KR20210158247A - Wireless charging system for electric vehicle - Google Patents

Abstract

The present invention relates to a wireless charging system which charges an electric vehicle and the like by using a capacitive wireless power transmission method. One aspect of the present invention is a wireless charging transmitting unit which provides electric power wirelessly through capacitive coupling with a receiving unit including at least two receiving unit conductive plates, and comprises: a pad unit which is capacitively coupled with the receiving unit conductive plate and includes larger numbers of conductive plates compared to the number of the receiving unit conductive plates; and a switching circuit which selectively connects each of the conductive plates with a direct current power supply. The present invention aims to reduce misalignment between the conductive plates of the transmitting unit and the conductive plates of the receiving units.

Description

Wireless charging system for electric vehicles {WIRELESS CHARGING SYSTEM FOR ELECTRIC VEHICLE}

The present invention relates to a wireless charging system. Specifically, the present invention relates to a wireless charging system for charging an electric vehicle or the like using a capacitive wireless power transmission method.

Wireless power transfer may be largely divided into an inductive wireless power transfer and a capacitive wireless power transfer.

The inductive wireless power transmission method is a method in which a transmitter and a receiver are magnetically coupled to each other to wirelessly transmit power. To this end, in the inductive wireless power transmission method, it is necessary to use coils for the transmitter and the receiver, respectively. When a magnetic material (ferrite core, etc.) is used to increase the magnetic coupling between the transmitter coil and the receiver coil in the inductive wireless power transmission method, an increase in volume and weight and an increase in price may become problems. If a magnetic material is not used, magnetic coupling occurs through an air gap with low magnetic permeability, so there is a problem in that the coupling coefficient is low, thereby reducing the efficiency of energy transfer.

In the capacitive wireless power transmission method, the conductor plate of the transmitter and the conductor plate of the receiver face each other, and power can be transmitted wirelessly by using a combination of an electric field formed between the conductor plate of the transmitter and the conductor plate of the receiver. That is, energy may be transferred using a capacitance formed between the transmitter conductive plate and the receiver conductive plate. Unlike the inductive wireless power transmission method, the capacitive wireless power transmission method has a simple structure and low-cost design because it does not need to use a bulky and heavy coil or magnetic material, and there is no loss due to eddy current or skin effect. There is this.

However, in the case of capacitive wireless power transmission, if the distance between the transmitting part and the receiving part conductor plate is long or poorly aligned, the amount of transmitted power or performance such as power transmission efficiency may be reduced. Therefore, countermeasures are required do.

According to an embodiment, an object of the present invention is to reduce misalignment between a transmitter conductor plate and a receiver conductor plate in a wireless charging system for a vehicle.

According to an embodiment, an object of the present invention is to reduce performance degradation of wireless power transmission despite misalignment between the transmitter conductor plate and the receiver conductor plate.

An object of the present invention is to reduce performance degradation due to misalignment by using a simple circuit according to an embodiment.

One aspect of the present invention for achieving the above object is a wireless charging transmitter that wirelessly provides power through capacitive coupling to a receiver including at least two receiver conductive plates, wherein the receiver conductive plate and capacitive coupling ( a pad portion comprising a number of conductive plates greater than the number of conductive plates of the receiver, which is capacitively coupled; and a switching circuit selectively connecting each of the conductor plates to a DC power supply.

In the wireless charging transmitter, each of the conductor plates is paired with another non-adjacent conductor plate, and in the switching circuit, any one of the two conductor plates forming the pair is connected to the high potential side of the DC power supply. In this case, the other one may operate to be connected to the low potential side of the DC power supply.

In the wireless charging transmitter, a capacitor may be connected between the two conductor plates forming the pair.

In the wireless charging transmitter, each of the conductive plates may be paired with a conductive plate disposed at a distance most similar to the reference distance among other conductive plates.

In the wireless charging transmitter, the reference distance may be a distance between the two conductor plates of the receiver.

In the wireless charging transmitter, each of the conductor plates belongs to any one of a first conductor plate group, a second conductor plate group, and a third conductor plate group, and the conductor plate of the first conductor plate group is the DC power supply. can be connected only to the high potential side of the third conductor plate group, the conductor plate of the third conductor plate group can be connected only to the low potential side of the DC power supply, and the conductor plate of the second conductor plate group is connected to the high potential side and the low potential side can be optionally connected to.

In the wireless charging transmitter, the conductor plates of the first conductor plate group may each be connected to the high potential side through one switch, and the conductor plates of the third conductor plate group may each be connected to the low potential side through one switch. side, and the conductor plates of the second conductor plate group may be selectively connected to the high potential side and the low potential side through two switches, respectively.

In the wireless charging transmitter, a conductive plate aligned with the receiver conductive plate among the conductive plates may be activated.

In the wireless charging transmitter, the activation target conductor plate may be determined based on an impedance measurement result.

In the wireless charging transmitter, the transmitter receives the distance between the two conductor plates of the receiver and the power information received by the receiver from the receiver, and the conductor plate of the pad part from the distance information between the two conductor plates of the receiver The pair may be matched, and a conductor plate capable of transmitting maximum power may be determined and activated based on the power information received by the receiver.

In the wireless charging transmitter, the activated pair of conductive plates may be plural, and conductive plates adjacent to each other in the plurality of pairs of conductive plates may be driven at substantially the same frequency and phase with each other.

In the wireless charging transmission unit, the transmission unit may be installed in the anti-collision block of the parking lot.

Another aspect of the present invention, a receiver including two receiver conductor plates; and a transmitter for wirelessly providing power to the receiver conductor plate through capacitive coupling, wherein the transmitter is capacitively coupled to the receiver conductor plate. a pad portion including a conductive plate of and a switching circuit selectively connecting each of the DC power source and the conductive plate to each other.

According to the present invention, according to an embodiment, it is possible to reduce misalignment between the transmitter conductor plate and the receiver conductor plate in the wireless charging system for a vehicle.

In addition, according to an embodiment, according to the present invention, performance degradation of wireless power transmission can be reduced despite misalignment between the transmitter conductor plate and the receiver conductor plate.

In addition, according to the embodiment, according to the present invention, performance degradation due to misalignment can be reduced by using a simple circuit.

1 illustrates a basic structure of a capacitive wireless charging circuit according to an embodiment of the present invention.
2 exemplifies capacitance formed in the case of using two transmitter conductor plates and two receiver conductor plates.
3 illustrates an equivalent circuit of the capacitive wireless charging circuit of FIG. 1 ;
4 and 5 illustrate the arrangement of the transmitter pad part and the receiver pad part according to an embodiment.
6 exemplifies the arrangement of the transmitter pad part and the receiver pad part according to the comparative example compared to FIG. 5 .
7 illustrates an arrangement of a transmitter pad unit and a receiver pad unit according to another exemplary embodiment.
8 illustrates a capacitive wireless charging system according to an embodiment.
FIG. 9 specifically illustrates the transmitter circuit of FIG. 8 .
10 illustrates an operating state of a switching circuit according to an embodiment.
11 and 12 illustrate the compensation circuit of FIG. 9 .
13 illustrates a circuit for the determination of an active conductor plate according to an embodiment.
14 and 15 illustrate a method of determining an active conductor plate according to an embodiment.
16 illustrates a capacitive wireless charging system according to an embodiment.
17 and 18 illustrate a wireless charging system for an electric kickboard according to an embodiment.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is formed between each component. It should be understood that elements may also be “connected,” “coupled,” or “connected.”

1 illustrates the basic structure of a capacitive wireless charging circuit.

Referring to FIG. 1 , the capacitive wireless charging circuit may include a transmitter circuit 110 , a transmitter pad unit 140 , a receiver pad unit 160 , and a receiver circuit 150 . The transmitter circuit 110 may include a transmitter switching circuit 120 and a transmitter compensation circuit 130 . The receiver circuit 150 may include a receiver compensation circuit 170 and a receiver rectifying circuit 180 .

The capacitive wireless charging circuit may transfer power received from the external power supply 10 to the external battery 20 in a wireless power transmission method through capacitive coupling. The power source 10 may be a direct current power source, but may also be used by rectifying an alternating current power source.

The transmitter switching circuit 120 may selectively connect the power supply 10 and each of the transmitter conductor plates 141 and 142 . According to an embodiment, the switching element included in the transmitter switching circuit 120 may apply an AC voltage (eg, a square wave voltage) to the transmitter compensation circuit 130 while repeating on/off at a switching frequency. A typical full-bridge switching circuit or a half-bridge switching circuit may be used for the transmitter switching circuit 120 , but is not limited thereto. A typical semiconductor switching device such as a MOSFET, an IGBT, an MCT, or a BJT may be used for the transmitter switching circuit 120 .

The transmitter compensation circuit 130 may be used as needed to increase the efficiency of power transfer between the transmitter switching circuit 120 and the transmitter pad unit 140 . According to an embodiment, the transmitter compensation circuit 130 may include an inductor, a capacitor, and the like. Illustratively, the transmitter compensation circuit 130 causes resonance with the capacitance formed by the transmitter pad unit 140 and the receiver pad unit 160 in the vicinity of the switching frequency of the transmitter switching circuit 120 to increase the efficiency of power transfer. can

The transmitter pad unit 140 may include a plurality of transmitter conductor plates 141 and 142 . The plurality of transmitter conductive plates 141 and 142 may be coupled to the plurality of receiver conductive plates 161 and 162 through an electric field. For example, the transmitter first conductor plate 141 forms a capacitor with the receiver first conductor plate 161 , and the transmitter second conductor plate 142 forms a capacitor with the receiver second conductor plate 162 . can be understood schematically.

According to an embodiment, the first conductive plate 141 of the transmitter and the second conductive plate 142 of the transmitter may operate in pairs. For example, a current flowing from the transmitting unit first conductor plate 141 to the receiving unit first conductor plate 161 and a current flowing from the transmitting unit second conductor plate 142 to the receiving unit second conductor plate 162 are substantially mutually exclusive. It may be understood that when the phases are opposite to each other, the first conductive plate 141 of the transmitter and the second conductive plate 142 of the transmitter operate in pairs.

The receiver pad unit 160 may include a plurality of receiver conductor plates 161 and 162 . The plurality of receiver conductive plates 161 and 162 may be coupled to the plurality of transmitter conductive plates 141 and 142 through an electric field.

The receiver compensation circuit 170 may be used as needed to increase the efficiency of power transfer between the receiver pad unit 160 and the receiver rectifier circuit 180 . According to an embodiment, the receiver compensation circuit 170 may include an inductor, a capacitor, and the like. Illustratively, the receiver compensation circuit 170 causes resonance with the capacitance formed by the transmitter pad unit 140 and the receiver pad unit 160 near the switching frequency of the transmitter switching circuit 120 to increase the efficiency of power transfer. can

The receiver rectifying circuit 180 may rectify the alternating (or alternating current) voltage/current transmitted through the receiver compensation circuit 170 to output a DC voltage/current. The DC voltage/current output from the rectifier circuit 180 may be used to charge the battery 20 . A typical full-bridge rectifier circuit or a half-bridge rectifier circuit using semiconductor diodes may be used as the rectifier circuit 180 , but is not limited thereto. Although the output of the rectifier circuit 180 is illustrated as being directly connected to the battery 20 in FIG. 1 , the output of the rectifier circuit 180 may be supplied to the battery 20 after additional processing according to an embodiment.

In the following, when there is no fear of confusion about the configuration of the transmitter such as the transmitter circuit 110, the transmitter switching circuit 120, the transmitter compensation circuit 130, and the transmitter pad 140, the term 'transmitter' is used for convenience of explanation. Expressions are sometimes omitted. The configuration of the receiver is referred to as 'receiver'. For example, the expression 'conductor plate' may be understood to mean a conductor plate of a transmitter.

2 exemplifies the capacitance formed when two transmitter conductor plates P1 and P2 and two receiver conductor plates P3 and P4 are used.

_{The two capacitances (C 13} , C ₂₄ ) formed between the two facing each other _{will have the largest relative value, and the capacitances (C 12} , C ₃₄ , C ₁₄ , C ₂₃ ) that are displaced from each other or do not face each other ) will have a relatively small capacitance.

Using the parasitic capacitances illustrated in FIG. 2 , the mutual capacitance C _M , the first self capacitance C _in1 , and the second self capacitance C _in2 may be defined as in Equations 1 to 3 below. Here, the mutual capacitance (C _M ) may be understood as a capacitance that is related to the coupling between the transmitter and the receiver and effectively acts on power transmission, and the first self-capacitance (C _in1 ) and the second self-capacitance (C _in2 ) are It can be understood as a capacitance mainly acting inside the transmitter and the receiver, respectively.

[Equation 1]

[Equation 2]

[Equation 3]

In FIG. 2 , the facing area of the first conductor plate P1 and the second conductor plate P2 and the facing area of the third conductor plate P3 and the fourth conductor plate P4 are sufficiently small compared to the distance between them. , when the shift between the first conductor plate P1 and the fourth conductor plate P4 and the shift between the second conductor plate P2 and the third conductor plate P3 is large, the capacitances C ₁₂ , C ₃₄ , C ₁₄ , C ₂₃ ) may be assumed to be sufficiently small compared to the capacitances C ₁₃ , C _{24 , and in this case, the mutual capacitance C M} of Equation 1 may be approximated as in Equation 4.

[Equation 4]

That is, the mutual capacitance C _{M is the capacitance C 13} between the first conductor plate P1 and the third conductor plate P3 and the capacitance between the second conductor plate P2 and the fourth conductor plate P4 . (C ₂₄ ) may increase proportionally.

As the mutual capacitance ( _CM ) increases, the impedance disposed in series in the power transmission path between the transmitter and the receiver decreases, so that the efficiency of power transmission may increase and the amount of transmitted power may increase. However, as can be seen from Equation 4, when the alignment of the conductor plate of the transmitter and the conductor plate of the receiver is misaligned, the mutual capacitance ( _CM ) decreases, so that the efficiency of power transmission may decrease and the amount of transmitted power may decrease.

3 illustrates an equivalent circuit of the capacitive wireless charging circuit of FIG. 1 ;

In FIG. 3 , a full-bridge switching circuit is exemplified in the switching circuit 120 , and a first inductor L ₁ and a first capacitor C ₁ are used in the compensation circuit 130 . The inside of the pad unit 140 _{is replaced by the first self-capacitance C in1} and the first current source I _M1 , and the inside of the receiving unit pad unit 160 is the second self-capacitance C _in2 and the second current source I _M2 ), which exemplifies an equivalent circuit of the pad unit 140 and the receiver pad unit 150 .

The first current source I _M1 is a voltage controlled current source operating as shown in Equation 5 below, and the second current source I _M2 is a voltage controlled current source operating as shown in Equation 6 below.

[Equation 5]

[Equation 6]

Here, ω _sw is each frequency of the switching frequency (f _sw ) at which the _{switching circuit 120 operates, C M} is the mutual capacitance described with reference to FIG. 2 , and V _C1 is the first self-capacitance (C _in1 ) of both ends. voltage, and V _C2 is the voltage across the second self-capacitance (C _{in2 ).}

_{A second inductor L 2} and a second capacitor C ₂ are exemplified in the receiver compensation circuit 170 , and a full-bridge diode rectifier circuit is exemplified in the receiver rectifier circuit 180 .

The DC voltage Vi provided by the DC power supply 10 is changed to an alternating voltage (or AC voltage) having a predetermined or variable switching frequency by the switching circuit 120 , and is applied to both ends of the compensation circuit 130 , alternately The voltage (or AC voltage) is converted back into direct current through the receiver rectifying circuit 180 through the transmitter compensation circuit 130 , the transmitter pad part 140 , the receiver pad part 160 , and the receiver compensation circuit 170 , and the battery (20) can be supplied.

At this time, if the distance between the transmitter pad unit 140 and the receiver pad unit 160 is relatively far compared to the size, the capacitance formed by the transmitter pad unit 140 and the receiver pad unit 160 is small, Since the capacitance having a large impedance is placed in series in the power transmission path, the efficiency of power transmission may be reduced. In consideration of this problem, according to the embodiment, the transmitter compensation circuit 130 and the receiver compensation circuit 170 have capacitance and resonance formed by the transmitter pad part 140 and the receiver pad part 160 in a switching frequency band. ) and effectively lowering the impedance of the power transmission path, the efficiency of power transmission can be increased.

In this way, when resonance is used, the voltage and current through the transmitter compensation circuit 130 , the transmitter pad part 140 , the receiver pad part 160 , and the receiver compensation circuit 170 have a shape similar to a sine wave. In this case, it is possible to understand the operation of the circuit by analyzing the fundamental wave component of the switching frequency (that is, since the effect of the fundamental component increases and the influence of the harmonic component becomes small due to resonance, the analysis of the fundamental wave component is simple and effective analysis method). If the active power transferred from the transmitter to the receiver is derived through the fundamental wave component analysis, it can be summarized as in Equation 7 below.

[Equation 7]

Here, θ is the phase difference _{between V C1} and V _{C2 .}

Through Equation 7, the power (P) transferred from the transmitter to the receiver is the switching frequency (f _sw ), the mutual capacitance ( _CM ), the absolute value of the first self-capacitance voltage (V _C1 ), and the second self-capacitance voltage ( It can be seen that it is proportional to the absolute value of V _{C2 ).} Therefore, it may be important from the viewpoint of power transmission to increase _{the mutual capacitance (CM} ) through the alignment of the transmitting part conductor plate and the receiving part conductor plate.

4 and 5 illustrate the arrangement of the transmitter pad unit 140 and the receiver pad unit 160 according to an embodiment.

As described above, accurate alignment between the transmitter pad unit 140 and the receiver pad unit 160 is an important factor for efficient power transmission. In addition, since the distance between the transmitter pad unit 140 and the receiver pad unit 160 may also _{significantly affect the mutual capacitance CM} , it needs to be considered as important. In particular, in the wireless charging system for a vehicle, the arrangement of the transmitter pad unit 140 and the receiver pad unit 160 may affect the distance between the transmitter pad unit 140 and the receiver pad unit 160 and the degree of alignment, so be careful. needs to be designed.

4 exemplifies the arrangement of the transmitter pad unit 140 and the receiver pad unit 160 according to an embodiment. 4 (b) illustrates a case in which the transmitter pad unit 140 is installed in a separate structure 50 disposed adjacent to the rear of the collision avoidance block 40 .

When the transmitter pad unit 140 is installed at any position within the parking area, misalignment may occur in both the X-axis direction (the width direction of the vehicle) and the Y-axis direction (the longitudinal direction of the vehicle) depending on the parking position of the vehicle 30 . chances are high On the other hand, since the wheels of the vehicle 30 are generally parked in close contact with or adjacent to the anti-collision block 40, the transmitter pad is based on the anti-collision block 40 as shown in FIG. 4(a) or FIG. 4(b). When the unit 140 and the receiver pad unit 160 are installed, it is possible to reduce misalignment in the Y-axis direction to increase the _{mutual capacitance C M .} In addition, when the transmitter pad unit 140 is installed on the anti-collision block 40 as shown in FIG. 4( a ) or on the structure 50 adjacent to the anti-collision block 40 as shown in FIG. Since the distance in the Z-axis direction (the height direction of the vehicle) between the unit 140 and the receiver pad unit 160 may be reduced, the _{mutual capacitance CM may be increased.}

5 exemplifies a case in which the size of the receiving unit pad unit 160 in the X-axis direction is larger than that of the transmitting unit pad unit 140 . In this case, as shown in FIG. 5( a ), when the transmitter pad part 140 and the receiver pad part 160 are well aligned in the X-axis direction, as shown in FIG. 5( b ), the transmitter pad part 140 and the receiver pad part When the alignment in the X-axis direction between (160) is shifted to some extent, the mutual capacitance ( _CM ) may not have much difference. In terms of power transfer, it is important not only to increase the _{mutual capacitance (CM} ), but also to reduce the deviation of the _{mutual capacitance (CM ).} As illustrated in FIG. 5 , when the size of the receiving unit pad unit 160 is larger than that of the transmitting unit pad unit 140 _{, the variation in mutual capacitance CM} due to misalignment can be reduced to increase the efficiency of power transmission.

FIG. 6 illustrates the arrangement of the transmitter pad part and the receiver pad part according to the comparative example compared to FIG. 5 , and illustrates a case where the transmitter pad part 140 and the receiver pad part 160 have the same size in the X-axis direction. In this case, when well aligned in the X-axis direction as shown in FIG. 6(a), there is no significant difference from the embodiment of FIG. 5(a), but when misalignment occurs as shown in FIG. 6(b), the mutual capacitance C _M ), the overall power transmission efficiency may deteriorate.

7 illustrates an arrangement of a transmitter pad unit and a receiver pad unit according to another exemplary embodiment.

Referring to FIG. 7 , the transmitter pad unit 140 is disposed elongated in the X-axis direction and is divided into a plurality of conductive plates so that some of the conductive plates can be selectively activated. When aligned as shown in Fig. 7(a), the conductive plate 743 at a position well aligned with the receiver pad unit 160 is selectively activated and operated, and when aligned as shown in Fig. 7(b), the receiver pad unit ( Another conductor plate 744 in a position well aligned with 160 may be selectively activated and operated. In this case, even if the position of the vehicle 30 in the X-axis direction is changed, the conductor plate at a position well aligned with the receiver pad unit 160 is selectively activated, thereby _{reducing the deviation of the mutual capacitance (CM} ) to increase the efficiency of power transmission. can be raised

As such, when the transmitter pad unit 140 is disposed on the collision avoidance block in the wireless charging system for a vehicle, by reducing misalignment in the Y-axis direction and reducing the distance in the Z-axis direction, while reducing the deviation of _{mutual capacitance (CM )} size can be increased. In addition, when some conductive plates well aligned with the receiver pad 160 are selectively activated while arranging the transmitter pad unit 140 divided into a plurality of conductor plates to be elongated in the X-axis direction, misalignment in the X-axis direction is prevented. impact can also be reduced.

8 illustrates a capacitive wireless charging system according to an embodiment of the present invention.

Referring to FIG. 8 , the capacitive wireless charging system may include a transmitter including a transmitter circuit 110 and a transmitter pad 840 , and a receiver including a receiver pad 860 and a receiver circuit 150 . have.

As for the transmitter circuit 110 and the receiver circuit 150 , what has been described with reference to FIGS. 1 to 3 may be applied.

The transmitter pad part 840 may include a plurality of conductive plates 840a to 840n. The plurality of conductor plates 840a to 840n may be divided and operated individually. According to an embodiment, each of the plurality of conductor plates 840a to 840n may be individually and selectively activated by the transmitter circuit 110 . The number of the conductive plates 840a to 840n of the pad part 840 may be greater than the number of the receiving part conductive plates 860a and 860b. According to an embodiment, the length of each of the conductor plates 840a to 840n in the arrangement direction may be smaller than the length of each of the receiver conductor plates 860a and 860b.

According to an embodiment, the switching circuit included in the transmitter circuit 150 may activate the selected conductor plate by selectively connecting each of the conductor plates 840a to 840n with a DC power source. According to an embodiment, among the conductor plates 840a to 840n, the conductor plates aligned with the receiver conductor plates 860a and 860b may be activated. For example, in FIG. 8 , the third to fifth conductive plates from the left may be activated, and the second to fourth conductive plates from the right may be activated. In this case, the third to fifth conductive plates from the left are driven at the same frequency and phase to operate as one large conductive plate, and may be capacitively coupled to the first conductive plate 860a of the receiver. In addition, the second to fourth conductor plates from the right are driven at the same frequency and phase with each other, so that they operate like one large conductor plate, and can be capacitively coupled to the second conductor plate 860b of the receiver.

The receiving unit pad unit 860 may include at least two receiving unit conductive plates 860a and 860b. Each of the receiver conductive plates 860a and 860b may operate in capacitive coupling with the activated conductive plate(s) among the conductive plates 840a to 840n.

9 illustrates the transmitter circuit of FIG. 8 .

Referring to FIG. 9 , the transmitter circuit 910 may include a plurality of transmitter circuit modules 910a to 910n. Each of the transmitter circuit modules 910a to 910n may be disposed to correspond to each of the transmitter conductor plates 840a to 840n.

According to an embodiment, the first transmitter circuit module 910a may include first switching circuits S1a and S2a and a first compensation circuit 130a. In addition, it may optionally further include a first input terminal capacitor 911a.

For the first switching circuits S1a and S2a, for example, a half-bridge configuration including two switches may be used. The first switching circuits S1a and S2a may selectively connect the first conductor plate 840a to any one of the wires 41 and 42 respectively connected to both terminals Vp and Vn of the DC power supply 10 . . Here, the wiring 41 is a wiring connected to the high potential side Vp of the DC power supply 10 , and the wiring 42 is a wiring connected to the low potential side Vn of the DC power supply 10 .

When the first switch S1a conducts in the first switching circuits S1a and S2a, the first conductor plate 840a may be connected to the high potential side Vp of the DC power supply 10 . At this time, a current flows from the high potential side Vp of the DC power supply 10 to the receiver first conductor plate 860a through the first switch S1a, the first compensation circuit 130a, and the first conductor plate 840a. A flow path may be provided. That is, when the first switch S1a is turned on, a path through which current is supplied from the high potential side Vp of the DC power supply 10 to the receiver may be provided.

When the second switch S2a conducts in the first switching circuits S1a and S2a, the first conductor plate 840a may be connected to the low potential side Vn of the DC power supply 10 . At this time, a path through which current flows from the first conductor plate 860a of the receiver to the low potential side Vn of the DC power supply 10 through the first conductor plate 840a and the second switch S2a may be provided. . That is, when the second switch S2a is turned on, a path through which the current is returned from the receiver to the low potential side Vn of the DC power supply 10 may be provided.

The first switching circuits S1a and S2a connect the first conductor plate 840a to the high potential side Vp of the DC power supply 10 within one switching period and then connect the first conductor plate 840a to the low potential side Vn again. By repeating , it is possible to cause resonance in the switching frequency band to transmit power from the transmitter to the receiver. According to an embodiment, the first switching circuits S1a and S2a may adjust the power transmitted from the transmitter to the receiver by changing the _{switching frequency f sw as shown in Equation 7 above.}

It can be understood that when both the first switch S1a and the second switch S2a do not conduct and maintain an off state in the entire section within one switching period, the first conductor plate 840a is not activated in the corresponding switching period. have.

As described above, the first conductor plate 840a may operate either in activation or inactivation by the operation of the first switching circuits S1a and S2a. In the activated state, the first switching circuits S1a and S2a may adjust the power transferred from the transmitter to the receiver by changing the switching frequency.

As described with reference to FIGS. 1 to 3 , the first compensation circuit 130a may be disposed between the first switching circuits S1a and S2a and the first conductor plate 840a to increase power transmission efficiency. .

The first input capacitor 911a may function as an input filter for stabilizing a voltage between the high potential side Vp and the low potential side Vn of the DC power supply 10 .

The configuration and operation of each of the other transmitter circuit modules 910b to 910n may be similar to those of the first transmitter circuit module 910a.

By the transmitter circuit 910 configured as described above, some of the conductive plates 840a to 840n may be activated and operated while others may not be activated. Also, according to an embodiment, the activated conductor plates may be operated in pairs by two. Here, the paired operation of the two conductor plates may be understood as complementary operations in a state in which each of the two conductor plates is connected to the DC power supply 10 . For example, each of the conductor plates may be alternately connected to the high potential side (Vp) and the low potential side (Vn) of the DC power source within the switching period through the switching circuits S1a and S2a. When connected to the upper side (Vp), the other conductor plate is connected to the low potential side (Vn), and when one conductor plate is connected to the low potential side (Vn), when the other conductor plate is connected to the high potential side (Vp) , it can be understood that the two conductor plates operate in pairs with each other. In this case, currents flowing through the two conductor plates forming a pair may have substantially opposite phases.

According to an embodiment, a plurality of pairs of conductive plates are activated, and conductive plates adjacent to each other in the plurality of pairs of conductive plates may be driven with substantially the same frequency and phase. In this case, since the conductor plates that are adjacent to each other and driven at substantially the same frequency and phase operate as one large conductor plate, the effect of interference between the conductor plates is reduced, thereby enabling efficient power transmission.

For example, in FIG. 9 , the conductor plates 840b and 840c aligned with the receiving unit first conductor plate 860a are activated, and the conductor plates 840m and 840n aligned with the receiving unit second conductor plate 860b are activated. can be activated. In this case, the conductive plate 840b may be paired with the conductive plate 840m, and the conductive plate 840c may operate in pairs with the conductive plate 840n. In addition, according to the embodiment, the two conductor plates 840b and 840c are driven with the same frequency and phase to operate as one conductor plate, and the two conductor plates 840m and 840n are driven with the same frequency and phase to each other. It can operate like a single conductor plate.

An operation waveform of the switching circuit in the case of forming the pair may be as illustrated in FIG. 10 . In FIG. 10 , S1b and S2b are the operating states of the switching circuit corresponding to the conductor plate 840b, S1c and S2c are the operating states of the switching circuit corresponding to the conductor plate 840c, and S1m and S2m are the operating states of the conductor plate 840m. ) are the operating states of the switching circuit, S1n and S2n are the operating states of the switching circuit corresponding to the conductor plate 840n, and T _sw is the reciprocal of the _{switching frequency f sw} as the switching period. 10 shows that the conductor plate 840b is paired with the conductor plate 840m and the conductor plate 840c is paired with the conductor plate 840n, but the conductor plate 840b and the conductor plate 840c are identical to each other. It exemplifies a situation in which it operates at the same frequency and phase and the conductor plate 840m and the conductor plate 840n operate at the same frequency and phase. However, the embodiment of the present invention is not limited thereto, and according to the embodiment, adjacent conductive plates may operate at different frequencies and/or phases. For example, in FIG. 10, the conductor plate 840b and the conductor plate 840c have the same frequency but operate in different phases, and the conductor plate 840m and the conductor plate 840n operate at the same frequency but different phases. have.

11 and 12 illustrate the compensation circuit of FIG. 9 .

First, referring to FIG. 11 , the compensation circuit of the first transmitter circuit module 1110a may include a first inductor L1a and a first capacitor C1a.

One end of the first inductor L1a may be connected to a connection node of the first switch S1a and the second switch S2a, and the other end of the first inductor L1a may be connected to the first conductor plate 840a.

One end of the first capacitor C1a may be connected to the first conductor plate 840a, and the other end of the first capacitor C1a may be connected to a conductor plate that is paired with the first conductor plate 840a. That is, the first capacitor C1a may be understood as a compensation capacitor connected between two conductive plates forming a pair to perform a compensation function. The first capacitor C1a is generally _{designed to have a relatively larger capacitance than the mutual capacitance C M} , and the first capacitor C1a having a relatively large capacitance is connected in parallel to each other having a relatively small capacitance. There is an advantage in that the size and volume of the first inductor L1a can be reduced by assisting the capacitance C _{M to resonate with the first inductor L1a.} In addition, since the first capacitor C1a having a relatively large capacitance _{assists the mutual capacitance C M} having a relatively small capacitance, the mutual capacitance C according to a change in alignment or distance between the transmitter conductor plate and the receiver conductor plate _M ) has the advantage of reducing the effect of the deviation on the performance.

According to an embodiment, each of the conductive plates 840a to 840n may be paired with another non-adjacent conductive plate. Also, according to an embodiment, each of the conductive plates 840a to 840n may be paired with a conductive plate disposed at a distance most similar to the reference distance among other conductive plates. Here, the reference distance may be the distance D2 between the two conductive plates 960a and 960b of the receiver. For example, when selecting a conductor plate to be a pair of any one of the conductor plates (eg, 840b) of the transmitter, the most similar distance (D1) based on the distance (D2) between the two conductor plates (960a, 960b) of the receiver ), a pair can be formed by selecting the conductor plate 840m having the

In this way, when two conductor plates at a distance similar to the distance D2 between the two conductor plates 960a and 960b of the receiver are configured as a pair, and a compensation capacitor C1 is connected between the pair of conductor plates , it is possible to increase the number of pairs of conductor plates that are well aligned with the two conductor plates 960a and 960b of the receiver (when both conductor plates of the pair are well aligned with the conductor plate of the receiver), and accordingly Among the conductor plates, there is an advantage in that the number of pairs of conductor plates operated with high efficiency by the compensation capacitor C1 increases. Unlike this embodiment, if two conductor plates at a distance different from the distance D2 between the two conductor plates 960a and 960b of the receiver are paired with each other, and a compensation capacitor ( When C1) is connected, in comparison with this embodiment, even though the number of activated conductor plates is the same, the number of conductor plate pairs on which the compensation capacitor C1 effectively operates among the activated conductor plates is reduced, so overall energy transfer efficiency This can be lowered.

12 illustrates a compensation circuit according to another embodiment. The compensation circuit illustrated in FIG. 12 is different from the compensation circuit illustrated in FIG. 11 in that it further includes second inductors L2a to L2n. The second inductors L2a to L2n are connected between the other ends of the first inductors L1a to L1n and the conductor plates 840a to 840n in each of the transmitter circuit modules 1210a to 1210n to perform a compensation function to transmit power. efficiency can be increased. In this case, as described with reference to FIG. 11 , two conductor plates at a distance similar to the distance D2 between the two conductor plates 960a and 960b of the receiver may be configured in pairs.

13 illustrates a circuit for the determination of an active conductor plate according to an embodiment.

Referring to FIG. 13 , each of the transmitter circuit modules 1310a to 1310n may further include an impedance sensing unit 1312a , a comparator 1313a , and an activation determining unit 1314a.

The impedance sensing unit 1312a may calculate the internal impedance Z _in using information on the voltage v and the current i _{sen inside the transmitter circuit module 1310a . The impedance Z in} inside the transmitter circuit module 1310a may vary according to the alignment degree of the transmitter conductive plate 840a and the receiver conductive plate. In this embodiment, using this principle, the internal impedance (Z _{in ) is calculated using the voltage (v) and current (i sen} ) inside the transmitter circuit module 1310a, and the corresponding transmitter conductor plate 840a and the receiver It is possible to determine whether the conductor plates are aligned. According to an embodiment, the impedance sensing unit 1312a detects a voltage at a connection node between the switching circuits S1a and S2a and the compensation circuit 1330a and a current flowing from the switching circuits S1a and S2a to the compensation circuit 1330a. Although it is possible to calculate the internal impedance Z _in by detection, the position at which the impedance sensing unit 1312a detects the voltage and current is not limited thereto.

The comparator 1313a may compare the detected internal impedance Z _in with a reference impedance Z _c . The reference impedance Z _c may be an impedance serving as a reference for determining whether the transmitter conductive plate 840a and the receiver conductive plate are aligned.

The activation determining unit 1314a may determine whether the corresponding transmission unit conductor plate 840a is activated based on the comparison result of the comparator 1313a.

The impedance sensing unit 1312a , the comparator 1313a , and the activation determining unit 1314a may be implemented by hardware, software, or a mixture thereof.

As such, the activation target conductor plate may be determined based on the impedance measurement result. Impedance measurements may be performed periodically. Illustratively, an activation conductor plate determination section may be periodically set in the middle of power transmission, and the activation conductor plate may be reset through impedance measurement in this section. According to the present embodiment, since it is possible to selectively activate in real time the conductor plate of the transmitter that is well aligned with the pad part of the receiver, it is possible to increase the efficiency of power transmission.

14 and 15 illustrate a method of determining an active conductor plate according to another embodiment. In FIG. 15, reference numerals 1540a to 1540m denote respective conductor plates constituting the pad part, and reference numerals 1560a and 1560b denote positions of the receiving part conductor plates.

First, the transmitter may obtain information on the size and distance of the conductor plate of the receiver from the receiver (S1401). For example, the size of the receiver conductive plate may be the length W2 of the first receiver conductive plate 1560a or the second receiver conductive plate 1560b in the transverse direction (the arrangement direction of the transmitter conductive plate) in FIG. 15 . Information on the size of the receiver conductor plates may be used to determine the number of the transmitter conductor plates to be activated. The distance of the receiving unit conductive plate may be the distance D2 between the horizontal center of the first receiving unit conductor plate 1560a and the horizontal center of the second receiving unit conductor plate 1560b in FIG. 15 . Distance information of the conductor plate of the receiver may be used to determine a pair of conductor plates of the transmitter. As described above, the distance between the pair of the two transmitting unit conductor plates may be set to be the same as or similar to the distance between the receiving unit conductor plates.

Next, the number and distance of the conductive plates to be activated may be determined (S1402). The number of conductive plates to be activated may be determined based on the size of the conductive plate of the receiver, and the distance of the conductive plate to be activated may be determined based on the distance of the conductive plate of the receiver. Here, the distance of the conductive plate to be activated may be a distance between the conductive plate groups to be activated. For example, referring to FIG. 15 , the number of conductor plates in one group is determined to be three corresponding to the size W2 of the receiving unit conductor plates 1560a and 1560b, and the distance between the conductor plate groups is the receiving unit conductor plate ( 1560a, 1560b) may be determined as a length corresponding to 10 conductor plates.

Next, the conductive plate group outside one side may be temporarily activated first ( S1403 ). For example, in FIG. 15 , three conductive plates 1540a to 1540c are activated as a first group, and three conductive plates 1540k, 1540l, and 1540m having a distance most similar to the reference distance from the first group are added to the second group. It can be set to and temporarily activated. Activation in this step can be understood as temporary activation to measure performance by temporarily operating to determine the conductor plate to be actually activated.

Next, the conductor plate to be temporarily activated may be moved (S1404). For example, referring to FIG. 15 , after setting and operating the temporarily activated conductor plates 1540a to 1540c and 1540k to 1540m from the leftmost side in step S1403, the temporarily activated conductor plate is moved to the right in step S1404 to improve the performance. can be measured In this case, the number and distance of the temporary active conductor plate may be maintained.

Next, the performance according to the temporarily activated conductor plate is evaluated (S1405), and when the performance is improved, the performance is evaluated while returning to step S1404 and continuously moving the temporarily activated conductor plate in the same direction. Proceeding to step S1406, it is possible to determine the temporarily activated conductor plate having the maximum performance before the performance is degraded as the conductor plate to be actually activated. For example, referring to FIG. 15 , when the performance is measured while setting the temporary activation conductor plate from the leftmost side and moving it to the right side, the best performance is obtained in the state aligned with the receiving unit conductor plate as shown in FIG. 15(e). Since the performance will deteriorate with further movement thereafter, the state illustrated in Fig. 15(e) will be determined as the conductor plate to be actually activated.

In step S1405 , power transmitted from the transmitter to the receiver may be used as a performance evaluation criterion. When the power transmitted from the transmitter to the receiver becomes the performance evaluation criterion, the transmitter may acquire information about the power received by the receiver from the receiver in real time. In this case, since the active conductor plate is determined based on the power information received by the receiver, there is an advantage in that maximum power can be transmitted within a possible range.

16 illustrates a capacitive wireless charging system according to another embodiment of the present invention.

Referring to FIG. 16 , the transmitter may include a switching circuit 1620 and a pad unit 1640 , and the receiver may include a receiver circuit 1650 and receiver pad units 1660a and 1660b . In FIG. 16 , it may be understood that for convenience of description of the configuration of the switching circuit, the illustration of other configurations other than the switching circuit and the conductor plate, such as the compensation circuit, is omitted. In addition, 9 conductor plates are exemplified in FIG. 16, which will be referred to as 1640a to 1640i in order from the left. The above description may be applied to the transmitter compensation circuit or the receiver circuit 1650 , and thus a redundant description will be omitted.

The transmitter pad unit 1640 is divided into three conductive plate groups 1640-1 to 1640-3, and each of the conductive plates 1640a to 1640i is a first conductive plate group 1640-1 and a second conductive plate. It may belong to any one of the group 1640-2 and the third conductive plate group 1640-3. The criterion for dividing the transmitter pad unit 1640 into three conductor plate groups 1640-1 to 1640-3 is that each conductor plate 1640a to 1640i is produced according to the movement of the receiver pad parts 1660a and 1660b. Can be coupled only to one receiver conductor plate 1660a or only to the second receiver conductor plate 1660b, or selectively to any one of the first receiver conductor plate 1660a and the second receiver conductor plate 1660b It can be determined depending on whether it can be combined. For example, even if the receiver pad unit 1660 moves in a state where the transmitter pad unit 1640 and the receiver pad unit 1660 are aligned enough to operate normally, the leftmost conductor plate 1640a is the first receiver conductor. Since it may be coupled to the plate 1660a but not to the second receiver conductive plate 1660b, it may be determined that the conductive plate 1640a belongs to the first conductive plate group 1640-1. Considering the movement range of the receiver pad unit 1660 in a state in which the transmitter pad unit 1640 and the receiver pad unit 1660 are aligned enough to operate normally, other conductive plates are classified into any group in a similar manner. can decide whether to

When the group to which each of the conductor plates 1640a to 1640i belongs is determined, the conductor plates 1640a to 1640c of the first conductor plate group 1640-1 can be connected only to the high potential side (Vp) of the DC power supply 10 . and the conductor plates 1640g to 1640i of the third conductor plate group 1640-3 can be connected only to the low potential side Vn of the DC power supply 10, and the second conductor plate group 1640-2 A switching circuit 1620 may be configured to selectively connect the conductive plates 1640d to 1640f to the high potential side Vp and the low potential side Vn.

To this end, according to an embodiment, the conductor plates 1640a to 1640c of the first conductor plate group 1640-1 may be connected to the high potential side Vp through one switch S1 to S3, respectively, and the third The conductor plates 1640g to 1640i of the conductor plate group 1640-3 may be connected to the low potential side Vn through one switch S7 to S9, respectively, and the second conductor plate group 1640-2 The conductive plates 1640d to 1640f may be selectively connected to the high potential side Vp and the low potential side Vn through two switches S4 to S6, respectively. Here, FIG. 16 exemplifies one 3-terminal selection switch for switches S4 to S6, but in order to selectively connect each conductor plate to the high potential side (Vp) and the low potential side (Vn) of the DC power supply 10, As illustrated in FIG. 9 , it is common to use two switches (eg, S1a and S2a) to form a half-bridge.

When the embodiment of Fig. 16 is compared with the embodiment of Fig. 9, for the first conductor plate group 1640-1 and the third conductor plate group 1640-3, if only one switch is used corresponding to each conductor plate, Therefore, it has the advantage of reducing the number of switches and enabling low-cost implementation. This embodiment can be effectively utilized when the size and distance information between the conductor plates of the receiver can be known in advance.

17 and 18 illustrate a wireless charging system for an electric kickboard according to an embodiment.

In FIG. 17, reference numeral 1740 denotes a transmitter pad part, and reference numeral 1740i denotes each conductive plate 1740i constituting the transmitter pad part. In the transmitter pad unit 1740 , for example, a plurality of individually and selectively activatable conductive plates 1740i may be two-dimensionally arranged in a honeycomb shape or other shape.

In this embodiment, even if the electric kickboard 80 is placed at an arbitrary position within the area of the transmitter pad unit 1740, the transmitter conductor plate 1745 in a position aligned with the receiver conductor plates 1760a and 1760b is detected and activated As a result, power transmission can be efficiently performed.

A method of detecting the transmitter conductor plate 1745 at a position aligned with the receiver conductor plate will be exemplarily described with reference to FIG. 18 . In FIG. 18, reference numerals 1760a and 1760b may be understood to indicate positions of the receiving unit conductor plate.

First, as shown in FIG. 18A , the transmitter conductor plates corresponding to the first receiver conductor plate 1760a may be determined. To this end, according to an embodiment, the method of detecting the activated conductor plate using the impedance described with reference to FIG. 13 may be used, but is not limited thereto. According to an embodiment, information on the size of the first receiving unit conductive plate 1760a may also be used. For example, when determining the transmitting unit conductor plates corresponding to the first receiving unit conductor plate 1760a, a method of detecting all impedances of each conductor plate is used, or a conductor plate having the strongest coupling with the receiving unit conductor plate is selected through impedance detection. and determine the conductor plates corresponding to the size of the first receiving unit conductor plate 1760a as the corresponding conductor plate with the conductor plate as the center, or information on the detected impedance and the size of the first receiving unit conductor plate 1760a together It can be used double.

Next, as shown in Fig. 18(b), a conductor plate at an arbitrary position spaced apart from the transmitting unit conductor plate corresponding to the first receiving unit conductor plate 1760a by a reference distance (distance between the receiving unit conductor plates) is placed on the second receiving unit conductor plate ( 1760b), it is possible to measure the power transmitted from the transmitter to the receiver by temporarily selecting it and then activating it.

Next, as illustrated in FIGS. 18 ( c ) to 18 ( f ), the transmission power is measured by moving the conductor plate along a circumference of the same distance as the transmitter conductor plate corresponding to the first receiving part conductor plate 1760a . Then, the conductive plates having the maximum transmitted power may be determined as the conductive plates corresponding to the second receiver conductive plate 1760b. In this case, the method described with reference to FIGS. 14 and 15 may be applied.

According to this embodiment, when using the transmitter pad part in which a plurality of conductor plates are arranged in two dimensions, even if the receiver pad part is placed at an arbitrary position in the transmitter pad part, by detecting and activating the transmitter conductor plate aligned with the receiver conductor plate, Power can be transmitted efficiently.

In the above-described embodiments, the control function of the switching circuit and the function of determining the active conductor plate may be performed by the controller. According to the embodiment, the controller is implemented as software and stored in a computer-readable storage medium (memory, etc.), and may perform its function by an arithmetic device such as a CPU or a microprocessor. According to an embodiment, the controller may be implemented in hardware such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like.

As described above, according to the present invention, according to an embodiment, it is possible to reduce misalignment between the transmitter conductor plate and the receiver conductor plate in the wireless charging system for a vehicle. In addition, according to an embodiment, it is possible to reduce performance degradation of wireless power transmission despite misalignment between the transmitter conductor plate and the receiver conductor plate. In addition, according to an embodiment, it is possible to reduce performance degradation due to misalignment by using a simple circuit.

Terms such as "include", "comprise" or "have" described above mean that the corresponding component may be embedded unless otherwise stated, so it does not exclude other components. It should be construed as being able to further include other components. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless otherwise defined. Terms commonly used, such as those defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related art, and are not interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (13)

A wireless charging transmitter for wirelessly providing power through capacitive coupling to a receiver including at least two receiver conductor plates,
a pad portion that is capacitively coupled to the receiver conductive plate and includes a number of conductive plates greater than the number of the receiver conductive plates; and
a switching circuit selectively connecting each of the conductor plates to a DC power supply;
A wireless charging transmitter comprising a. The method according to claim 1,
Each of the conductor plates is paired with another non-adjacent conductor plate,
The switching circuit, when any one of the two conductor plates forming the pair is connected to the high potential side of the DC power source, the other is connected to the low potential side of the DC power wireless charging transmitter, characterized in that operable to operate. 3. The method according to claim 2,
A wireless charging transmitter, characterized in that a capacitor is connected between the two conductor plates forming the pair. 3. The method according to claim 2,
Each of the conductive plates is a wireless charging transmitter, characterized in that paired with a conductive plate disposed at a distance most similar to the reference distance among other conductive plates. 5. The method according to claim 4,
The reference distance is a wireless charging transmitter, characterized in that the distance between the two conductor plates of the receiver. The method according to claim 1,
Each of the conductor plates belongs to any one of a first conductor plate group, a second conductor plate group, and a third conductor plate group, and the conductor plate of the first conductor plate group can be connected only to the high potential side of the DC power supply. and that the conductor plate of the third conductor plate group can be connected only to the low potential side of the DC power source, and the conductor plate of the second conductor plate group can be selectively connected to the high potential side and the low potential side Characterized by a wireless charging transmitter. 7. The method of claim 6,
Each of the conductor plates of the first conductor plate group may be connected to the high potential side through one switch, and the conductor plates of the third conductor plate group may be respectively connected to the low potential side through one switch, and The conductive plate of the second group of conductive plates may be selectively connected to the high potential side and the low potential side through two switches, respectively. The method according to claim 1,
A wireless charging transmitter, characterized in that among the conductor plates, a conductor plate aligned with the receiving unit conductor plate is activated. 9. The method of claim 8,
The activation target conductor plate is a wireless charging transmitter, characterized in that determined based on the impedance measurement result. 9. The method of claim 8,
The transmitter receives information about the distance between the two conductor plates of the receiver and the power received by the receiver from the receiver,
matching the pair of conductor plates of the pad unit from the distance information between the two conductor plates of the receiving unit;
A wireless charging transmitter, characterized in that for determining and activating a conductor plate capable of transmitting maximum power based on the power information received by the receiver. 11. The method of claim 10,
the activated conductor plate pair is plural;
In the plurality of pairs of conductive plates, adjacent conductive plates are driven at substantially the same frequency and phase as each other. The method according to claim 1,
The transmitter is a wireless charging transmitter, characterized in that installed in the collision prevention block of the parking lot. a receiver including two receiver conductor plates; and
A transmitter for wirelessly providing power through capacitive coupling to the receiver conductor plate; including,
The transmitter is
a pad portion that is capacitively coupled to the receiver conductive plate and includes a number of conductive plates greater than the number of the receiver conductive plates; and
A wireless charging system comprising a; a switching circuit selectively connecting each of the conductor plates to a DC power supply.

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