KR20130023290A - A wireless power transmission device and trnasmission method - Google Patents

Abstract

PURPOSE: A wireless power transmission device capable of controlling the strength of power output and a wireless power transmission method thereof are provided to detect the existence of a receiving device positioned on the periphery of the transmission device and to selectively transmit power to the receiving device. CONSTITUTION: A wireless power transmission method is composed of the following steps: Electricity is supplied in a time-sharing method(S101). The intensity of the magnetic field according to the power being supplied is detected(S102). The existence of a receiving device is detected(S103). The existence of the receiving device is confirmed. The electricity with a fixed intensity is continually supplied(S104). The intensity of the detected magnetic field increases. The output strength of the power source is reduced(S105). [Reference numerals] (AA) Start; (BB) No; (CC) Yes; (DD) End; (S101) Outputting electricity periodically with a time-sharing method and transmitting a magnetic field; (S102) Detecting the state of the transmitted magnetic field; (S103) Receiving device exists?; (S104) Continually outputting electricity and transmitting a magnetic field; (S105) Adjusting the intensity of the outputted electricity according to the detected state of the magnetic field

Description

Wireless power transmitter and its wireless power transmission method {A WIRELESS POWER TRANSMISSION DEVICE AND TRNASMISSION METHOD}

The present invention relates to a wireless power device and a wireless power transmission method thereof, and more particularly, to a wireless power transmitter and a wireless power transmission method thereof capable of efficiently transmitting power through active control according to the recognition of the receiving device.

Wireless power transmission technology (wireless power transmission or wireless energy transfer), which wirelessly transfers electrical energy to a desired device, began to use electric motors or transformers using electromagnetic induction principles in the 1800's, and then radio waves and lasers A method of transmitting electrical energy by radiating the same electromagnetic wave has also been attempted. Our electric toothbrushes and some wireless shavers are actually charged with 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.

The wireless power transmission system includes a transmitter and a receiver, and the transmitter transmits power wirelessly to the receiver, and the receiver receives power transmitted from the transmitter and performs an operation accordingly. .

At this time, since the transmitter cannot check the operation state of the receiver, the transmitter continuously transmits power to the receiver so that the receiver can operate normally.

However, as described above, the transmitting apparatus always transmits power to the receiving apparatus regardless of whether the receiving apparatus is operated or not, thereby causing a problem that power is consumed insignificantly.

In addition, since the transmitter transmits a predetermined amount of power to the receiver regardless of the amount of power required by the receiver, power consumption other than the power used by the receiver occurs.

Prior art related to this is disclosed in Japanese Patent Laid-Open Publication No. 10-2011-0009227 (published: January 27, 2011, title of the invention: transmission power control for a wireless charging system).

In an embodiment according to the present invention, it is possible to detect the existence of a receiver located around the transmitter and selectively transmit power to the receiver according to the detection result.

In addition, the embodiment according to the present invention recognizes the amount of power required by the receiver, and accordingly allows to selectively transmit only the power required by the receiver.

Technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above are clearly understood by those skilled in the art to which the embodiments proposed from the following description belong. Could be.

The wireless power transmitter for wirelessly transmitting power to a wireless power receiver according to an embodiment of the present invention uses a power source for generating AC power in a time-division manner at regular intervals and an AC power supplied from the power source by using resonance. The transmission resonant coil transmitted to the wireless power receiver and the output of converting the AC power supplied from the power source into direct current power and the output of converting the AC power transmitted from the transmission resonant coil into direct current power, And a detector configured to detect the presence or absence of a wireless power receiver, wherein the wireless power transmitter adjusts the output of the power source according to a detection result of the detector.

In a wireless power transmission method of a wireless power transmitter for wirelessly transmitting power to a wireless power receiver according to an embodiment of the present invention, generating AC power in a time division manner at a predetermined cycle and receiving and transmitting the generated AC power. Transmitting the wireless power receiver to the wireless power receiver by using a resonance through a resonant coil; and converting the AC power supplied from the power source into DC power and the AC power transmitted from the resonant coil for transmission into DC power. Comparing one output, detecting the existence of the wireless power receiver according to the comparison result, and adjusting the output of the power source according to the detection result.

According to an embodiment of the present invention, by determining whether or not the output of the power according to the presence of the receiving device, and by adjusting the output strength of the power in accordance with the proximity of the receiving device, minimizing wasted waste of power loss can do.

1 is a diagram illustrating a wireless power transmission system according to an embodiment of the present invention.
2 is an equivalent circuit diagram of a transmission coil according to an exemplary embodiment of the present invention.
3 is an equivalent circuit diagram of a power source and a transmitter according to an embodiment of the present invention.
4 is an equivalent circuit diagram of a reception resonance coil, a reception coil, a rectifier circuit, and a load according to an embodiment of the present invention.
5 is a view showing a coil according to an embodiment of the present invention.
6 is a diagram illustrating a transmission apparatus according to an embodiment of the present invention.
7 is a diagram for describing a power transmission state according to an exemplary embodiment of the present invention.
8 is a flowchart illustrating a wireless power transmission method according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

1 is a diagram illustrating a wireless power transmission system according to an embodiment of the present invention.

Referring to FIG. 1, a wireless power transmission system includes a power source 10, a transmission device 20, a reception device 30, a rectifier circuit 40, and a load 50.

Referring to the operation of the wireless power transmission system configured as described above, the power generated in the power source 10 is transmitted to the transmission device 20, and resonates with the transmission device 20 by the magnetic resonance phenomenon, that is, resonance The frequency values are delivered to the same receiving device 30.

Power delivered to the receiving device 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.

In more detail, the power source 10 is an AC power source that provides AC power of a preset frequency.

The transmitting device 20 is composed of a transmitting coil 21 and a transmitting resonant coil 22.

The transmitting coil 21 is connected to the power source 10, through which an 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.

The power delivered to the transmission resonant coil 22 is transferred to the reception device 30 which forms a resonance circuit with the transmission device 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 power can be transmitted at a higher efficiency to a far distance than power transmission by electromagnetic induction.

The receiving device 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 AC current flows through the receiving resonant coil 31.

The power transmitted 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.

In this case, the receiving device 30 includes a rectifying diode including a rectifying diode and a smoothing capacitor for smoothing the rectified signal at the rear end of the receiving coil 32 when DC power is required according to the type of the electronic device to be supplied with power. Although the circuit 40 is installed, in the case of a component requiring AC power supply, the rectifier circuit 40 such as the diode and the smoothing capacitor may be omitted.

In addition, the coil as described above may be adopted and manufactured to increase the transmission efficiency of wireless power, and may be manufactured using only one of them or not used at all.

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 transmitting coil 21 may be composed of an inductor L1 and a capacitor C1, thereby forming a circuit having an appropriate inductance and capacitance value.

The capacitor C1 may be a variable capacitor, and impedance matching may be performed by adjusting the variable capacitor. In this case, the variable capacitors may be connected in series or alternatively may be connected in parallel. The equivalent circuit diagram of the transmitting resonant coil 22, the receiving resonant coil 31, and the receiving coil 32 may be configured in the same manner as shown in FIG.

3 is an equivalent circuit diagram of a power source 10 and a 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 each include inductors L1 and L2 and capacitors C1 and C2 each having a predetermined inductance value and a capacitance value. Can be.

4 is an equivalent circuit diagram of a reception resonance coil 31, a reception coil 32, a rectifier circuit 40, and a load 50 according to an embodiment of the present invention.

Referring to FIG. 4, the receiving resonant coil 31 and the receiving coil 32 may be configured of inductors L3 and L4 and capacitors C3 and C4 having predetermined inductance values and capacitance values.

The rectifier circuit 40 may be composed of a diode D1 and a smoothing capacitor C5, and converts AC power into DC power and outputs the 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 a direct current power source.

The inductance L and the parasitic capacitance C of the solenoid type coil illustrated in FIG. 5 may be represented by the following Equations 1 and 2 below.

l: solenoid coil length

r: radius of solenoid

D: diameter of solenoid

N: number of turns

Hereinafter, the wireless power transmitter as described above will be described in more detail.

6 is a diagram illustrating a transmission apparatus according to an embodiment of the present invention, and FIG. 7 is a diagram for describing a power transmission state according to an embodiment of the present invention.

6 includes configurations of the power source 10 and the transmitter 20 of FIG. 1. In FIG. 6, the remaining components except for the power source 10, the transmitting coil unit 21, and the transmitting resonant coil unit 22 may be included in the transmitting apparatus 20, and alternatively, the power source 10 may be included in the power source 10. Could be

Referring to FIG. 6, the transmission device 20 includes a power source 10 for supplying transmission power, a transmission coil unit 21 connected to the power source 10, and forming a magnetic field by the supplied power. A detection unit 23 which detects the presence of a transmission resonant coil unit 22 coupled to the transmission coil unit 21 to transmit electric power, a receiver 30, and the detection unit 23 As a result, it may include a control unit 29 for controlling the state of the power supplied through the power source 10.

The detection unit 23 detects a state of the magnetic field transmitted through the transmission resonant coil unit 22, and transmits a detection result of the state of the magnetic field to the control unit 29.

In this case, the detector 23 may be configured as a current sensor.

Alternatively, the detection unit 23 is transmitted from the first power detector 24 for detecting the intensity of the power output through the power source 10 and converting it into direct current, and the resonant coil unit 22 for transmission. A detection coil 25 for detecting the strength of the magnetic field, a second power detection unit 26 for converting the power generated by the magnetic field detected by the detection coil 25 into a direct current, and the first power detection unit ( The output unit 24 may include a comparison unit 28 that compares the output of the second power detection unit 26 and transmits the comparison result to the control unit 29.

In addition, the detector 23 may further include an amplifier 27 that amplifies the DC converted by the second power detector 26.

The detector 23 detects the intensity of the magnetic field generated by the resonant coil unit 23 for transmission, and the controller 29 determines that the intensity of the magnetic field detected by the detector 23 is equal to or greater than a predetermined reference value. It is determined that there is no receiving apparatus for receiving the transmitted magnetic field, and if the strength of the magnetic field is less than a predetermined reference value, it is determined that the receiving apparatus exists.

An object of the transmitting apparatus according to the present invention is that the receiving apparatus is far from the transmitting apparatus so that the receiving apparatus hardly receives the power transmitted from the transmitting apparatus, or there is no receiving apparatus in proximity to the transmitting apparatus. If the transmitter does not need to generate power, it is to detect this situation so that the power is not automatically transmitted.

This is because when the wireless power transmitter is installed indoors and the wireless power receiver is mounted on the mobile phone or the notebook, when the mobile phone or the notebook does not exist or is far away, the power is not automatically output from the transmitter. Alternatively, the intensity of the output power may be reduced to minimize power loss.

The principle of the transmission device according to an embodiment of the present invention is as follows. In FIG. 6, the transmission resonance coil 22 stores power through resonance. The amount of energy stored in the transmission resonant coil 22 is input power * Q (Q = Quality Factor), and the Q value of the transmission resonant coil 22 has a large amount of power received by the receiving device in proximity to the transmitting device. The lower the quality.

In addition, since the magnetic force generated in the transmission resonant coil 22 is proportional to the energy stored in the transmission resonant coil 22, as a result, the closer the receiver is, the amount of energy stored in the transmission resonant coil 22 is increased. The strength of the magnetic field generated by the weakening is weakened. Accordingly, the amount of power detected by the detecting coil 25 is also reduced.

The detection coil 25 is coupled to a magnetic field generated by the transmission resonant coil 22 and converted by the second power detector 26 into a DC voltage signal. Since the output signal of the second power detector 26 is very small, the output signal can be amplified by the amplifier 27.

Since the output of the first power detector 24 is constant, it can be used as a reference value. In this case, the comparator 28 outputs a comparison result according to the output signal of the second power detector 26 based on the output signal of the first power detector 24 to the controller 29.

If the receiving device is far from the transmitting device or does not exist, the energy stored in the transmitting resonant coil 22 is increased, thereby increasing the intensity of the magnetic field detected by the second power detector 24. do.

At this time, the comparison result signal output through the comparator 28 is the difference between the output signal of the first power detector 24 and the second power detector 26, the receiver around the transmitter If present, the output signal of the comparator 28 is 0, but has a value close to zero. At this time, when the receiving device is further away from the transmitting device, the output value of the comparator 28 is gradually increased, and if the receiver is not present, the output value of the comparator 28 is It may be equal to the output value of the first power detector 24.

Accordingly, the control unit 29 checks whether or not the receiving apparatus exists or does not exist according to the detection result of the detection unit 23.

If it is determined that the receiver does not exist, the controller 29 stops the power output of the power source 10. In addition, when it is determined that the receiving device exists, the controller 29 allows the power source 10 to continuously output power.

In the meantime, the controller 29 periodically checks whether or not the receiver is present in the state where the receiver is not present (powered by the receiver). To be printed.

In addition, the controller 29 reconfirms the presence or absence of the receiving device based on the power outputted at each predetermined period, and accordingly, continuously stops the output of the power or releases the output of the power.

In this case, the controller 29 allows the power to be output in a time division manner every predetermined period in order to minimize the loss of power.

In other words, when the power is continuously output for a certain period of time at a certain period of time, a loss of power occurs accordingly, so that the control unit 29 outputs the time-divided power at a predetermined time interval for the specific time. Accordingly, the existence of the receiver is checked based on the time-divided and output power.

On the other hand, the control unit 29 periodically checks the detection result of the detection unit 23, and adjusts the intensity of the power based on the detection result accordingly.

For example, when the amount of power supplied from the power source 10 and the amount of power received by the receiver are the same or insignificant, the controller 29 is output from the power source 10. Increase the power strength

On the contrary, when the amount of power received by the receiving device is significantly lower than the amount of power supplied from the power source 10, the controller 29 decreases the intensity of the power output from the power source 10. Let's do it.

As described above, according to the exemplary embodiment of the present invention, the presence or absence of the reception apparatus 20 is detected by using the strength of the magnetic field generated by the transmission apparatus 20, and accordingly, the magnetic field is continuously generated in the transmission apparatus 20. Transmit or stop transmission of the magnetic field.

At this time, in order to detect the existence of the receiving device 30 in a state where the receiving device 30 does not exist, the magnetic field is generated by a time division method at regular intervals, thereby minimizing the loss of power and receiving the receiving device 30. Detects the presence of

In addition, even when the receiver 30 is present, the strength of the magnetic field is continuously detected so that only the amount of power received by the receiver 30 is supplied from the power source 10.

8 is a flowchart for explaining a power transmission method step by step according to an embodiment of the present invention.

Hereinafter, the power transmission method will be described with reference to FIGS. 7 and 8.

First, in a state in which the receiving device 30 does not exist, power is supplied in a time division manner every predetermined period (A) (step 101).

Then, the strength of the magnetic field according to the power supplied in the time division method is detected (step 102). In this case, it is determined whether the receiver 30 exists based on the detected strength of the magnetic field (step 103).

If it is confirmed in the above that the receiver 30 does not exist, the process returns to (A) (step 101), and if it is confirmed that the receiver 30 exists, the power of a certain intensity (a) is continuously (B) (step 104).

At this time, the strength of the magnetic field is continuously detected even in the state B in which the receiver 30 is present and the power is continuously supplied.

Then, the existence of the receiver 30 is reconfirmed based on the detected intensity of the magnetic field.

In addition, when the intensity of the detected magnetic field is increased while the power of the predetermined intensity (a) is supplied, a greater amount of power is required than the power required by the receiving device (30). Since the state is being supplied through, the output intensity (b) of the power source 10 is reduced (C) (step 105).

In addition, the intensity of the magnetic field is continuously monitored even when power is supplied at the intensity b, thereby increasing or decreasing the intensity b again (D).

On the other hand, if the intensity of the detected magnetic field is significantly increased while the power is being supplied, it is determined that the receiver does not exist and the output of the power is stopped.

Then, the power is supplied in a time division manner every predetermined period to check the existence of the receiver (E).

According to this embodiment according to the present invention, by determining whether or not the output of the power according to the presence of the receiving device, and by adjusting the output strength of the power in accordance with the proximity of the receiving device, the loss of power wastelessly wasted Can be minimized.

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, but, on the contrary, It will be understood that various modifications and applications other than those described above are possible. For example, each component shown in detail in the embodiment of the present invention may be modified. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

10: power source
20: transmitting device
30: receiver
40: rectifier circuit
50: load

Claims (10)

A wireless power transmitter for wirelessly transmitting power to a wireless power receiver,
A power source for generating alternating current power in a time division manner at regular intervals;
A transmission resonant coil for transmitting the AC power supplied from the power source to the wireless power receiver using resonance; And
A detection unit for detecting the presence of the wireless power receiver by comparing an output of converting AC power supplied from the power source into DC power and an output of converting AC power transmitted from the transmission resonance coil into DC power; and,
The wireless power transmitter adjusts the output of the power source according to a detection result of the detector.
Wireless power transmitter. The method of claim 1,
The detection unit
A first power detector for converting and outputting AC power supplied from the power source into DC power;
A second power detector configured to convert AC power transmitted from the resonant coil for transmission into DC power and output the DC power;
Comprising a comparison unit for comparing the output of the first power detector and the second power detector
Wireless power transmitter. The method of claim 2,
The detection unit
Further comprising a detecting coil for detecting a magnetic field transmitted from the transmitting resonant coil,
The second power detector
Converting AC power generated by the magnetic field detected by the detecting coil into DC power
Wireless power transmitter. The method of claim 1,
The wireless power transmission device
If the wireless power receiver does not exist, stops the power supply of the power source,
When the wireless power receiver is present, to maintain the power supply of the power source
Wireless power transmitter. The method of claim 1,
The detection unit
Detecting the existence of the wireless power receiver according to the AC power generated by the time division method
Wireless power transmitter. The method of claim 1,
The wireless power transmission device
Determining whether the wireless power receiver is close according to the strength of the magnetic field transmitted from the resonant coil for transmission, and adjusting the output of the power source according to the checked proximity.
Wireless power transmitter. A wireless power transmission method of a wireless power transmitter for wirelessly transmitting power to a wireless power receiver,
Generating alternating current power in a time division manner every predetermined period;
Receiving the generated AC power and transmitting the generated AC power to the wireless power receiver by using a resonance through a transmission resonant coil;
Comparing an output of converting AC power supplied from the power source into DC power and an output of converting AC power transmitted from the transmission resonant coil into DC power;
Detecting the existence of the wireless power receiver according to the comparison result; And
Adjusting the output of the power source according to the detection result;
Wireless power transmission method of a wireless power transmission device. The method of claim 7, wherein
Converting the AC power transmitted from the resonant coil for transmission into DC power
Detecting a magnetic field transmitted from the resonant coil for transmission;
Converting the AC power generated by the detected magnetic field into direct current power;
Wireless power transmission method of a wireless power transmission device. The method of claim 7, wherein
Adjusting the output of the power source according to the detection result
If the wireless power receiver does not exist, stops the power supply of the power source,
Maintaining the power supply of the power source if the wireless power receiver is present;
Wireless power transmission method of a wireless power transmission device. The method of claim 7, wherein
Determining whether the wireless power receiver is close according to the strength of the magnetic field transmitted from the resonant coil for transmission, and adjusting the output of the power source according to the checked proximity.
Wireless power transmission method of a wireless power transmission device.

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