KR102502145B1 - Efficient wireless power charging apparatus and method thereof - Google Patents

Abstract

The present invention relates to an efficient wireless power charging device and method thereof, comprising: a plurality of transmission terminals each including a transmission resonator unit that transmits power using power provided from a power supply unit and includes one capacitor and one inductor; at least one receiving end each including a receiving resonator that receives the power transmitted from the transmission resonator and includes a capacitor and an inductor and a load that performs charging using the received power; After determining the output current of each of the plurality of transmitting ends, the present invention relates to a device including a control unit for compensating for the determined output current in consideration of mutual inductance between the plurality of transmitting ends and applying the compensated output current to each of the plurality of transmitting ends.

Description

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

The present invention relates to an efficient wireless power charging device and method, and relates 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 since devices requiring power can be charged wirelessly without connecting to a power outlet, related research is being actively conducted. Magnetic induction method, magnetic resonance method, microwave method, etc. are being studied for wireless power transmission technology.

A wireless power transmitter includes a transmitter that wirelessly transmits power and a receiver that receives the transmitted power. The transmitter transmits power to the receiver by generating a magnetic field and radiating it to the receiver. For power transmission, a transmitter and a receiver use coils, and when they have the same resonant frequency, maximum power transfer can occur in a wireless power transmitter.

Meanwhile, coils included in the transmitting end and the receiving end have self inductance as well as mutual inductance between the transmitting end and the receiving end and mutual inductance between the transmitting coils. At the receiving end that has received power, it is possible to charge power wirelessly if the charging infrastructure is equipped, and it is important to create a charging environment to maximize power transmission efficiency in wireless charging. To this end, a method for optimizing the mutual inductance between the transmitting end and the receiving end and minimizing the effect caused by the mutual inductance between the transmitting coils is required.

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

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

The present invention transmits power using power provided from the power supply unit and includes a plurality of transmission stages each including a transmission resonance unit including one capacitor and one inductor; at least one receiving end each including a receiving resonator that receives the power transmitted from the transmission resonator and includes a capacitor and an inductor and a load that performs charging using the received power; After determining the output current of each of the plurality of transmitting ends, the wireless power charging device includes a controller for compensating for the determined output current in consideration of mutual inductance between the plurality of transmitting ends and applying it to each of the plurality of transmitting ends.

Here, the control unit determines mutual inductance between each transmission resonator and each reception resonator, and uses the mutual inductance to independently perform wireless charging in the plurality of transmission terminals and the at least one reception terminal. And the output current may be determined by determining at least one subset consisting of a receiving end.

In addition, when a plurality of transmitting ends are composed of first and second transmitting ends, the control unit corresponds to a conjugate value of a current flowing through each of the first and second transmitting ends due to mutual inductance between the first and second transmitting ends. A current may be applied to each of the first and second transmitters.

On the other hand, the present invention transmits power to at least one receiver including a receiving resonator including one capacitor and one inductor using power supplied from the power supply and a load that performs charging using the received power, and , determining an output current of each of a plurality of transmission terminals each including a transmission resonator including one capacitor and one inductor; It relates to a wireless power charging method comprising compensating for the determined output current in consideration of mutual inductance between the plurality of transmitting ends and applying the compensated output current to each of the plurality of transmitting ends.

Here, the process of determining the output current may include determining a mutual inductance between the plurality of transmit resonator units and the at least one receive resonator unit; determining at least one subset composed of a transmitting end and a receiving end independently performing wireless charging between the plurality of transmitting ends and the at least one receiving end using the respective mutual inductance; The method may include determining an output current of each of the plurality of transmitters using the subset.

In addition, when a plurality of transmitting ends are composed of first and second transmitting ends, the applying process is a conjugate value of a current flowing through each of the first and second transmitting ends due to mutual inductance between the first and second transmitting ends. It may include a process of applying a current corresponding to each of the first and second transmission terminals.

According to the present invention, since the current applied to the transmitting coil is adjusted in consideration of the effect caused by the mutual inductance between the transmitting coils, 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 diagram for explaining a transmitting end and a receiving end of a wireless power charging device according to an embodiment of the present invention.
3 is a diagram for explaining a method of determining mutual inductance between a transmitting end and a receiving end in a control unit of a wireless power charging device according to an embodiment of the present invention.
4A is a diagram for explaining a connection relationship between a plurality of transmitting ends and a plurality of receiving ends of a wireless power charging device according to an embodiment of the present invention;
4B is a diagram for explaining a method of determining output currents of a plurality of transmitters by setting a subset of a wireless power charging device according to an embodiment of the present invention.
5A to 5C are diagrams for explaining a method for compensating current applied to first and second transmission terminals in consideration of mutual coupling between transmission coils according to an embodiment of the present invention;
6A to 6C are diagrams illustrating experimental examples of compensating currents applied to first and second transmission terminals according to an embodiment of the present invention;
7 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 drawings. In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description 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.

Referring to FIG. 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 resonator unit 140, a rectifier 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 supplies AC (Alternating Current) or DC (Direct Current) power, for example.

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

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

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 transmits power by resonance between coils, and includes a plurality of transmit resonator units each including a capacitor and an inductor and at least one receive resonator unit.

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

The conversion unit 160 is for maintaining a constant voltage provided for charging in order 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 control unit 140 controls the wireless power charging device 10 as a whole of the present invention, such as determining mutual inductance, current, or voltage of the resonator 140 so that wireless power charging can proceed with maximum efficiency.

2 is a diagram 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 device 10 of the present invention includes a transmitting end 200 for transmitting power and a receiving end 210 for receiving power to enable charging.

The transmitter 200 includes a control unit 170, a power supply unit 100, an amplifier 110, and a transmission resonator 220, and the receiver 210 includes a reception resonator 230, a rectifier 150, and a conversion unit. (160) and load R _L . 2 shows the control unit 170 as the transmitting end 200, the control unit 170 is configured to control the wireless power charging device 10 of the present invention as a whole, including not only the transmitting end 200 but also the receiving end 210. can

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

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

V _P : Output voltage of the amplifier 110

I _P : output current of the transmitting end 200

C _P : capacitance of the transmission resonator 220

L _P : Self-inductance of the transmitting resonator 220

M : mutual inductance

I _S : receiving current of the receiving terminal 210

C _S : capacitance of the receiving resonator 230

L _S : self-inductance of the receiving resonator 230

V _R : output voltage of the rectifier 150

V _Out : Charging voltage of the load of the receiving end 210

R _L : Load impedance of the receiving end 210

3 is a diagram for explaining a method of determining mutual inductance between a transmitting end and a receiving end in the control unit 170 of the wireless power charging device 10 according to an embodiment of the present invention.

In the present invention, in order to transmit power from the transmitting end 200 of the wireless power charging device 10 to the receiving end 210 with maximum efficiency, it is necessary to determine an appropriate mutual inductance between the transmitting resonator and the receiving resonant unit. For example, the control unit 170 of the present invention may determine the mutual inductance through the method described in Application No. 10-2019-0092894 (filed date: 2019.07.31), and the present invention is the method described in Application No. 10-2019-0092894 The mutual inductance determined through can be used.

For example, as shown in FIG. 3, the equivalent circuit of the wireless power charging device includes the first to t transmission resonators 300, 320, and 340, the first to t power supply units V _S1 , V _{S2 , and} V _St , and the first to q reception units. A case consisting of the resonator units 310 , 330 , and 350 and the load resistors R _{L1 ,} R _{L2 , and} R _Lq will be described. When power is supplied to the first to t-th transmission resonators 300 , 320 , and 340 from the first to t-th power supply units V _S1 , V _{S2 , and} V _St , the input voltage (V _P1 , V _{P2 ,} and V _Pt ) are generated, and reception voltages V _{R1 ,} V _{R2 , and} V _Rq are generated in the first to qth reception resonators 310 , 330 , and 350 .

At this time, a mutual inductance value for efficiently transmitting power from the first to t-th transmission resonators 300, 320, and 340 to the first to q-th reception resonators 310, 330, and 350 is determined as in [Equation 1].

[Equation 1]

At this time, M _tq : Mutual inductance between the t-th transmit resonator and the q-th receive resonator

I _Pt : input current of the t-th transmission resonator

w: operating angular frequency

R _Lq : load resistance of the qth reception resonator

V _Rq : receiving voltage of the qth receiving resonator

Z _Sq : Impedance of the qth reception resonator,

C _Sq : capacitance of the qth receiving resonator

L _Sq : Self-inductance of the qth receiving resonator

R _Sq : Internal resistance of the qth receiving resonator

In the present invention, in order to determine the mutual inductance value, the mutual inductance value is determined through [Equation 1] in a state in which power is supplied to only one transmission resonance unit and power supply is cut off to the other resonance unit.

For example, after supplying the current I _P1 only to the first transmission resonator 300 and cutting off the power supply to the second transmission resonator to the t-th transmission resonator 320 and 340, mutual interactions related to the first transmission resonator 300 Determine the inductance (M _11, M ₁₂ to M _1q ). Thereafter, the current I _P2 is supplied only to the second transmission resonator 320 and the power supply is cut off to the first transmission resonator 300 and the third transmission resonator (not shown) to the t-th resonator 340. Mutual inductances (M _{21 ,} M ₂₂ to M _2q ) related to the second transmission resonator 320 are determined. All mutual inductance values can be determined by proceeding to the t-th transmission resonator 340 in the same way.

Meanwhile, when the mutual inductance value is determined, the sign of the mutual inductance is determined, and the sign of the mutual inductance is determined as in [Equation 2].

[Equation 2]

if) V _Rq,in-phase > V _{Rq,out of phase} (+)

if) V _Rq,in-phase < V _{Rq,out of phase} (-)

In this case, V _Rq,in-phase is a voltage generated in the q-th reception resonator when a predetermined current of the same magnitude and same phase is supplied to the reference transmission resonator and the transmission resonator for determining the code, and V _{Rq,out of phase} is a voltage generated at the q-th receiving resonator when currents of the same magnitude and opposite phases flow to the reference transmission resonator and the transmission resonator for determining a code. At this time, the power supply is cut off to other transmission resonance units other than the reference transmission resonance unit and the transmission resonance unit for determining the code.

If the sign of the mutual inductance is (+), it indicates the case where the phase is the same, and (-) indicates the case where the phase is opposite. In addition, the reference transmission resonator can be arbitrarily determined, and all signs of mutual inductances related to the reference transmission resonator are (+).

For example, when the first transmission resonator 300 is determined as the reference transmission resonator, the signs of mutual inductances M ₁₁ to M _1q related to the first transmission resonator 300 all become (+).

The first transmission resonator 300 as a reference for determining the sign of the mutual inductance (M ₂₁ to M _2q ) related to the second transmission resonator 320 and the second transmission resonator 320 for determining the sign A current of the same magnitude and phase is supplied to the receiving voltages of the first to qth receiving resonators 310 and 350 . Thereafter, currents of the same magnitude and opposite phase are supplied to the first transmission resonator 300 and the second transmission resonator 320 to measure the received voltages of the first to qth reception resonators 310 and 350 . do. When the reception voltages of the first to qth reception resonators 310 and 350 are measured, a mutual inductance sign is determined using [Equation 2].

The mutual inductance codes of the third transmission resonator (not shown) to the t-th transmission resonator 340 may also be determined by the method described above. For example, currents of the same magnitude and phase are supplied to the first transmission resonator 300 and the t-th transmission resonator 340 as references, and currents of the same magnitude and phase opposite to each other are supplied to receive the first signal. After measuring the reception voltages of the resonator to the q-th reception resonator 310 and 350, respectively, a mutual inductance sign may be determined using [Equation 2].

4A is a diagram for explaining a connection relationship between a plurality of transmitting ends 200a, 200b, and 200c and a plurality of receiving ends 210a, 210b, and 210c of the wireless power charging device 10 according to an embodiment of the present invention.

Hereinafter, a case in which power is transmitted from a plurality of transmitting ends to a plurality of receiving ends will be described, and the same can be applied even when there is only one receiving end.

Referring to FIG. 4A, the wireless power charging device 10 according to an embodiment of the present invention includes first through t transmitting terminals 200a, 200b, and 200c and first through q receiving terminals 210a, 210b, and 210c. It is configured so that power charging can proceed in the first through q-th receiving nodes 210a, 210b, and 210c using the power transmitted by the first to t-th transmitting nodes 200a, 200b, and 200c. At this time, each of the first to t-th transmitting ends 200a, 200b, and 200c may include the same or similar configuration as the transmitting terminal 200 described in FIG. 2, and the first to q-th receiving ends 210a, 210b, and 210c may include the same or similar configuration as the receiving end 210 of FIG. 2 .

In addition, each of the first to t-th transmitting terminals 200a, 200b, and 200c and the first to q-th receiving terminals 210a, 210b, and 210c have the same size as the other receiving terminals, such as capacitance, inductance, and impedance, or They can be configured differently from each other. For example, the power supply unit 100, the communication unit 120, and the control unit 170 are configured as one component and applied to the wireless power charging device 10 as a whole, and the amplification unit 110 and the transmission resonator unit 220 , The sensing unit 130 is composed of a plurality of components included in each of the first to t-th transmitting ends 200a, 200b, and 200c, and includes a receiving resonance unit 230, a rectifying unit 150, a conversion unit 160, and a sensing unit. The unit 130 may be composed of a plurality of components included in each of the first to qth receiving terminals 210a, 210b, and 210c. In addition, the control unit 170 controls the power supplied to the first through t-th transmitting terminals 200a, 200b, and 200c by using the power supplied from the power supply unit 100.

4B shows the output currents (I _{P1 ,} I _{P2 ,} I _Pt ) of the plurality of transmitters 200a, 200b and 200c by setting a subset of the wireless power charging device 10 according to an embodiment of the present invention. It is a drawing for explaining how to determine.

In the present invention, in order to transmit power from the transmitter 200 of the wireless power charging device 10 to the receiver 210 with maximum efficiency, it is necessary to determine an appropriate current applied to each transmission resonator. For example, the control unit 170 of the present invention controls the current applied to each transmission resonance unit of the plurality of transmission stages 200a, 200b, and 200c through the method described in Application No. 10-2020-0118743 (filed date: 2020.09.16). can be determined, and the present invention can use the current applied to each transmission resonance unit determined through the method described in Application No. 10-2020-0118743.

For example, since power is transmitted and received between a plurality of transmitters and a plurality of receivers, the control unit 170 determines a subset that can be regarded as an independent transmitter or receiver that is not affected by other transmitters or receivers in order to increase charging efficiency. do. When the subset is determined, the current applied to each transmission resonator of the first through t-th transmission terminals 200a, 200b, and 200c for maximum efficiency can be determined more quickly.

The control unit 170 determines a subset using a matrix of mutual inductance (M _tq ). In the matrix, a row denotes a transmitting end, a column denotes a receiving end, and i row and j column denote mutual coupling between the ith transmitting end and the jth receiving end. In this configured state, if all the elements of the row and column preceding the predetermined mutual inductance are '0', it is regarded as a separate subset from the mutual inductance.

As an example, FIG. 4B shows the wireless charging device 10 as first to fourth transmitting ends (Tx ₁ , Tx ₂ , Tx ₃ , Tx ₄ ) and first to third receiving ends (Rx ₁ , Rx ₂ , Rx ₃ ). If configured, it shows how to determine the subset. In FIG. 4B , the first receiving end (Rx ₁ ) receives power from the first and second transmitting ends (Tx ₁ and Tx ₂ ), and the second receiving end (Rx ₂ ) receives power from the second and third transmitting ends (Tx ₂ and Tx _{3 )} . ), and the third receiving terminal (Rx ₃ ) receives power from the fourth transmitting terminal (Tx ₄ ). Mutual inductance (M ₄₃ ) between the third receiving terminal (Rx ₃ ) and the fourth transmitting terminal (Tx ₄ ) constitutes a separate subset because elements in the previous row and column are all '0'. Accordingly, the mutual inductances M ₁₁ , M ₂₁ , M ₂₂ , and M ₃₂ constitute one subset, and the mutual inductance M ₄₃ constitute one subset. That is, the third receiver (Rx ₃ ) and the fourth transmitter (Tx ₄ ) constitute one subset, and the remaining transmitters and receivers constitute one subset.

을 구하며, 이때, Particle Swarm Optimization, Simmulated Annealing, Generic Algorithm 등을 이용할 수 있다. 또한, 충전 환경은 수많은 인자들이 작용할 수 있기 때문에 충전 제한 조건을 만족하는지 여부에 따라 결정된 제1 내지 제t 송신단(200a,200b,200c)의 각 송신공진부에 인가되는 전류를 조정한다.Meanwhile, when the subsets are determined, an optimization algorithm is applied to each subset to determine the current applied to each transmission resonator of the first through t-th transmission terminals 200a, 200b, and 200c. For example, in consideration of the limiting conditions when charging the wireless charging device 10

is obtained, and at this time, Particle Swarm Optimization, Simmulated Annealing, Generic Algorithm, etc. can be used. In addition, since numerous factors may act on the charging environment, the current applied to each transmission resonator of the first to t-th transmission terminals 200a, 200b, and 200c determined according to whether or not the charging limiting condition is satisfied is adjusted.

For example, looking at a method of adjusting the current using a hill-climb method, the control unit 170 checks whether the first to q-th receiving ends 210a, 210b, and 210c satisfy the charging limit condition. The charging limiting condition can be confirmed by checking whether the power and voltage supplied to the loads of the first to q receiving terminals 210a, 210b, and 210c are within a predetermined range, and are within the predetermined range and satisfy the charging condition. If it is below or above the predetermined range, it is determined that the charging condition is not satisfied and needs to be adjusted.

When the power and voltage supplied to the loads of the first to q receiving ends 210a, 210b, and 210c are within a predetermined range, the current of the transmitting end for transmitting power to each receiving end is adjusted in the direction of increasing, and the first to q When the power and voltage supplied to the loads of the receiving ends 210a, 210b, and 210c are within a predetermined range, the current of the transmitting end transmitting power to each receiving end is adjusted in a direction of decreasing. At this time, the control unit 170 may first adjust the current of the transmitting terminal for transmitting power to the receiving terminal with high urgency in consideration of the urgency between the first to q receiving terminals 210a, 210b and 210c, and may first adjust the current of the first to q receiving terminals. The urgency between (210a, 210b, 210c) can be determined in consideration of the current state of each receiving end, the difference between the power and voltage supplied to the load of each receiving end and a predetermined range. For example, in consideration of the degree to which the power and voltage supplied to the load of each receiving terminal are spaced apart within a predetermined range, the higher the distance difference, the higher the urgency.

In addition, when one receiving end receives power from a transmitting end that transmits power only to the corresponding receiving end and a transmitting end that transmits power to both the corresponding receiving end and other receiving ends, the power and voltage supplied to the load of the corresponding receiving end are within a predetermined range or less. Alternatively, if there is an abnormality and adjustment is required, the controller 170 may adjust only the current flowing through the transmitting terminal that transmits power only to the corresponding receiving terminal. As an example, in FIG. 4B , the first receiving end (Rx ₁ ) receives power from the first and second transmitting ends (Tx ₁ and Tx ₂ ), but the first transmitting end (Tx ₁ ) only receives power from the first receiving end (Rx ₁ ). Power is transmitted, and the second transmitter Tx ₂ transmits power to the first and second receivers Rx 1 _and Rx ₂ . Accordingly, when the power and voltage supplied to the load of the first receiving terminal (Rx ₁ ) are lower than or greater than a predetermined range and need to be adjusted, only the current flowing through the first transmitting terminal (Tx ₁ ) may be adjusted.

5A to 5C are diagrams for explaining a method of compensating current applied to first and second transmission terminals 200a and 200b in consideration of mutual coupling between transmission coils according to an embodiment of the present invention. am.

The wireless power charging device 10 of the present invention transmits power from a plurality of transmitting ends such as the first to t transmitting ends 200a, 200b and 200c between the first to t transmitting ends 200a, 200b and 200c. Mutual inductance is generated, which lowers power transmission efficiency. Therefore, after the output currents of the first to t-th transmitting ends 200a, 200b, and 200c are determined, the controller 140 considers the mutual inductance generated between the transmitting coils of the first to t-th transmitting stages 200a, 200a, and 200c. 200b, 200c) compensates for the output current.

As an example, a method for compensating the output current of the first and second transmitting ends 200a and 200b when charging the first receiving end 210a by transmitting power from the first and second transmitting ends 200a and 200b is described below. Take a look.

5A is a diagram illustrating an equivalent circuit for a case in which power is transmitted from the first and second transmitting ends 200a and 200b to the first receiving end 210a according to an embodiment of the present invention.

A description of the characters shown in FIG. 5A is as follows.

V _T1 : Output voltage of the controller 170 of the first and second transmitters 200a and 200b

R _Tx1 : Equivalent internal resistance of the amplifier 110 of the first transmitter 210a

R _Tx2 : Equivalent internal resistance of the amplifier 110 of the second transmitter 200b

R _P1 : Equivalent internal resistance of the transmission resonator 220 of the first transmission terminal 200a

R _P2 : Equivalent internal resistance of the transmission resonator 220 of the second transmitter 200b

C _P1 : capacitance of the transmission resonator 220 of the first transmission terminal 200a

C _P2 : capacitance of the transmission resonator 220 of the second transmission terminal 200b

L _P1 : Self inductance of the transmission resonator 220 of the first transmission terminal 200a

L _P2 : Self-inductance of the transmission resonator 220 of the second transmitter 200b

M ₁₁ : Mutual inductance between the first transmitting end 200a and the first receiving end 210a

M ₂₁ : Mutual inductance between the second transmitting end 200b and the first receiving end 210a

M _Tx : Mutual inductance between the first and second transmitters 200a and 200b

I _S : received current of the first receiving terminal 210a

R _S : Equivalent internal resistance of the receiving resonator 230 of the first receiving end 210a

R _L : load impedance of the first receiving terminal 210a

C _S : capacitance of the receiving resonator 230 of the first receiving end 210a

w ₀ : resonant angular frequency of the resonator 140

In FIG. 5A, if mutual inductance M _Tx is provided between the first and second transmitters 200a and 200b, by M _Tx Since an induced current is generated, it is difficult to obtain desired power transmission efficiency due to the current applied to the first and second transmission terminals 200a and 200b. Therefore, when current is applied to the first and second transmission ends 200a and 200b, the current applied to the first and second transmission ends 200a and 200b is compensated by considering the current induced by the mutual inductance M _Tx . .

Looking at the method of compensating the current applied to the first and second transmission ends 200a and 200b, if the initial current I _P1 is applied to the first transmission end 200a and the initial current I _P2 is applied to the second transmission end 200b An equivalent circuit for the first transmission terminal 200a is shown in FIG. 5B, and an equivalent circuit for the second transmission terminal 200b is shown in FIG. 5C. Applying Kirchhoff's law to the equivalent circuit for the first transmitter 200a in FIG. 5B, the following equation can be obtained.

At this time, in the equivalent circuit for the first transmission terminal 200a, the current I _p1 initially applied to the first transmission terminal 200a and the current I _induced2 induced by the second transmission terminal 200b are summed so that I _p1 'flows. Able to know.

In addition, if the equivalent circuit Kirchhoff's law is applied to the second transmitter 200b in FIG. 5C, the following equation can be obtained.

At this time, in the equivalent circuit for the second transmission terminal 200b, the current I _p2 initially applied to the second transmission terminal 200b and the current I _induced1 induced by the first transmission terminal 200a are added to form I _p2 '. Able to know.

As described above, when I _p1 'and I _p2 ' flow through the first and second transmitting terminals 200a and 200b, the current induced thereby affects each transmitting terminal again, and Kirchhoff's law is applied to each equivalent circuit. By doing so, we can obtain the following equation:

The currents induced by I _p1 'and I _p2 ' affect each transmitting end so that I _p1 '' and I _p2 '' flow in each transmitting end, and inductively, the currents I _comp1 and I _comp2 finally flowing in each transmitting end are as follows can be expressed as

At this time, since the sigma term converges to a single value, it is not calculated to infinity, and when the difference between the value up to i=N and the value up to i=N+1 is 0.01 or less, approximation is possible and no further calculation is required. .

by M _Tx Considering the effect of the induced current, the current flowing through each transmitting terminal is summarized as follows.

I _comp1 = I _p1 + I _{induced2, total}

I _comp2 = I _p2 + I _{induced1, total}

I _p1 and I _p2 are the currents applied to each transmitting terminal to obtain the highest power transmission efficiency when the mutual coupling between the transmitting coils is not considered, and I _{induced1, total} and I _{induced2, total} are the currents induced by the mutual coupling between the transmitting coils am. by M _Tx To minimize the effect of the induced current, current must be applied to each transmitter so that I _comp1 = I _p1, I _comp2 = I _p2 , or I _{comp1 ≒} I _p1, I _{comp2 ≒} I _p2 as much as possible. To this end, I ^* _comp1 , which is a conjugate value of I _comp1 , is applied to the first transmitter 200a, When I * _{comp2, which is the conjugate value of I comp2 ,} ^is applied to the second transmitter 200b, by M _Tx The effect of induced current can be minimized.

6A to 6C are diagrams illustrating experimental examples of compensating currents applied to the first and second transmission terminals 200a and 200b according to an embodiment of the present invention.

, f₀ = 1MHz 인 상태에서 실험하였다.In FIGS. 6A to 6C, R _Tx1 = R _Tx2 = 14mΩ, R _P1 = R _P2 = 0.6Ω, C _P1 = C _P2 = 4.1nF, L _P1 = L _P2 = 6.2uH, Ls = 6.8uH, R _S = 1.5Ω, R _L = 15Ω, C _S = 6.3nF,

, f ₀ = 1 MHz.

6a shows M ₁₁ = 600nH, M ₂₁ = 300nH, M _Tx = 0 nH, and FIGS. 6b and 6c show M ₁₁ = 600nH, M ₂₁ = 300nH, M _Tx = 300 nH, and FIG. 6b is a case in which the current applied to the first and second transmission terminals 200a and 200b is not compensated, and FIG. 6C is a case in which the current applied to the first and second transmission terminals 200a and 200b is compensated.

Referring to FIGS. 6A and 6B, it can be seen that the power transmission efficiency is rapidly reduced due to M _Tx . Referring to FIGS. 6B and 6C, the current applied to the first and second transmitters 200a and 200b is compensated. It can be seen that the power transfer efficiency increases.

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

Referring to FIG. 7, in the present invention, in a state in which power charging is not in progress, the control unit 170 of the first to t-th transmitting terminals 200a, 200b, and 200c transmits a pulse signal to minimize power consumption, A standby mode for monitoring the existence of loads in the q-th receivers 210a, 210b, and 210c proceeds (700). When confirming the presence of a load (Yes in 710), the control unit 170 determines the mutual inductance (M) between the first to t-th transmitting ends 200a, 200b, and 200c and the first to q-th receiving ends 210a, 210b, and 210c. _tq ) is determined (720).

When the mutual inductance (M _tq ) is determined, the control unit 170 generates a matrix for the mutual inductance (M _tq ) to determine a subset of the wireless charging device 10 (730), and applies an optimization algorithm to each subset to obtain Optimum output currents of the first through t-th transmitting terminals 200a, 200b, and 200c are determined (740). In addition, although numerous factors may act on the charging environment, since it is difficult to apply all environmental factors to each equation and optimization algorithm, the control unit 170 determines the output current of the first to t-th transmitters 200a, 200b, and 200c. Adjust (750). In addition, in order to minimize the effect of the current induced by the mutual inductance (M _Tx ) between the first to t-th transmission terminals 200a, 200b, and 200c, the output current of the first to t-th transmission terminals 200a, 200b, and 200c Compensate (760).

When the output currents of the first to t-th transmitting nodes 200a, 200b, and 200c are determined, the first to t-th transmitting nodes 200a, 200b, and 200c supply power to the first to q-th receiving nodes 210a, 210b, and 210c. so that charging can proceed (770). At this time, since the charging environment may change due to a change in the position of a load during charging, the control unit 170 periodically monitors the charging environment, and when there is a change in the charging environment (yes in 780), the mutual inductance ( The process of determining M _tq ) to the process of compensating for the output currents of the first to t-th transmitters 200a, 200b, and 200c are performed again.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but 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 defined by not only the scope of the claims to be described later, but also those equivalent to the scope of these claims.

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 (8)

In the wireless power charging device,
a plurality of transmitters each including a transmission resonator unit including one capacitor and one inductor for transmitting power using power supplied from the power supply unit;
at least one receiving end each including a receiving resonator that receives the power transmitted from the transmission resonator and includes a capacitor and an inductor and a load that performs charging using the received power;
After determining the output current of each of the plurality of transmitting ends, a control unit for compensating the determined output current in consideration of mutual inductance between the plurality of transmitting ends and applying the compensated output current to each of the plurality of transmitting ends,
When the plurality of transmitting ends are composed of first and second transmitting ends,
wherein the control unit applies a current corresponding to a conjugate value of a current flowing in each of the first and second transmission ends to the first and second transmission ends due to mutual inductance between the first and second transmission ends.
According to claim 1,
The control unit determines mutual inductance between each transmission resonator and each reception resonator, and uses each mutual inductance to independently perform wireless charging in the plurality of transmission terminals and the at least one reception terminal, and An apparatus for determining the output current by determining at least one subset comprising receiving ends.
delete According to claim 1,
When the plurality of transmitting ends are composed of first and second transmitting ends,
The control unit applies I ^* _comp1 , which is a conjugate of I _comp1 , to the first transmitter, A device that applies I ^* _comp2 , a conjugate value of I _comp2 , to the second transmitter.

At this time, I _P1 : output current of the first transmitting terminal before compensation
I _P2 : output current of the second transmitter before compensation
I _comp1 : current flowing through the first transmission terminal due to mutual inductance between the first and second transmission terminals
I _comp2 : current flowing through the second transmission terminal due to mutual inductance between the first and second transmission terminals
R _Tx1 : Equivalent internal resistance of the amplifier that amplifies and outputs the power supplied from the power supply unit that supplies power from the first transmitter
R _Tx2 : Equivalent internal resistance of the amplifier that amplifies and outputs the power supplied from the power supply unit that supplies power from the second transmitter
R _P1 : Equivalent internal resistance of the transmission resonator of the first transmitter
R _P2 : Equivalent internal resistance of the transmission resonator of the second transmitter
M _Tx : Mutual inductance between the first and second transmitters
w _o : resonant angular frequency between the first and second transmitting ends and at least one receiving end
In the wireless power charging method,
Power is transmitted to at least one receiver including a receiving resonator including one capacitor and one inductor using power provided from the power supply and a load that performs charging using the received power, and the one capacitor and determining an output current of each of a plurality of transmission terminals, each of which includes a transmission resonator including one inductor;
Compensating for the determined output current in consideration of mutual inductance between the plurality of transmitting ends and applying the compensated output current to each of the plurality of transmitting ends,
When the plurality of transmitting ends are composed of first and second transmitting ends, the applying process,
and applying a current corresponding to a conjugate value of a current flowing through each of the first and second transmission ends to the first and second transmission ends due to mutual inductance between the first and second transmission ends.
According to claim 5,
The process of determining the output current,
determining mutual inductance between the plurality of transmission resonators and the at least one reception resonator;
determining at least one subset composed of a transmitting end and a receiving end independently performing wireless charging between the plurality of transmitting ends and the at least one receiving end using the respective mutual inductance;
and determining an output current of each of the plurality of transmitters using the subset.
delete According to claim 5,
When the plurality of transmitting ends are composed of first and second transmitting ends, the applying process,
To the first transmitter, I ^* _comp1 , which is the conjugate of I _comp1 , is applied, and and applying I ^* _comp2, which is a conjugate value of I _comp2 , to the second transmitter.

At this time, I _P1 : output current of the first transmitting terminal before compensation
I _P2 : output current of the second transmitter before compensation
I _comp1 : current flowing through the first transmission terminal due to mutual inductance between the first and second transmission terminals
I _comp2 : Current flowing through the second transmission terminal due to mutual inductance between the first and second transmission terminals
R _Tx1 : Equivalent internal resistance of the amplifier that amplifies and outputs the power supplied from the power supply unit that supplies power from the first transmitter
R _Tx2 : Equivalent internal resistance of the amplifier that amplifies and outputs the power supplied from the power supply unit that supplies power from the second transmitter
R _P1 : Equivalent internal resistance of the transmission resonator of the first transmitter
R _P2 : Equivalent internal resistance of the transmission resonator of the second transmitter
M _Tx : Mutual inductance between the first and second transmitters
w _o : resonant angular frequency between the first and second transmitting ends and at least one receiving end

Images