KR20220057218A - 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, capable of charging electric power with maximum efficiency. The efficient wireless power charging device includes: a plurality of sending ends sending electric power by using power provided by a power unit and individually including a sending resonating unit including one capacitor and one inductor; at least one receiving end receiving the electric power transferred by the sending resonating unit and individually including a receiving resonating unit including one capacitor and one inductor and a load performing charging by using the received electric power; and a control unit determining output current of each of the sending ends and applying compensated output current to each of the sending ends by compensating the determined output current by considering mutual inductance between the plurality of sending ends.

Description

EFFICIENT WIRELESS POWER CHARGING APPARATUS AND METHOD THEREOF

The present invention relates to an efficient wireless power charging device and method, 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 being actively conducted because devices that require power can be charged wirelessly without connecting them to a power outlet. As for wireless power transmission technology, magnetic induction method, magnetic resonance method, microwave method, etc. are being studied.

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

Meanwhile, coils included in the transmitting end and the receiving end have not only self inductance, but also a mutual inductance between the transmitting end and the receiving end and a mutual inductance between the transmitting coils. When the charging infrastructure is equipped at the receiving end that receives power, wireless power charging is possible. For wireless charging, it is important to create a charging environment to maximize power transmission efficiency. To this end, a method for optimizing the mutual inductance between the transmitting end and the receiving end and minimizing the influence caused by the mutual inductance between the transmitting coils is required.

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

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 by using the power supplied from the power supply, and includes: a plurality of transmitting terminals each including a transmission resonator including one capacitor and one inductor; at least one receiving end each including a receiving resonator receiving power transmitted from the transmitting resonator and including one capacitor and one inductor, and a load performing charging using the received power; After determining the output current of each of the plurality of transmitters, it relates to a wireless power charging device comprising a controller for compensating for the determined output current in consideration of mutual inductance between the plurality of transmitters and applying the output current to each of the plurality of transmitters.

Here, the control unit determines a mutual inductance between each of the transmission resonator and each reception resonator, and uses each of the mutual inductances to independently perform wireless charging at the plurality of transmitting ends and the at least one receiving end. and determining at least one subset composed of a receiving end to determine the output current.

In addition, when the plurality of transmitters are configured as first and second transmitters, the control unit corresponds to the conjugate value of the current flowing through each of the first and second transmitters due to mutual inductance between the first and second transmitters 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 receiving end each including a receiving resonator including one capacitor and one inductor and a load performing charging using the received power using the power provided from the power supply, , 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 the step of compensating for the determined output current in consideration of the mutual inductance between the plurality of transmission terminals and applying to each of the plurality of transmission terminals.

Here, the process of determining the output current may include: determining a mutual inductance between the plurality of transmission resonators and the at least one reception resonator; determining at least one subset comprising 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 inductances; The method may include determining an output current of each of the plurality of transmitters by using the subset.

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

In 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 view for explaining a transmitting end and a receiving end of the wireless power charging device according to an embodiment of the present invention.
3 is a view for explaining a method of determining the mutual inductance between the transmitting end and the receiving end in the control unit of the wireless power charging device according to an embodiment of the present invention.
4A is a view for explaining a connection relationship between a plurality of transmitters and a plurality of receivers of a wireless power charging device according to an embodiment of the present invention;
4B is a view for explaining a method of determining output currents of a plurality of transmitters by setting a subset of a wireless power charging apparatus according to an embodiment of the present invention;
5A to 5C are views for explaining a method of compensating for currents applied to first and second transmitting terminals in consideration of mutual coupling between transmitting coils according to an embodiment of the present invention;
6A to 6C are diagrams illustrating experimental examples for compensating currents applied to first and second transmitters according to an embodiment of the present invention;
7 is a flowchart for explaining 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 the description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the 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.

Referring to FIG. 1 , the wireless power charging device 10 of the present invention includes a power supply unit 100 , an amplifier unit 110 , a communication unit 120 , a sensing unit 130 , a resonance 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, for example, alternating current (AC) or direct current (DC) power.

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

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

The sensing unit 130 detects a 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 the coils, and includes a plurality of transmission resonators each including a capacitor and an inductor, and at least one reception resonator.

The rectifier 150 is for converting alternating current into direct current, and may be configured as a rectifier. The rectifier 150 rectifies the current generated in the reception resonator.

The converter 160 is to constantly maintain a voltage provided for charging in order to satisfy a voltage condition for charging, and may be configured as a DC-DC converter. The converter 160 may adjust the voltage according to a conversion ratio.

The controller 140 as a whole controls the wireless power charging device 10 of the present invention, such as determining the mutual inductance, current, or voltage of the resonator 140 so that the 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 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 transmitting end 200 includes a control unit 170, a power unit 100, an amplifying unit 110, and a transmitting resonator 220, and the receiving end 210 is a receiving resonator 230, a rectifying unit 150, a conversion unit (160) and load (R _L ). In FIG. 2, the control unit 170 is shown as the transmitting end 200, but the control unit 170 includes the transmitting end 200 as well as the receiving end 210 to control the wireless power charging device 10 of the present invention as a whole. can

In addition, although not shown in FIG. 2 , the sensing unit 130 may detect a voltage or current at predetermined positions of the transmitting end 200 and the receiving end 210 , and may communicate with each other through the communication unit 120 . For example, the detected current or voltage may be transmitted/received through Bluetooth communication, 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 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 : the charging voltage of the load of the receiving terminal 210

R _L : load impedance of the receiving end 210

FIG. 3 is a diagram for explaining a method of determining a mutual inductance between a transmitting end and a receiving end in the controller 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 to the receiving end 210 of the wireless power charging device 10 with maximum efficiency, it is necessary to determine an appropriate mutual inductance between the transmit resonator and the receive resonator. As an example, the control unit 170 of the present invention may determine the mutual inductance through the method described in Application No. 10-2019-0092894 (application date: 2019.07.31), and the present invention is the method described in Application No. 10-2019-0092894 It is possible to use the mutual inductance determined through

For example, as shown in FIG. 3, the equivalent circuit of the wireless power charging device includes first to t-th transmission resonators 300, 320, 340, first to t-th power supply units (V _S1 , V _S2, V _St ), first to q-th reception A case in which the resonators 310 , 330 , and 350 and the load resistors R _{L1 ,} R _{L2 , and} R _Lq are configured will be described. When power is supplied from the first to t-th power supply units V _S1 , V _{S2 , and} V _St to the first to t-th transmission resonator units 300 , 320 , and 340 , the first to t-th transmission resonator units 300 , 320 and 340 have an input voltage V _P1 , V _{P2 ,} V _Pt ) is generated, and reception voltages V _{R1 ,} V _{R2 ,} V _Rq are generated in the first to q-th reception resonators 310 , 330 , and 350 .

In this case, mutual inductance values 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 are 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 transmit resonance part

w : angular frequency of operation

R _Lq : load resistance of the q-th receiving resonant part

V _Rq : Receiving voltage of the q-th receiving resonator

Z _Sq : Impedance of the q-th receiving resonant part,

C _Sq : capacitance of the q-th reception resonant part

L _Sq : self-inductance of the q-th receiving resonant part

R _Sq : internal resistance of the q-th receiving resonant part

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

As an 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 t-th transmission resonator 320 and 340 , the mutual relation related to the first transmission resonator 300 Determine the inductances M _{11 ,} M ₁₂ to M _1q . After that, 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. In the same way, all mutual inductance values can be determined by proceeding to the t-th transmission resonator 340 .

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} (-)

At this time, V _Rq,in-phase is a voltage generated in the q-th reception resonator when a predetermined same magnitude and the same phase current is supplied to the reference transmission resonator and the transmission resonator for determining a sign, and V _{Rq,out of phase} is a voltage generated in the q-th reception resonator when currents of the same magnitude and opposite phases are passed through the reference transmission resonator and the transmission resonator for determining a sign. At this time, the power supply is cut off to the transmission resonator other than the reference transmission resonator and the transmission resonator for determining the sign.

A case in which the sign of the mutual inductance is (+) indicates the case of the same phase, and (-) indicates a case in which the phase is opposite. In addition, the reference transmission resonator may be arbitrarily determined, and the signs of mutual inductances related to the reference transmission resonator are all (+).

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

The first transmission resonator 300 serving as a reference to determine the sign of the mutual inductances M ₂₁ to M _2q associated with the second transmission resonator 320 and the second transmission resonator 320 for determining the sign By supplying currents of the same magnitude and the same phase to the , the reception voltages of the first to q-th reception resonators 310 and 350 are measured. Thereafter, currents of the same magnitude and opposite phases are supplied to the first transmission resonator 300 and the second transmission resonator 320 to measure the reception voltages of the first reception resonator to qth reception resonators 310 and 350 . do. When the reception voltages of the first to q-th reception resonators 310 and 350 are measured, the sign of the mutual inductance is determined using [Equation 2].

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

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

Hereinafter, a case in which power is transmitted from a plurality of transmitters to a plurality of receivers will be described, and the same may be applied to a case where there is only one receiver.

Referring to FIG. 4A , the wireless power charging device 10 according to an embodiment of the present invention includes first to t-th transmitting terminals 200a, 200b, and 200c and first to q-th receiving terminals 210a, 210b, and 210c. It is configured so that power charging can proceed in the first to q-th receiving terminals 210a, 210b, and 210c using the power transmitted from the first to t-th transmitting terminals 200a, 200b, and 200c. In this case, each of the first to t-th transmitters 200a, 200b, and 200c may include the same or similar configuration to the transmitter 200 illustrated in FIG. 2 , and the first to q-th receivers 210a, 210b, and 210c, respectively may include the same or similar configuration to the receiving end 210 shown in 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, 210c configures the size of each component, such as capacitance, inductance, and impedance, to be the same as that of the other receiving terminals, or They may be configured differently from each other. As an example, the power supply unit 100 , the communication unit 120 , and the control unit 170 are each configured as one component and applied to the entire wireless power charging device 10 , 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 terminals 200a, 200b, and 200c, and the receiving resonator 230, the rectifying unit 150, the converting unit 160, the sensing 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 to t-th transmitting terminals 200a, 200b, and 200c by using the power supplied from the power supply unit 100 .

Figure 4b shows the output currents (I _P1, I _P2, I _Pt ) of the plurality of transmitting terminals (200a, 200b, 200c) by setting a subset of the wireless power charging device 10 according to an embodiment of the present invention. It is a diagram for explaining a method of determining.

In the present invention, in order to transmit power from the transmitting end 200 to the receiving end 210 of the wireless power charging device 10 with maximum efficiency, it is necessary to determine an appropriate current applied to each transmit resonator. As an example, the control unit 170 of the present invention controls the current applied to each transmission resonator of the plurality of transmission terminals 200a, 200b, and 200c through the method described in Application No. 10-2020-0118743 (application date: September 16, 2020). can be determined, and the present invention can use the current applied to each transmission resonator determined through the method described in Application No. 10-2020-0118743.

For example, the controller 170 determines a subset that can be viewed as an independent transmitter or receiver that has no influence with other transmitters or receivers in order to increase charging efficiency because power is transmitted and received between a plurality of transmitters and a plurality of receivers. do. When the subset is determined, it is possible to more quickly determine the current applied to each transmission resonant unit of the first to t-th transmission terminals 200a, 200b, and 200c for maximum efficiency.

The control unit 170 determines the subset by using the matrix of mutual inductance (M _tq ). In the matrix, a row means a transmitter and a column means a receiver, and row i and column j mean a mutual coupling between the i-th transmitter and the j-th receiver. In this configuration, if the elements of the previous row and column are all '0' from the predetermined mutual inductance, it is regarded as a separate subset from the corresponding mutual inductance.

As an example, FIG. 4b shows that the wireless charging device 10 includes first to fourth transmitting terminals (Tx ₁ , Tx ₂ , Tx ₃ , Tx ₄ ) and first to third receiving terminals (Rx ₁ , Rx ₂ , Rx ₃ ). If configured, a method for determining a subset is shown. In Figure 4b, the first receiving end (Rx ₁ ) receives power from the first and second transmitting ends (Tx ₁ , Tx ₂ ), the second receiving end (Rx ₂ ) is the second and third transmitting terminals (Tx ₂ , Tx ₃ ) ), and the third receiving end (Rx ₃ ) receives power from the fourth transmitting end (Tx ₄ ). The mutual inductance (M ₄₃ ) between the third receiving end (Rx ₃ ) and the fourth transmitting end (Tx ₄ ) constitutes a separate subset because all elements of the previous row and column are '0'. Accordingly, the mutual inductances M ₁₁ , M ₂₁ , M ₂₂ , M ₃₂ constitute one subset, and the mutual inductance M ₄₃ constitutes one subset. That is, the third receiving end (Rx ₃ ) and the fourth transmitting end (Tx ₄ ) constitute one subset, and the other transmitting end and the receiving end 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 a subset is determined, an optimization algorithm is applied to each subset to determine the current applied to each transmission resonant unit of the first to t-th transmission terminals 200a, 200b, and 200c. As an example, in consideration of the limiting conditions when charging the wireless charging device 10 ,

In this case, Particle Swarm Optimization, Simmulated Annealing, Generic Algorithm, etc. can be used. In addition, since a number of factors can act in the charging environment, the current applied to each transmission resonant unit of the first to t-th transmission terminals 200a, 200b, and 200c determined according to whether the charging limit condition is satisfied is adjusted.

As an example, looking at a method of adjusting the current using a method such as hill-climb, the control unit 170 checks whether the first to q-th receiving terminals 210a , 210b , and 210c satisfy the charging limit condition, for example The charging limit condition can be confirmed by whether the power and voltage supplied to the loads of the first to q-th receiving terminals 210a, 210b, and 210c are within a predetermined range, and is within a predetermined range and satisfies the charging condition. It is determined, and when it is less than or equal to a predetermined range, it is determined that the charging condition is not satisfied and adjustment is necessary.

When the power and voltage supplied to the loads of the first to q-th receiving terminals 210a, 210b, and 210c are below a predetermined range, the first to q-th receiving terminals are adjusted in a direction to increase the current of the transmitting terminal transmitting power to each receiving terminal. When the power and voltage supplied to the loads of the receiving terminals 210a, 210b, and 210c are above a predetermined range, the current of the transmitting terminal that transmits power to each receiving terminal is adjusted in a direction to decrease. In this case, the control unit 170 may first adjust the current of the transmitter transmitting power to the receiving end with high urgency in consideration of the urgency between the first to qth receiving ends 210a, 210b, and 210c, and the first to qth receiving ends The urgency between 210a, 210b, and 210c may 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 determined in advance. For example, in consideration of the degree to which the power and voltage supplied to the load of each receiver are spaced apart in a predetermined range, the higher the spaced difference, the higher the urgency.

In addition, when any one receiving end receives power from the transmitting end that transmits power only to the corresponding receiving end and the transmitting end that transmits power to both the corresponding receiving end and the other receiving end, the power and voltage supplied to the load of the corresponding receiving end is less than or equal to a predetermined range Alternatively, when adjustment is required because of an abnormality, the control unit 170 may adjust only the current flowing through the transmitting end that transmits power only to the corresponding receiving end. For example, in FIG. 4b , the first receiving end Rx ₁ is receiving power from the first and second transmitting ends Tx ₁ , Tx ₂ , the first transmitting end Tx ₁ is only the first receiving end Rx ₁ ) Power is transmitted, and the second transmitting end (Tx ₂ ) transmits power to the first and second receiving ends (Rx _{1 ,} Rx ₂ ). Therefore, when the power and voltage supplied to the load of the first receiving terminal (Rx ₁ ) are less than or equal to a predetermined range and thus adjustment is required, only the current flowing through the first transmitting terminal (Tx ₁ ) can be adjusted.

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

The wireless power charging device 10 of the present invention is a first to t-th transmission terminal (200a, 200b, 200c) between the first to t-th transmission terminals (200a, 200b, 200c) when transmitting power from a plurality of transmission terminals, such as the first to t-th transmission terminals (200a, 200b, 200c). Mutual inductance occurs, which lowers power transmission efficiency. Therefore, after the output currents of the first to t-th transmitting terminals 200a, 200b, and 200c are determined, the control unit 140 considers the mutual inductance occurring between the transmitting coils of each transmitting end in consideration of the first to t-th transmitting terminals 200a, 200a, The output current of 200b, 200c) is compensated.

As an example, below, when charging by transmitting power from the first and second transmitters 200a and 200b to the first receiver 210a, a method of compensating the output current of the first and second transmitters 200a and 200b will be described. Let's take a look.

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

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

V _T1 : the output voltage of the control unit 170 of the first and second transmitting terminals 200a and 200b

R _Tx1 : Equivalent internal resistance of the amplifier 110 of the first transmitting terminal 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 transmission terminal 200b

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

C _P2 : capacitance of the transmission resonator 220 of the second transmitting end 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 transmitting terminal 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

_IS : Receiving current of the first receiving end 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 end (210a)

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

w ₀ : resonant angular frequency of the resonator 140

In FIG. 5A, if there is a mutual inductance M _Tx between the first and second transmitting terminals 200a and 200b, by M _Tx Since an induced current is generated, it is difficult to obtain a desired power transmission efficiency by the current applied to the first and second transmitting terminals 200a and 200b. Therefore, when a current is applied to the first and second transmitting terminals 200a and 200b, the current applied to the first and second transmitting terminals 200a and 200b is compensated in consideration of the current induced by the mutual inductance M _Tx .

Looking at the method of compensating the current applied to the first and second transmitters 200a and 200b, when the initial current I _P1 is applied to the first transmitter 200a and the initial current I _P2 is applied to the second transmitter 200b, An equivalent circuit for the first transmitter 200a may be the same as that of FIG. 5B , and an equivalent circuit for the second transmitter 200b may be represented as shown in FIG. 5C . When Kirchhoff's law is applied 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 transmitting end 200a, the current I _p1 initially applied to the first transmitting end 200a and the current I _induced2 induced by the second transmitting end 200b are summed so that I _p1 ' flows. Able to know.

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

At this time, in the equivalent circuit for the second transmitting end 200b, the current I _p2 initially applied to the second transmitting end 200b and the current I _induced1 induced by the first transmitting end 200a are summed so that I _p2 ' flows. Able to know.

As described above, when I _p1 ' and I _p2 ' flow in the first and second transmitting terminals 200a and 200b, the current induced by this again affects each transmitting terminal, and Kirchhoff's law is applied to each equivalent circuit. Then we can get the following formula:

The current induced by I _p1 ' and I _p2 ' affects each transmitting end, so that I _p1 '_' and I _p2 '' _flow in each transmitting end. can be expressed as

At this time, since the sigma term converges to one value, it is not calculated to infinity, and if 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 influence of the induced current, the current flowing through each transmitter is summarized as follows.

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

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

I _p1 , I _p2 are the currents applied to each transmitter to obtain the best 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 In order to minimize the influence of the induced current, current should 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 influence of the induced current can be minimized.

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

, f₀ = 1MHz 인 상태에서 실험하였다.R _Tx1 = in FIGS. 6A to 6C 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.

Also, FIG. 6A is a case in which M ₁₁ = 600 nH, M ₂₁ = 300 nH, M _Tx = 0 nH, and FIGS. 6B and 6C are a case in which M ₁₁ = 600 nH, M ₂₁ = 300 nH, M _Tx = 300 nH. is a case in which the current applied to the first and second transmitters 200a and 200b is not compensated, and FIG. 6C is a case in which the current applied to the first and second transmitters 200a and 200b is compensated.

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

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, the control unit 170 of the first to t-th transmitting terminals 200a, 200b, and 200c transmits a pulse signal to minimize power consumption in a state in which power charging is not in progress. A standby mode for monitoring the presence of a load of the q-th receiving terminals 210a, 210b, and 210c is performed (700). If the presence of the load is confirmed (YES in 710), the control unit 170 controls the first to t-th transmitting terminals 200a, 200b, and 200c and the first to q-th receiving terminals 210a, 210b, and 210c mutual inductance (M) _tq ) is determined (720).

When the mutual inductance (M _tq ) is determined, the controller 170 generates a matrix regarding the mutual inductance (M _tq ) to determine a subset of the wireless charging device 10 ( 730 ), and applies an optimization algorithm to each subset. An optimal output current of the first to t-th transmitting terminals 200a, 200b, and 200c is determined (S740). In addition, since it is difficult to apply all environmental factors to each equation and optimization algorithm, although numerous factors may act in the charging environment, the control unit 170 controls the output currents of the determined first to t-th transmission terminals 200a, 200b, and 200c. is adjusted (750). In addition, in order to minimize the influence of the current induced by the mutual inductance (M _Tx ) between the first to t-th transmitting terminals 200a, 200b, and 200c, the output current of the first to t-th transmitting terminals 200a, 200b, and 200c is compensated for (760).

When the output currents of the first to t-th transmitters 200a, 200b, and 200c are determined, the first to t-th transmitters 200a, 200b, and 200c supply power to the first to q-th receivers 210a, 210b, and 210c to allow charging to proceed ( 770 ). At this time, since the charging environment may change due to a change in the position of the load during charging, the control unit 170 periodically monitors the charging environment to determine if there is a change in the charging environment (example of 780) the mutual inductance ( M _tq ) from the process of determining to the process of compensating the output currents of the first to t-th transmitters 200a, 200b, and 200c are 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 defined by the claims described below as well as the claims and equivalents.

100: power unit 110: amplification unit
120: communication unit 130: sensing 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 transmitting power using the power provided from the power supply and each including a transmission resonator including one capacitor and one inductor;
at least one receiving end each including a receiving resonator receiving power transmitted from the transmitting resonator and including one capacitor and one inductor, and a load performing charging using the received power;
and a controller configured to determine the output current of each of the plurality of transmitters, compensate the determined output current in consideration of mutual inductance between the plurality of transmitters, and apply the compensation to each of the plurality of transmitters.
According to claim 1,
The control unit determines a mutual inductance between each of the transmission resonator and each reception resonator, and uses each of the mutual inductances to independently perform wireless charging at the plurality of transmitting ends and the at least one receiving end. And An apparatus for determining the output current by determining at least one subset comprising a receiving end.
According to claim 1,
When the plurality of transmitters are configured as first and second transmitters,
The control unit applies a current corresponding to a conjugate value of a current flowing through each of the first and second transmitters to each of the first and second transmitters due to mutual inductance between the first and second transmitters.
According to claim 1,
When the plurality of transmitters are configured as first and second transmitters,
The control unit applies I ^* _comp1 , which is a conjugate value of I _comp1 , to the first transmitter, and the A device for applying I ^* _comp2 , which is the conjugate value of I _comp2 , to the second transmitter.

At this time, I _P1 : output current of the first transmitter before compensation
I _P2 : Output current of the second transmitter before compensation
I _comp1 : Current flowing in the first transmitting end due to the mutual inductance between the first and second transmitting end
I _comp2 : Current flowing through the second transmitting end due to the mutual inductance between the first and second transmitting end
R _Tx1 : Equivalent internal resistance of the amplifier of the first transmitting stage
R _Tx2 : Equivalent internal resistance of the amplifier of the second transmitting stage
R _P1 : Equivalent internal resistance of the transmission resonance part of the first transmission stage
R _P2 : Equivalent internal resistance of the transmit resonance part of the second transmitting end
M _Tx : Mutual inductance between the first and second transmitting ends
In the wireless power charging method,
Transmitting power to at least one receiving terminal each including a reception resonator including one capacitor and one inductor and a load performing charging using the received power using the power provided from the power supply, one capacitor and determining an output current of each of a plurality of transmission terminals each including a transmission resonator including one inductor;
and compensating for the determined output current in consideration of mutual inductance between the plurality of transmitters and applying the compensation to each of the plurality of transmitters.
6. The method of claim 5,
The process of determining the output current is
determining a mutual inductance between the plurality of transmission resonators and the at least one reception resonator;
determining at least one subset comprising 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 inductances;
and determining an output current of each of the plurality of transmitting terminals by using the subset.
6. The method of claim 5,
When the plurality of transmitters are configured as first and second transmitters, the applying process includes:
and applying a current corresponding to a conjugate value of a current flowing through each of the first and second transmitters to each of the first and second transmitters due to mutual inductance between the first and second transmitters.
6. The method of claim 5,
When the plurality of transmitters are configured as first and second transmitters, the applying process includes:
Applying I ^* _comp1 which is a conjugate value of I _comp1 to the first transmitter, A method comprising the step of 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 transmitter before compensation
I _P2 : Output current of the second transmitter before compensation
I _comp1 : Current flowing in the first transmitting end due to the mutual inductance between the first and second transmitting end
I _comp2 : Current flowing through the second transmitting end due to the mutual inductance between the first and second transmitting end
R _Tx1 : Equivalent internal resistance of the amplifier of the first transmitting stage
R _Tx2 : Equivalent internal resistance of the amplifier of the second transmitting stage
R _P1 : Equivalent internal resistance of the transmission resonance part of the first transmission stage
R _P2 : Equivalent internal resistance of the transmit resonance part of the second transmitting end
M _Tx : Mutual inductance between the first and second transmitting ends

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