KR20170055749A - Method of transmitting and receiving wireless power - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a wireless power transmission / reception method for improving transmission efficiency.
A wireless power transmission / reception method for transmitting power to a reception unit including a reception resonant coil and a reception induction coil wirelessly in a transmission unit including a transmission induction coil and a transmission resonant coil according to an embodiment of the present invention includes the steps of: And controlling at least one of a distance between the transmission induction coil and the transmission resonance coil, an angle of the transmission resonance coil, and an axial position between the transmission induction coil and the transmission resonance coil, corresponding to the distance.

Description

[0001] METHOD OF TRANSMITTING AND RECEIVING WIRELESS POWER [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless power transmission / reception method, and more particularly, to a wireless power transmission / reception method capable of increasing transmission efficiency.

Wireless power transmission (wireless power transmission or wireless energy transfer), which can transmit power without a power line, has been used in various applications. For example, wireless power transmission technology has been commercially available in the form of electric toothbrushes and smartphone chargers.

Such wireless power transmission techniques include an electromagnetic induction method for a short distance of several millimeters, a magnetic resonance method for a medium distance of several centimeters to several meters, and an electromagnetic method for long distance transmission. Among them, the magnetic resonance method is not only limited in the distance limitation as compared with the electromagnetic induction method, but also has a small absorption rate in the electromagnetic wave body, which is suitable for small electronic apparatuses and medical electronic apparatuses.

However, the magnetic resonance method has a disadvantage in that the efficiency is greatly changed according to the change of the position of the transmitter for transmitting power and the receiver for receiving power. Therefore, a method for increasing the efficiency in the magnetic resonance method is required.

Accordingly, the present invention provides a wireless power transmission / reception method capable of increasing transmission efficiency.

A wireless power transmission / reception method for transmitting power to a reception unit including a reception resonant coil and a reception induction coil wirelessly in a transmission unit including a transmission induction coil and a transmission resonant coil according to an embodiment of the present invention includes the steps of: And controlling at least one of a distance between the transmission induction coil and the transmission resonance coil, an angle of the transmission resonance coil, and an axial position between the transmission induction coil and the transmission resonance coil, corresponding to the distance.

According to the wireless power transmission / reception method of the embodiment of the present invention, at least one of the distance, angle, and axial position between the transmission induction coil and the transmission resonance coil included in the transmission unit, It is possible to increase the transmission efficiency.

Further, in the present invention, at least one of the distance, the angle and the axial position between the reception resonance coil and the reception induction coil included in the reception unit can be additionally controlled so as to have the maximum transmission efficiency corresponding to the change in position of the transmission unit and the reception unit, Thereby improving the transmission efficiency.

1 is a block diagram of a wireless power transceiver according to an embodiment of the present invention.
2 is an equivalent circuit diagram of each of the coils shown in Fig.
3 is an equivalent circuit diagram of the wireless power transceiver shown in FIG.
4 is a graph showing a graph of Equation (5).
FIG. 5 is a diagram showing the geometric and electrical elements between the transmission induction coil and the transmission resonance coil in a simplified manner. FIG.
6 is a view showing an embodiment of the axial position change between the transmission induction coil and the transmission resonance coil shown in Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention and other details necessary for those skilled in the art to understand the present invention with reference to the accompanying drawings. However, the present invention may be embodied in many different forms within the scope of the appended claims, and therefore, the embodiments described below are merely illustrative, regardless of whether they are expressed or not.

That is, the present invention is not limited to the embodiments described below, but may be embodied in various forms. In the following description, it is assumed that a part is connected to another part, As well as the case where they are electrically connected to each other with another element interposed therebetween. It is to be noted that, in the drawings, the same constituent elements are denoted by the same reference numerals and symbols as possible even if they are shown in different drawings.

1 is a block diagram of a wireless power transceiver according to an embodiment of the present invention.

Referring to FIG. 1, a wireless power transmitter / receiver according to an embodiment of the present invention includes a transmitter 200 and a receiver 300.

The transmitting unit 200 transmits the power from the power source Vs to the receiving unit 300 using the resonance phenomenon. To this end, the transmitter 200 includes a transmission induction coil 210 and a transmission resonance coil 220.

The transmission induction coil 210 is physically spaced apart from the transmission resonance coil 220. The transmission induction coil 210 is inductively coupled to the transmission resonance coil 220. An AC current is generated in the transmission induction coil 210 by the AC power from the power source Vs and an AC current is induced in the transmission resonance coil 220 which is physically spaced apart by the electromagnetic induction by the AC current .

The transmission resonance coil 220 transmits the power generated by the electromagnetic induction to the receiver 300 using a frequency resonance method. Two LC circuits whose impedances are matched can transmit power by resonance. Such a resonance-based power transmission (i.e., a magnetic resonance method) has an advantage that power can be transmitted with a higher transmission efficiency to a far distance as compared with an electromagnetic induction method.

The receiving unit 300 is located at a distance physically separated from the transmitting unit 200 by a predetermined distance D, and receives power to be transmitted wirelessly. To this end, the receiving unit 300 includes a receiving resonant coil 310 and a receiving induction coil 320. The reception resonant coil 310 and the reception induction coil 320 are physically spaced apart from each other.

The reception resonance coil 310 has the same resonance point as the transmission resonance coil 220. That is, the reception resonance coil 310 has the same resonance frequency as the transmission resonance coil 220, and receives power from the transmission resonance coil 220 by a frequency resonance method. When power is received in the reception resonant coil 310, a predetermined alternating current is generated.

The reception induction coil 320 is inductively coupled with the reception resonance coil 310. Therefore, an alternating current is generated in the reception induction coil 320 physically spaced by the electromagnetic induction by the alternating current generated in the reception resonance coil 310. The power generated by the reception induction coil 320 may be supplied to a lower end (not shown) via a rectifying part (not shown) or the like.

2 is an equivalent circuit diagram of each of the coils shown in Fig.

2, each of the transmission induction coil 210, the transmission resonance coil 220, the reception resonance coil 310 and the reception induction coil 320 includes an inductor L, a resistor R, and a capacitor C . The inductance value of the inductor L, the resistance value of the resistor R, and the capacitance of the capacitor C can be appropriately adjusted in consideration of impedance matching and the like.

3 is an equivalent circuit diagram of the wireless power transceiver shown in FIG.

Referring to FIG. 3, the transmission induction coil 210 may include a first capacitor C1, a first resistor R1, and a first inductor L1. The transmission induction coil 210 generates a first current I1 corresponding to the power from the power source Vs. Additionally, Rs shown in FIG. 3 is an equivalent representation of the resistance component of the power source Vs.

The transmitting resonant coil 220 may be composed of a second inductor L2, a second resistor R2, and a second capacitor C2. The second current I2 corresponding to the first current I1 is induced in the transmission resonance coil 220 by electromagnetic induction.

The reception resonant coil 310 may be composed of a third capacitor C3, a third resistor R3, and a third inductor L3. The reception resonance coil 310 has the same resonance point as the transmission resonance coil 220. Therefore, the reception resonant coil 310 receives the third current I3 corresponding to the second current I2 of the transmission resonant coil 220 (that is, receives power wirelessly).

The reception induction coil 320 is composed of a fourth inductor L4, a fourth resistor R4 and a fourth capacitor C4. In the reception induction coil 320, the fourth current I4 is induced corresponding to the third current I3. The fourth current I4 derived from the reception induction coil 320 may be supplied to the load (i.e., RL). Here, RL is equivalent load.

Meanwhile, K ₁₂ , K ₂₃ , and K ₃₄ shown in FIG. 3 represent coupling coefficients. Coupling coefficients (K ₁₂ , K ₂₃ , K ₃₄ ) mean the degree of magnetic coupling between the coils and range from 0 to 1. The coupling coefficients K ₁₂ , K ₂₃ , and K ₃₄ may vary depending on the relative positions and distances between the coils. In addition, the coupling coefficient K ₁₂ transmits the induction coil 210 and the transmission resonant coil 220, the coupling coefficient, the coupling coefficient K ₂₃ is the coupling coefficient, the coupling coefficient between the transmitting resonance coil 220 and the reception resonant coil 310 between the K ₃₄ Denotes a coupling coefficient between the reception resonant coil 310 and the reception induction coil 320. [

Based on the equivalent circuit diagram of FIG. 3, the power supplied from the power source Vs to the load resistance RL can be represented by a matrix expressed by Equation (1) using the Kirchhoff's law.

Referring to Equation _1, Z 1 is the impedance of the transmission induction coil (210), Z ₂ is the impedance of the transmission resonant coil (220), Z ₃ is the impedance of a receiving resonant coil (310), Z ₄ is receiving the induction coil ( 320 < / RTI > And, M ₁₂ is a cross between the transmitter inductive coil 210 and the transmission resonant coil 220 inductance, M ₂₃ is the mutual inductance between the transmitting resonance coil 220 and the receiving resonance coil (310), M ₃₄ is a receiving resonant coil (310 And the reception induction coil 320. The inductance of the reception induction coil 320 is the same as the inductance of the reception induction coil 320. [

Based on Equation 1 and Equivalent Circuit Diagram of FIG. 3, the impedances Z ₁ to Z ₄ can be expressed by Equation (2).

Using Equations (1) and (2), the relationship between the power source (Vs) and the fourth current (I4) can be expressed by Equation (3).

In addition, the power efficiency? Is set as shown in Equation (4).

In Equation (4), Pout denotes power output from the reception induction coil 320, Pin denotes power input to the transmission induction coil 210, and VL denotes the voltage of the reception induction coil 320. [ S21 denotes a transfer function, which is a function indicating the input / output property.

Solving Equations (3) and (4) leads to Equation (5).

On the other hand, the coupling coefficient can be expressed by Equation (6).

In Equation (6), xy may be set to 12, 23, 34.

Expression (7) can be expressed as Equation (7) by expressing the point at which the coupling coefficient K ₁₂ exhibits the highest efficiency based on Equation (5).

Equation (7) shows the coupling coefficient K ₁₂ having the maximum power transfer value (highest efficiency) for the coupling coefficients K ₂₃ and K ₃₄ . Here, the coupling coefficient K ₂₃ is a value varying in accordance with the distance, angle, and deviation (or axial position) between the transmitting resonant coil 220 and the receiving resonant coil 310, 200).

4 is a graph showing a graph of Equation (5).

Referring to FIG. 4, the coupling coefficient K ₂₃ varies in accordance with the distance between the transmitting resonant coil 220 and the receiving resonant coil 310. Here, the dotted line represents the case where the coupling coefficient K ₂₃ is low, and the solid line represents the case where the coupling coefficient K ₂₃ is high.

In addition, the value of the coupling coefficient K ₁₂ having the maximum efficiency corresponding to the change of the coupling coefficient K ₂₃ is also changed. That is, from FIG. 4, it can be seen that when the coupling coefficient K ₂₃ changes, the value of the coupling coefficient K ₁₂ must be changed so as to have the maximum efficiency.

Here, the coupling coefficient K ₁₂ is changed by the geometric structure, and can be controlled using the distance, angle, and deviation (or axial position) between the transmission induction coil 210 and the transmission resonance coil 220.

FIG. 5 is a diagram showing the geometric and electrical elements between the transmission induction coil and the transmission resonance coil in a simplified manner. FIG.

Referring to FIG. 5, the transmission induction coil 210 has a radius of r1 and generates a first current I1 corresponding to the power from the power source Vs.

The transmission resonance coil 220 is physically spaced apart from the transmission induction coil 210 by a first distance D ₁₂ . The transmission resonance coil 220 is formed by being inclined by a predetermined angle? About the horizontal. The second current I2 is induced in the transmission resonance coil 220 in accordance with the first current I1. In addition,? 2, 1 and? 1, 2 shown in FIG. 5 are magnetic fluxes that generate a second current I2 by a first current I1, respectively, and a first current I1 by a second current I2 Means a magnetic flux to be generated.

5, the central portion of the transmission resonant coil 220 is shown as overlapping the central portion of the transmission induction coil 210, but the present invention is not limited thereto. 6, the central portion of the transmitting resonant coil 220 may be located in an edge region of the transmission induction coil 210 (i.e., an off-axis or an axial position change). In other words,

The coupling coefficient K ₁₂ considering the geometric and electrical factors shown in FIG. 5 can be expressed by Equation (8).

In Equation (8),? Represents the permeability. The magnetic permeability can be changed by the material properties added before and / or after the coils.

The coupling coefficient K ₂₃ is changed as the distance between the transmitting resonant coil 220 and the receiving resonant coil 310 is changed. In this case, by adjusting at least one of the distance D ₁₂ between the transmission induction coil 210 and the transmission resonance coil 220 and the angle? Of the transmission resonance coil 220 as shown in Equation 8, The coupling coefficient K ₁₂ can be controlled. Also, as shown in FIG. 6, the coupling coefficient K ₁₂ can be controlled so as to achieve the maximum efficiency by controlling the axial position between the transmission induction coil 210 and the transmission resonance coil 220.

To this end, in the present invention, at least one of the distance (D ₁₂ ), the angle (?), And the axial position is mechanically (mechanically) interposed between the transmitting resonant coil 220 and the receiving resonant coil 310, Configuration can be added. The mechanical configuration for changing the distance D ₁₂ , angle θ and axis position can be implemented by various techniques now known.

On the other hand, the above-described explanation, of the distance (D _12), the transmission resonance angle (θ) and the axial position of the coil 220 of the transmission induction coil 210 and the transmission resonant coil 220 in response to the change of the coupling coefficient K ₂₃ It is to be understood that the present invention is not limited thereto. For example, the distance, angle, and axial position of the reception resonant coil 310 and the reception induction coil 320 can be further changed corresponding to the change of the coupling coefficient K ₂₃ .

In addition, in the present invention, a magnetic material or the like is additionally provided between the transmission induction coil 210 and the transmission resonance coil 220, and the magnetic permeability can be further controlled using the magnetic substance.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention.

The scope of the present invention is defined by the following claims. The scope of the present invention is not limited to the description of the specification, and all variations and modifications falling within the scope of the claims are included in the scope of the present invention.

200: Transmitting section 210: Transmission induction coil
220: transmission resonance coil 300:
310: receiving resonance coil 320: receiving induction coil

Claims (1)

A wireless power transmission / reception method for wirelessly transmitting power to a reception unit including a reception resonant coil and a reception induction coil in a transmission unit including a transmission induction coil and a transmission resonance coil,
Controlling at least one of a distance between the transmission induction coil and the transmission resonance coil, an angle of the transmission resonance coil, an axial position between the transmission induction coil and the transmission resonance coil corresponding to a distance between the transmission section and the reception section Gt; transmitting / receiving < / RTI >

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