KR20120046027A - Capacitive and transformer coupling method for resonance based wireless power transfer - Google Patents

Abstract

PURPOSE: A capacitive and transformer coupling method for a resonant wireless power transmission system is provided to improve transmission efficiency due to impedance changed according to a load and a distance of the resonant wireless power transmission system by changing the number of turns in a primary coil and a secondary coil. CONSTITUTION: A transmission unit or a reception unit includes a transformer. A self-resonant coil is connected to both sides of a secondary coil or a primary coil of the transformer.

Description

Capacitive and Transformer Coupling Method for Resonance based Wireless Power Transfer}

The present invention relates to a resonant wireless power transmission method and system, and more particularly, to a resonant wireless power transmission system incorporating capacitive and transformer coupling capable of easily performing impedance matching depending on load and transmission distance. It is about.

In the wireless power transmission method using parallel resonance disclosed in International Patent No. PCT / KR2005 / 002468 (WO 2006/011769 A1), a magnetic inductive coupling is simply used for coupling between a source / load and a resonant coil. In the wireless power transmission method using parallel resonance disclosed in Patent No. 2009-0224856, only magnetic inductive coupling is used for coupling with a resonance coil.

As described above, in the conventional wireless power transmission method using parallel resonance, magnetic inductive coupling is used for power transmission between the source / load and the resonant coil. That is, the source coil is positioned between the source and the source resonant coil on the source side, and the load coil (or device coil) is positioned between the load and the receive resonance coil on the receiving side. In this way, to improve impedance matching and power factor, the distance between the source coil or device coil and the resonant coil may be adjusted or the shape of the coil may be changed to adjust the mutual coupling value between the source coil / device coil and the resonant coil. Adjust to improve matching and power factor. The most difficult in this case is that it is very difficult to induce accurate mutual inductance between the source / device coil and the resonant coil, and various problems are caused by the implementation and iteration process in actual system fabrication.

In addition, accurate matching is very difficult because the source / device coil must be physically relocated or the structure changed to adjust the system to achieve impedance matching. In particular, when the position of the receiving side is changed, the impedance varies according to the change of the distance and the change of the load, and there is a difficulty in performing matching by changing the position or the structure of the source / device coil at every change.

In the rectifying circuit on the receiving side, the phase of the received current and voltage passing through the resonant coil is changed, and this phenomenon lowers the power factor of the receiving side. Accordingly, there is also a need for a method of improving the power factor of the reception current and voltage.

Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to use a transformer between a source / load and a resonant coil, in particular, the primary side of the transformer is connected to the source / load and the secondary side Is connected to the resonant coil so that the AC signal induced on the primary side induces an AC signal on the secondary side and is applied to the resonant coil, and adjusts the inductance by adjusting the winding ratio of the primary side and the secondary side to adapt the system. The present invention provides a resonance type wireless power transmission system capable of transmitting wireless power by optimizing adaptive impedance matching and power factor.

In addition, a capacitive coupling using a capacitor is used between the source / load and the resonant coil. In particular, the source and the capacitor are directly connected, and the capacitance of the transmitter / receiver is changed according to the area coupled with the resonant coil. By improving impedance matching and power factor, the present invention provides a resonance type wireless power transmission system capable of transmitting wireless power by optimizing impedance matching conditions of a system that is changed according to mutual inductance change and load change.

In addition, the rectifier circuit of the receiver is to provide a parallel resonant wireless power transmission system that can improve the power factor using an inductor to make a continuous mode.

First, to summarize the features of the present invention, in accordance with one aspect of the present invention for achieving the object of the present invention, by wirelessly transmitting a time-varying magnetic field generated from the source of the transmission unit, the transmission using the receiving resonator of the receiver In the resonant wireless power transmission system, the transmitter or the receiver includes a transformer, and includes a self resonance coil connected to both ends of the primary coil or the secondary coil of the transformer.

Impedance matching and power factor improvement are achieved by adjusting the inductance value by the number of turns of the primary coil or the secondary coil.

The primary coil may be wound with a predetermined number of turns so that the number of turns of the primary coil decreases as the distance between the transmission resonance coil of the transmitter and the reception resonance coil of the receiver increases.

Both ends of the input source are connected to both ends of the primary coil of the transformer of the transmitter, and a transmission resonant coil is connected to both ends of the secondary coil of the transformer of the transmitter.

An additional capacitor may be further included between one terminal of the input source and one terminal of the primary coil of the transformer of the transmitter.

A receiving resonance coil is connected to both ends of the secondary coil of the transformer of the receiver, and a rectifier circuit or a load is directly connected to both ends of the primary coil of the transformer of the receiver.

An additional capacitor may be further included between one terminal of the primary coil of the transformer of the receiver and one terminal of the rectifier circuit.

In addition, according to another aspect of the present invention, a resonant wireless power transmission system including a receiver for receiving a time-varying magnetic field generated from a coil of a transmitter, the transmitter or the receiver includes a flat plate capacitor, connected to the flat capacitor The plate capacitor includes a resonant coil, wherein the plate capacitor includes a second both metal plate between first and second metal plates, and both ends of the resonant coil are connected to both ends of the second both metal plates.

Impedance matching and power factor improvement are achieved by capacitance formed between each metal plate of the first both metal plates and the corresponding opposite metal plate of the second both metal plates.

Both ends of the input source are connected to the first both metal plates of the plate capacitor of the transmitter, and both ends of the transmit resonant coil in the form of a single loop coil are connected to the second both metal plates of the plate capacitor of the transmitter.

Both ends of the second both metal plates of the plate capacitor of the receiver and the receiving resonance coil in the form of a single loop coil are connected, and both first and second metal plates of the plate capacitor of the receiver are connected to both ends of the rectifier circuit.

The rectifier circuit includes an inductor connected between the DC conversion circuit and the output terminal.

Equation L> R / 3ω is satisfied between the capacitance L of the inductor, the input resistance R seen in the DC converter circuit, and the angular frequency ω of the input current flowing into the DC converter circuit.

According to the resonant wireless power transmission method and system according to the present invention, the capacitive coupling and the transformer coupling can easily compensate for the impedance and the bad power factor which change according to the load variation and the distance variation. That is, the capacitive coupling can be compensated by changing the capacitance with the resonant coil, and the transformer coupling only needs to change the number of turns of the primary and secondary coils. Through this, it is possible to improve the transmission efficiency due to the impedance changed according to the variation of the distance and the load of the resonance type wireless power transmission system.

In addition, the transformer method may adjust the voltage and current of the transceiver as well as impedance matching. In other words, the commonly used coil has a limit of allowable current and voltage, but it is possible to adjust the appropriate current and voltage by using a transformer.

In addition to the transmission and reception, the power factor may be improved in the rectifier circuit of the receiver to improve transmission efficiency of the entire system.

1A is a view for explaining an embodiment of a resonant wireless power transmission system.
FIG. 1B is an equivalent circuit of FIG. 1A.
2A is a diagram for describing a transformer and a resonant coil for application to a resonant wireless power transmission system according to an embodiment of the present invention.
FIG. 2B is an equivalent circuit when the transformer and the resonant coil of FIG. 2A are applied to the transmitter and the receiver.
3 is a view for explaining a resonance type wireless power transmission system according to another embodiment of the present invention.
4A is a diagram illustrating a capacitor and a resonance coil for application to a resonance type wireless power transmission system according to another embodiment of the present invention.
4B is an equivalent circuit when the capacitor and the resonance coil of FIG. 4A are applied to the transmitter and the receiver.
5 is a view for explaining a rectifier circuit used in the resonance type wireless power transmission system according to another embodiment of the present invention.
FIG. 6 is an input / output waveform diagram of the rectifier circuit for explaining the case where there is no inductor in the rectifier circuit of FIG. 5.
FIG. 7 is an input / output waveform diagram of a rectifier circuit for describing a case where an inductor is included in the rectifier circuit of FIG. 5.
FIG. 8 is a diagram for describing a magnetic core of the transformer of FIG. 2A.
9 is an equivalent circuit of a transformer to which the toroidal core of FIG. 8 is applied.
FIG. 10 illustrates a system manufactured for measuring power transmission efficiency using a transformer and a transmission resonant coil of the transmitter Tx of the present invention and a transformer and a reception resonant coil of the receiver Rx.
FIG. 11 shows a value obtained by measuring changes in coupling coefficient and inductance according to the number of primary coil turns of a transformer of the present invention.
12 shows a value of measuring the change in the number of coil windings for mutual inductance and impedance matching according to the distance between the transmission and reception resonant coils of the present invention.
FIG. 13 is a graph illustrating efficiency calculated values and measured values according to distances between the transmission and reception resonant coils of the present invention, together with the maximum efficiency values.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

1A is a view for explaining an embodiment of a resonant wireless power transmission system. FIG. 1B is an equivalent circuit of FIG. 1A.

1A and 1B, the resonant wireless power transmission system may include a transmitter Tx and a receiver Rx. The transmitter Tx is a source coil (Rs, Ls of an equivalent circuit) connected to an input source Vs (time-varying magnetic field source), and a transmission resonance coil (equivalent circuit) that forms a source coil and a magnetic field inductive coupling (coupling coefficient Ks). R1, L1, and C1, and the receiving unit Rx comprises a receiving resonance coil (R2, L2, C2 of an equivalent circuit) that forms a strong magnetic coupling (mutual inductance M) by the transmission resonance coil and the resonance. Device coils (RL and LL of equivalent circuits) forming a magnetic field inductive coupling (coupling coefficient KL) with the coils, rectifier circuits for rectifying AC inputs from the device coils, loads or DC-to power supplied from the rectifier circuits. -Includes a DC converter.

As described above, in the resonant wireless power transmission system, a time-varying magnetic field generated from a source coil is induced to a transmission resonance coil, and rectifies an AC signal induced into a reception resonance coil and a device coil through magnetic induction coupling. Power will be supplied to the load or DC-to-DC converter.

However, in such a structure, when the environment changes between the source coil, the transmission resonant coil, the reception resonant coil, and the device coil, for example, when the distance and the direction of the coil change, the mutual inductance is changed in the corresponding portion, and the maximum power The impedance matching condition and the maximum power factor environment for the transmission are changed, and the method of physically adjusting the coils is used to obtain the optimum matching and power factor for the new environment.

 By using a transformer or a capacitor in the transmitter (Tx) or the receiver (Rx) to transmit the wireless power by optimizing the impedance matching conditions of the system, by using an inductor in the rectifier circuit of the receiver by satisfying the continuous mode conditions Embodiments of the wireless power transmission system of the present invention that can improve the power factor are described.

2A is a view for explaining a resonance type wireless power transmission system according to an embodiment of the present invention. FIG. 2B is an equivalent circuit when the transformer and the resonant coil of FIG. 2A are applied to the transmitter and the receiver.

2A and 2B, a resonant wireless power transmission system according to an exemplary embodiment of the present invention includes a transformer in which a primary coil and a secondary coil are wound around a ferrite magnetic core as shown in FIG. 2A, and a primary coil of a transformer. Or a structure in which a structure in which a helical self-resonance coil is connected to both ends of the secondary coil as a transmitting or receiving resonant coil is applied to the transmitting unit Tx or the receiving unit Rx. The primary and secondary coils of the transformer may be wound in overlap. Here, an example in which a helical magnetic resonance coil is connected to a transformer has been described, but the present invention is not limited thereto, and various types of self-resonance coils may be used by modifying the helical coil. Can be.

2B, both ends of the input source Vs (time-varying magnetic field source) are connected to both ends of the primary coils (equivalent circuits Rs and Ls) of the transmitter Tx transformer, and the secondary coils of the transmitter Tx transformer ( Transmission resonant coils (equivalent circuits R1, L1, C1 ') are connected to both ends of the equivalent circuits RT1, LT1. In addition, the receiving resonant coils (equivalent circuits R2, L2, C2 ') are connected to both ends of the secondary coils (equivalent circuits RT2, LT2) of the receiver Rx transformer, and the primary coils (equivalent circuit) of the receiver Rx transformer. Both ends of RL and LL may be connected to the rectifier circuit.

In such a transformer coupling structure, there is generally little resonance frequency shift by the transformer since the secondary side inductance of the transformer is much larger than the inductance of the (transmit / receive) resonant coil. In the resonant structure, a high voltage (high current) is induced, and when a large power is transmitted, a very high voltage (high current) is induced between coils, and insulation is destroyed. In order to avoid such breakdown, the transformer may be used to adjust the voltage and current induced in the resonator. In particular, even when a predetermined voltage or more is required to be charged as a load in the receiver Rx, it is possible to adjust the voltage using a transformer. In addition, when the transformer is used, impedance adjustment of the input / output unit can be obtained by simply changing the number of turns of the transformer. Kurs, A. Karalis, R. Moffatt, J. D. Joannopoulos, P. Fisher, and M. Soljacic, “Wireless power transfer via strongly coupled magnetic resonances”, Science express, vol. 317, pp. 83-86, July 2007] no matching by physical movement of the coupling coil is required.

3 is a view for explaining a resonance type wireless power transmission system according to another embodiment of the present invention.

As shown in FIG. 3, an additional capacitor Cs may be added between one terminal of the input source Vs and one terminal of the primary coils (equivalent circuits Rs and Ls) of the transmitter Tx transformer, and the receiver Tx. An additional capacitor C _L may be added between one terminal of the transformer's primary coil (equivalent circuits RL, LL) and one terminal of the rectifier circuit. Accordingly, the reactance component of the transmission input impedance through the primary coils (equivalent circuits Rs and Ls) of the transmitter Tx transformer is minimized, and the primary coils (equivalent circuits R _L and L _L ) of the receiver Tx transformer are minimized. By minimizing the reactance component of the output impedance through the receiver, the power factor can be improved, resulting in higher power efficiency.

4A is a diagram illustrating a capacitor and a resonance coil for application to a resonance type wireless power transmission system according to another embodiment of the present invention. 4B is an equivalent circuit when the capacitor and the resonance coil of FIG. 4A are applied to the transmitter and the receiver.

4A and 4B, the resonant wireless power transmission system according to another exemplary embodiment of the present invention includes a transmission unit (Tx) having a structure in which a single loop coil is connected to a parallel plate capacitor as a transmission or reception resonance coil as shown in FIG. 4A. ) Or a structure applied to the receiver Rx. The parallel plate capacitor includes a second both metal plate between the first both metal plates serving as ports, and the second both metal plates extend beyond the edges of the first both metal plates. Both ends of the single loop coil are respectively connected to both ends of the second both metal plates. The predetermined dielectric ε _r2 may be filled between the second both metal plates, and the predetermined dielectric ε _r1 may also be filled between each metal plate of the first both metal plates and the corresponding opposite metal plate of the second both metal plates. Here, an example in which a single loop coil is connected to a parallel plate capacitor has been described. However, the present invention is not limited thereto, and various types of magnetic resonance coils may be used by deforming the single loop coil.

As shown in FIG. 4B, parallel plate capacitors as shown in FIG. 4A may be connected between both ends of the input source Vs and both ends of the transmission resonant coils (equivalent circuits R ₁ , L ₁ , C ₁ ) in the form of a single loop coil. That is, both ends of the input source Vs may be connected to the first both metal plates of the transmitting side parallel plate capacitor, and the transmission resonant coil (equivalent to the second both metal plates of the transmitting side parallel plate capacitor as shown in FIG. Both ends of the circuits R ₁ , L ₁ , C ₁ ) may be connected. In addition, parallel plate capacitors as shown in FIG. 4A may be connected between both ends of the rectifier circuit and both ends of the reception resonance coils (equivalent circuits R ₂ , L ₂ , C ₂ ) in the form of a single loop coil. That is, both ends of the receiving resonant coils (equivalent circuits R ₁ , L ₁ , C ₁ ) in the form of a single loop coil may be connected with the second both metal plates of the receiving side parallel plate capacitor as shown in FIG. 4A, and The first both metal plates may be connected to both ends of the rectifier circuit.

In such a capacitive coupling structure, the voltage applied to the port (first both metal plates) is applied to the capacitor of the resonant coil through the capacitive coupling. 4A is not necessarily filled with a dielectric plate ε _r2 or a dielectric ε _r1 , and may be air, and such a parallel plate capacitor can be easily manufactured using a printed circuit board. Accordingly, it is not necessary to perform impedance matching by shifting the position of the transmitting coil or the device coil as in the conventional magnetic inductive coupling, and matching control is easy because the matching is performed by adjusting the amount of coupling capacitance of the parallel plate capacitor as shown in FIG. 4A. It is also easy to improve the power factor.

5 is a view for explaining a rectifier circuit used in the resonance type wireless power transmission system according to another embodiment of the present invention.

Referring to FIG. 5, the rectifier circuit used in the resonant wireless power transmission system includes a DC converter circuit and an inductor L and a capacitor C connected in series between both ends of the DC converter circuit, and both ends of the capacitor C. Power can be supplied from the output stage to the load or DC-to-DC coverter.

As illustrated in FIG. 5, the DC conversion circuit may be configured as a device capable of acting as a switch such as a MOSFET, a diode, a thyristor, or the like, and for example, a bridge diode may be used. Through the inductor (L) which is a smoothing element connected to the DC conversion circuit can improve the power factor and obtain a more stable DC voltage. That is, the inductor L, which is a smoothing element, is connected to reduce the size of the AC component, thereby reducing the pulsation rate of the output voltage.

When there is no inductor in the rectifying circuit of FIG. 5, the fundamental frequency component I _s of the input current Is coming into the DC converter circuit as shown in FIG _{. The} phase difference between _h1 and the input voltage V _S occurs as shown by the waveforms of the input current Is, the inductor voltage V _L , and the inductor current I _L , resulting in a lower power factor. However, if there is an inductor in the rectifier circuit of FIG. 5, the power factor can be compensated as shown in FIG. Equation 1 must be satisfied between frequencies ω (2πf: f is the frequency of the input signal).

[Equation 1]

L> R / 3ω

When the Equation 1 is not satisfied, the waveform is formed similarly to the case where the inductor is not connected, and as a result, the power factor is lower than that when the inductor satisfying the Equation 1 is connected.

Meanwhile, the relationship between the number of windings of the coil of the transformer of FIG. 2A and the magnetic resonance coil (transmitting or receiving resonant coil) for impedance matching will be described in more detail.

FIG. 8 is a diagram for describing a magnetic core of the transformer of FIG. 2A. Transformers usually use high magnetic materials such as ferrite to focus the magnetic field. The magnetic material should have low magnetic loss at the frequency to be used. Also, make sure that you can achieve the inductance of the primary and secondary coils for your system. When using a toroidal magnetic core as shown in Figure 8 in the transformer, S is the cross-sectional area of the toroidal magnetic body (width W x height h), r _in is the inner radius of the toroidal core, r _in is the saturation of the toroidal core It can be designed according to the magnetic flux density. _{1 turn} is the length of the conductor when winding once, μ ₀ is the permeability in vacuum, and μ _r is the relative permeability of the magnetic material. Given the size and permeability of the core, the inductance A _L for winding the lead once is given by Equation 2. Given A _L , the inductance of the coil wound N times can be obtained as shown in [Equation 3].

[Equation 2]

&Quot; (3) "

9 is an equivalent circuit of a transformer to which the toroidal core of FIG. 8 is applied. There is no loss in the core, and the inter-winding capacitance between the primary and secondary coils is not considered to have a significant effect on the system. In addition, the self-capacitance of the primary coil is usually neglected because it has a small value because the number of turns of the primary coil is not large. In FIG. 9, R _S and L _l1 represent resistance components and leakage inductance of the transformer primary coil. R _T and L _l2 represent the resistance component and leakage inductance of the transformer secondary coil. L _p is the magnetizing inductance of the primary coil, and N ₁ and N ₂ are the number of turns of the primary and secondary coils, respectively. C _T is the self capacitance generated by the transformer secondary coil.

10 is a wireless power manufactured to measure the power transmission efficiency using the transformer and the transmission resonant coil (Tx resonant coil) of the transmitter (Tx) of the present invention, the transformer and the Rx resonant coil of the receiver (Rx). Represents a transmission system. The basic principle is as described in Figure 2b / 3.

As shown in FIG. 10, in order to verify a wireless power transmission system using a transformer coupling, each resonant coil is a helical coil of a rectangular shape having a width of 62 cm, a height of 33 cm, and a height of 4 cm. Was produced. The Tx and Rx transformers are wound around primary and secondary coils using a toroidal core (see FIGS. 8 and 9). At this time, a toroidal core made of Ni-Zn material having W = 1.2 cm, H = 3.7 cm, r _in = 2.7 cm and a relative permeability of 350 was used. If the ferrite core is used as it is, the relative permeability is large, and thus the inductance according to the number of turns is increased, thereby providing an air gap between the cores. At this time, an insulating tape was used to give a gap. Ferrite cores are so large that the permeability process error is ± 25%, so the voids are properly adjusted to match the core's permeability. The A _L values of the fabricated Tx and Rx transformers are 0.56 and 0.53, respectively. In order to adjust the resonance frequency, the Tx transformer secondary coil was wound 91 times and the Rx transformer secondary coil was wound 94 times. The lumped capacitor connected in parallel with the resonant coil used a high-Q capacitor of 1 nF.

The table below shows the parameter measurement values of the system fabricated as shown in FIG. As a result of the measurement, it was confirmed that the resonant frequency (fr1 / fr2) of the transmitter and receiver was about the same at about 257 kHz. Each parameter was measured using a vector network analyzer (Agilent 4395A) and an LCR meter (GWInstek LCR 8110G).

FIG. 11 shows a value obtained by measuring changes in coupling coefficient and inductance according to the number of primary coil turns of a transformer of the present invention.

As shown in FIG. 11, when the coupling coefficient of the manufactured transformer and the inductance value of the primary coil are represented by the number of turns, the coupling coefficient is about 0.9 without significant change depending on the number of turns of the primary coil in both the transformer and the transmitter. Constant values were shown. Depending on the number of turns of the primary coil, the inductance increased from about 2.5 μH to 25 μH.

12 shows a value of measuring the change in the number of coil windings for mutual inductance and impedance matching according to the distance between the transmission and reception resonant coils of the present invention.

The impedance matching condition varies according to the change in the distance D between the transmission and reception resonant coils, which can be adjusted by changing the number of turns of the transformer primary coil. As shown in FIG. 12, when the distance D varies from 40 cm to 100 cm, the mutual inductance M ₁₂ between the resonant coils and the number of matching turns N _m of the transformer primary coil at that time decreases. In particular, it can be seen that the number of turns of the primary coil (N _m ) for impedance matching is reduced from 6 to 2 circuits. That is, as the mutual inductance M ₁₂ between the resonant coils is smaller, the impedance can be easily matched by reducing the number of turns of the primary coil.

FIG. 13 is a graph illustrating efficiency calculated values and measured values according to a distance D between transmission and reception resonant coils of the present invention, together with maximum efficiency values.

As shown in FIG. 13, it can be seen that the efficiency calculation calculated through the circuit analysis and the efficiency measurement measured using the network analyzer are almost identical based on the extraction of each parameter. The maximum efficiency with diamond marks in FIG. 13 is described in reference [A. Kurs, A. Karalis, R. Moffatt, JD Joannopoulos, P. Fisher, and M. Soljacic, “Wireless power transfer via strongly coupled magnetic resonances”, Science express, vol. 317, pp. 83-86, July 2007.] calculated using the maximum efficiency equation (eff _max = fom ² / (1+ (1 + fom ² ) ^0.5 ) ² , fom = ωM ₁₂ / (R ₁ R ₂ ) ^0.5 ) Efficiency value. It can be seen that impedance matching to achieve maximum efficiency is achieved by adjusting the number of turns / ratio of the transformer. Thus, the transformer coupling scheme proposed in the present invention can model a system through an equivalent circuit, and have a high efficiency of about 90% at a distance (D) of 40 cm between resonant coils and about 55% at 100 cm. It was confirmed.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

Transmitter (TX)
Receiver (RX)
Source coil (Rs, Ls of equivalent circuit)
Transmission resonant coil (R1, L1, C1 of equivalent circuit)
Receive resonant coils (R2, L2, C2 of equivalent circuit)
Device coils (RL, LL in equivalent circuit)

Claims (13)

In a resonance type wireless power transmission system for wirelessly transmitting a time-varying magnetic field generated from a source of a transmission unit and transmitting using a reception resonator of a reception unit,
The transmitter or the receiver comprises a transformer,
Self-resonance coils connected to both ends of the primary coil or secondary coil of the transformer
Resonant wireless power transmission system comprising a. The method of claim 1,
Resonant wireless power transmission system, characterized in that impedance matching and power factor is improved by the number of windings of the primary coil or the secondary coil. The method of claim 2,
Resonant wireless power transmission system characterized in that the winding of the primary coil with a predetermined number of turns so that the number of turns of the primary coil decreases as the distance between the transmission resonance coil of the transmitter and the receiving resonance coil of the receiver increases. . The method of claim 1,
Resonant wireless power transmission system, characterized in that both ends of the input source is connected to both ends of the primary coil of the transformer of the transmitter, the transmission resonant coil is connected to both ends of the secondary coil of the transformer of the transmitter. The method of claim 4, wherein
And an additional capacitor between one terminal of the input source and one terminal of the primary coil of the transformer of the transmitter. The method of claim 1,
A reception resonance coil is connected to both ends of the secondary coil of the transformer of the receiver, and a rectifier circuit is connected to both ends of the primary coil of the transformer of the receiver. The method of claim 6,
And a further capacitor between one terminal of the primary coil of the transformer of the receiver and one terminal of the rectifier circuit. In the resonance type wireless power transmission system including a receiver for receiving a time-varying magnetic field generated from the coil of the transmitter,
The transmitter or the receiver comprises a flat plate capacitor,
Including a resonant coil connected to the plate capacitor,
The plate capacitor includes a second both metal plate between first and second metal plates, and both ends of the resonant coil are connected to both ends of the second both metal plates. The method of claim 8,
And the impedance matching and the power factor are improved by capacitance formed between each metal plate of the first both metal plates and the corresponding opposite metal plate of the second both metal plates. The method of claim 8,
Resonant wireless power, characterized in that both ends of the input source is connected to the first both metal plates of the plate capacitor of the transmitter, the both ends of the plate capacitor of the transmitter and the both ends of the transmission resonant coil in the form of a single loop coil. Transmission system. According to claim 8,
Resonant wireless power, characterized in that the second both metal plates of the plate capacitor of the receiving unit and the both ends of the receiving resonant coil in the form of a single loop coil, the first both metal plates of the plate capacitor of the receiving unit is connected to both ends of the rectifier circuit. Transmission system. The method according to claim 6 or 11, wherein
The rectifier circuit is a resonant wireless power transmission system comprising a inductor connected between the DC conversion circuit and the output terminal. The method of claim 12,
Equation L > R / 3ω is satisfied between the capacitance L of the inductor, the input resistance R seen in the DC converter circuit, and the angular frequency ω of the input current flowing into the DC converter circuit. Resonant wireless power transmission system.

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