KR20160121698A - Apparatus and Method for wireless power transmission capable of frequency selection for LED panel - Google Patents

Abstract

The present invention relates to a wireless power transmission apparatus for wirelessly transmitting power to a plurality of wireless chargers having different resonance frequencies, and more particularly, A plurality of capacitors having different capacitances and a transmission coil; a detection unit for detecting a resonance frequency of the wireless charging device; and a control unit for controlling the resonance frequency of the wireless charging device to match the resonance frequency of the wireless charging device And a controller for adjusting the resonance frequency of the wireless power supply by adjusting the total capacitance value by switching different capacitors of the wireless power supply. According to the present invention, by switching the capacitors having different capacitance values so that the wireless power supply device receives the resonance frequency information from the wireless charging device and charges the target device to be charged, different resonance frequencies are supplied to one wireless power supply device It is possible to stably supply the wireless power to the microwave ovens having the microwave ovens and also to make efficient use of the space. In addition, since the switch is controlled as a digital signal, various resonance frequencies can be selected as compared with the conventional method.

Description

[0001] The present invention relates to a wireless power transmission apparatus and a method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless power transmission apparatus for a LED electric sign board capable of frequency selection, and more particularly, to an LED electric sign board having a plurality of wireless chargers having different resonant frequencies, The present invention relates to a wireless power transmission apparatus for a LED electric signboard capable of selectively selecting a frequency and a method thereof.

Wireless power transmission or wireless energy transfer, which transfers electric energy to a desired device wirelessly, started to use electric motors or transformers based on electromagnetic induction principally. After that, electromagnetic waves such as radio waves or lasers To transfer electrical energy.

A conventional portable terminal has a detachable or built-in battery pack, and the user charges the battery pack according to the remaining battery capacity. Conventional portable terminals charge a battery pack through a separate charger. Recently, interest in wireless charging has been increasing for user's convenience. Such wireless charging has been applied to various electric devices.

Up to now, a power transmission system using a wireless system has been used such as a magnetic induction system, a magnetic resonance system, and a remote transmission technology using a short wavelength radio frequency. Recently, a power transmission method using a magnetic resonance method has been actively studied due to the advantage that a power transmission distance is long and power can be transmitted to a plurality of receivers. It is progressing.

In the wireless power transmission system using magnetic resonance (or self-resonance), since the electric signals formed on the transmission side and the reception side are wirelessly transmitted through the resonance frequency between the coil and the capacitor, the user can easily charge the electronic device such as a portable device .

However, when the resonance frequencies are different from each other, it is necessary to install the additional coils so as to match the resonance frequency of the charging devices because the wireless power transmission is impossible. However, since the size of the coils is relatively large, fatal problems arise in terms of area and efficiency.

On the other hand, in the following prior art document (Korean Patent Registration No. 10-1241481), a variable capacitor is applied and the capacitance value of the variable capacitor is adjusted to adjust the resonance frequency and output. However, such a variable capacitor is expensive, and when a variable capacitor is applied, the capacitance value of the variable capacitor must be adjusted, which makes it difficult to drive and control such a variable capacitor.

That is, in the prior art, the resonance frequency is adjusted by varying the capacitance value by attaching a variable capacitor. In order to control the variable capacitor, a continuous signal must be applied, the resonance frequency that can be varied is limited, The frequency range in which resonance can be made is narrow.

Korean Patent Publication No. 10-2012-0078676 (published on July 10, 2012) Korean Registered Patent No. 10-1241481 (published on March 11, 2013)

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a system for wirelessly transmitting electric power to an LED display board using radio devices having different resonance frequencies, comprising: a plurality of capacitors having different capacitances from one coil; The present invention provides a wireless power transmission apparatus for a LED electric sign board capable of selecting a frequency that can supply wireless power to a plurality of wireless devices having different resonance frequencies by controlling a resonance frequency by switching the LEDs .

In addition, the present invention can reduce the error due to internal resistance by applying a switch for switching a capacitor to a CMOS switch, and can control the frequency by selecting a frequency that can be selected from a variety of frequencies It is another object of the present invention to provide a wireless power transmission apparatus and a method thereof.

According to an aspect of the present invention, there is provided a wireless power transmission apparatus for wirelessly transmitting electric power to an LED electric signboard having a plurality of wireless chargers having different resonance frequencies, A wireless power supply unit including a plurality of capacitors and a transmission coil for transmitting power supplied from a power supply unit and having different capacitance values; A detector for detecting a resonance frequency of the wireless charging device; And a controller for adjusting the resonance frequency of the wireless power supply unit by adjusting the total capacitance value by switching different capacitors of the wireless power supply unit so as to match the resonance frequency of the wireless charging device detected by the detection unit.

The plurality of capacitors of the wireless power supply unit are connected in parallel to each other, and the switches are connected to the capacitors. The controller adjusts the resonance frequency by adjusting the total capacitance value by turning on / off each of the switches.

According to one aspect of the present invention, the switch is a CMOS switch.

On the other hand, the switch is connected to both ends of the capacitor.

According to an aspect of the present invention, there is provided a method of wirelessly transmitting power to a plurality of wireless chargers having different resonance frequencies using the wireless power transmission device, A) receiving resonant frequency information from the wireless charging device; b) adjusting the resonant frequency of the wireless power transmitter by adjusting the total capacitance value by switching different capacitors of the wireless power transmitter to match the resonant frequency of the received wireless charging device; c) supplying power of a constant frequency to the wireless power transmitter; And d) transmitting the wireless power of the wireless power transmitter to the wireless charger based on a self resonance scheme.

According to the present invention, resonance frequency information is received from a plurality of wireless charging devices having different resonance frequencies, and a plurality of capacitors having different capacitance values are switched to adjust the total capacitance value, The resonance frequency can be adjusted in accordance with the resonance frequency. Therefore, it is possible to stably supply the radio power to the radio equipment having different resonance frequencies by using one radio power transmission device having one coil, and also it is possible to utilize the space of the device efficiently.

Further, by applying a switch element for switching a capacitor to a CMOS switch, an error due to an internal resistance is reduced, and an accurate switching operation can be performed.

In addition, since the switch is controlled as a digital signal, various resonance frequencies can be selected as compared with the conventional method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram schematically showing the entire configuration of a wireless power transmission device for a LED electric signboard and a wireless charging device capable of frequency selection according to an embodiment of the present invention;
FIG. 2 is a block diagram of a wireless power transmission device and a wireless charging device for a frequency-selectable LED electric sign board according to an embodiment of the present invention;
FIG. 3 is a circuit diagram of a wireless power transmission apparatus for LED electric sign board capable of frequency selection according to an embodiment of the present invention,
FIG. 4 is a circuit diagram of a wireless power transmission apparatus for a frequency-selectable LED electric sign board according to another embodiment of the present invention,
5 is a flowchart illustrating a method of wireless power transmission by a wireless power transmission device for LED electric sign board capable of frequency selection according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a wireless power transmission apparatus capable of selecting a frequency according to the present invention and a method thereof will be described in detail with reference to the accompanying drawings.

In describing the present invention, the sizes and shapes of the components shown in the drawings may be exaggerated or simplified for clarity and convenience of explanation. In addition, the terms defined in consideration of the configuration and operation of the present invention may be changed according to the intention or custom of the user, the operator. These terms are to be construed in accordance with the meaning and concept consistent with the technical idea of the present invention based on the contents throughout the present specification.

1 and 2, a wireless power transmission apparatus 100 capable of frequency selection according to an embodiment of the present invention includes a plurality of wireless charging devices 110a, 110b, and 110n having different resonance frequencies, So that power is transmitted wirelessly. Here, the wireless charger may be understood to mean a portable electronic device having a battery pack or a built-in battery and an LED electronic signboard using the portable electronic device.

The wireless power supply 100 includes a power supply unit 210, a filter unit 230, a rectifier circuit unit 260, a wireless power supply unit 220, a detection unit 250, and a control unit 240.

The power supply unit 210 is an AC power source for providing AC power of a predetermined frequency and outputs AC power at a constant frequency.

The filter unit 230 removes noise, and the rectifying circuit unit 260 changes the AC power output from the power supply unit 210 to DC power.

The wireless power supply unit 220 outputs the converted DC power output from the power supply unit 210 to the wireless power reception unit 330 of the wireless transmission device. The wireless power supply unit 220 generates a resonance by self-resonance phenomenon, And transmits power to the wireless charger. The wireless power supply unit 220 includes one transmission coil (antenna) and a plurality of capacitors having different capacitance values.

The detection unit 250 detects the resonance frequencies of the plurality of wireless charging devices 110 and transmits the detected resonance frequencies to the control unit 240. The wireless power supply unit 220 receives a feedback response signal from the wireless power receiving unit 330 of the wireless charging device. The detecting unit 250 serves as a demodulator that restores the feedback response signal. And detects the resonance frequency information and transmits it to the control unit 240.

The control unit 240 controls the overall operation of the wireless power supply. In particular, the control unit 240 determines the resonance frequency for power transmission based on the resonance frequency of the wireless charging device 110 detected by the detection unit 250. The control unit 240 switches the different capacitors of the wireless power supply unit 220 The resonance frequency is determined in accordance with the resonance frequency of the wireless charging device 110 detected by the detection unit 250 by adjusting the total capacitance value.

Hereinafter, the wireless power supply unit 220 and the control unit 240 will be described in detail.

3 and 4, the wireless power supply unit 220 includes one transmission coil (inductor, L1) and a plurality of capacitors C1, C2, and C3. The plurality of capacitors C1, C2, and C3 are connected in parallel with each other and have different capacitance values. According to the embodiment of the present invention, three capacitors are provided, but the present invention is not limited thereto, and more than three capacitors may be provided.

Meanwhile, switches S1, S1 ', S2, S2', S3, and S3 'are connected to the plurality of capacitors C1, C2, and C3, respectively.

 The switch may be a switching device capable of performing an on / off function, and the switching device may be a MOSFET as shown in FIG. 3 according to an embodiment of the present invention, A CMOS in which a pMOSFET and an nMOSFET are connected in parallel can be applied as shown in FIG.

It is common for a single MOSFET switch to be applied for the switching control of the capacitors C1, C2, C3, which is likely to result in inaccurate operation of the switch on / off operation due to the presence of internal resistance in the structure . Therefore, when the COMS switch of FIG. 4 is applied, there is an advantage that the error due to the internal resistance described above can be reduced with respect to the ON / OFF operation of the switch.

That is, it can be modeled as a resistor structure between the channels inside the transistor. Therefore, when designing a switch with a single FET, the resistance increases when designing with only the n-MOSFET switch for the low signal, and when the design is made with only the p-MOSFET switch for the high signal, The signal may not be completely transmitted due to the internal resistance of the switch passing through the switch. However, in the CMOS switch structure in which the p-MOSFET and the n-MOSFET are designed in parallel, the internal resistance of each transistor is calculated in parallel, so that the internal resistance value can be lowered.

The switches S1, S2 ', S2, S2', S3, and S3 may be connected to only one (one end) of the capacitors C1, C2, 'May be connected to both (both ends) of the capacitors C1, C2, and C3 to switch. At this time, the switches S1, S1 ', S2, S2', S3, and S3 'located on both sides of the capacitors C1, C2, and C3 receive the same signal and are turned on and off at the same time.

When a switch is connected to only one side, since the signal continues to be ON at one polarity of the capacitor, the capacitor having the OFF operation can flow into the leakage signal lamp. In this case, the values of the entire capacitors of the system are changed, so that the resonance frequency may fluctuate and the wireless power can not be supplied smoothly.

The control unit 240 determines the resonance frequency for power transmission based on the resonance frequency of the wireless charging device 110 detected by the detection unit 250. At this time, the wireless power receiving unit 330 of the wireless charging device 110 The resonance frequency is determined by turning on / off the switches connected to the respective capacitors of the wireless power supply unit 220 in accordance with the resonance frequency to adjust the total capacitance value.

The resonance frequency f1 of the wireless power supply unit 220 and the resonance frequency f2 of the wireless power receiving unit 330 of the wireless charging device 110 must be the same and the resonance frequencies f1 and f2 are expressed by the following equations 1 < / RTI >

That is, since the resonance frequencies F2 of the different wireless charging devices 110 are different from each other, the resonance frequency F1 of the wireless power supply 220 must be adjusted accordingly. Here, since L is fixed, it is necessary to change C, and the control unit 240 can adjust the value of the entire C by switching the plurality of capacitors C1, C2, and C3. Since the values of the capacitors C1, C2, and C3 are predetermined, the controller 240 can turn on or off each of the capacitors to adjust the total capacitance value in accordance with the resonance frequency of the corresponding wireless charging device.

When the resonant frequency of the wireless power receiving unit 330 of the wireless charging device 110 is equal to the resonant frequency of the wireless power supplying unit 220, the power of the wireless power supplying unit 220 is transmitted to the wireless power receiving unit 330 do.

In the wireless power receiving unit 330, the power transmitted by the wireless power supply unit 220 is received, rectified through the rectifying circuit of the rectifying circuit unit 320, and transmitted to the load 310.

As described above, according to the present invention, it is possible to adjust and output the resonance frequency by connecting a switch and a capacitor having a relatively small size and a coil in parallel without installing a coil having a large size. There is an advantage in that the wireless power can be efficiently supplied to a plurality of churning devices having different resonance frequencies.

Also, in the above-mentioned prior art document (Korean Patent Registration No. 10-1241481), it is disclosed that a variable capacitor is applied and the capacitance value of the variable capacitor is adjusted to adjust the resonance frequency and output. However, in this case, a continuous signal must be applied in order to control the variable capacitor, which may degrade the ability to match the resonance frequency of the received wireless charging device. In addition, since the variable capacitor varies the capacitance value by the analog method and matches the frequency, there is a problem that the matching frequency band is narrow.

However, according to the present invention, since the variable of the capacitor is controlled by the ON / OFF operation of the digital signal, it is possible to output the resonance frequency more accurately than the prior art, thereby providing an advantage that the power supply can be stably and smoothly performed. There is an advantage that the frequency can be matched.

Further, the present invention is advantageous in that an error due to an internal resistance is reduced by applying a switch for switching a capacitor to a CMOS switch.

Hereinafter, a wireless power supply method by the wireless power supply apparatus 100 having the above configuration will be described with reference to FIG.

First, the resonance frequency information is received from the wireless charging device to be charged among the plurality of wireless charging devices through the detection section (S510).

Then, the resonance frequency of the wireless power transmitter is adjusted to match the resonance frequency of the received wireless charging device (S520). That is, the control unit appropriately switches capacitors having different capacitance values to adjust the total capacitance value, thereby adjusting the resonance frequency of the wireless power transmission unit to coincide with the resonance frequency of the wireless charging device.

When a power of a certain frequency is supplied to the wireless power transmission unit by the power supply unit (S530), the wireless power of the wireless power supply unit is transmitted to the wireless power reception unit of the wireless charging device based on the self resonance method (S540).

The embodiments of the present invention described above and shown in the drawings should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art can improve and modify the technical idea of the present invention in various forms. Accordingly, these modifications and variations are intended to fall within the scope of the present invention as long as it is obvious to those skilled in the art.

100: wireless power supply 110: wireless charging device
210: power supply unit 220: wireless power supply unit
C1, C2, C3: capacitors S1, S2, S3, S1 ', S2', S3 '
L1: Transfer coil (inductor)
240: control unit 250: detection unit

Claims (5)

The present invention relates to a wireless power transmission apparatus for an LED electric signboard that transmits power wirelessly to an LED electric signboard having a plurality of wireless chargers having different resonance frequencies,
A wireless power supply unit including a plurality of capacitors and a transmission coil for transmitting power supplied from a power supply unit and having different capacitance values;
A detector for detecting a resonance frequency of the wireless charging device; And
And a control unit for adjusting the resonance frequency of the wireless power supply unit by adjusting the total capacitance value by switching different capacitors of the wireless power supply unit to match the resonance frequency of the wireless charging device detected by the detection unit Wireless power transmission device for LED electric signboards with frequency selectable.
The method according to claim 1,
Wherein a plurality of capacitors of the wireless power supply unit are connected in parallel to each other and switches are respectively connected to the capacitors,
Wherein the controller adjusts the resonance frequency by adjusting the total capacitance value by turning on / off each of the switches.
3. The method of claim 2,
Characterized in that the switch is a CMOS switch.
3. The method of claim 2,
And the switch is connected to both ends of the capacitor.
A method for wirelessly transmitting power to an LED electronic signboard having a plurality of wireless chargers having different resonance frequencies using the wireless power transmission device for LED electronic signboards according to any one of claims 1 to 4,
a) receiving resonant frequency information from the wireless charging device;
b) adjusting the resonant frequency of the wireless power transmitter by adjusting the total capacitance value by switching different capacitors of the wireless power transmitter to match the resonant frequency of the received wireless charging device;
c) supplying power of a constant frequency to the wireless power transmitter; And
and d) transmitting the wireless power of the wireless power transmitter to the wireless charger based on the self resonance method.

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