KR20210034282A - Efficient wireless power charging apparatus and method thereof - Google Patents

Abstract

The present invention relates to an efficient wireless power charging device and a method thereof. The device includes: a transmitting terminal including a power supply unit for supplying power and a transmitting resonator unit for transmitting the power using the power provided from the power supply unit and including one capacitor and one inductor; a plurality of receiving terminals receiving power transmitted from the transmitting resonator by using a resonance phenomenon, and each including a receiving resonator including one capacitor and one inductor, and a load performing charging using the received power; and a control unit determining a mutual inductance between the transmitting resonator and the each receiving resonators and an equivalent load impedance of the each receiving terminal, and determining an output current of the transmitting terminal by using the each mutual inductances and the equivalent load impedance of the each receiving terminal.

Description

Efficient wireless power charging device and its method {EFFICIENT WIRELESS POWER CHARGING APPARATUS AND METHOD THEREOF}

The present invention relates to an efficient wireless power charging device and method thereof, and to a wireless power charging device and method capable of charging with maximum efficiency.

Wireless power transmission refers to supplying power to electronic devices wirelessly instead of wired, and related research is actively being conducted since devices requiring power can be charged wirelessly without connecting them to a power outlet. As for wireless power transmission technology, magnetic induction method, magnetic resonance method, and microwave method are being studied.

The wireless power transmission apparatus is composed of a transmitter that transmits power wirelessly and a receiver that receives the transmitted power. The transmitting end transmits power to the receiving end by generating a magnetic field and copying it to the receiving end. For power transmission, the transmitting end and the receiving end use a coil. When they have the same resonance frequency, maximum power transmission may occur in the wireless power transmission device.

The coils included in the transmitting end and the receiving end have mutual inductance as well as self inductance. Since mutual inductance has a great influence on power transmission, it is important to determine an optimal mutual inductance value in order to obtain maximum wireless transmission efficiency. In addition, if the charging infrastructure is equipped at the receiving end receiving power, power can be charged wirelessly. However, since the wireless charging efficiency is greatly affected by the charging environment and various environmental factors exist in the charging environment, it is difficult to obtain the maximum wireless charging efficiency.

The present invention relates to an efficient wireless power charging apparatus and method thereof.

In addition, the present invention relates to a wireless power charging apparatus and method capable of charging electric power with maximum efficiency.

The present invention includes a transmission terminal including a power supply supplying power and a transmission resonator including a capacitor and an inductor and transmitting power by using the power provided from the power supply; A plurality of reception terminals each including a reception resonator including one capacitor and one inductor, and a load for performing charging using the received power, receiving power transmitted from the transmission resonator using a resonance phenomenon; Determine the mutual inductance between the transmitting resonator and each of the receiving resonators and the equivalent load impedance of each receiving end, and determine the output current of the transmitting end using the respective mutual inductance and the equivalent load impedance of each receiving end. It relates to a device including a control unit.

Here, the present invention further comprises an amplifying unit for amplifying the power provided from the power supply unit and supplying the power to the transmission resonator, and each of the plurality of receiving ends supplies a rectifier unit for rectifying the current generated from the receiving resonator unit and the load. It may further include a conversion unit for maintaining a constant voltage.

In addition, the control unit determines a plurality of equivalent load impedances for each receiving end for each of the plurality of receiving ends, and determines the equivalent load impedance of each receiving end using a plurality of equivalent load impedances for each receiving end, and The plurality of equivalent load impedances for the receiving end may include a first equivalent load impedance with respect to a predetermined equivalent load impedance of each receiving end and a second equivalent load impedance determined by a predetermined method.

In addition, when the second equivalent load impedance of each receiving end is greater than or equal to the first equivalent load impedance of each receiving end, the control unit determines the second equivalent load impedance as the equivalent load impedance of each receiving end, and determines the second equivalent load impedance of each receiving end. 2 If the equivalent load impedance is less than the first equivalent load impedance of each receiving end, the first equivalent load impedance may be determined as the equivalent load impedance of each receiving end.

In addition, the first equivalent load impedance for each receiving end may be the same as the load impedance of each receiving end.

In addition, the control unit may determine the second equivalent load impedance for each receiving end using the following equation.

At this time, Z _C,q is the second equivalent load impedance of the qth receiving end

R _S,q : Equivalent internal resistance of the receiving resonant part of the qth receiving end

R _P : Equivalent internal resistance of the transmission resonant part

w ₀ : resonance angular frequency

M _1q : Mutual inductance between the qth receiving end and the transmitting end

In addition, the control unit may determine the output currents of the plurality of transmitting terminals corresponding to each of the plurality of receiving terminals by using the following equation.

At this time, I _opt,q is the output current of the transmitting end corresponding to the qth receiving end

Z _opt,q is the equivalent load impedance of the qth receiving end

R _S,q : Equivalent internal resistance of the receiving resonant part of the qth receiving end

V _Out,q : Charging voltage of the load at the qth receiving end

w ₀ : resonance angular frequency

M _1q : Mutual inductance between the qth receiving end and the transmitting end

R _L,q : load impedance of the qth receiving end

In addition, the control unit may determine the largest current among the output currents of the plurality of transmitting terminals as the output currents of the transmitting terminals for the plurality of receiving terminals.

Meanwhile, a transmission resonator that transmits power including one capacitor and one inductor, and a plurality of receptions each including one capacitor and one inductor, respectively, receive the power transmitted from the transmission resonator using a resonance phenomenon. Determining mutual inductance between the resonance units; A process in which each receiving end determines an equivalent load impedance for each of a plurality of receiving ends including one receiving resonator and a load performing charging using the received power; The present invention relates to a method including a process of determining an output current of a transmission terminal including a power supply unit for supplying power and the transmission resonator using the mutual inductance and the equivalent load impedance for each of the plurality of reception terminals.

Here, the present invention comprises a step of amplifying power provided from a power source and supplying the power to the transmission resonator; Rectifying a current generated from the reception resonator at each of the plurality of reception terminals; The step of constantly supplying a voltage generated by using the rectified current at each of the plurality of receiving terminals to the load may be further included.

In addition, the process of determining the equivalent load impedance for each of the plurality of receiving ends may include determining a plurality of equivalent load impedances for each receiving end for each of the plurality of receiving ends; And determining an equivalent load impedance for each of the plurality of receiving ends by using a plurality of equivalent load impedances for each receiving end,

The plurality of equivalent load impedances for each receiving end may include a first equivalent load impedance related to a predetermined equivalent load impedance of each receiving end and a second equivalent load impedance determined by a predetermined method.

In addition, in the process of determining the equivalent load impedance for each of the plurality of reception terminals using a plurality of equivalent load impedances for each reception terminal, the second equivalent load impedance of each reception terminal is greater than the first equivalent load impedance of each reception terminal. If greater than or equal to, the second equivalent load impedance is determined as the equivalent load impedance of each receiving end, and if the second equivalent load impedance of each receiving end is less than the first equivalent load impedance of each receiving end, the first equivalent load impedance is determined. It can be determined by the equivalent load impedance of each receiving end.

In addition, the first equivalent load impedance may be the same as the load impedance of each receiving end.

In addition, the second equivalent load impedance may include a process of determining using the following equation.

At this time, Z _C,q is the second equivalent load impedance of the qth receiving end

R _S,q : Equivalent internal resistance of the receiving resonant part of the qth receiving end

R _P : Equivalent internal resistance of the transmission resonant part

w ₀ : resonance angular frequency

M _1q : Mutual inductance between the qth receiving end and the transmitting end

In addition, the process of determining the output current of the transmitter may include determining the output current of the plurality of transmitters corresponding to each of the plurality of receivers using the following equation.

At this time, I _opt,q is the output current of the transmitting end corresponding to the qth receiving end

Z _opt,q is the equivalent load impedance of the qth receiving end

R _S,q : Equivalent internal resistance of the receiving resonant part of the qth receiving end

V _Out,q : Charging voltage of the load at the qth receiving end

w ₀ : resonance angular frequency

M _1q : Mutual inductance between the qth receiving end and the transmitting end

R _L,q : load impedance of the qth receiving end

In addition, the process of determining the output current of the transmitter may include determining the largest current among the output currents of the plurality of transmitters as the output current of the transmitter for the plurality of receivers.

In the present invention, since the charging efficiency is controlled by controlling the output current of the transmitting end that transmits power, wireless charging can be performed with maximum efficiency.

1 is a diagram showing the configuration of a wireless power charging device according to an embodiment of the present invention.
2 is a view for explaining a transmitting end and a receiving end of a wireless power charging device according to an embodiment of the present invention.
FIG. 3A is a diagram illustrating a connection relationship between one transmitting end and a plurality of receiving ends of a wireless power charging device according to an embodiment of the present invention, and FIG. 3B is a diagram showing an equivalent circuit of the wireless power charging device described in FIG. 3A .
4A to 4F are diagrams showing experimental examples of a wireless power charging device according to an embodiment of the present invention.
5 is a flowchart illustrating a power charging method of a wireless power charging device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

1 is a diagram showing the configuration of a wireless power charging device 10 according to an embodiment of the present invention.

1, the wireless power charging device 10 of the present invention includes a power supply unit 100, an amplification unit 110, a communication unit 120, a sensing unit 130, a resonance unit 140, a rectifying unit 150, It includes a conversion unit 160 and a control unit 170.

The power supply unit 100 supplies power to the wireless power charging device 10 of the present invention, and, for example, supplies alternating current (AC) or direct current (DC) power.

The amplification unit 110 amplifies the power supplied from the power supply unit 100 and may be configured as a power amplifier.

The communication unit 120 is for communication within an external device or the wireless power charging device 10 of the present invention, and a short-range communication means such as Bluetooth or Wi-Fi, or LTE, 5G (5th Generation) It may include a communication means capable of communicating by accessing a mobile communication network according to various mobile communication standards, such as.

The sensing unit 130 detects voltage or current at a predetermined position of the wireless power charging device 10 of the present invention, and may include various sensors.

The resonator 140 allows power to be transmitted by a resonance phenomenon between coils, and includes one transmission resonator and a plurality of reception resonators each including a capacitor and an inductor.

The rectifier 150 is for changing an AC current into a DC current, and may be configured as a rectifier. The rectifier 150 rectifies the current generated in the reception resonator.

The conversion unit 160 is for maintaining a constant voltage provided for charging to meet a voltage condition for charging, and may be configured as a DC-DC converter. The conversion unit 160 may adjust the voltage according to a conversion ratio.

The controller 140 overall controls the wireless power charging device 10 of the present invention, such as determining mutual inductance, an equivalent load impedance of the receiving end 210, current or voltage, etc. so that wireless power charging can proceed with maximum efficiency.

2 is a view for explaining the transmitting end 200 and the receiving end 210 of the wireless power charging device 10 according to an embodiment of the present invention.

Referring to FIG. 2, the wireless power charging apparatus 10 of the present invention includes a transmitter 200 for transmitting power and a receiver 210 for receiving power to enable charging.

The transmitting end 200 includes a control unit 170, a power supply unit 100, an amplifying unit 110 and a transmitting resonating unit 220, and the receiving end 210 is a receiving resonating unit 230, a rectifying unit 150, and a conversion unit. 160 and a load (R _L ). In FIG. 2, the control unit 170 is shown at the transmitting end 200, but the control unit 170 is configured to control the wireless power charging device 10 of the present invention including the transmitting end 200 as well as the receiving end 210 as a whole. I can.

In addition, although not shown in FIG. 2, the transmitting end 200 and the receiving end 210 detect the magnitude of a voltage or current at a predetermined position through the sensing unit 130 and can communicate with each other through the communication unit 120. . For example, current or voltage sensed through Bluetooth communication may be transmitted and received, or control information may be transmitted and received.

A description of each character shown in FIG. 2 is as follows.

V _P : output voltage of the amplification unit 110, I _P : output current of the transmitter 200

C _P : capacitance of the transmission resonator 220, L _P : self-inductance of the transmission resonator 220

M: mutual inductance, I _S : receiving current of the receiving end 210

C _S : capacitance of the reception resonator 230, L _S : self inductance of the reception resonator 230

V _R : output voltage of the rectifier 150, V _Out : charging voltage of the load of the receiving terminal 210

R _L : Load impedance of receiver 210

3A is a view for explaining a connection relationship between one transmitting end 200 and a plurality of receiving ends 210a, 210b, 210c of the wireless power charging device 10 according to an embodiment of the present invention, and FIG. 3B is It is a diagram showing an equivalent circuit of the wireless power charging device 10 described in 3a.

Referring to FIG. 3A, the wireless power charging device 10 of the present invention is composed of one transmitting end 200 and first to qth receiving ends 210a, 210b, and 210c, and the power transmitted by one transmitting end 200 The power charging can be performed in the first to qth receiving terminals 210a, 210b, and 210c by using. In this case, each of the first to qth receiving terminals 210a, 210b, and 210c may have the same or similar configuration as the receiving terminal 201 shown in FIG. 2. In addition, each of the first to qth receiving terminals 210a, 210b, and 210c may have the same size as the other receiving terminals or differently from each other.

3B is a diagram showing an equivalent circuit of the wireless power charging device 10 configured as in FIG. 3A.

)를 가지는 인덕터 및 상호 인덕턴스(M_11,M_12,M_1q)를 가지는 인덕터를 포함하여 구성된다. 이때, 전류원(I_P), 복수의 저항(R_Tx, R_P), 캐패시턴스(C_P)를 가지는 캐패시터 및 자기 인덕턴스(

)를 가지는 인덕터는 직렬 연결되며, 상호 인덕턴스(M_11,M_12,M_1q)를 가지는 인덕터는 제1 내지 제q 수신단(210a,210b,210c) 사이에 연결될 수 있다.Referring to FIG. 3B, the equivalent circuit of the wireless power charging device 10 of the present invention is a capacitor having a current source (I _P ), a plurality of resistors (R _Tx , R _P ), and capacitance (C _P ). And self inductance (

) And an inductor having mutual inductances (M _11, M _12, M _1q ). At this time, a _{capacitor having a current source (I P} ), a plurality of resistors (R _Tx , R _P ), and a capacitance (C _P ), and a self inductance (

The inductors having) are connected in series, and the inductors having mutual inductances M _11, M _{12, and} M _1q may be connected between the first to qth receiving terminals 210a, 210b, and 210c.

In addition, the first receiving end 210a includes an inductor having a self inductance (L _S1 -M ₁₁ ), a _{capacitor having a capacitance (C S1} ), a resistance (R _S1 ), an impedance (Z _L1 ), and a mutual inductance (M ₁₁ ). The branch is comprised of an inductor. In addition, the second receiving end 210b includes an inductor having a self inductance (L _S2 -M ₁₂ ), a _{capacitor having a capacitance (C S2} ), a resistance (R _S2 ), an impedance (Z _L2 ), and a mutual inductance (M ₁₂ ). The branch is comprised of an inductor. In addition, the q-th receiving end 210c includes an inductor having a self inductance (L _Sq -M _1q ), a _{capacitor having a capacitance (C Sq} ), a resistance (R _Sq ), an impedance (Z _Lq ), and a mutual inductance (M _1q ). The branch is comprised of an inductor. At this time, the first receiving end 210a has an inductor having a self inductance (L _S1 -M ₁₁ ), a _{capacitor having a capacitance C S1} , a resistance R _S1 and an impedance (Z _L1 ) are connected in series, and the second receiving end (210b) is an inductor having a magnetic inductance (L _S2 -M ₁₂ ), a _{capacitor having a capacitance (C S2} ), a resistance (R _S2 ) and an impedance (Z _L2 ) are connected in series, and the q-th receiving end 210c is magnetic An inductor having an inductance (L _Sq -M _1q ), a _{capacitor having a capacitance (C Sq} ), a resistance (R _Sq ), and an impedance (Z _Lq ) may be connected in series.

A description of each character shown in FIG. 3B is as follows.

V _T : output voltage of the control unit 170 of the _{transmitting end 200, I P} : output current of the transmitting end 200

C _P : capacitance of the transmission resonator 220, L _P : self-inductance of the transmission resonator 220

R _P : equivalent internal resistance of the transmission resonator 220, R _Tx : equivalent internal resistance of the amplification unit 110

w: operating angular frequency, w ₀ : resonant angular frequency of the resonator 140

f: operating frequency, f ₀ : resonance frequency of the resonator 140

M _1q : Mutual inductance between the qth receiving end 210c and the transmitting end 200

I _Sq : the receiving current of the qth receiving end 210c,

L _Sq : self inductance of the qth receiving end 210c

C _Sq : capacitance of the qth receiving end 210c

V _Rq : the output voltage of the rectifier 150 of the qth receiving end 210c

R _Sq : equivalent internal resistance of the receiving resonator 230 of the qth receiving end 210c

Z _Lq : equivalent load impedance of the qth receiving end 210c,

R _Lq : load impedance of the qth receiving end 210c

V _Out,q : charging voltage of the load of the qth receiving terminal 210c

Z _Coil.SIMO : Impedance viewed from the amplification unit 110 of the transmitter 200

Z _ref,q : Impedance facing the q-th receiving end 210c from the transmitting resonator 220 of the transmitting end 200

The present invention enables wireless power charging to proceed with maximum efficiency in a state configured as shown in FIGS. 3A and 3B. _{In performing wireless power charging, the output current (I P} ) of the transmitting end 200 is set in response to a charging environment such as the location of each of the first to q-th receiving ends 210a, 210b, and 210c and the capacity of the load that needs to be charged. It is important to keep it in optimal condition. Accordingly, the present invention maintains the value of the output current (I _P ) of the transmitter 200 in an optimal state in response to the charging environment so that wireless charging can proceed with maximum efficiency.

In the present invention, a method for maintaining _{the output current I P} in an optimal state in response to the charging environment is as follows.

Hereinafter, for convenience, when',' is indicated in the current, resistance, impedance, etc. of the qth receiving end 210, it is regarded as the same as the case where',' is omitted. For example I _sq = Same as I _{s,q, etc.}

First, looking at [Equation 1] to [Equation 3], it can be seen that the system efficiency η is changed by the mutual inductance and equivalent load impedance of each of the first to qth receiving terminals 210a, 210b, and 210c. .

[Equation 1]

[Equation 2]

[Equation 3]

Each of the first to qth receiving terminals 210a, 210b, and 210c has an optimum impedance for the maximum efficiency of each receiving end, but the corresponding impedance is affected by the output current of the transmitting end 200. q It is difficult to perform charging while each of the receiving terminals 210a, 210b, and 210c simultaneously satisfies the impedance for its maximum efficiency. Therefore, it is important to determine the output current of the transmission terminal 200 that can generate the maximum efficiency as a whole of the first to qth reception terminals 210a, 210b, and 210c. _{To this end, the control unit 170 determines the equivalent load impedance (Z C,q} ) of each receiving end, which is a critical point at which each of the first to qth receiving ends 210a, 210b, and 210c can have maximum efficiency. Determine as in [Equation 4].

[Equation 4]

At this time, Z _C,q is the equivalent load impedance that becomes the critical point of the qth receiving end 210c

Next, the controller 170 considers the limiting condition of the wireless charging device. For example, as a limiting condition, each of the first to qth receiving terminals 210a, 210b, and 210c needs a minimum power to perform charging, and each receiving terminal 210a, 210b, 210c has a minimum equivalent load impedance (Z It can be considered that it has _{L,min,q ). At this time, the minimum equivalent load impedance (Z L,min,q} ) of the first to qth receiving terminals 210a, 210b, 210c is determined as in [Equation 5], and the minimum equivalent load impedance (Z _L,min,q ) Can be predetermined.

[Equation 5]

At this time, Z _L,min,q is the minimum equivalent load impedance of the qth receiving end 210c

In consideration of such a limiting condition, the control unit 170 calculates the optimal equivalent load impedance (Z _opt,q ) for each of the first to qth receiving terminals 210a, 210b, and 210c to have the maximum efficiency [Equation 6 ].

[Equation 6]

At this time, Z _opt,q is the optimal equivalent load impedance considering the limiting condition of the qth receiving end 210c

_{When the optimal equivalent load impedance (Z opt,q} ) for each of the first to qth receiving ends 210a, 210b, 210c is determined, the control unit 170 uses the first to qth receiving ends _{(210a, 210b, 210c) The output current (I opt,q} ) of the transmitting terminal 200 that can provide the maximum efficiency to each is determined.

[Equation 7]

At this time, I _opt,q is the output current of the transmitting end 200 that can provide the maximum efficiency of the q-th receiving end 210c

R _S,q : equivalent internal resistance of the receiving resonator of the qth receiving end 210c

R _L,q : load impedance of the qth receiving end 210c

As described above, since it is difficult for the transmitter 200 to simultaneously supply current for providing maximum efficiency to each of the first to qth receivers 210a, 210b, and 210c, the controller 170 ], the largest current among _{the output currents (I opt,q} ) of the transmitter 200 that can provide maximum efficiency to each of the first to qth receivers 210a, 210b, and 210c is output from the transmitter 200 It is determined by current (I _{opt, SIMO ).}

[Equation 8]

At this time, I _{opt, SIMO} is the output current of the transmitting end 200 that can provide the maximum overall efficiency to the first to q-th receiving ends 210a, 210b, and 210c.

Meanwhile, the control unit 170 may determine the mutual inductance through the method described in Application No. 10-2019-0092894 (Application Date: July 31, 2019), and the present invention can determine the mutual inductance determined through the method described in Application No. 10-2019-0092894. Inductance can be used. Therefore, in the present invention, a detailed description thereof will be omitted.

4A to 4F are diagrams showing experimental examples of the wireless power charging apparatus 10 according to an embodiment of the present invention.

4A to 4F illustrate the case of the transmitting end 200, the first receiving end 210a, and the second receiving end 210b as an embodiment of the present invention. In addition, in the case of mutual inductance M ₁₁ =700nH, M ₁₂ =400nH, f=f ₀ =1MHz.

Referring to FIG. 4A, it is shown that there exist equivalent load impedances as many as the number of receiving terminals 210a and 210b, and accordingly, the efficiency changes and an impedance having the maximum efficiency exists.

Referring to FIG. 4B, since the optimal impedance providing the maximum efficiency of each receiving end 210a, 210b is dependent on the output current of the transmitting end 200, the optimal impedance of each receiving end 210a, 210b can be satisfied at the same time. It shows that it is difficult.

4C shows that the equivalent load impedance Z _{C,1 that} is the critical point of the first receiving end 210a is greater than the minimum equivalent load impedance Z _L,min,1 of the first receiving end 210a, and the second receiving end ( When the equivalent load impedance (Z _C,2 ) that becomes the critical point of 210b) is greater than the minimum equivalent load impedance (Z _L,min,2 ) of the second receiving end 210b, the output current of the transmitting end 200 (I _opt ) It indicates to determine.

4D shows that the equivalent load impedance Z _{C,1 that} is the critical point of the first receiving end 210a is smaller than the minimum equivalent load impedance Z _L,min,1 of the first receiving end 210a, and the second receiving end ( When the equivalent load impedance (Z _C,2 ) that becomes the critical point of 210b) is less than the minimum equivalent load impedance (Z _L,min,2 ) of the second receiving end 210b, the output current of the transmitting end 200 (I _opt ) It indicates to determine.

_{4E shows that the output currents I opt and SIMO} of the transmitter 200 for maximum efficiency of the receivers 210a and 210b are determined according to a change in the charging environment of the receivers 210a and 210b. Experimental conditions are L _P = 6.53uH, L _S = 9.17uH, R _P = 0.9Ω, R _S1 = R _S2 = 0.7Ω, f ₀ =1MHz. In Figure 4e, MEPT (Maximum Efficiency Point Tracking) determines the output current (I _{opt, SIMO} ) of the transmitter 200 for maximum efficiency of the receivers 210a and 210b, and is adaptively determined in response to changes in the charging environment. It shows that it becomes.

4F shows a change in the charging environment of the receiving terminals 210a and 210b, and for example, shows a change in the state and number of loads, and a change in the location of the receiving end.

5 is a flowchart illustrating a power charging method of the wireless power charging apparatus 10 according to an embodiment of the present invention.

Referring to FIG. 5, in the present invention, in a state in which power is not charged, the controller 170 transmits a pulse signal to monitor the presence of a load in order to consume a minimum amount of power in a standby mode (500). When confirming the presence of the load (example of 510), the control unit 170 determines the mutual inductance through the method described in application number 10-2019-0092894 (application date: 2019.07.31) (520). _{Thereafter, in order to provide the maximum charging efficiency, the optimum equivalent load impedance (Z opt,q} ) at which each of the first to qth receiving terminals 210a, 210b, and 210c can have the maximum efficiency is calculated by [Equation 6]. It is determined by using (430). Specifically, the minimum power required to perform charging at the first to qth receiving terminals 210a, 210b, and 210c and the minimum equivalent load impedance of each of the first to qth receiving terminals 210a, 210b and 210c (Z _{L Regardless of ,min,q ), the equivalent load impedance (Z C,q} ) of the first to qth receiving terminals 210a, 210b, 210c, which are critical points that can provide maximum efficiency for wireless charging, is determined by [Equation _{4], and the minimum equivalent load impedances Z L,min,q of} the first to qth receiving terminals 210a, 210b, and 210c are determined through [Equation 5] and compared with each other.

_{When the equivalent load impedance (Z Opt,q} ) of the first to qth receiving terminals 210a, 210b, and 210c is determined in order to provide the maximum charging efficiency, the control unit 170 uses [Equation 8] to provide maximum efficiency. _{The output current (I opt, SIMO} ) of the transmitting end 200 for providing the signal is determined (540). _{Specifically, the control unit 170 calculates the output current (I opt,q} ) of the transmission terminal 200 that can provide maximum efficiency to each of the first to q-th reception terminals 210a, 210b, and 210c [Equation 7] And the largest current among _{the output currents (I opt,q} ) of the transmitting end 200 that can provide maximum efficiency to each of the first to q-th receiving ends 210a, 210b, and 210c It is determined by the output current of (I _{opt, SIMO ).}

In addition, a number of factors may act in the charging environment, but since [Equation 8] is difficult to apply all environmental factors, the control unit 170 _{adjusts the determined output current (I Opt, SIMO} ) of the transmitter 200 ( 550). For example, Hill-Climbing there optimization techniques can be used, the efficiency of the determined output current (I _{Opt, SIMO)} for the determining the efficiency by using a current and the output current (I _{Opt, SIMO)} determined within a predetermined range based on the Compare and adjust the determined output current (I _{Opt,SIMO) to provide maximum efficiency.}

When the output current (I _{Opt, SIMO} ) of the transmission terminal 200 is determined, the transmission terminal 200 supplies power to the first to qth reception terminals 210a, 210b, and 210c to allow charging to proceed (560). At this time, since the charging environment may change due to a change in the position of the load while charging is in progress, the controller 170 periodically monitors the charging environment to determine the mutual inductance when there is a change in the charging environment (example of 570). From the determining process to the process _{of adjusting the output current (I Opt, SIMO} ) of the transmitting terminal 200 is performed again.

Meanwhile, although specific embodiments have been described in the detailed description of the present invention, various modifications are possible without departing from the scope of the present invention.

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

100: power supply unit 110: amplification unit
120: communication unit 130: detection unit
140: resonance unit 150: rectification unit
160: conversion unit 170: control unit

Claims (16)

In the wireless power charging device,
A transmission terminal including a power supply unit for supplying power and a transmission resonator unit including a capacitor and an inductor for transmitting power using power provided from the power supply unit;
A plurality of receiving terminals each including a receiving resonator including one capacitor and one inductor, and a load performing charging using the received power, receiving power transmitted from the transmitting resonator using a resonance phenomenon;
Determine the mutual inductance between the transmitting resonator and each of the receiving resonators and the equivalent load impedance of each receiving end, and determine the output current of the transmitting end using the respective mutual inductance and the equivalent load impedance of each receiving end. An apparatus comprising a control unit.
The method of claim 1,
The transmitting end further includes an amplifying unit for amplifying the power provided from the power supply and supplying the amplifying power to the transmission resonator,
Each of the plurality of receiving terminals further includes a rectifying unit for rectifying a current generated from the receiving resonator and a conversion unit for maintaining a constant voltage supplied to the load.
The method of claim 1,
The control unit determines a plurality of equivalent load impedances for each receiving end for each of the plurality of receiving ends, and determines the equivalent load impedance of each receiving end using a plurality of equivalent load impedances for each receiving end,
The plurality of equivalent load impedances for each receiving end includes a first equivalent load impedance related to a predetermined equivalent load impedance of each receiving end and a second equivalent load impedance determined by a predetermined method.
The method of claim 3,
When the second equivalent load impedance of each receiving end is greater than or equal to the first equivalent load impedance of each receiving end, the control unit determines the second equivalent load impedance as the equivalent load impedance of each receiving end, and the second equivalent load impedance of each receiving end is equal to or greater than the first equivalent load impedance of each receiving end. When the equivalent load impedance is less than the first equivalent load impedance of each receiving end, the first equivalent load impedance is determined as the equivalent load impedance of each receiving end.
The method of claim 3,
The device, characterized in that the first equivalent load impedance for each receiving end is the same as the load impedance of each receiving end.
The method of claim 3,
The control unit determines a second equivalent load impedance for each receiving end by using the following equation.

At this time, Z _C,q is the second equivalent load impedance of the qth receiving end
R _S,q : Equivalent internal resistance of the receiving resonant part of the qth receiving end
R _P : Equivalent internal resistance of the transmission resonant part
w ₀ : resonance angular frequency
M _1q : Mutual inductance between the qth receiving end and the transmitting end
The method of claim 1,
The control unit determines the output currents of the plurality of transmitting terminals corresponding to each of the plurality of receiving terminals by using the following equation.

At this time, I _opt,q is the output current of the transmitting end corresponding to the qth receiving end
Z _opt,q is the equivalent load impedance of the qth receiving end
R _S,q : Equivalent internal resistance of the receiving resonant part of the qth receiving end
V _Out,q : Charging voltage of the load at the qth receiving end
w ₀ : resonance angular frequency
M _1q : Mutual inductance between the qth receiving end and the transmitting end
R _L,q : load impedance of the qth receiving end
The method of claim 7,
The control unit determines the largest current among the output currents of the plurality of transmitters as the output currents of the transmitters for the plurality of receivers.
In the wireless power charging method,
A transmission resonator for transmitting power including one capacitor and one inductor, and
Determining mutual inductance between a plurality of reception resonators each including one capacitor and one inductor, receiving power transmitted from the transmission resonator using a resonance phenomenon;
A process in which each receiving end determines an equivalent load impedance for each of a plurality of receiving ends including one receiving resonator and a load performing charging using the received power;
And determining an output current of a transmission terminal including a power supply unit for supplying power and the transmission resonator using the mutual inductance and the equivalent load impedance for each of the plurality of reception terminals.
The method of claim 9,
Amplifying power provided from the power source and supplying the power to the transmission resonator;
Rectifying a current generated from the reception resonator at each of the plurality of reception terminals;
The method further comprising the step of constantly supplying a voltage generated by using the rectified current in each of the plurality of receiving terminals to the load.
The method of claim 9,
The process of determining the equivalent load impedance for each of the plurality of receiving terminals,
Determining a plurality of equivalent load impedances for each receiving end for each of the plurality of receiving ends;
And determining an equivalent load impedance for each of the plurality of receiving ends by using a plurality of equivalent load impedances for each receiving end,
The plurality of equivalent load impedances for each receiving end includes a first equivalent load impedance related to a predetermined equivalent load impedance of each receiving end and a second equivalent load impedance determined by a predetermined method.
The method of claim 11,
The process of determining the equivalent load impedance for each of the plurality of receiving ends using a plurality of equivalent load impedances for each receiving end,
If the second equivalent load impedance of each receiving end is greater than or equal to the first equivalent load impedance of each receiving end, the second equivalent load impedance is determined as the equivalent load impedance of each receiving end, and the second equivalent load impedance of each receiving end If is less than the first equivalent load impedance of each receiving end, the first equivalent load impedance is determined as the equivalent load impedance of each receiving end.
The method of claim 11,
The first equivalent load impedance is characterized in that the same as the load impedance of each receiving end.
The method of claim 11,
And determining the second equivalent load impedance using the following equation.

At this time, Z _C,q is the second equivalent load impedance of the qth receiving end
R _S,q : Equivalent internal resistance of the receiving resonant part of the qth receiving end
R _P : Equivalent internal resistance of the transmission resonant part
w ₀ : resonance angular frequency
M _1q : Mutual inductance between the qth receiving end and the transmitting end
The method of claim 9,
The process of determining the output current of the transmitting end,
And determining output currents of a plurality of transmitting terminals corresponding to each of the plurality of receiving terminals by using the following equation.

At this time, I _opt,q is the output current of the transmitting end corresponding to the qth receiving end
Z _opt,q is the equivalent load impedance of the qth receiving end
R _S,q : Equivalent internal resistance of the receiving resonant part of the qth receiving end
V _Out,q : Charging voltage of the load at the qth receiving end
w ₀ : resonance angular frequency
M _1q : Mutual inductance between the qth receiving end and the transmitting end
R _L,q : load impedance of the qth receiving end
The method of claim 15,
The process of determining the output current of the transmitting end,
And determining the largest current among the output currents of the plurality of transmitters as the output currents of the transmitters for the plurality of receivers.

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