KR20120088266A - Wireless power transmitter and wireless power transferring method thereof - Google Patents

Abstract

PURPOSE: A wireless power transmitter and a wireless power transmission method thereof are provided to increase output power by amplifying a power signal using a balancing structure. CONSTITUTION: A wireless power transmitter(100) includes a power generation circuit(120) and a non-radial electromagnetic wave generation circuit(140). The power generation circuit includes a balanced amplifier(124) generating an AC power signal. The non-radial electromagnetic wave generation circuit includes a transmission coil(1401) and a transmission resonant coil(1402). A wireless power receiver(200) generates a power signal by receiving the non-radial electromagnetic wave from the wireless power transmitter. The wireless power receiver includes a non-radial electromagnetic wave reception circuit(220) and a load circuit(240).

Description

Wireless power transmitter and its wireless power transmission method {WIRELESS POWER TRANSMITTER AND WIRELESS POWER TRANSFERRING METHOD THEREOF}

The present invention relates to a wireless power transmitter and a method for wireless power transmission thereof.

Recently, the miniaturization and portability of electronic products including home appliances have been rapidly progressing. In addition, since all information and signals are wirelessly processed, wires connected to the device are almost lost. In the case of home appliances, attempts have also been made to wirelessly transmit power. Electromagnetic induction is most commonly used as a method of transmitting power wirelessly. Specifically, wireless power transmission using electromagnetic induction is used in electric toothbrushes and the like. However, even if the distance is a little, the transmission efficiency is too low and there is a problem that can cause unnecessary and dangerous heat generation due to eddy currents.

 The magnetic resonance wireless power transmission method, which is a non-radiative energy transmission technology that has been recently studied, can obtain a high transmission efficiency even at a distance of a few meters farther than the conventional electromagnetic induction method. This technique is based on attenuation wave coupling, where electromagnetic waves travel from one medium to another through the near field when two media resonate at the same frequency, and energy is transferred only when the resonant frequencies between the two media are the same. The unused energy is then absorbed back into the electromagnetic field. Therefore, unlike other electromagnetic waves, it is harmless to the surrounding machinery or human body.

The magnetic resonance type wireless power transmission system includes one resonator which causes resonance at a transmission frequency at a transmitter and a receiver. Highly efficient transmission is possible when the resonance frequencies of the two resonators are exactly the same. When the actual system is configured, since the resonant frequencies of the two resonators vary slightly, a device for adjusting the resonant frequency may be included in the transmitter or the receiver to adjust this. A variable capacitor can be used as the frequency adjusting device. In this case, the breakdown voltage of the capacitor must be very large because a very large voltage is generated at both ends of the coil. In addition, impedance matching of the transmitter and the receiver is necessary at the transmission frequency, and this problem must be solved by adjusting the distance between the transmission coil and the power coil and the distance between the reception coil and the load coil according to the transmission distance.

The resonant frequency used in the conventional resonant wireless power system was 10 MHz. Also, since the Colpitts circuit was used to generate the resonant frequency, the rectifier circuit was not needed at the receiver. However, in order to apply a variety of resonance type wireless power transmission, a high frequency and high output rectifier circuit is required.

An object of the present invention is to provide a wireless power transmitter and its wireless power transmission method applicable at high frequency.

Wireless power transmitter according to an embodiment of the present invention, the power generation circuit for generating a power signal of the AC type; And a non-radioactive electromagnetic wave generation circuit having a transmission coil receiving the generated power signal and a transmission resonance coil receiving energy through magnetic induction from the transmission coil and generating resonance by generating resonance. The generating circuit includes a balanced amplifier implemented in a balanced structure.

In an embodiment, the power generation circuit may include a phase lock circuit for generating a frequency signal; And a driving amplifier for amplifying the frequency signal and outputting a high frequency signal.

The balance amplifier may include: a first coupler for distributing the high frequency signal into a first signal and a second signal having a 90 ° phase difference from the first signal; A first power amplifier that amplifies the power of the first signal based on a bias voltage; A second power amplifier that amplifies the power of the second signal based on the bias voltage; And a second coupler for combining the output signals of the first and second power amplifiers.

In an embodiment, the first and second couplers are 3 dB couplers.

In an embodiment, the bias voltage is a fixed value.

In example embodiments, the bias voltage may vary according to a power value received from a wireless power transmitter.

The display device may further include a high band filter connected between the phase lock circuit and the driving amplifier and high band filter the frequency signal output from the phase lock circuit.

In an embodiment, the apparatus further includes a power control circuit for controlling the bias voltage.

The power control circuit may be configured to receive power data corresponding to a power value from a wireless power receiver, detect a bias current value of the balance amplifier, and based on the power data and the bias current value. A detection circuit for generating a control signal; A pulse width modulated signal generator for generating a pulse width modulated signal in response to the duty control signal; And a DC / DC converter for controlling the bias voltage in response to the pulse width modulated signal.

The detection circuit may include: a decoder configured to convert the power data into a corresponding analog signal; A subtractor for subtracting the converted analog signal from the detected current value; And a duty controller for generating the duty control signal corresponding to the output value of the subtractor.

The electronic device may further include an impedance matching circuit connected between the balance amplifier and the non-radiative electromagnetic wave generator and configured to maintain a constant output impedance of the wireless power transmitter.

In an embodiment, the impedance matching circuit adjusts the impedance of the wireless power transmitter to 50 Ω.

A wireless power transmission method of a wireless power transmitter according to an embodiment of the present invention, generating a high frequency signal; Equilibrating and amplifying the generated high frequency signal to generate a power signal, and adjusting power of the power signal based on power data received from a wireless power receiver; And receiving the power signal and transmitting non-radioactive electromagnetic waves using resonance.

As described above, the wireless power transmitter and the wireless power transmission method thereof according to the present invention can amplify a power signal using a balance structure, thereby increasing output power, improving reflected wave characteristics, and improving reliability. .

1 is a block diagram showing a wireless power transmission apparatus according to an embodiment of the present invention.
2 is a view showing a first embodiment of a power generation circuit according to the present invention.
3 is a view showing a second embodiment of a power generation circuit according to the present invention.
4 is a view showing a third embodiment of a power generation circuit according to the present invention.
FIG. 5 is a diagram illustrating an embodiment of a power control circuit shown in FIG. 4.
FIG. 6 is a diagram illustrating an embodiment of a detection circuit shown in FIG. 5.
7 is a view showing a fourth embodiment of a power generation circuit according to the present invention.
8 is a diagram illustrating a wireless power transmission method according to an embodiment of the present invention by way of example.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention.

1 is a block diagram showing a wireless power transmission apparatus 10 according to an embodiment of the present invention. Referring to FIG. 1, the wireless power transmitter 10 includes a wireless power transmitter 100 and a wireless power receiver 200.

The wireless power transmission apparatus 10 according to the present invention transmits power according to a non-radiative wireless power transfer technology. The non-radiative wireless power transmission technology can transmit power at a greater distance than electromagnetic radiation at a far distance than general electromagnetic induction.

Here, non-radiative wireless power transmission technology is based on attenuated wave coupling in which electromagnetic waves move from one medium to another through a near field when two media resonate at the same frequency. At this time, power is transmitted when the resonant frequencies between the two media are the same, and unused power is reabsorbed into the electromagnetic field without being radiated into the air. As a result, the electromagnetic waves used in the non-radio type wireless power transmission technology, unlike other electromagnetic waves, are harmless to other machines or the human body.

The wireless power transmitter 100 includes a power generation circuit 120 and a non-radiative electromagnetic wave generation circuit 140.

The power generation circuit 120 receives a high frequency signal and generates a power signal. In particular, the power generation circuit 120 includes a balanced amplifier 124 for generating an AC type power signal from an input power source. Here, the balanced amplifier 124 is implemented in a balanced structure (structure in which the same power amplifiers are connected in parallel) to process the reflected wave.

The non-radioactive electromagnetic wave generation circuit 140 receives a power signal generated from the power generation circuit 120 and generates non-radioactive electromagnetic waves through resonance. The non-radiative electromagnetic wave generation circuit 140 includes a transmission coil 1401 and a transmission resonance coil 1402.

The transfer coil 1401 receives a power signal from the power generation circuit 120, and transmits energy corresponding to the power signal to the transmission resonance coil 1402. Although the number of turns is usually 1, a plurality of turns may be used for impedance matching. To reduce the loss of resistance, use a metal that is thicker than the skin depth at the frequency of use and has good electrical conductivity. The transfer coil 1401 is disposed at an optimal optimum distance from the transmit resonant coil 1402 for impedance matching.

The transmission resonance coil 1402 receives energy from the transmission coil 1401 through magnetic induction, and generates resonance by generating resonance. The transmit resonant coil 1402 has an inherent resonant frequency. Here, the resonant frequency may be greater than 10 MHz. For example, the resonant frequency may be 13.56 MHz.

The transmission resonant coil 1402 also uses a metal that is thicker than the skin thickness of the frequency used and has good electrical conductivity to reduce the loss of resistance. As shown in FIG. 1, the transmission resonant coil 1402 may be implemented in a helical structure or a spiral structure.

In the wireless power transmitter 100 according to an exemplary embodiment of the present invention, when an area to which wireless power is to be transmitted is not a symmetrical structure, an impedance matching circuit (not shown) is disposed in front of the transfer coil 1401, thereby providing wireless power. It is possible to adjust the distribution of transmission efficiency in the area where transmission takes place.

The wireless power receiver 200 receives a non-radiative electromagnetic wave from the wireless power transmitter 100 to generate a power signal, and transmits power data corresponding to the power value of the power signal. The wireless power receiver 200 may be various types of electronic devices such as a mobile terminal, a portable computer, a tablet, and the like. These electronic devices will either be driven directly with power received via non-radiated electromagnetic waves or will charge the battery.

The wireless power receiver 200 includes a non-radioactive electromagnetic wave receiving circuit 220 and a load circuit 240. The non-radioactive electromagnetic wave receiving circuit 220 receives the non-radioactive electromagnetic wave and outputs a corresponding power signal. The non-radiative electromagnetic wave reception circuit 220 includes a reception resonance coil 2201 and a load coil 2202.

The reception resonant coil 2201 receives non-radioactive electromagnetic waves generated from the transmission resonant coil 1412 through resonance. The resonant frequency of the receive resonant coil 2201 may be the same as that of the transmit resonant coil 1402. In an embodiment, the reception resonance coil 2201 may have a helical structure or a spiral structure.

The load coil 2202 receives energy corresponding to the non-radiated electromagnetic wave received through the magnetic induction from the reception resonance coil 2201, and transmits the corresponding power signal to the load circuit 240. The load coil 2202 is disposed at an optimum optimum distance from the receiving resonant coil 2201 for impedance matching.

The load circuit 240 converts the power signal output from the non-radiative electromagnetic wave receiving circuit 220 into a direct current (including rectification), and generates and uses necessary voltages. In addition, the load circuit 240 may generate power data corresponding to the power value of the power signal, and transmit the generated power data to the wireless power transmitter 100.

In general, a wireless power transmission apparatus has a high reflection wave characteristic when high frequency is applied, thereby reducing power transmission efficiency.

On the other hand, the wireless power transmitter 10 according to the embodiment of the present invention includes a wireless power transmitter 100 that amplifies a power signal using balanced amplification, thereby increasing output power at high frequency, The reflected wave characteristics can be improved. Accordingly, the wireless power transmission apparatus 10 of the present invention can effectively perform wireless power transmission even at a high frequency (for example, 13.56 MHz).

2 is a view showing a first embodiment of a power generation circuit according to the present invention. 2, the power generation circuit 120 includes a phase locked circuit 121, a driving amplifier 123, and a balance amplifier 124.

The phase locked circuit 121 generates a high frequency signal in response to the clock. Here, the high frequency signal may be 9 to 11 MHz, and the output power may be about 20 dBm. The magnitude of the high frequency signal output from the phase synchronization circuit 121 is insignificant. Accordingly, the output signal of the phase synchronization circuit 121 needs to be amplified.

The driving amplifier 123 amplifies the high frequency signal output from the phase synchronization circuit 121. In an embodiment, the driving amplifier 123 may be implemented to have a gain of 15 dB. In an embodiment, the output power of the driving amplifier 123 may be 31 dBm.

The balance amplifier 124 receives the amplified signal from the driving amplifier 123 and outputs an AC power signal. Balanced amplifier 124 includes first and second couplers 1241 and 1242, and first and second power amplifiers 1243 and 1243. In an embodiment, the balance amplifier 124 may be implemented to have a gain of 13 dB. According to an embodiment, the output power of the balance amplifier 124 may be 41 dBm (12.59 Watt).

The first coupler 1241 divides the high frequency signal output from the driving amplifier 123 into two signals (hereinafter, referred to as 'first signal and second signal' for convenience of description). Here, the first and second signals may be attenuated by 3 dB than the signal amplified from the driving amplifier 123. In addition, the first and second signals have a phase difference of 90 ° with each other.

The second coupler 1242 receives the output signals of the first and second power amplifiers 1243 and 1244, synthesizes them, and outputs them to the output terminal Pout. The output signal of the second coupler 1242 may be amplified by 3 dB than the output signal of the first and second power amplifiers 1243 and 1244. That is, the output signal of the second coupler 1242 is in-phase synthesized with the output signals of the first and second power amplifiers 1243 and 1244. Accordingly, the magnitude of the output signal of the second coupler 1424 has twice the magnitude of the first and second signals.

In an embodiment, the first and second couplers 1241 and 1242 may be 3 dB couplers.

The first power amplifier 1243 receives one of the signals (first signal) distributed from the first coupler 1241 according to the bias voltage Vin and amplifies the power. Here, the bias voltage Vin may be a fixed DC voltage or a variable DC voltage.

The second power amplifier 1244 receives the other one of the signals (second signal) distributed from the first coupler 1241 according to the bias voltage Vin and amplifies the power.

The first and second power amplifiers 1243 and 1244 are implemented in the same structure, and the output signals of the first and second power amplifiers 1243 and 1244 have a phase difference of 90 ° from each other.

The balance amplifier 124 according to the embodiment of the present invention may improve the reflected wave characteristic. To illustrate this, it is assumed that the output signals of the first and second power amplifiers 1243 and 1244 are totally reflected outside the pass frequency band. When the output signal of the drive amplifier 123 is reflected back from the first power amplifier 1243 and the second power amplifier 1244, respectively, the output signal of the first power amplifier 1243 and the second power amplifier 1244 The reflected signal cancels out by having a 180 ° phase difference. Although only the reflected wave of the input signal of the balanced amplifier 124 has been described here, the reflected wave of the output signal of the balanced amplifier 124 will also be described.

In summary, the power generation circuit 120 according to the embodiment of the present invention may include the balanced amplifier 124 to cancel the reflected wave of the input / output signal and greatly improve the input / output reflection characteristic.

In addition, the power generation circuit 120 according to an embodiment of the present invention by outputting the combined output signals of each of the first and second power amplifiers (1243, 1244) through the second coupler (1242), thereby doubling the power Has an amplifying effect.

In addition, the power generation circuit 120 according to the embodiment of the present invention can improve the reliability of the power generation circuit 120 by using another power amplifier even if one power amplifier is damaged.

3 is a view showing a second embodiment of a power generation circuit according to the present invention. Referring to FIG. 3, the power generation circuit 120a further includes a high band filter 122 in comparison with the power generation circuit 120 shown in FIG. 2. The high band filter 122 receives the output signal of the phase lock circuit 121 and performs high band filtering. The phase lock circuit 121, the drive amplifier 123, and the balance amplifier 124, which are components other than the high band filter 122, have been described in FIG. 2 and will not be described in detail.

4 is a view showing a third embodiment of a power generation circuit according to the present invention. Referring to FIG. 4, the power generation circuit 120b further includes a power control circuit 125 in comparison with the power generation circuit 120a shown in FIG. 3. Here, the power control circuit 125 generates a bias voltage Vin for transmitting the maximum power to the wireless power receiver 200 (see FIG. 1), and provides it to the balance circuit 124. The phase lock circuit 121, the high band filter 122, the drive amplifier 123, and the balance amplifier 124, which are the remaining components except for the power control circuit 125, have been described in FIG. 2 and FIG. I will skip the explanation.

FIG. 5 is a diagram illustrating an embodiment of the power control circuit 125 shown in FIG. 4. Referring to FIG. 5, the power control circuit 125 includes a detector circuit 1251, a pulse width modulated signal generator 1255, and a DC / DC converter 1256.

The detection circuit 1251 receives power data RPWD from the wireless power receiver 200 (see FIG. 1), detects an actual current value Ireal flowing through the first and second power amplifiers 1243 and 1244. The duty control signal DCS is generated based on the input power data RPWD and the current value Ireal. Here, the power data includes data corresponding to the power value of the power signal received by the wireless power receiver 200, and the duty control signal DCS is a signal indicating a ratio between a high level and a low level.

The pulse width modulated signal generator 1255 generates a pulse width modulated signal PWM in response to the duty control signal DSC.

The DC / DC converter 1256 varies / controls / adjusts the bias voltage Vin in response to the pulse width modulated signal PWM. In an embodiment, the DC / DC converter 1256 may be a step-down converter. The DC / DC converter 1256 includes a transistor MTpwc, an inductor Lpwc, a capacitor Cpwc, and a diode Dpwc. In another embodiment, the DC / DC converter 1256 may be a step-up converter.

FIG. 6 is a diagram illustrating an embodiment of the detection circuit 1251 illustrated in FIG. 5. Referring to FIG. 6, the detection circuit 1251 includes a decoder 1252, a subtractor 1253, and a duty controller 1254.

The decoder 1252 decodes the power data RPWD into a corresponding analog signal.

Subtractor 1253 subtracts the output signal of decoder 1252 from the measured current value Ireal.

The duty controller 1254 generates a duty control signal DCS corresponding to the output signal of the subtractor 1253.

7 is a view showing a fourth embodiment of a power generation circuit according to the present invention. Referring to FIG. 7, the power generation circuit 120c further includes an impedance matching circuit 126 as compared to the power generation circuit 120b of FIG. 4. The impedance matching circuit 126 may be implemented such that the output impedance of the wireless power transmitter 100 (see FIG. 1) has 50 Ω. The phase lock circuit 121, the high band filter 122, the drive amplifier 123, the balance amplifier 124, and the power control circuit 125, which are components other than the impedance matching circuit 126, are illustrated in FIG. 2. 3 and 4, detailed description thereof will be omitted.

The wireless power transmitter according to the embodiment of the present invention amplifies a power signal using a balance structure, transmits non-radioactive electromagnetic waves corresponding to the amplified power signal, and amplifies the power signal based on the received power data. A wireless power transmitter having a controlled power signal, a transmission coil configured to receive the power signal, and a transmission resonance coil receiving energy through magnetic induction from the transmission coil and generating resonance by generating resonance; And a load resonant coil which causes resonance to receive the non-radiative electromagnetic wave, and a load coil that receives energy from the receive resonant coil through magnetic induction and generates a power signal, wherein the power data corresponds to the transmitted power signal. It includes a wireless power receiver for transmitting.

8 is a diagram illustrating a wireless power transmission method according to an embodiment of the present invention by way of example. 1 to 8, a wireless power transmission method is as follows.

The phase lock circuit 121 (see FIG. 2) generates a frequency signal, and the driving amplifier 123 amplifies the frequency signal to generate a high frequency signal (S110). A detailed description of the generation process of the high frequency signal is omitted in FIG. 2.

The balance amplifier 124 (see FIG. 2) balances and amplifies a high frequency signal to generate an AC power signal (S120). A detailed description of the process of generating the power signal is omitted in FIG. 2. Meanwhile, the power control circuit 125 (see FIG. 4) may adjust the power of the power signal based on the power data received from the wireless power receiver (see FIG. 1, 200). A detailed description of the power adjustment of the power signal is omitted in FIG. 4.

The non-radioactive electromagnetic wave transmitting circuit 140 receives the power signal and transmits the non-radioactive electromagnetic wave by using resonance (S130). A detailed description of the transmission of non-radioactive electromagnetic waves is described in FIG. 1 and will be omitted.

In the wireless power transmission method according to an embodiment of the present invention, the power signal is amplified using a balance structure, and the power of the power signal is adjusted based on the received power data.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by the equivalents of the claims of the present invention as well as the claims of the following.

10: wireless power transmitter
100: wireless power transmitter
200: wireless power receiver
120: power generation circuit
140: non-radioactive electromagnetic wave transmission circuit
220: non-radiating electromagnetic wave reception circuit
240: load circuit
121: phase locked circuit
122: high-band filter
123: drive amplifier
124: balanced amplifier
1241, 1242: Coupler 1243, 1244: Power Amplifier
125: power control circuit 1251: detection circuit

Claims (13)

A power generation circuit for generating a power signal of AC type; And
And a non-radiative electromagnetic wave generation circuit having a transmission coil receiving the generated power signal and a transmission resonance coil receiving energy through magnetic induction from the transmission coil and generating resonance by generating resonance.
The power generation circuit includes a balance amplifier implemented in a balanced structure. The method of claim 1,
The power generation circuit,
A phase lock circuit for generating a frequency signal in response to a clock; And
And a driving amplifier for amplifying the frequency signal and outputting a high frequency signal. The method of claim 2,
The balance amplifier,
A first coupler for distributing the high frequency signal into a first signal and a second signal having a 90 ° phase difference from the first signal;
A first power amplifier that amplifies the power of the first signal based on a bias voltage;
A second power amplifier that amplifies the power of the second signal based on the bias voltage; And
And a second coupler for combining the output signals of the first and second power amplifiers. The method of claim 3, wherein
And the first and second couplers are 3 dB couplers. The method of claim 3, wherein
And the bias voltage is a fixed value. The method of claim 3, wherein
And the bias voltage is varied according to a power value received from the wireless power transmitter. The method of claim 3, wherein
And a high band filter coupled between the phase lock circuit and the drive amplifier, for high band filtering the frequency signal output from the phase lock circuit. The method of claim 3, wherein
And a power control circuit for controlling the bias voltage. The method of claim 8,
The power control circuit,
A detection circuit for receiving power data corresponding to a power value from a wireless power receiver, detecting a bias current value of the balance amplifier, and generating a duty control signal based on the power data and the bias current value;
A pulse width modulated signal generator for generating a pulse width modulated signal in response to the duty control signal; And
And a DC / DC converter for controlling the bias voltage in response to the pulse width modulated signal. The method of claim 9,
The detection circuit,
A decoder for converting the power data into a corresponding analog signal;
A subtractor for subtracting the converted analog signal from the detected current value; And
And a duty controller for generating the duty control signal corresponding to the output value of the subtractor. The method of claim 3, wherein
And an impedance matching circuit coupled between the balance amplifier and the non-radiative electromagnetic wave generator and for maintaining a constant output impedance of the wireless power transmitter. The method of claim 11,
The impedance matching circuit adjusts the impedance of the wireless power transmitter to 50 Ω. In the wireless power transmission method of the wireless power transmitter:
Generating a high frequency signal;
Equilibrating and amplifying the generated high frequency signal to generate a power signal, and adjusting power of the power signal based on power data received from a wireless power receiver; And
Receiving the power signal and transmitting a non-radioactive electromagnetic wave using resonance.

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