KR20150045875A - Method and apparatus for wireless power transfer of improving spectrum efficiency and space efficiency based on impedance matching and realy resonance - Google Patents

Abstract

Provided are a method and apparatus for transmitting wireless power for improving the efficiency of a space and a spectrum based on a relay resonator and impedance matching. The method for transmitting wireless power includes the steps of: detecting input impedance in a resonant frequency; and matching transmission port impedance with the real number of the detected input impedance. Also, the method for transmitting wireless power includes the step of transmitting the power to a reception resonator which is smaller than a transmission resonator by using the relay resonator.

Description

METHOD AND APPARATUS FOR WIRELESS POWER TRANSFER OF IMPROVING SPECTRUM EFFICIENCY AND SPACE EFFICIENCY BASED ON IMPEDANCE MATCHING AND REALY RESONANCE FOR IMPROVED SPECTRAL EFFICIENCY AND SPACER EFFICIENCY BASED ON IMPEDANCE MATCHING &

The following description relates to a wireless power transmission method and apparatus for improving spectral efficiency and spatial efficiency using impedance matching and a relay resonator.

A technology for transmitting wireless energy with mutual resonance based on magnetic field resonance was proposed by MIT in 2007. The proposed technique is a helical structure with a resonance frequency of 10 MHz, a structural helical resonator size of 600 mm in diameter, a helical of 5.25 turns, a head diameter of 6 mm, a total helical thickness of 200 mm, Is 250 mm. At this time, when the magnetic resonators are brought close to each other, the resonance frequency of the resonators is split. Thus, a phenomenon occurs in which the resonance frequency is different from the initial resonance frequency. This phenomenon is a physical phenomenon that occurs in most resonant structures. The problem of the variation of the resonance frequency causes inconvenience of tracking the resonance frequency.

In addition, the technology for transmitting radio energy can be applied to a wider range of applications as the reception resonator is smaller. However, as the reception resonator is smaller, the transmission distance of the electric power is significantly reduced, so that the reception resonator of small size has a space constraint. Particularly, when the diameter of the receiving resonator is R, it is difficult to design and manufacture a small resonator with a transmission distance (RF efficiency of 80% or more) equal to the diameter of the resonator. Further, even if such a small resonator is developed, the transmission distance of the small resonator is limited to the diameter of the resonator. Generally, the technology of wireless power transmission using magnetic resonance has characteristics of medium distance transmission of about 1m. Particularly, it is a general feature of the technique that the diameter size of the resonator is regarded as the limit of the transmission distance. Therefore, a technique capable of increasing the transmission distance is required.

The present invention can provide an apparatus and method that can be easily implemented by matching only the impedance of the transmission port except for the reception port impedance and matching only the real number of the transmission port impedance.

The present invention can provide an apparatus and method for maximizing spectral efficiency by unifying the resonance frequency even when the transmission resonator and the reception resonator are brought close to each other by matching the impedance of the transmission port with the real value of the input impedance.

The present invention can provide an apparatus and method for maximizing efficiency, minimizing surplus power by supplying power of a required load, and unifying the resonance frequency by controlling power and input impedance in consideration of the situation of a wireless power receiving apparatus have.

The present invention can provide an apparatus and method for increasing the transmission distance of power by using a reception resonator having a size smaller than that of the transmission resonator by placing a relay resonator having the same size as the transmission resonator behind the reception resonator.

The present invention can provide an apparatus and method for extending the near-field for power transmission by overcoming the spatial limitation of power transmission by increasing the transmission distance of the small-sized reception resonator by using the relay resonator.

An apparatus for wireless power transmission according to an exemplary embodiment of the present invention includes an input impedance detector for detecting an input impedance of a transmission resonator connected to a wireless power transmission apparatus at a resonant frequency; A control signal output unit for outputting a control signal for adjusting a transmission port impedance based on the input impedance; A transmission port impedance conversion unit for converting a transmission port impedance based on the control signal; And a power transmitting unit for transmitting power to the wireless power receiving apparatus through a transmitting resonator based on the converted transmitting port impedance and at a resonant frequency, wherein the input impedance is a value between the transmitting resonator and the receiving resonator connected to the wireless power receiving apparatus It can be changed according to the distance.

In the wireless power transmission apparatus according to an embodiment of the present invention, the transmission port impedance conversion unit may convert the impedance of the transmission port to match the real value of the input impedance according to the control signal.

In the wireless power transmission apparatus according to an embodiment of the present invention, the transmission port impedance conversion unit may convert a transmission port impedance by controlling a distance between a feeding coil and a transmission resonator that supply power to the transmission resonator.

In the wireless power transmission apparatus according to an embodiment of the present invention, the control signal output unit outputs a control signal based on the input impedance, the power consumed in the wireless power reception apparatus, and the RF / DC conversion efficiency of the wireless power reception apparatus can do.

A wireless power receiving apparatus according to an embodiment of the present invention includes a power receiving unit that receives power from a transmitting resonator connected to a wireless power transmitting apparatus at a resonant frequency; And a load section that consumes the received power, and the radio power transmission apparatus can convert the transmission port impedance based on the input impedance of the transmission resonator detected at the resonant frequency, and transmit the power through the transmission resonator .

In the wireless power receiving apparatus according to an embodiment of the present invention, the wireless power transmission apparatus may convert the impedance of the transmitting port to match the real value of the input impedance.

In the wireless power receiving apparatus according to an embodiment of the present invention, the wireless power transmitting apparatus can convert the impedance of the transmitting port by controlling the distance between the feeding coil and the transmitting resonator that supplies power to the transmitting resonator.

In the wireless power receiving apparatus according to an embodiment of the present invention,

May be changed according to the distance between the transmission resonator and the reception resonator connected to the wireless power receiving apparatus.

A wireless power transmission apparatus according to an embodiment of the present invention includes a transmission resonator that transmits power generated in a wireless power transmission apparatus to a reception resonator at a resonance frequency; And a reception resonator receiving power from the transmission resonator using a relay resonator and having a size smaller than that of the transmission resonator, wherein the relay resonator controls the reception efficiency of the reception resonator by adjusting a distance from the reception resonator .

In the wireless power transmission apparatus according to the embodiment of the present invention, the wireless power transmission apparatus can convert the transmission port impedance and generate power based on the input impedance of the transmission resonator detected at the resonance frequency.

In the wireless power transmission apparatus according to an embodiment of the present invention, the wireless power transmission apparatus may convert the impedance of the transmission port to match the real value of the input impedance.

In the wireless power transmission apparatus according to an embodiment of the present invention, the wireless power transmission apparatus can convert a transmission port impedance by controlling a distance between a feeding coil and a transmission resonator that supply power to the transmission resonator.

In the wireless power transmission apparatus according to an embodiment of the present invention, the input impedance may be changed according to the distance between the transmission resonator and the reception resonator connected to the wireless power reception apparatus.

In the wireless power transmission apparatus according to an embodiment of the present invention, the relay resonator may have the same size as the transmission resonator.

A wireless power transmission method according to an embodiment of the present invention includes: detecting an input impedance of a transmission resonator connected to a wireless power transmission apparatus at a resonant frequency; Outputting a control signal for adjusting a transmission port impedance based on the input impedance; Converting a transmission port impedance based on the control signal; And transmitting power to a wireless power receiving device via a transmitting resonator at a resonant frequency based on the transformed transmitting port impedance, wherein the input impedance is a distance between the transmitting resonator and a receiving resonator connected to the wireless power receiving device . ≪ / RTI >

In the wireless power transmission method according to an embodiment of the present invention, the step of converting the transmission port impedance may convert the impedance of the transmission port to match the real value of the input impedance according to the control signal.

In the wireless power transmission method according to an embodiment of the present invention, the step of converting the transmission port impedance may convert the transmission port impedance by controlling the distance between the feeding coil and the transmission resonator that supplies power to the transmission resonator.

A wireless power receiving method according to an embodiment of the present invention includes receiving power through a transmitting resonator connected to a wireless power transmitting apparatus at a resonant frequency; And the wireless power transmission apparatus is capable of converting the transmission port impedance based on the input impedance of the transmission resonator detected at the resonant frequency and transmitting the power through the transmission resonator .

In the wireless power receiving method according to an embodiment of the present invention, the wireless power transmission apparatus may convert the impedance of the transmission port to match the real value of the input impedance.

In the wireless power receiving method according to an embodiment of the present invention, the wireless power transmission apparatus can convert a transmitting port impedance by controlling a distance between a feeding coil and a transmitting resonator that supply power to the transmitting resonator.

According to an embodiment of the present invention, only the impedance of the transmission port excluding the reception port impedance is matched and only the real number value of the transmission port impedance is matched.

According to one embodiment of the present invention, by matching the transmission port impedance to the real value of the input impedance, even when the transmission resonator and the reception resonator become close to each other, the spectrum efficiency can be maximized by unifying the resonance frequency.

According to an embodiment of the present invention, power and input impedance are controlled in consideration of the situation of a wireless power receiving apparatus, thereby maximizing efficiency, minimizing surplus power by supplying power of a required load, have.

According to an embodiment of the present invention, the transmission distance of the power can be increased by using a reception resonator having a size smaller than that of the transmission resonator by placing a relay resonator of the same size as the transmission resonator behind the reception resonator.

According to an embodiment of the present invention, by using the relay resonator, the transmission distance of the small-sized receiving resonator can be increased to overcome the spatial limitation of the power transmission, thereby extending the near-field for power transmission.

1 is an illustration of an example of a wireless power delivery apparatus including a transmit resonator and a receive resonator of the same size according to one embodiment.
2 is a diagram illustrating a transfer function S ₂₁ and input impedance based on coupling coefficients k ₁₂ , k ₃₄ , according to one embodiment.
3 is a diagram illustrating a transfer function and an input impedance based on a coupling coefficient k ₂₃ of a transmission resonator and a reception resonator according to an embodiment.
FIGS. 4 and 5 are diagrams illustrating efficiency of power transmission according to a transmission distance based on the same-sized transmitting resonator and receiving resonator, according to an embodiment.
FIGS. 6 to 8 are diagrams illustrating efficiency of power transmission according to a transmission distance based on a transmitting resonator and a receiving resonator which match transmission port impedances according to an exemplary embodiment.
FIG. 9 is a detailed configuration of a wireless power transmission system according to an embodiment.
10 is a diagram illustrating an example of a wireless power transfer apparatus including a reception resonator of a smaller size than a transmission resonator and a transmission resonator according to an embodiment.
11 and 12 are diagrams illustrating efficiency of power transmission according to a transmission distance based on a reception resonator having a smaller size than a transmission resonator according to an embodiment.
13 and 14 are diagrams illustrating efficiency of power transmission according to a transmission distance based on a reception resonator matching transmission port impedance and smaller than a transmission resonator according to an exemplary embodiment.
15 is an illustration of an example of a wireless power delivery apparatus that utilizes a relay resonator in accordance with one embodiment.

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

1 is a diagram illustrating an example of a wireless power transmission apparatus including a transmitting resonator and a receiving resonator having the same size of a resonator according to an embodiment.

The wireless power delivery device may include a feeding coil 110, a transmitting resonator 120, a receiving resonator 130 and a receiving coil 140.

The feeding coil 110 may feed the power generated in the wireless power transmission apparatus to the transmission resonator 120. The feeding coil 110 can adjust the coupling coefficient k ₁₂ based on the distance from the transmitting resonator 120. The feeding coil 110 can control the impedance of the transmitting port by adjusting the coupling coefficient k ₁₂ . Thus, the feeding coil 110 can match the transmission port impedance to the input impedance.

The transmission resonator 120 is connected to the wireless power transmission apparatus and can transmit power to the reception resonator 130. [ The transmission resonator 120 can transmit power to the reception resonator 130 using the same resonance frequency as that of the reception resonator 130.

The receiving resonator 130 is connected to the wireless power receiving apparatus and can receive power from the transmitting resonator 120. The reception resonator 130 can receive power from the transmission resonator 120 using the same resonance frequency as that of the transmission resonator 120. [ For example, the reception resonator 130 may have the same size as the transmission resonator 120.

Here, the coupling coefficient k ₂₃ between the resonators can be determined based on the distance D between the transmitting resonator 120 and the receiving resonator 130. The coupling coefficient k ₂₃ may decrease as the distance D between the transmitting resonator 120 and the receiving resonator 130 increases.

The receiving coil 140 may transmit the power received by the receiving resonator 130 to the wireless power receiving apparatus. The receiving coil 140 may adjust the coupling coefficient k ₃₄ based on the distance from the receiving resonator 130. The receiving coil 140 can control the reception port impedance by adjusting the coupling coefficient k ₃₄ . Thus, the receiving coil 140 can match the receiving port impedance.

Here, the distance D between the transmission resonator 120 and the reception resonator 130 can change the characteristics of power transmission.

2 is a diagram illustrating a transfer function S ₂₁ and input impedance based on coupling coefficients k ₁₂ , k ₃₄ , according to one embodiment.

Herein, the input impedance Z _in may refer to the impedance of the wireless power transmission apparatus viewed from the wireless power transmission apparatus.

Referring to the graphs 210 and 220, the transfer function S ₂₁ can increase together as the coupling coefficients k ₁₂ and k ₃₄ increase. Then, the input impedance Z _in can increase together with the coupling coefficients k ₁₂ and k ₃₄ . For example, when the input impedance (Z _in ) in a 50 Ω system is matched to 50 Ω, the transfer function S ₂₁ can have a maximum value.

Here, the coupling coefficient k ₁₂ may increase as the distance between the feeding coil and the transmitting resonator decreases. Further, the coupling coefficient k ₃₄ may increase as the distance between the receiving resonator and the receiving coil decreases. The constant coupling coefficient k ₂₃ may mean that the distance between the transmission resonator and the reception resonator is constant.

The input impedance Z _in can have a value near 50? By increasing the coupling coefficient k ₁₂ , k ₃₄ . That is, by adjusting the feeding coil and the receiving coil in the 50? System, the input impedance (Z _in ) must be matched to 50? To achieve smooth power transfer.

3 is a diagram illustrating a transfer function and an input impedance based on a coupling coefficient k ₂₃ of a transmission resonator and a reception resonator according to an embodiment.

Referring to the graphs 310 and 320, the transfer function S ₂₁ can generally increase together as the coupling coefficient k ₂₃ increases. However, the transfer function S ₂₁ may not increase as the coupling coefficient k ₂₃ increases in the vicinity of 1 × 10 ⁷ Hz. The input impedance Z _in can decrease as the coupling coefficient k ₂₃ increases. That is, since the input impedance Z _in increases as the distance between the transmission resonator and the reception resonator increases, the transfer function S ₂₁ can decrease as the distance between the transmission resonator and the reception resonator increases. For example, when the input impedance (Z _in ) in a 50 Ω system is matched to 50 Ω, the transfer function S ₂₁ can have a maximum value.

Here, the coupling coefficient k ₂₃ may increase as the distance between the transmission resonator and the reception resonator decreases. The coupling coefficients k ₁₂ and k ₃₄ are constant, which means that the distance between the feeding coil and the transmitting resonator is constant and the distance between the receiving resonator and the receiving coil is constant. Further, the transfer function S ₂₁ may indicate the efficiency of power transfer.

Consequently, the wireless power transmission using the transmit resonator and the receive resonator can be based on input impedance and transmit port impedance. Here, the input impedance can be reduced as the distance between the transmission resonator and the reception resonator becomes closer. That is, the input impedance can be changed according to the distance between the transmission resonator and the reception resonator.

FIGS. 4 and 5 are diagrams showing a transfer function and a Smith chart according to a transmission distance based on the same size of a transmitting resonator and a receiving resonator, according to an embodiment.

The transfer function shown in Figs. 4 and 5 can be measured through a network analyzer based on a transmission resonator of 30 cm in diameter and a reception resonator of 30 cm in diameter. At this time, the impedance of the transmission port and the impedance of the reception port may be 50?.

The graph 410 may show a transfer function S ₂₁ and a Smith chart when the distance between the transmitting and receiving resonators is 20 cm. Graph 410 may indicate that a 50 < RTI ID = 0.0 > OMEGA < / RTI > match is formed at a resonant frequency of 1.935 MHz. At this time, the transfer function S ₂₁ may be -0.775 dB and the efficiency may be 83.6%.

The graph 420 may show a transfer function S ₂₁ and a Smith chart when the distance between the transmit resonator and the receive resonator is 15 cm. At this time, the resonance frequency is divided into two, and at the front resonance frequency of 1.854 MHz, the transfer function S ₂₁ is -0.691 dB and the efficiency can be 85.3%. And, at 1.935 MHz, the transfer function S ₂₁ may be -1.472 dB and the efficiency may be 71.2%. In other words, the efficiency was reduced as compared with the case where the distance between the transmission resonator and the reception resonator was 20 cm.

The graph 510 may show a transfer function S ₂₁ and a Smith chart when the distance between the transmit resonator and the receive resonator is 10 cm. At this time, the resonance frequency is separated into two, and the interval of the resonance frequencies is further widened. At the front resonance frequency of 1.767 MHz, the transfer function S ₂₁ may be -0.658 dB and the efficiency may be 85.9%. At 1.935 MHz, the transfer function S ₂₁ may be -4.562 dB and the efficiency may be 34.9%. That is, the efficiency is further reduced as compared with the case where the distance between the transmission resonator and the reception resonator is 20 cm.

The graph 520 may show a transfer function S ₂₁ and a Smith chart when the distance between the transmit resonator and the receive resonator is 5 cm. At this time, the resonance frequency is divided into two, and the interval of the resonance frequencies can be further broadened. At the front resonance frequency of 1.704 MHz, the transfer function S ₂₁ may be -0.590 dB and the efficiency may be 87.3%. At 1.935 MHz the transfer function S ₂₁ may be -10.4 dB and the efficiency may be 9.1%. As a result, the efficiency further decreases as the distance between the transmission resonator and the reception resonator decreases.

From the above results, it can be seen that in order to keep the efficiency constant, a frequency tracking function is required to track the resonance frequency so that power can be transmitted at the front resonance frequency. However, the power transmission technique using the frequency tracking function is technically feasible, but it may be inefficient in terms of frequency since a wide frequency band is required. Therefore, a technique capable of maintaining the initial resonance frequency is needed.

FIGS. 6 to 8 are diagrams illustrating efficiency of power transmission according to a transmission distance based on a transmitting resonator and a receiving resonator which match transmission port impedances according to an exemplary embodiment.

The graphs 610, 710, and 810 may represent a transfer function S ₂₁ of a magnetic resonance structure in which both a transmitting port impedance and a receiving port impedance are both 50 Ω. The graphs 620, 720 and 820 may represent a transfer function S ₂₁ of a magnetic resonance structure in which the reception port impedance is set to 50 Ω and the transmission port impedance is set to a real value of the input impedance detected at the resonance frequency of 1.935 MHz .

The graph 610 may show a transfer function S ₂₁ and a Smith chart when the distance between the transmitting and receiving resonators is 15 cm. At this time, the resonance frequency is divided into two, and at the front resonance frequency of 1.854 MHz, S ₂₁ is -0.691 dB and the efficiency can be 85.3%.

The graph 620 may represent the result of matching the transmit port impedance to the real value of the input impedance detected at 1.935 MHz. For example, the input impedance detected at 1.935 MHz is 18.683-j 0.585 Ω, and the transmit port impedance can be matched to 18 Ω. In this case, the resonance frequency may be equal to the resonance frequency when the distance between the transmitting resonator and the receiving resonator is 20 cm. At a resonance frequency of 1.935 MHz, the transfer function S ₂₁ is -0.444 dB and the efficiency can be improved to 90.28%.

The graph 710 may represent a transfer function S ₂₁ and a Smith chart when the distance between the transmitting and receiving resonators is 10 cm. At this time, the resonance frequencies are separated by a wider interval, and the transfer function S ₂₁ at -0.658 dB and the efficiency at 85.9% at the front resonance frequency of 1.767 MHz.

The graph 720 can represent the result of matching the impedance of the transmission port to the real value of the input impedance detected at 1.935 MHz. For example, the input impedance detected at 1.935 MHz is 5.54-j1.35, and the transmit port impedance can be matched to 5. In this case, the resonance frequency may be equal to the resonance frequency when the distance between the transmitting resonator and the receiving resonator is 20 cm. At a resonance frequency of 1.935 MHz, the transfer function S ₂₁ is -0.095 dB and the efficiency can be improved to 97.8%.

The graph 810 may represent a transfer function S ₂₁ and a Smith chart when the distance between the transmit resonator and the receive resonator is 5 cm. At this time, the resonance frequencies are separated at wider intervals, and the transfer function S ₂₁ at -0.590 dB and the efficiency at 87.3% at the front resonance frequency of 1.704 MHz.

The graph 820 can represent the result of matching the transmit port impedance to the real value of the input impedance detected at 1.935 MHz. For example, the transmit port impedance can be matched to a real value of 3 Ω of the input impedance detected at 1.935 MHz. In this case, the resonance frequency may be equal to the resonance frequency when the distance between the transmitting resonator and the receiving resonator is 20 cm. At a resonance frequency of 1.935 MHz, the transfer function S ₂₁ is -0.069 dB and the efficiency can be improved to 98.4%.

As described above, by detecting the input impedance at the desired resonance frequency and matching the transmission port impedance to the real value of the detected input impedance, higher power transmission efficiency can be obtained and efficiency in terms of frequency can be expected. Further, by matching only the impedance of the transmission port except for the reception port impedance and matching only the real number of the impedance of the transmission port, the implementation can be facilitated. Further, by matching the transmission port impedance to the real number value of the input impedance, even when the transmission resonator and the reception resonator are brought close to each other, the spectrum efficiency can be maximized by unification of the resonance frequency.

FIG. 9 is a detailed configuration of a wireless power transmission system according to an embodiment.

The wireless power transmission system may include a wireless power transmission device 910, a wireless power transfer device 920, and a wireless power reception device 930. Here, the wireless power transmission apparatus 910 can transmit the generated power to the wireless power reception apparatus 930 through the wireless power transmission apparatus 920. [

The wireless power transmission apparatus 910 includes an input impedance detection unit 911, a control signal output unit 912, a power generation unit 913, a power control unit 914, a transmission port impedance conversion unit 915, and a power transmission unit 916, . ≪ / RTI >

The input impedance detecting section 911 can detect the impedance that the wireless power transmitting apparatus 910 has viewed from the wireless power transmitting apparatus 920 at an input impedance at a resonant frequency. For example, the input impedance detector 911 may detect the input impedance of the transmit resonator 922 coupled to the wireless power transmitter 910 at the resonant frequency. For example, the input impedance detector 911 may detect the input impedance by measuring the power and reflected power input to the wireless power delivery device 920 using a network analyzer.

Here, the resonance frequency means a frequency at which resonance occurs between the transmission resonator 922 and the reception resonator 923, and can be adjusted by the user. The wireless power transmission device 910 may transmit power at the resonant frequency to the wireless power reception device 930. [

The control signal output unit 912 may output a control signal for adjusting the frequency and magnitude of the power and the impedance of the transmission port. For example, the control signal output unit 912 may output a control signal for adjusting the impedance of the transmission port based on the input impedance detected by the input impedance detection unit 911. The control signal output unit 912 may further consider the power consumed in the wireless power receiving apparatus 930 received from the communication unit 935 and the RF / DC conversion efficiency of the wireless power receiving apparatus 930. [ Specifically, in the case of constant current (CC) charging, the voltage supplied to the load section 933 may rise according to the charged value. At this time, the control signal output unit 912 outputs a control signal to the load unit 933 obtained on the basis of the power consumed in the wireless power receiving apparatus 930 and the RF / DC conversion efficiency of the wireless power receiving apparatus 930 It is possible to output a control signal based on the control signal.

The power generation unit 913 can generate power of a specific frequency based on the control signal of the control signal output unit 912. [ The power generation unit 913 can generate power from AC (Alternating Current) to RF (Radio Frequency).

The power control unit 914 can adjust the magnitude of the power generated in the power generation unit 913 based on the control signal of the control signal output unit 912. [

The transmission port impedance conversion section 915 can convert the transmission port impedance based on the control signal of the control signal output section 912. [ For example, the transmission port impedance conversion unit 915 may convert the transmission port impedance so as to match the real value of the input impedance in accordance with the control signal. More specifically, the transmission port impedance conversion section 915 can convert the transmission port impedance by controlling the distance between the feeding coil 921 and the transmission resonator 922. [

For example, the transmission port impedance conversion unit 915 can automatically convert the transmission port impedance using an RF tuner.

The power transmitter 916 can transmit power to the wireless power receiver 930 via the transmit resonator 922 based on the converted transmit port impedance and at the resonant frequency.

The wireless power transfer apparatus 920 may include a feeding coil 921, a transmission resonator 922, a reception resonator 923 and a reception coil 924. [

The feeding coil 921 can feed the power generated in the wireless power transmitting device 910 to the transmitting resonator 922. [

The transmit resonator 922 is coupled to the wireless power transmitter 910 and can transmit power to the receive resonator 923 at the resonant frequency.

The receive resonator 923 is connected to the wireless power receiving device 930 and can receive power from the transmit resonator 922 at the resonant frequency.

The receiving coil 924 can transmit the power received by the receiving resonator 923 to the wireless power receiving device 930. [

The wireless power receiving apparatus 930 may include a power receiving unit 931, an RF / DC converting unit 932, a load unit 933, a power measuring unit 934, and a communication unit 935.

The power receiver 931 can receive power from the transmit resonator 922 coupled to the wireless power transmitter 910 at the resonant frequency.

The RF / DC converting unit 932 can convert the power received from the power receiving unit 931 from RF to DC (direct current).

The load section 933 can consume the received power. That is, the load unit 933 may consume the DC power converted by the RF / DC converting unit 932. [

The power measuring unit 934 can measure the power consumed in the load unit 933 and the RF / DC conversion efficiency of the RF / DC converting unit 932.

The communication unit 935 can transmit the consumed power measured by the power measuring unit 934 and the RF / DC conversion efficiency to the control signal output unit 912 of the wireless power transmitting apparatus 910.

Here, a solid line indicating the relationship between the blocks means a flow of electric power, and a dotted line can mean a control signal excluding electric power.

The wireless power transmission system maximizes the efficiency by controlling the power and input impedance in consideration of the situation of the wireless power receiving apparatus, minimizes the surplus power by supplying the required load power, and can uniformize the resonant frequency.

10 is a diagram illustrating an example of a wireless power transfer apparatus including a reception resonator of a smaller size than a transmission resonator and a transmission resonator according to an embodiment.

10, a wireless power transmission apparatus may include a feeding coil 1010, a transmission resonator 1020, and a reception resonator 1030. [

The reception resonator 1030 may have a smaller size than the transmission resonator 1020. [ Also, the receive resonator 1030 may include a receive coil.

11 and 12 are diagrams illustrating efficiency of power transmission according to a transmission distance based on a reception resonator having a smaller size than a transmission resonator according to an embodiment.

The power transmission efficiency shown in Figs. 11 and 12 can be measured based on a transmission resonator having a diameter of 30 cm and a reception resonator having a diameter of 7 cm. At this time, the impedance of the transmission port and the impedance of the reception port may be 50?.

The graph 1110 may represent a transfer function S ₂₁ and a Smith chart when the distance between the transmit resonator and the receive resonator is 5 cm. At this time, the resonance occurs at 1.894 MHz, the transfer function S ₂₁ is -2.513 dB, and the efficiency may be 56%. The impedance of the transmit port and the impedance of the receive port are formed near 140? Which is considerably larger than 50 ?, which may result in low efficiency.

Looking at the graphs 1120, 1210, and 1220, the efficiency can be significantly reduced as the transmission distance increases. When the distance between the transmission resonator and the reception resonator is 20 cm, the transmission port impedance increases to 480?, And the transfer function S ₂₁ can be reduced to -18.86 dB.

13 and 14 are diagrams illustrating efficiency of power transmission according to a transmission distance based on a reception resonator matching transmission port impedance and smaller than a transmission resonator according to an exemplary embodiment.

The efficiency of power transmission shown in Figs. 13 and 14 corresponds to the impedance of the transmission port, and can be measured based on a transmission resonator having a diameter of 30 cm and a reception resonator having a diameter of 7 cm.

The graph 1310 may represent a transfer function S ₂₁ and a Smith chart when the distance between the transmit resonator and the receive resonator is 5 cm. At this time, the impedance of the transmission port can be matched to 143 Ω which is the real value of the input impedance. The resonance frequency is 1.894 MHz, the transfer function S ₂₁ is -1.65 dB, and the efficiency can be 68%. That is, the efficiency is slightly improved rather than the graph 1110, but it is still not enough.

Looking at the graphs 1320, 1410, and 1420, it can be seen that, even though the transmission port impedance is matched, the efficiency is not more than 70% when the transmission distance is far away.

15 is an illustration of an example of a wireless power delivery apparatus that utilizes a relay resonator in accordance with one embodiment.

15, the wireless power transmission apparatus 1500 may include a feeding coil 1510, a transmission resonator 1520, a reception resonator 1530, and a relay resonator 1540. [

The transmission resonator 1520 can transmit the power generated in the wireless power transmission apparatus to the reception resonator 1530 at the resonance frequency.

The receive resonator 1530 receives power from the transmit resonator 1520 using the relay resonator 1540 and may have a smaller size than the transmit resonator 1520. [ Also, the receive resonator 1530 may include a receive coil.

The relay resonator 1540 can control the reception efficiency of the reception resonator 1530 by adjusting the distance D 'from the reception resonator 1530. The relay resonator 1540 may have the same size as the transmission resonator 1520. The relay resonator 1540 may have the same axis as the transmission resonator 1520.

For example, when the receiving resonator 1530 is brought close to the transmitting resonator 1520, the relay resonator 1540 may switch the role of the transmitting resonator 1520 to prevent the efficiency of the power transmission from deteriorating.

Specifically, the wireless power transfer apparatus 1500 may include a switch in the intermediate T region with power fed to the transmit resonator 1520 and the relay resonator 1540. At this time, the wireless power transmission apparatus 1500 can change the role of the relay resonator 1540 and the transmission resonator 1520 by controlling the switch.

The reception resonator 1530 can easily perform the impedance matching as the relative resonator is closer. Accordingly, the wireless power transfer apparatus 1500 may impedance match the reception resonator 1530 with either the relay resonator 1540 or the transmission resonator 1520 located closest to the reception resonator 1530. Thereby, the wireless power transfer apparatus 1500 can prevent the efficiency of power transmission from decreasing.

Here, the size of the resonator may mean the diameter of the resonator.

For example, when the diameter of the transmission resonator 1520 is 30 cm, the diameter of the reception resonator 1530 is 7 cm, and the diameter of the relay resonator 1540 is 30 cm, the transfer function S ₂₁ may be expressed as follows.

The transfer function S ₂₁ according to the distance D 'between the reception resonator 1530 and the relay resonator 1540 is shown in Table 1 when the distance D between the transmission resonator 1520 and the reception resonator 1530 is 15 cm.

The mismatch may be the case where the impedance of the transmit port and the impedance of the receive port are set to 50 Ω. At this time, the efficiency can be reduced as the distance D 'between the reception resonator 1530 and the relay resonator 1540 moves from 3 cm to 7 cm.

The transmit port impedance match may be when the transmit port impedance is matched to the real value of the input impedance, 24 Ω. At this time, it can be seen that the efficiency of the transmission port impedance matching is improved compared to the case of the unmodulated.

Distance between the reception resonator and the relay resonator [cm] 3 5 7 Non-matching (50 Ω)
_[21 S] -0.95 dB -1.4 dB -2.08 dB Transmit port impedance match (P ₁ = 24 Ω)
_[21 S] -1.04 dB -1.05 dB -1.39 dB

The transfer function S ₂₁ according to the distance D 'between the reception resonator 1530 and the relay resonator 1540 is shown in Table 2 when the distance D between the transmission resonator 1520 and the reception resonator 1530 is 10 cm.

The mismatch may be the case where the impedance of the transmit port and the impedance of the receive port are set to 50 Ω. At this time, the efficiency can be reduced as the distance D 'between the reception resonator 1530 and the relay resonator 1540 moves from 3 cm to 7 cm.

The transmit port impedance match may be when the transmit port impedance is matched to the real value of the input impedance, 24 Ω. At this time, it can be seen that the efficiency of the transmission port impedance matching is improved compared to the case of the unmodulated.

Distance between the reception resonator and the relay resonator [cm] 3 5 7 Distance between the reception resonator and the relay resonator [cm] -2.6 dB -3.5 dB -4.6 dB Transmit port impedance match (P ₁ = 9 Ω)
_[21 S] -2.6 dB -0.56 dB -1.07 dB

The transfer function S ₂₁ according to the distance D 'between the reception resonator 1530 and the relay resonator 1540 is shown in Table 3 when the distance D between the transmission resonator 1520 and the reception resonator 1530 is 5 cm.

The mismatch may be the case where the impedance of the transmit port and the impedance of the receive port are set to 50 Ω. At this time, the efficiency can be reduced as the distance D 'between the reception resonator 1530 and the relay resonator 1540 moves from 3 cm to 7 cm.

The transmit port impedance match may be when the transmit port impedance is matched to the real value of the input impedance, 24 Ω. At this time, it can be seen that the efficiency of the transmission port impedance matching is improved compared to the case of the unmodulated.

Distance between the reception resonator and the relay resonator [cm] 3 5 7 Non-matching (50 Ω)
_[21 S] -5.0 dB -6.3 dB -7.2 dB Transmit port impedance match (P ₁ = 5 Ω)
_[21 S] -0.1 dB -0.34 dB -0.91 dB

As described above, the wireless power transfer apparatus 1500 includes a reception resonator 1530 having a smaller size than the transmission resonator 1520 by placing a relay resonator 1540 of the same size as the transmission resonator 1520 behind the reception resonator 1530. [ The transmission distance of the electric power can be increased. In addition, the wireless power transfer apparatus 1500 can obtain greater power transmission efficiency when using the transmission port impedance matching.

Also, by using the relay resonator 1540, the transmission distance of the small reception resonator 1530 can be increased to overcome the space limitation of the power transmission. That is, by using the relay resonator 1540, the near-field for power transmission can be extended.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA) A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

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. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced. Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

110: Feeding coil
120: transmission resonator
130: receiving resonator
140: Receive coil

Claims (20)

An input impedance detector for detecting an input impedance of a transmission resonator connected to a wireless power transmission apparatus at a resonant frequency;
A control signal output unit for outputting a control signal for adjusting a transmission port impedance based on the input impedance;
A transmission port impedance conversion unit for converting a transmission port impedance based on the control signal; And
A power transmission section for transmitting power to the wireless power receiving apparatus through the transmission resonator based on the converted transmission port impedance and at a resonance frequency;
Lt; / RTI >
The input impedance
Wherein the transmission power is varied according to a distance between the transmission resonator and a reception resonator connected to the wireless power reception device. The method according to claim 1,
Wherein the transmission port impedance conversion unit comprises:
And converts the impedance of the transmission port to match the real value of the input impedance in accordance with the control signal. The method according to claim 1,
Wherein the transmission port impedance conversion unit comprises:
Wherein the transmission port impedance is changed by controlling the distance between the feeding coil and the transmission resonator that supplies power to the transmission resonator. The method according to claim 1,
Wherein the control signal output unit comprises:
And outputs a control signal based on the input impedance, the power consumed in the wireless power receiving apparatus, and the RF / DC conversion efficiency of the wireless power receiving apparatus. A power receiver for receiving power from a transmit resonator coupled to the wireless power transmitter at a resonant frequency; And
The load unit
Lt; / RTI >
The wireless power transmission apparatus comprising:
Converts the transmission port impedance based on the input impedance of the transmission resonator detected at the resonance frequency, and transmits the power through the transmission resonator. 6. The method of claim 5,
The wireless power transmission apparatus comprising:
And converts the impedance of the transmission port to match the real value of the input impedance. 6. The method of claim 5,
The wireless power transmission apparatus comprising:
And converts a transmission port impedance by controlling a distance between a feeding coil and a transmission resonator that supplies power to the transmission resonator. 6. The method of claim 5,
The input impedance
And the distance between the transmitting resonator and the receiving resonator connected to the wireless power receiving apparatus is changed. A transmission resonator for transmitting the power generated by the wireless power transmission device to a reception resonator at a resonance frequency; And
A reception resonator for receiving power from the transmission resonator using a relay resonator,
Lt; / RTI >
The relay resonator includes:
And controls the reception efficiency of the reception resonator by adjusting the distance to the reception resonator. 10. The method of claim 9,
The wireless power transmission apparatus comprising:
And converts the transmit port impedance based on the input impedance of the transmit resonator detected at the resonant frequency and generates power. 11. The method of claim 10,
The wireless power transmission apparatus comprising:
And converts the transmit port impedance to match the real value of the input impedance. 11. The method of claim 10,
The wireless power transmission apparatus comprising:
And converts a transmission port impedance by controlling a distance between a feeding coil and a transmission resonator that supplies power to the transmission resonator. 11. The method of claim 10,
The input impedance
And the distance between the transmitting resonator and the receiving resonator connected to the wireless power receiving device. 10. The method of claim 9,
The relay resonator includes:
And has the same size as the transmit resonator. Detecting an input impedance of a transmit resonator coupled to the wireless power transmission device at a resonant frequency;
Outputting a control signal for adjusting a transmission port impedance based on the input impedance;
Converting a transmission port impedance based on the control signal; And
Transmitting power to the wireless power receiving device via the transmitting resonator at a resonant frequency based on the converted transmit port impedance
Lt; / RTI >
The input impedance
Wherein the transmission power is varied according to a distance between the transmission resonator and a reception resonator connected to the wireless power reception device. 16. The method of claim 15,
Wherein the step of converting the transmit port impedance comprises:
And converts the impedance of the transmission port to match the real value of the input impedance in accordance with the control signal. 16. The method of claim 15,
Wherein the step of converting the transmit port impedance comprises:
Wherein a transmission port impedance is converted by controlling a distance between a feeding coil and a transmission resonator that supply power to the transmission resonator. Receiving power through a transmit resonator coupled to a wireless power transmission device at a resonant frequency; And
The step of consuming the received power
Lt; / RTI >
The wireless power transmission apparatus comprising:
Converts the transmit port impedance based on the input impedance of the transmit resonator detected at the resonant frequency, and transmits power through the transmit resonator. 19. The method of claim 18,
The wireless power transmission apparatus comprising:
And converts the transmit port impedance to match the real value of the input impedance. 19. The method of claim 18,
The wireless power transmission apparatus comprising:
Wherein the transmission port impedance is converted by controlling a distance between a feeding coil and a transmission resonator that supplies power to the transmission resonator.

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