KR20120116801A

KR20120116801A - A wireless power transmission circuit, a wireless power transmitter and receiver

Info

Publication number: KR20120116801A
Application number: KR1020110034456A
Authority: KR
Inventors: 배수호
Original assignee: 엘지이노텍 주식회사
Priority date: 2011-04-13
Filing date: 2011-04-13
Publication date: 2012-10-23

Abstract

PURPOSE: A wireless power transmission circuit and a wireless power transmitter and receiver are provided to omit a coating removal process of a litz wire by forming a coil in which a litz wire with a general single wire are combined. CONSTITUTION: A wireless power transmission circuit comprises a litz coil part, a single wire coil part, and a capacitor. The litz coil part is formed by winding a litz wire. The single wire part is formed by winding the single wire while being closer to the litz coil part. A capacitor is connected to the single wire coil part. Either the litz coil part or the single wire coil part is wound in a solenoid-type. Either the litz coil part or the single wire coil part is wound in a spiral type.

Description

A WIRELESS POWER TRANSMISSION CIRCUIT, A WIRELESS POWER TRANSMITTER AND RECEIVER}

The present invention relates to wireless power transfer technology. More specifically, the present invention relates to a coil structure and a transmitter and a receiver including the coil structure in a wireless power transmission using a so-called self-resonant phenomenon. The present invention relates to a wireless power transmission circuit, a wireless power transmitter, and a receiver that can compensate for the disadvantages of the REITs coil, which is mainly used.

Wireless power transmission technology (wireless power transmission or wireless energy transfer), which transfers electric energy wirelessly to a desired device, has already started to use electric motors or transformers using electromagnetic induction principles in the 1800's. A method of transmitting electrical energy by radiating the same electromagnetic wave has also been attempted. Electric toothbrushes and some wireless razors that we commonly use are actually charged with the principle of electromagnetic induction. To date, energy transmission methods using wireless methods include magnetic induction, magnetic resonance, and long-distance transmission technology using short wavelength radio frequencies.

Conventionally, in order to connect a capacitor to a coil composed of a litz wire, as shown in FIG. 5 (b), a coating coated on the litz wire should be removed. Because Litz wire consists of many insulated wires, both cases are time-consuming and expensive.

Wireless power transmission circuit according to an embodiment of the present invention, the Litz coil unit formed by winding a Litz (Litz) wire; A single wire coil part formed by winding a single wire close to the litz coil part; And a capacitor connected to the single wire coil unit.

According to an embodiment of the present invention, a wireless power transmitter includes a transmission coil unit connected to a power source to form a magnetic field, and a transmission coil unit coupled to the transmission coil unit to transmit power. A part or transmission resonant coil portion, each of which comprises: a litz coil portion formed by winding a litz wire; A single wire coil part formed by winding a single wire close to the litz coil part; And a capacitor connected to the single wire coil unit.

A wireless power receiver according to an embodiment of the present invention, the receiving resonant coil unit for receiving power wirelessly from the transmitting resonant coil unit; And a receiving coil unit configured to receive the power received by the receiving resonant coil unit and transmit the received power to a load, wherein the receiving resonant coil unit and the receiving coil unit each include a litz coil unit formed by winding a litz wire; A single wire coil part formed by winding a single wire close to the litz coil part; And a capacitor connected to the single wire coil unit.

According to the present invention, it is possible to reduce the time and cost for manufacturing the coil by eliminating the stripping work of the litz wire by combining the litz wire and a common single wire to form a coil.

1 illustrates a wireless power transmission system according to an embodiment of the present invention.
2 is an equivalent circuit diagram of a transmitting coil 21 according to an embodiment of the present invention.
3 is an equivalent circuit of the power source 10 and the transmitter 20 according to an embodiment of the present invention.
4 shows an equivalent circuit of the receiving resonant coil 31, the receiving coil 32, the smoothing circuit 40 and the load 50, according to an embodiment of the invention.
5 shows a configuration of a coil according to the prior art.
6 shows a coil wound in a solenoid type according to the present invention, Figure 7 shows a coil wound in a spiral type.
8 shows the structure of the litz wire.
9 shows a structure of a coil according to an embodiment of the present invention.
10 illustrates a solenoid type coil structure according to an embodiment of the present invention, and FIG. 11 illustrates a spiral type coil structure.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings.

1 illustrates a wireless power transmission system according to an embodiment of the present invention.

The power generated by the power source 10 is transmitted to the transmitter 20, and is transmitted to the receiver 30, which resonates with the transmitter 20 by a magnetic resonance phenomenon, that is, the resonance frequency values are the same. Power delivered to the receiver 30 is delivered to the load 50 via the rectifier circuit 40. The load 50 may be a rechargeable battery or any device that requires power.

More specifically, the power source 10 is an AC power source that provides an AC power of a predetermined frequency.

The transmitter 20 is composed of a transmitting coil 21 and a transmitting resonant coil 22. The transmission coil 21 is connected to the power source 10, the alternating current flows. When an alternating current flows through the transmission coil 21, an alternating current is also induced in the transmission resonant coil 22 which is physically spaced by electromagnetic induction. Power transmitted to the transmission resonant coil 22 is transmitted to the receiver 30 forming a resonant circuit with the transmitter 20 by magnetic resonance.

Power transmission by magnetic resonance is a phenomenon in which power is transmitted between two LC circuits of which impedance is matched, and thus power can be transmitted with greater efficiency up to a far distance than power transmission by electromagnetic induction.

The receiver 30 is composed of a receiving resonant coil 31 and a receiving coil 32. The power transmitted by the transmitting resonant coil 22 is received by the receiving resonant coil 31 so that an alternating current flows through the receiving resonant coil 31. Power delivered to the receiving resonant coil 31 is transmitted to the receiving coil 32 by electromagnetic induction. Power delivered to the receiving coil 32 is rectified through the rectifier circuit 40 and delivered to the load 50.

2 is an equivalent circuit diagram of a transmitting coil 21 according to an embodiment of the present invention. As shown in FIG. 2, the transmission coil 21 may be composed of an inductor L1 and a capacitor C1, thereby forming a circuit having appropriate inductance and capacitance values. The capacitor C1 may be a variable capacitor, and impedance matching may be performed by adjusting the variable capacitor. The equivalent circuit of the transmitting resonant coil 22, the receiving resonant coil 31, and the receiving coil 32 may be the same as that shown in FIG.

3 is an equivalent circuit of the power source 10 and the transmitter 20 according to an embodiment of the present invention. As shown in FIG. 3, the transmitting coil 21 and the transmitting resonant coil 22 may be formed of inductors L1 and L2 and capacitors C1 and C2 having predetermined inductance values and capacitance values, respectively.

4 shows an equivalent circuit of the receiving resonant coil 31, the receiving coil 32, the smoothing circuit 40 and the load 50, according to an embodiment of the invention.

As shown in FIG. 4, the receiving resonant coil 31 and the receiving coil 32 may be formed of inductors L3 and L4 and capacitors C3 and C4 having predetermined inductance values and capacitance values, respectively. The smoothing circuit 40 may be composed of a diode D1 and a smoothing capacitor C5, and outputs AC power by converting DC power. The load 50 is represented by a 1.3V direct current power source, but may be any rechargeable battery or device that requires direct current power.

5 shows a configuration of a coil according to the prior art. Conventionally, as shown in FIG. 5 (a), a coil is simply wound to form a coil, or in order to secure a capacitance value, the capacitor is further connected as shown in FIG. 5 (b). The coil configured as shown in FIG. 5 was used as the transmitting coil 21, the transmitting resonant coil 22, the receiving resonant coil 31, or the receiving coil 32.

Substantially, the coil shown in FIG. 5 may be wound in a solenoid type as shown in FIG. 6, or may be wound in a spiral type as shown in FIG. 7. The solenoid type coil is formed by mounting the bobbin 42 on the core 41 and winding the wire 43 in the longitudinal direction of the bobbin 42. The spiral type coil is formed by winding a wire outward from the center of the core 51.

As a wire of the coil illustrated in FIG. 6 or 7, a Litz wire illustrated in FIG. 8B is typically used. Unlike the single line shown in (a) of FIG. 8, the litz wire shown in (b) of FIG. 8 is an electric wire made of several strands of wires insulated from each other. The reason for the use of Litz wire is to make the surface area change due to the skin effect, because the electric current flows only toward the surface of the wire, so that almost no current flows in the middle of the wire. Since the surface area of the wire can be prevented while increasing the surface area, it is possible to prevent the resistance of the coil from increasing.

According to one embodiment of the present invention, by forming a coil by combining a Litz wire and a general single line, it is possible to simplify the stripping operation of the wire.

9 shows a structure of a coil according to an embodiment of the present invention. As shown in FIG. 9, the coil 60 is composed of a litz coil portion 61 composed of litz wire and a single line coil portion 62 composed of a general single line. The single wire coil portion 62 is configured to be close to or in close contact with the litz coil portion 61, but is insulated from the litz wires of the litz coil portion 61 by, for example, wire coating. A capacitor 63 may be connected to the single wire coil part 62.

The coil according to an embodiment of the present invention may be implemented as a solenoid type as shown in FIG. 10, or may be implemented as a spiral type as shown in FIG.

In the case of implementing the solenoid type as shown in FIG. 10, the bobbin 72 may be mounted on the core 71, and the litz wire 73 and the single wire 74 may be wound on the bobbin 72. . The capacitor 75 may be connected to the single line 74. Depending on the embodiment, the core 71 may be a ferromagnetic material or may be composed of air.

In the case of the spiral type as illustrated in FIG. 11, the LITZ wire 83 may be wound from the inside of the core 81 to the outside, and the single wire 84 may be wound outside the core 81. Similarly, the capacitor 85 may be connected to the single wire 84. As with the solenoid type, the core 81 may be ferromagnetic or may be composed of air.

The coil configured as described above may be used as the above-described transmitting coil 21, the transmitting resonant coil 22, the receiving resonant coil 31, or the receiving coil 32.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

10: power source
20: transmitter
21: transmitting coil
22: resonant coil for transmission
30: receiver
31: resonant coil for reception
32: receiving coil
40: rectifier circuit
50: load

Claims

A Litz coil part formed by winding a Litz wire;
A single wire coil part formed by winding a single wire close to the litz coil part; And
And a capacitor connected to the single line coil unit.

The method of claim 1,
And at least one of the litz coil unit or the single wire coil unit is wound in a solenoid type.

The method of claim 1,
At least one of the litz coil unit or the single-line coil unit is wound in a spiral type.

A transmission coil part connected to a power source to form a magnetic field and a transmission coil part coupled to the transmission coil part to transmit power,
The transmitting coil portion or the resonant coil portion for transmission, respectively,
A litz coil unit formed by winding the litz wire;
A single wire coil part formed by winding a single wire close to the litz coil part; And
Wireless power transmitter comprising a capacitor connected to the single-line coil unit.

The method of claim 4, wherein
At least one of the litz coil unit or the single wire coil unit is wound in a solenoid type.

The method of claim 4, wherein
At least one of the litz coil unit or the single wire coil unit is wound in a spiral type.

A reception resonant coil unit which wirelessly receives power from the transmission resonant coil unit; And
It includes a receiving coil unit for receiving the power received by the receiving resonant coil unit to deliver to the load,
The receiving resonant coil unit and the receiving coil unit, respectively,
A litz coil unit formed by winding the litz wire;
A single wire coil part formed by winding a single wire close to the litz coil part; And
And a capacitor connected to the single line coil unit.

The method of claim 7, wherein
And at least one of the litz coil unit or the single wire coil unit is wound in a solenoid type.

The method of claim 7, wherein
At least one of the litz coil unit or the single wire coil unit is wound in a spiral type.