging rate required by the first target receiver 700 and s ₂ is the charging rate requested by the second target receiver 800.

Controller 640 calculates or determines the _{'s 1 · e 1 (f1} ) · t 1 + s 2 · e 2 (f2) · t 2' is f1 to have a maximum value, f2, t ₁ and t ₂ . The control unit 640 as described with reference to Equation (2), by considering the overhead due to the switching of the resonant frequency to determine the f1, f2, t ₁ and t _2. If the first target receiver 700 and the second target receiver 800 allocate the delay constraints T1 and T2, respectively, the charging rate s _i of Equation (3) = the transmission requested by the ith target receiver Capacity / Ti, (i = 1, 2).

Meanwhile, the controller 640 may determine the time division scheme considering at least one of the transmission capacity required by the second target receiver 800, the latency of the battery, and the quality of the service provided by the second target receiver 800 have. The latency of the battery means the time it takes for the battery to drain. For example, if the battery remaining amount of the first target receiver 700 is 20%, the latency is 1 hour, the remaining amount of the battery of the second target receiver 800 is 10%, and the latency is 10 minutes, 2 < / RTI > target receiver 800 at a time t2.

When the time division method and the second resonance frequency are determined by the above-described [Expression 2] or [Expression 3], the controller 640 controls the measuring unit 630 to measure the transmission efficiency while varying the value of the matching parameter do. Thereby determining the highest efficiency matching value with the first target receiver 700 and the second target receiver 800, respectively. The matching with the determined ith target receiver (i = 1, 2) is m _i (i = 1, 2). In this case, m ₁ may use the matching value previously used for transmission with the first target receiver 700.

Accordingly, the control unit 640 determines the resonant frequency and the time-sharing method necessary for transmitting the radio power to the second target receiver 800. [

The communication unit 620 transmits the first resonance frequency, the second resonance frequency, the time-sharing method, and the impedance matching information obtained by the above-described process to the first target receiver 700 and the second target receiver 800, respectively. The time division scheme includes information on the time to transmit the radio power to the first target receiver 700 and the second target receiver 800. [ The first resonance frequency, the second resonance frequency, and the impedance matching information are information necessary for transmission and reception of radio power.

More specifically, the first resonant frequency and the second resonant frequency are resonant frequencies used for frequency synchronization between the WP transmitter 600 and the second target receiver 800. [ The impedance matching information is a parameter value required for impedance matching between the WP transmitter 600 and the second target receiver 800. Since the impedance matching has been described with reference to FIG. 1, a detailed description thereof will be omitted.

The source unit 610 synchronizes the resonant frequency with the second target receiver 800 using the second resonant frequency and the impedance matching information, and performs impedance matching. Then, the source unit 610 transmits the radio power to the second target receiver 800.

The storage unit 650 stores the information about the resonant frequency formed between the first target receiver 700 and the WP transmitter 600 and the first impedance matching information. In addition, the storage unit 650 stores the first resonance frequency determined by Equation (2) or (3), and the second resonance frequency stores the time division system and the impedance matching information.

9 is a diagram showing a resonance frequency and a transmission efficiency that vary according to a time division method.

Referring to FIG. 9, the source unit 610 changes the resonance frequency according to the determined time division scheme to transmit the radio power to the first target receiver 700 or the second target receiver 800. [ For example, the source unit 610 transmits the wireless power to the first target receiver 700 using the first resonant frequency f ₁ for the set time t ₁ . When the set time t ₁ elapses, the source unit 610 transmits the radio power to the second target receiver 800 using the second resonant frequency f ₂ . Thus, the transmission efficiency of the first target receiver 700 is higher than the transmission efficiency of the second target receiver 800 during the time t ₁ . At this time, the transmission efficiency of the second target receiver 800 may have a value of zero or more. The transmission efficiency of the second target receiver 800 is higher than the transmission efficiency of the first target receiver 700 during the time t ₂ by the time division method.

According to another embodiment of the present invention, the control unit 640 may calculate the common resonance frequency f used together in the first target receiver 700 and the second target receiver 800 using Equation (4) have. When the common resonance frequency is calculated, the controller 640 may not use the time division method.

Referring to Equation 4], WP _MAX is the transmission of _{'e 1 (f) + e} 2 (f)' a maximum value of, f is the common resonance frequency, e ₁ (f) is the first target receiver 700 The efficiency e ₂ (f) is the transmission efficiency of the second target receiver 800. The control unit 640 calculates or determines f such that 'e ₁ (f) · t ₁ + e ₂ (f) · t ₂ ' has the maximum value when the time division scheme is not used. In this case, because there is no alternate transmission, the transmission efficiency may be higher than when the two target receivers 700 and 800 alternately use radio power.

Alternatively, the control unit 640 may determine the charging rate requested by the first target receiver 700, the charging rate requested by the second target receiver 800, and the transmission efficiency of the measured second target receiver 800, , A time division method or a common resonance frequency can be determined. This expression is expressed by Equation (5).

Referring to Equation (5), WP _MAX is a maximum value of s _{1 ·} e ₁ (f) + s _{2 ·} e ₂ (f), and f is a common resonance frequency. S ₁ is the charging rate required by the first target receiver 700 and s ₂ is the charging rate requested by the second target receiver 800.

The control unit 640 calculates or determines f such that 's ₁ · e ₁ (f) + s ₂ · e ₂ (f)' has the maximum value. The control unit 640 determines f by considering the overhead due to the switching of the resonance frequency, as described with reference to Equation (5). The determined f may be used as the first resonance frequency and the second resonance frequency. If the first target receiver 700 and the second target receiver 800 allocate the delay constraints T1 and T2, respectively, the charging rate s _i of Equation (3) = the transmission requested by the ith target receiver Capacity / T _i , (i = 1, 2).

Meanwhile, the controller 640 may determine the time division scheme considering at least one of the transmission capacity required by the second target receiver 800, the latency of the battery, and the quality of the service provided by the second target receiver 800 have. The latency of the battery means the time it takes for the battery to drain. For example, if the battery remaining amount of the first target receiver 700 is 20%, the latency is 1 hour, the remaining amount of the battery of the second target receiver 800 is 10%, and the latency is 10 minutes, 2 < / RTI > target receiver 800 at a time t2.

When the resonance frequency is determined by the above-described [Equation 4] or [Equation 5], the controller 640 controls the measuring unit 630 to measure the transmission efficiency while varying the value of the matching parameter. The matching parameters used are parameters for impedance matching and can be real and imaginary.

10 is a graph showing the relationship between the transmission efficiency and the matching parameter.

Referring to FIG. 10, the real number and the imaginary number are the impedance matching parameter (m). e ₁ (m) is the transmission efficiency of the first target receiver 700, e ₂ (m) is the transmission efficiency of the second target receiver 800, and f is the frequency. e ₁ (m) and e ₂ (m) are transmission efficiencies calculated by using the resonance frequency determined by one of the equations (2) to (5) as a fixed value and changing the value of the matching parameter. The center of each transmission efficiency (e ₁ (m), e ₂ (m)) indicated by a circle has the highest transmission efficiency.

The impedance matching information indicates the value of the best matching parameter required to transmit the radio power to the first target receiver 700 and the second target receiver 800. [ The impedance matching information and the value of the optimum matching parameter are the same, and are mixed in consideration of the convenience of explanation below.

The controller 640 may determine a value of an optimal matching parameter for transmitting wireless power to the second target receiver 800 based on the measured transmission efficiency of the wireless power. This expression is expressed by Equation (6).

F in the equation (6) has a value determined by the equation (4) or (5). WP _MAX is the maximum value of 'e ₁ (m) + e ₂ (m)', and m is a matching parameter expressed as a real number and an imaginary number. The control unit 640 calculates or determines the value of the optimal matching parameter such that 'e ₁ (m) + e ₂ (m)' has the maximum value.

In this way, the control unit 640 determines the resonant frequency required to transmit the radio power to the second target receiver 800.

The communication unit 620 transmits the resonance frequency and impedance matching information obtained by the above-described process to the first target receiver 700 and the second target receiver 800. [ The time division scheme includes information on the time to transmit the radio power to the first target receiver 700 and the second target receiver 800. [ The resonance frequency and impedance matching information are information necessary for transmission and reception of wireless power.

More specifically, the resonant frequency is a resonant frequency used for frequency synchronization between the WP transmitter 600 and the first target receiver 700 and the second target receiver 800. The impedance matching information is a value of a parameter required for impedance matching between the WP transmitter 600 and the first target receiver 700 and the second target receiver 800. Since the impedance matching has been described with reference to FIG. 1, a detailed description thereof will be omitted.

The source unit 610 synchronizes the resonance frequency with the first target receiver 700 and the second target receiver 800 and performs impedance matching using the resonance frequency and the impedance matching information. Then, the source unit 610 transmits the radio power to the first target receiver 700 and the second target receiver 800. [

11 is a flowchart for explaining an example of a wireless power transmission method.

The wireless power transmission method of FIG. 11 may be operated by the WP transmitter 600, the first target receiver 700, and the second target receiver 800 described with reference to FIGS.

In step 1110, the WP transmitter transmits wireless power to the first target receiver.

In step 1120, while transmitting the wireless power to the first target receiver, the WP transmitter receives a message requesting transmission of the wireless power from the second target receiver. The received message includes information on the transmission capacity and the charging rate required by the second target receiver.

In step 1130, the WP transmitter transmits the radio power to the second target receiver while changing the frequency, and measures the transmission efficiency of the transmitted radio power for each frequency.

In step 1140, the WP transmitter determines at least one of a time division scheme and a second resonant frequency for alternately transmitting wireless power to the first target receiver and the second target receiver, based on the measured transmission efficiency. The WP transmitter can determine at least one of the time-division mode and the second resonance frequency using [Equation 2] or [Equation 3].

When the time division manner and the second resonant frequency are determined, in step 1150, the WP transmitter measures the transmission efficiency while varying the value of the matching parameter. The matching parameters used are parameters for impedance matching, including real and imaginary numbers.

In step 1160, the WP transmitter may determine a value of an optimal matching parameter for transmitting wireless power to a second target receiver based on the measured transmission efficiency of the wireless power.

In step 1170, the WP transmitter transmits the values of the determined second resonant frequency, time-sharing scheme, and optimal matching parameter to the second target receiver, and performs synchronization and impedance matching of the second resonant frequency.

In step 1180, the WP transmitter alternately transmits wireless power to the first target receiver and the second target receiver in a time division manner. For example, the WP transmitter transmits wireless power to a first target receiver for a time tl using a first resonant frequency, a time-sharing scheme, and first impedance matching information. The WP transmitter then transmits the wireless power to the second target receiver for a time t2 using the second resonant frequency, the time-sharing scheme, and the second impedance matching information.

In step 1180, if the first and second resonant frequencies are the same, the WP transmitter alternately changes the value of the optimal matching parameter to transmit the radio power alternately to the first target receiver and the second target receiver do.

On the other hand, when the time division scheme is not used, the WP transmitter sets the frequency at which the result obtained by adding the transmission efficiencies of the first target receiver and the second target receiver becomes the maximum to the resonant frequencies of the first target receiver and the second target receiver .

Alternatively, when the time division scheme is not used, the WP transmitter calculates the transmission rate of the second target receiver based on the charging rate requested by the first target receiver, the charging rate requested by the second target receiver, 1 < / RTI > target receiver and the second target receiver.

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

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

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

110: resonance power transmission device 120: resonance power reception device
600: WP transmitter 700: first target receiver
800: second target receiver

Claims (17)

A source portion for transmitting wireless power to a first target receiver; And
Wherein when receiving the request for transmission of the radio power from a second target receiver transmitting radio power to the first target receiver, the first target receiver and the second target, using the resonant frequency and time- And a control unit for controlling the source unit to transmit the radio power to the receiver
And a wireless power transmission device. The method according to claim 1,
A measurement unit measuring a frequency-dependent transmission efficiency of the second target receiver;
Further comprising:
Wherein the control unit determines the time division manner for alternately transmitting the radio power to the first target receiver and the second target receiver based on the measured transmission efficiency. 3. The method of claim 2,
Wherein the control unit determines the resonant frequency required to transmit the radio power to the second target receiver based on the measured transmission efficiency. 3. The method of claim 2,
A communication unit for receiving from the second target receiver information on a transmission capacity and a charging speed of the wireless power requested by the second target receiver;
Further comprising:
Wherein the control unit determines the resonant frequency required to transmit the radio power to the second target receiver based on the charging rate requested by the second target receiver and the measured transmission efficiency, Device. The method according to claim 1,
When the resonance frequency and the time division scheme are determined, the measurement unit measures transmission efficiency of the value of the matching matching parameter.
Further comprising:
Wherein the control unit determines a value of an optimal matching parameter for transmitting the radio power to the second target receiver based on the measured transmission efficiency. 6. The method of claim 5,
Wherein the control unit alternately changes values of optimal matching parameters of the first target receiver and the second target receiver to transmit the radio power when the first target receiver and the second target receiver have the same resonance frequency And controls the source unit. 3. The method of claim 2,
The control unit sets a frequency at which the result obtained by adding the transmission efficiencies of the first target receiver and the second target receiver becomes the maximum is transmitted to the first target receiver and the second target receiver, Wherein the resonant frequency is defined as a resonant frequency. 3. The method of claim 2,
If the time division scheme is not used, the control unit calculates the charging rate requested by the first target receiver, the charging rate requested by the second target receiver, and the transmission efficiency of the measured second target receiver And determines a resonant frequency of the first target receiver and the second target receiver. Transmitting wireless power to a first target receiver;
Receiving a request for transmission of the wireless power from a second target receiver transmitting wireless power to the first target receiver; And
Transmitting the wireless power to the first target receiver and the second target receiver using the resonant frequency and time-sharing scheme of the second target receiver
/ RTI > 10. The method of claim 9,
Measuring a transmission efficiency for each frequency of the second target receiver; And
Determining the time division scheme for alternately transmitting the radio power to the first target receiver and the second target receiver based on the measured transmission efficiency
Further comprising the step of: 11. The method of claim 10,
Determining the resonant frequency required to transmit the wireless power to the second target receiver based on the measured transmission efficiency
Further comprising the step of: 11. The method of claim 10,
Receiving information on a transmission capacity and a charging rate of the wireless power requested by the second target receiver from the second target receiver; And
Determining the resonant frequency required to transmit the radio power to the second target receiver based on the time-divisional scheme and the second target receiver, based on the charging rate requested by the second target receiver and the measured transmission efficiency
Further comprising the step of: 10. The method of claim 9,
Measuring transmission efficiency with respect to a value of a matching matching parameter when the resonance frequency and the time division method are determined; And
Determining a value of an optimal matching parameter for transmitting the wireless power to the second target receiver based on the measured transmission efficiency
Further comprising the step of: 14. The method of claim 13,
Wherein the transmitting comprises:
And transmitting the wireless power by alternately changing values of optimal matching parameters of the first target receiver and the second target receiver when the first target receiver and the second target receiver have the same resonance frequency, Way. 11. The method of claim 10,
Dividing a frequency at which a result of adding the transmission efficiencies of the first target receiver and the second target receiver to a maximum is set to a resonant frequency of the first target receiver and the second target receiver when the time- step
Further comprising the step of: 11. The method of claim 10,
Division scheme is not used, based on the charging rate requested by the first target receiver, the charging rate requested by the second target receiver, and the transmission efficiency of the measured second target receiver, 1 < / RTI > target receiver and the second target receiver,
Further comprising the step of: A computer-readable recording medium recording a program for executing the method of any one of claims 9 to 16 in a computer.

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