JP2020145790A - Wireless power transmission system, wireless power transmission method, and wireless power transmission device - Google Patents

Abstract

To provide a technology for realizing a power transmitter having a compact and simple structure and being capable of saving power and following a power transmission beam at high speed even under an environment in which wireless communication and wireless power transmission are simultaneously used.SOLUTION: A wireless power transmission system includes a power reception device including a reception unit that receives a radio wave, a power conversion unit that converts the radio wave received by the reception unit to power, and a transmission unit that transmits a beacon which is a radio wave having a prescribed waveform, and a power transmission device that is a Van Atta array or PON array which receives the beacon and radiates a radio wave having the same frequency as that of the beacon and having an amplitude equal to or larger than that of the beacon. The power transmission device includes a filter that allows a radio wave having the frequency of the beacon to pass therethrough and does not allow a radio wave having a frequency different from the frequency of the beacon to pass therethrough, and an amplifier that amplifies the radio wave having passed through the filter.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wireless power transmission system, a wireless power transmission method, and a wireless power transmission device.

In recent years, there has been increasing interest in wireless power transmission technology, which is a technology for wirelessly supplying electric power to electric devices such as communication devices and home appliances.
<Previous technology: Wireless power transmission by phased array>
Patent Document 1 is a practical example of wireless power transmission technology. FIG. 16 shows an operation flow in the technique disclosed in Patent Document 1. In the technique disclosed in Patent Document 1, as shown in FIG. 16, when a beacon is transmitted from a power receiver to a power transmitter, the power transmitter directs the beacon in the direction of arrival, that is, in the direction of the power receiver. It is a technology that transmits electric power. In Patent Document 1, a phased array is used for the power transmitter.

<Previous technology: Retro directive array>
There is a retrodirective array as a technology for transmitting radio waves in the direction of arrival of radio waves. There are two main types of retrodirective arrays, the Van Atta array and the Pon array (Non-Patent Document 1).

The Van Atta Array is one of the simplest retro directive arrays. FIG. 17 shows a 4-element van-atter array. In the van-atter array, a plurality of antenna elements are arranged at equal intervals, and the antenna elements located symmetrically with respect to the center of the array are connected by a wire having an equal path length. When a plane wave incident on the van-atter array is received in the order of antenna elements # 4, # 3, # 2, and # 1, the antenna elements # 1, # 2, # 3, and # are passed through the connection after a certain period of time. It is re-radiated in the order of 4. At this time, the re-radiated wave strengthens each other in phase with respect to the arrival direction of the plane wave. Although FIG. 17 shows an example of a linear array, a planar array can be realized in the same manner.

The Pon array is also known as the Hetrodyne retrodirective array. FIG. 18 shows an embodiment of a two-element pong array. In the pong array, a top-conjugated signal is generated by using a mixer for the received signal.

For one antenna element of FIG. 18, frequency f _r of the received signal, when the phase phi, the waveform of the received signal can be expressed as _{cos (2πf r t + φ)} . In addition, t represents the elapsed time from a predetermined time. When the frequency of the oscillator is f _L0 , the waveform of the received signal is modulated by the mixer into the waveform represented by the following equation (1).

Therefore, if the high frequency component is removed by the filter, only the signal represented by the following equation (2) can be extracted. The filter is, for example, a band pass filter (Band Pass Filter: BPF) or a low pass filter (Low Pass Filter: LPF).

Particularly, in the case of f _{L0 =} 2f _r, the signal taken out by the filter is a signal represented by following equation (3).

Equation (3) is a phase conjugate of the received signal _{cos (2πf r t + φ)} . Therefore, the signal extracted by the filter is a phase-conjugated signal of the received signal.

The pong array re-radiates the phase-conjugated signal represented by the equation (3) from the antenna element. The phase-conjugated signals re-radiated from the plurality of antenna elements intensify each other in the arrival direction of the received signal in the same phase to form a beam propagating in the arrival direction of the received signal. Electric power is transmitted by the formed beam. Hereinafter, the beam that transmits electric power is referred to as a power transmission beam.

Retrodirective arrays such as van-atter arrays and pong arrays do not require signal processing like phased arrays to form power transmission beams in the direction of arrival of radio waves. Therefore, the power transmission beam can be formed automatically and instantly in the direction of arrival of the radio wave, and the time from the reception of the radio wave to the formation of the power transmission beam in the direction of arrival is that of the phased array. Overwhelmingly short in comparison.

In particular, the van-atter array does not require a signal processor or phase shifter like a phased array. Therefore, the structure of the array can be significantly simplified, and the array can be miniaturized and reduced in cost. Further, since the signal processing and the phase shifter as described above are not required, the power required for them can be reduced and the power saving can be realized.

For a Pong array, you need an oscillator, a mixer, and a filter, but you don't need a signal processor or phase shifter like a phased array. Therefore, the structure of the array can be simplified, though not as much as the van-atter array, and the array can be miniaturized and reduced in cost. In addition, since signal processing and a phase shifter are not required, power saving can be realized as in the case of van-atter array.

<Conventional example: Wireless power transmission by van-atter array>
Non-Patent Document 2 is an example of applying the van-atter array to wireless power transmission. The operation flow in the technique disclosed in Non-Patent Document 2 is the same as that in Patent Document 1. That is, in the technique disclosed in Non-Patent Document 2, when a power receiver transmits a beacon to a power transmitter, the power transmitter transmits power in the direction of arrival of the beacon, that is, in the direction of the power receiver. To do. Non-Patent Document 2 employs a van-atter array in which a bidirectional amplifier is added to the wiring for the power transmitter.

FIG. 19 is an excerpt of two antenna elements symmetrical with respect to the center of the array and the connection between the two antenna elements in the van-atter array of Non-Patent Document 2. In FIG. 19, it is assumed that beacon elements # 2 and # 1 are received in this order. The beacon received by the antenna element # 2 is sent to the lower connection by the circulator, the power is amplified by the amplifier, and then sent to the antenna element # 1 by the circulator and re-radiated. The beacon received by the antenna element # 1 is sent to the upper connection by the circulator, the power is amplified by the amplifier, and then sent to the antenna element # 2 by the circulator and re-radiated. At this time, the plurality of re-radiated beacons strengthen each other in phase with each other in the direction of arrival of the beacon. Therefore, the plurality of re-radiated beacons form a power transmission beam propagating in the direction of arrival of the beacon.

<Conventional example: Wireless power transmission by Pon array>
Pong array is also applied to wireless power transmission, for example, as shown in Non-Patent Document 3. In the technique disclosed in Non-Patent Document 3, the operation flow is the same as in Patent Document 1 and Non-Patent Document 2. Non-Patent Document 3 employs a pong array in which an amplifier is added to a power transmitter.

FIG. 20 shows a conventional example of a power transmitter using a pong array, and is a power transmitter in which an amplifier is added to the pong array of FIG. For one antenna element of FIG. 20, the frequency of the beacon antenna element receives f _r, When the phase phi, the waveform of the received beacon can be expressed as _{cos (2πf r t + φ)} . When the frequency of the oscillator is f _L0 , the beacon waveform is modulated by the mixer into the waveform represented by the equation (1).

Therefore, if the high frequency component is removed by the filter, only the signal represented by the equation (2) can be extracted. The filter is, for example, a band pass filter (Band Pass Filter: BPF) or a low pass filter (Low Pass Filter: LPF).

_{Particularly,} in the case of f L0 = 2f _r, the signal taken out by the filter is a signal represented by the number (3). Therefore, if the amplitude of the signal extracted by the filter is multiplied by A by the amplifier, the waveform of the re-radiated signal is represented by the following equation (4).

Equation (4) is a phase conjugate of the beacon amplitude received and A times _{cos (2πf r t + φ)} . Therefore, the signal extracted by the filter is a signal obtained by amplifying the amplitude of the phase conjugate signal of the beacon.

The pong array re-radiates the signal represented by the equation (4) from the antenna element. The signals re-radiated from the plurality of antenna elements strengthen each other in phase in the direction of arrival of the beacon to form a power transmission beam propagating in the direction of arrival of the beacon.

U.S. Pat. No. 8,854,176

Vincent Fusco, and Neil Buchanan “Developments in retrodirective array technology” IET Microwaves, Antennas & Propagation, 2013, Vol. 7, Iss. 2, pp. 131-140 Ying Li, and Vikram Jandhyala “Design of retrodirective antenna arrays for short-range wireless power transmission” IEEE Transactions on Antennas and Propagation, Vol. 60, No. 1, (2012), pp. 206-211 Alan J. Sangster “Electromagnetic Foundations of Solar Radiation Collection” Springer, (2014), pp. 207-240

<Problems of conventional examples by phased array>
<Issue 1: High-speed tracking of power transmission beam in phased array>
In Patent Document 1, a phased array is used to transmit power in the direction of arrival of the beacon. Therefore, it is essential that the power transmitter performs signal processing such as estimating the arrival direction of the beacon. Since signal processing is essential, there is a delay between the power transmitter receiving the beacon and the formation of the power transmission beam in the direction of arrival of the beacon. Therefore, when high-speed tracking of the power transmission beam to the power receiver is required, such as wireless power transfer to a drone that moves quickly and in small steps, the phased array may not be able to perform appropriate wireless power transmission. ..

<Issue 2: Simplification and Miniaturization in Phased Array>
As the installation location of the power transmitter, the ceiling and the wall surface are considered in many examples, and in order to install the power transmitter on the ceiling and the wall surface, it is necessary to simplify the structure and miniaturize the power transmitter. However, in Patent Document 1, since a phased array is used for the power transmitter, it is necessary to add a phase shifter to the power transmitter. Therefore, in the technique disclosed in Patent Document 1, the structure of the power transmitter becomes complicated, and the power transmitter may not be miniaturized to a size that can be installed in a predetermined installation place such as a ceiling or a wall surface.

<Issue 3: Power Saving in Phased Array>
Power saving is also required for the spread of wireless power transmission technology. However, in Patent Document 1, since a phased array is used for the power transmitter, a large amount of power is consumed for the above signal processing and operation of the phase shifter.

In Non-Patent Document 2, by using a van-atter array for the power transmitter, signal processing and a phase shifter are not required to form the power transmission beam, and the tracking speed of the power transmission beam is compared with that of Patent Document 1. Improvement, simplification of structure, miniaturization, and power saving have been achieved.
However, in Non-Patent Document 2, in the power transmitter, only a bidirectional amplifier is added to the connection connecting the antenna elements, so that the power transmitter amplifies the received radio wave of an arbitrary frequency and re-radiates it. Resulting in.

<Problems of conventional examples by Van Atta Array>
<Issue 1: Sharing with wireless communication in Van Atta Array>
FIG. 21 shows the relationship between the frequency spectrum of the radio wave received by the power transmitter of Non-Patent Document 2 and the frequency spectrum of the transmitted radio wave. FIG. 21 shows an example of the frequency spectrum of the radio wave received by the power transmitter of Non-Patent Document 2. Specifically, an example of the frequency spectrum of the beacon from the power receiver and the frequency spectrum of the radio wave other than the beacon will be shown. FIG. 22 shows an example of the frequency spectrum of the signal transmitted by the power transmitter of Non-Patent Document 2. The signal transmitted by the power transmitter of Non-Patent Document 2 is a signal in which the amplitude of the radio wave of FIG. 21 received by the power transmitter of Non-Patent Document 2 is amplified.

In this way, when the power transmitter of Non-Patent Document 2 receives the signal for communication use, the power transmitter of Non-Patent Document 2 amplifies the signal for communication use at that frequency and transmits it to the communication terminal. Resulting in. Therefore, it interferes with the communication terminal. For this reason, it is a prerequisite that the power transmitter of Non-Patent Document 2 is used in an environment where wireless communication is not performed.

In recent years, many studies and practical applications of wireless power transmission to wireless communication terminals such as smartphones have been studied and put into practical use, and it is considered that an environment in which wireless communication and wireless power transmission can be used at the same time will be essential in the near future. However, since the power transmitter of Non-Patent Document 2 interferes with the communication terminal, it may be difficult to use it in an environment where wireless communication and wireless power transmission can be used at the same time.

<Issue 2: Power Saving in Van Atta Array>
Although the power transmitter of Non-Patent Document 2 only needs to amplify the beacon, it also amplifies radio waves other than the beacon. Therefore, the power transmitter of Non-Patent Document 2 consumes originally unnecessary power by amplifying radio waves other than the beacon.

<Problems of the conventional example by Pon Array>
<Issue 1: Sharing with wireless communication in Pon Array>
In Non-Patent Document 3, a pong array is used as a power transmitter. In the technique disclosed in Non-Patent Document 3, since a pong array is used, an oscillator, a mixer, and a filter are required to form a power transmission beam, but no signal processing or a phase shifter is required. Therefore, the technology disclosed in Non-Patent Document 3 is improved in tracking speed of the power transmission beam, simplified in structure, downsized, and reduced in power consumption as compared with the technology disclosed in Patent Document 1. ..

However, Non-Patent Document 3 and the like mention only the removal of high frequency components generated by the mixer for the added filter, and depending on the frequency removed by the filter, the frequency is irrelevant to wireless power transmission. It amplifies the radio waves.

23 to 26 are diagrams showing changes in the frequency spectrum up to the power transmitter according Pont Array Using oscillator f _{L0 =} 2f _r is reradiated from the reception of the radio waves. FIG. 23 shows the frequency spectra of the beacon (frequency _fr ) from the power receiver and the radio waves (frequency f _n ) other than the beacon.

FIG. 24 shows the frequency spectrum of the radio wave received by the power transmitter and having the frequency spectrum of FIG. 23 after the radio wave is frequency-mixed by the mixer. Figure 24 shows that the frequency _{f r,} the radio wave _{2f r -f n, 2f r +} f n and 3f _r generated.

FIG. 25 shows the frequency spectrum of the radio wave after the high frequency component is removed by LPF or BPF from the radio wave of FIG. 24 generated by the mixer.
FIG. 25 shows that radio waves other than the beacon (that is, radio waves having a frequency of 2 _fr- f _n ) pass through the LPF or BPF depending on the characteristics of the LPF or BPF.
FIG. 26 shows the frequency spectrum of the radio wave after the amplitude of the radio wave of FIG. 25 is amplified by the amplifier.

As described above, the power transmitter described in Non-Patent Document 3 has a frequency of 2 fr _r −f in the direction of arrival when the power transmitter receives a signal of frequency f _n , depending on the filter added to the pong array. The signal of _n is transmitted. Therefore, when the signal of the frequency 2f _r -f _n is accidentally matches the frequency of the signal of the communication applications, the signal of the frequency 2f _r -f _n exerts interference to communications.

Since there is a possibility of interference with communication, the power transmitter described in Non-Patent Document 3 should be used in an environment where wireless communication is not performed depending on the filter added to the pong array of the power transmitter. It is a technology that presupposes.

<Issue 2: Power Saving in Pon Array>
In the power transmitter described in Non-Patent Document 3, radio waves other than beacons (that is, radio waves having a frequency of 2 _fr- f _n ) may pass through the LPF or BPF. The power transmitter described in Non-Patent Document 3 also amplifies radio waves other than beacons transmitted through LPF or BPF. Therefore, the power transmitter described in Non-Patent Document 3 consumes unnecessary power.

In view of the above circumstances, the present invention realizes a power transmitter capable of saving power and high-speed tracking of a power transmission beam even in an environment in which wireless communication and wireless power transmission are used at the same time, with a compact and simple structure. The purpose is to provide technology that can be used.

One aspect of the present invention includes a receiving unit that receives radio waves, a power conversion unit that converts radio waves received by the receiving unit into electric waves, and a transmitting unit that transmits a beacon that is a radio wave having a predetermined waveform. A receiving device and a power transmitting device that is a van-atter array or a pon array that receives the beacon and emits a radio wave having the same frequency as the beacon and emitting a radio wave having an amplitude equal to or higher than the amplitude of the beacon. The power transmission device includes a filter that transmits radio waves of the beacon frequency and does not transmit radio waves of frequencies other than the beacon frequency, and an amplifier that amplifies the radio waves that have passed through the filter. Is.

One aspect of the present invention is the wireless power transmission system, wherein the power transmission device includes two antenna elements that receive the beacon, one of the two antenna elements is the first antenna element, and the other. The power transmitting device includes, as the filter, a u filter that transmits the beacon received by the u antenna element (u is 1 or 2), and the power transmitting device is described. As an amplifier, a u-amplifier that amplifies the beacon that has passed through the u-filter is provided, and the beacon amplified by the first amplifier is radiated from the second antenna element and amplified by the second amplifier. The beacon is emitted from the first antenna element, and the time from when the first antenna element receives the beacon to when the second antenna element emits the amplified beacon is defined as the first elapsed time. The first elapsed time and the second elapsed time are defined as the time from when the second antenna element receives the beacon to when the first antenna element emits the amplified beacon as the second elapsed time. It is the same.

One aspect of the present invention is the wireless power transmission system, wherein the circuit including the u-antenna element, the u-filter, and the u-amplifier is a high-frequency circuit, and the power transmission device is plural. The high frequency circuit of the above is provided.

One aspect of the present invention is the wireless power transmission system, wherein the power transmitting device includes two antenna elements for receiving the beacon, and the power transmitting device further has twice the frequency of the beacon. The power transmitting device further comprises an oscillator that outputs a sinusoidal wave having a frequency of, one of the two antenna elements is a first antenna element, and the other is a second antenna element. The power transmission device includes a u-th mixer that generates a radio wave having a waveform phase-coupled to the waveform of the beacon by mixing the beacon received by the antenna element (u is 1 or 2) with the oscillator sinusoidal wave. The u-filter includes a u-filter that transmits radio waves of the frequency of the beacon received by the u-antenna element (u is 1 or 2), and the power transmission device serves as the amplifier. A u-amplifier for amplifying the radio wave transmitted through the antenna is provided, and the radio wave amplified by the u-amplifier is used as a u-amplified phase-conjugated beacon, and the u-amplified phase-conjugated beacon is emitted from the u-antenna element. The time from when the first antenna element receives the beacon to when the first antenna element emits the first amplified phase conjugate beacon is after the second antenna element receives the beacon. It is the same as the time until the second antenna element emits the second amplified phase conjugate beacon.

In one aspect of the present invention, a circuit including the u-antenna element, the u-mixer, the u-filter, and the u-amplifier is used as a high-frequency circuit, and the power transmission device comprises a plurality of the high-frequency circuits. It has a circuit.

One aspect of the present invention is the power transmission method performed by the wireless power transmission system, wherein the power receiving device included in the wireless power transmission system transmits a beacon which is a radio wave having a predetermined waveform, and the transmission step. A first reception step in which the power transmission device included in the wireless power transmission system receives the beacon, an amplification step in which the power transmission device amplifies a radio wave having a frequency of the beacon, and an amplification step in which the power transmission device amplifies the radio wave of the frequency of the beacon. A wireless power transmission method comprising a radiation step for radiating the radio wave amplified in the above and a second reception step for the power receiving device to receive the radio wave radiated in the radiation step.

One aspect of the present invention includes an oscillator having two antenna elements for receiving a beacon which is a radio wave having a predetermined waveform and outputting a sinusoidal wave having a frequency twice the frequency of the beacon, and the above-mentioned 2 One of the two antenna elements is used as the first antenna element, and the other is used as the second antenna element. The beacon received by the u antenna element (u is 1 or 2) and the oscillator sinusoid are mixed to form the beacon. A u-mixer that generates radio waves having a waveform phase-coupled to the waveform of the above, a u-filter that transmits radio waves of the frequency of the beacon received by the u-antenna element (u is 1 or 2), and the u-th A u-amplifier that amplifies the radio wave that has passed through the filter is provided, and the radio wave amplified by the u-amplifier is used as a u-amplified phase-conjugated beacon, and the u-amplified phase-conjugated beacon is the u-antenna. The time from when the first antenna element receives the beacon to when the first antenna element emits the first amplified phase-coupled beacon when it is radiated from the element is such that the second antenna element receives the beacon. A wireless power transmission device having the same time as the time from when the second antenna element is emitted until the second antenna element emits the second amplified phase conjugate beacon.

INDUSTRIAL APPLICABILITY According to the present invention, a technology capable of realizing a power transmitter capable of saving power and high-speed tracking of a power transmission beam with a small size and a simple structure even in an environment in which wireless communication and wireless power transmission are used at the same time It will be possible to provide.

The figure which shows an example of the system configuration of the wireless power transmission system 1 of 1st Embodiment. The figure which shows an example of the functional structure of the electric power transmission device 20 in 1st Embodiment. The figure which shows the time change of the intensity in the 1st antenna element 211-1 and the 2nd antenna element 201-2 of the beacon in 1st Embodiment. The figure which shows the time change of the intensity of the 1st amplified beacon in the 1st antenna element 211-1 and the time change of the intensity of the 2nd amplified beacon in the 2nd antenna element 201-2. The figure which shows an example of the frequency spectrum of the radio wave received by the power transmission apparatus 20 in 1st Embodiment. The figure which shows an example of the frequency spectrum of the radio wave transmitted by the power transmission apparatus 20 in 1st Embodiment. The flowchart which shows an example of the processing flow in the wireless power transmission system 1 of 1st Embodiment. The figure which shows an example of the system configuration of the wireless power transmission system 1a of 2nd Embodiment. The figure which shows an example of the functional structure of the electric power transmission device 20a in 2nd Embodiment. The figure which shows an example of the frequency spectrum of the radio wave received by the power transmission apparatus 20a in 2nd Embodiment. The figure which shows an example of the frequency spectrum of the radio wave mixed by the u-th mixer 206-u in the 2nd Embodiment. The figure which shows an example of the frequency spectrum of the radio wave after passing through the u-filter 203a-u in 2nd Embodiment. The figure which shows an example of the frequency spectrum of the radio wave transmitted by the power transmission apparatus 20a in the 2nd Embodiment. The flowchart which shows an example of the processing flow in the wireless power transmission system 1a of 2nd Embodiment. The figure which shows the application example of the wireless power transmission system 1 or 1a of embodiment. Explanatory drawing explaining the operation of the conventional wireless power transmission. Explanatory drawing explaining the conventional 4-element van atter array. Explanatory drawing explaining the conventional two-element pon array. The first explanatory diagram explaining the structure of the conventional power transmitter. The second explanatory diagram explaining the structure of the conventional power transmitter. The figure which shows an example of the reception spectrum of the conventional power transmitter. The figure which shows an example of the transmission spectrum of the conventional power transmitter. The figure which shows an example of the frequency spectrum of the radio wave at the time of reception of a conventional power transmitter. The figure which shows an example of the frequency spectrum of the radio wave at the time of frequency mixing of a conventional power transmitter. The figure which shows an example of the frequency spectrum of the radio wave when passing through a filter of a conventional power transmitter. The figure which shows an example of the frequency spectrum of the radio wave at the time of transmission of the conventional power transmitter.

(First Embodiment)
FIG. 1 is a diagram showing an example of a system configuration of the wireless power transmission system 1 of the first embodiment. The wireless power transmission system 1 includes a power receiving device 10 and a power transmitting device 20.

The power receiving device 10 includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and functions as a device by executing a program.
The power receiving device 10 functions as a device including a receiving unit 101, a power conversion unit 102, and a transmitting unit 103 by executing a program.

The receiving unit 101 receives radio waves.
The power conversion unit 102 converts the radio wave received by the reception unit 101 into electric power.
The transmission unit 103 transmits a beacon. A beacon is a radio wave having a predetermined waveform.

The power receiving device 10 may be located at any position as long as it can transmit a beacon and can receive radio waves. The power receiving device 10 may be built in, for example, an electric device such as a communication terminal or a home appliance. In such a case, the power receiving device 10 may supply electric power to the electric device. The power receiving device 10 may be built in the drone.

FIG. 2 is a diagram showing an example of the functional configuration of the power transmission device 20 according to the first embodiment.
The power transmission device 20 includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and functions as a device by executing a program. The power transmission device 20 functions as a device including the high frequency circuit 200 by executing the program.

The high frequency circuit 200 includes a first antenna element 201-1, a second antenna element 201-2, a first circulator 202-1, a second circulator 202-2, a first filter 203-1 and a second filter 203-2. It is a circuit including 1 amplifier 204-1 and 2nd amplifier 204-2.

The first antenna element 211-1 and the second antenna element 201-2 receive the beacon and radio waves other than the beacon. The first antenna element 211-1 and the second antenna element 201-2 radiate radio waves.

The first circulator 202-1 and the second circulator 202-2 are circulators for electronic components. The first circulator 202-1 and the second circulator 202-2 include three or more ports including three ports, a first port, a second port, and a third port. The connection destinations of the first port, the second port, and the third port are different from each other.

Specifically, the first terminal of the first circulator 202-1 is connected to the first antenna element 201-1. The second terminal of the first circulator 202-1 is connected to the first filter 203-1. The third terminal of the first circulator 202-1 is connected to the second amplifier 204-2.

The first terminal of the second circulator 202-2 is connected to the second antenna element 201-2. The second terminal of the second circulator 202-2 is connected to the second filter 203-2. The third terminal of the second circulator 202-2 is connected to the first amplifier 204-1.

The first filter 203-1 and the second filter 203-2 transmit radio waves of the beacon frequency and do not transmit radio waves of frequencies other than the beacon frequency. The first filter 203-1 and the second filter 203-2 may be any filter as long as they transmit radio waves of the beacon frequency and do not transmit radio waves of frequencies other than the beacon frequency. The first filter 203-1 and the second filter 203-2 may be, for example, a band pass filter (BPF) that transmits radio waves having a beacon frequency. The first filter 203-1 and the second filter 203-2 may be, for example, a low-pass filter (LPF) that transmits radio waves having a beacon frequency.

The first filter 203-1 is connected to the second terminal of the first circulator 202-1 and the first amplifier 204-1. The second filter 203-2 is connected to the second terminal of the second circulator 202-2 and the second amplifier 204-2.

The first amplifier 204-1 amplifies the amplitude of the radio wave transmitted through the first filter 203-1. The first amplifier 204-1 is connected to the first filter 203-1 and the third terminal of the second circulator 202-2.

The second amplifier 204-2 amplifies the amplitude of the radio wave transmitted through the second filter 203-2. The second amplifier 204-2 is connected to the second filter 203-2 and the third terminal of the first circulator 202-1.

(Wiring length)
Here, the length of the wiring between each functional unit included in the power transmission device 20 will be described. In the power transmission device 20, the length of the wiring from the first antenna element 201-1 to the second circulator 202-2 is substantially the same as the length of the wiring from the second antenna element 201-2 to the first circulator 202-1. Is. More specifically, the route lengths of the first route and the second route are substantially the same. The first path is a path from the first antenna element 201-1 to the second circulator 202-2 via the first circulator 202-1, the first filter 203-1 and the first amplifier 204-1. The second path is a path from the second antenna element 201-2 to the first circulator 202-1 via the second circulator 202-2, the second filter 203-2, and the second amplifier 204-2.

Further, the length of the wiring between the first circulator 202-1 and the first antenna element 201-1 and the length of the wiring between the second circulator 202-2 and the second antenna element 201-2 are substantially the same. Is. Hereinafter, the length of the wiring between the first circulator 202-1 and the first antenna element 201-1 is referred to as the first antenna wiring length. Hereinafter, the length of the wiring between the second circulator 202-2 and the second antenna element 201-2 is referred to as the second antenna wiring length.

(About the propagation path)
The propagation path of the radio wave received by the power transmission device 20 in the power transmission device 20 will be described.

First, the propagation path of the radio wave received by the first antenna element 2011-1 will be described. The radio wave received by the first antenna element 201-1 propagates to the first circulator 202-1. The radio wave propagated to the first circulator 202-1 propagates from the first circulator 202-1 to the first filter 203-1.
Hereinafter, for the sake of simplicity, it is assumed that among the radio waves received by the first antenna element 211-1 and the second antenna element 201-2, the radio wave having the beacon frequency is only the beacon.

Of the radio waves propagated to the first filter 203-1, only the radio waves having the beacon frequency pass through the first filter 203-1. The beacon that has passed through the first filter 203-1 propagates from the first filter 203-1 to the first amplifier 204-1.

The amplitude of the beacon propagating to the first amplifier 204-1 is amplified. The beacon whose amplitude is amplified by the first amplifier 204-1 (hereinafter referred to as “first amplified beacon”) propagates from the first amplifier 204-1 to the second circulator 202-2. The first amplified beacon propagated to the second circulator 202-2 propagates from the second circulator 202-2 to the second antenna element 201-2 and is emitted from the second antenna element 201-2.

Next, the propagation path of the radio wave received by the second antenna element 201-2 will be described. The radio wave received by the second antenna element 201-2 propagates to the second circulator 202-2. The radio wave propagated to the second circulator 202-2 propagates from the second circulator 202-2 to the second filter 203-2.

Of the radio waves propagated to the second filter 203-2, only the radio waves having the beacon frequency pass through the second filter 203-2. The beacon that has passed through the second filter 203-2 propagates from the second filter 203-2 to the second amplifier 204-2.

The amplitude of the beacon propagating to the second amplifier 204-2 is amplified. The beacon whose amplitude is amplified by the second amplifier 204-2 (hereinafter referred to as “second amplified beacon”) propagates from the second amplifier 204-2 to the first circulator 202-1. The second amplified beacon propagated to the first circulator 202-1 propagates from the first circulator 202-1 to the first antenna element 211-1 and is radiated from the first antenna element 201-1.

(About radio waves emitted by the power transmitter 20)
The radio wave emitted by the power transmission device 20 will be described.
Hereinafter, it is assumed that the beacon is emitted from the power receiving device 10 at time t0.
The time when the beacon radiated from the power receiving device 10 reaches the first antenna element 211-1 at time t0 is defined as the first arrival time t_in_1. The time when the beacon emitted from the power receiving device 10 reaches the second antenna element 201-2 at the time t0 is defined as the second arrival time t_in_2.

When the first optical path length and the second optical path length are equal, the first arrival time t_in_1 and the second arrival time t_in_2 are the same. The first optical path length is the distance between the power receiving device 10 and the first antenna element 201-1. The second optical path length is the distance between the power receiving device 10 and the second antenna element 201-2.
On the other hand, when the first optical path length and the second optical path length are different, the first arrival time t_in_1 and the second arrival time t_in_2 are different.

Since the path length of the first path and the path length of the second path are substantially the same, and the wiring length of the first antenna and the wiring length of the second antenna are substantially the same, the first arrival time t_in_1 and the second arrival time t_in_2 The first modulated signal and the second modulated signal are different in the time when they start to be emitted. Specifically, when the first arrival time t_in_1 is later than the second arrival time t_in_2 by the time Δt, the first radiation time t_out_1 is a time Δt earlier than the second radiation time t_out_2. The first radiation time t_out_1 is the time when the first modulation signal starts to be emitted from the first antenna element 211-1. The second radiation time t_out_2 is the time when the second modulation signal starts to be emitted from the second antenna element 201-2.

In this way, since the path length of the first path and the path length of the second path are substantially the same, and the wiring length of the first antenna and the wiring length of the second antenna are substantially the same, the first arrival time t_in_1 to the second The value obtained by subtracting the arrival time t_in_2 is equal to the value obtained by subtracting the first radiation time t_out_1 from the second radiation time t_out_2. Therefore, the power transmission device 20 is a van-atter array antenna.

Hereinafter, in the first embodiment, the time from when the first antenna element 201-1 receives the beacon to when the second antenna element 201-2 emits the amplified beacon is referred to as the first elapsed time. Hereinafter, in the first embodiment, the time from when the second antenna element 201-2 receives the beacon to when the first antenna element 201-1 emits the amplified beacon is referred to as a second elapsed time.

The path length of the first path and the path length of the second path are the same, and the wiring length of the first antenna and the wiring length of the second antenna are the same. Therefore, the first elapsed time and the second elapsed time are the same.

FIG. 3 shows the time variation of the intensity of the beacon incident on the power transmitting device 20 in the first antenna element 201-1 and the intensity of the beacon incident on the power transmitting device 20 in the second antenna element 201-2 in the first embodiment. It is a figure which shows the time change of. For the sake of simplicity, it is assumed that the beacon is a sine wave in FIGS. 3 and 4.

FIG. 3 shows that the time when the beacon arrives at the first antenna element 201-1 is later than the time when the beacon arrives at the second antenna element 201-2 by L / c. L is the difference between the first optical path length and the second optical path length. Hereinafter, L is referred to as an optical path difference. c represents the speed of light. The difference in L / c means that there is a phase difference of 2πL / λ. λ is the wavelength of the beacon in the space where the beacon propagates. More specifically, λ is a value obtained by dividing λ0 by the dielectric constant of the space in which the beacon propagates, where λ0 is the wavelength in vacuum.

FIG. 4 is a diagram showing a time change of the intensity of the first amplified beacon in the first antenna element 211-1 and a time change of the intensity of the second amplified beacon in the second antenna element 201-2.

FIG. 4 shows that the time when the first amplified beacon starts to be emitted by the first antenna element 211-1 is L / c earlier than the time when the second amplified beacon starts to be emitted by the second antenna element 201-2. Is shown.

Since the first arrival time is L / c later than the second arrival time, the first radiation time is L / c earlier than the second radiation time. Therefore, the first amplified beacon and the second amplified beacon strengthen each other in phase in the direction of propagation to the power receiving device 10 (that is, the direction of arrival of the beacon). Since the first amplified beacon and the second amplified beacon strengthen each other in phase with each other, a beam propagating toward the power receiving device 10 is formed. The formed beam is a composite wave of the first amplified beacon and the second amplified beacon. Hereinafter, the formed beam is referred to as a power transmission beam. The power transmission beam is a radio wave.

The power transmission beam propagates toward the power receiving device 10 and is received by the power receiving device 10. The received power transmission beam is converted into electric power by the electric power receiving device 10.

The power transmission device 20 configured in this way includes a first filter 203-1 and a second filter 203-2. Therefore, the power transmission device 20 configured in this way can amplify the radio wave of the beacon without amplifying the radio wave other than the beacon.

The reason why the radio waves other than the beacon are not amplified and the radio waves of the beacon are amplified by providing the first filter 203-1 and the second filter 203-2 will be described.

Even if the power transmitting device 20 receives a radio wave having a frequency other than the beacon frequency, the received radio wave having a frequency other than the beacon frequency is cut by the first filter 203-1 or the second filter 203-2. To. Therefore, radio waves having a frequency other than the beacon frequency may be amplified by the first amplifier 204-1 or the second amplifier 204-2, and may be re-radiated from the first antenna element 201-1 or the second antenna element 201-2. It will not be done. Therefore, the power transmitting device 20 does not amplify radio waves having a frequency other than the beacon frequency and transmit the radio waves to the power receiving device 10.

FIG. 5 is a diagram showing an example of the frequency spectrum of the radio wave received by the power transmission device 20 in the first embodiment.
FIG. 5 shows that the power transmission device 20 receives a beacon and a radio wave having a frequency different from that of the beacon as radio waves. FIG. 5 shows that the intensity of the beacon received by the power transmission device 20 is the intensity E0.

FIG. 6 is a diagram showing an example of the frequency spectrum of the radio wave transmitted by the power transmission device 20 in the first embodiment.
FIG. 6 shows that the frequency of the radio wave transmitted by the power transmission device 20 is the frequency of the beacon and the intensity is E0 or more. FIG. 6 shows that the power transmitter 20 transmits an amplified beacon. Further, FIG. 6 shows that the power transmission device 20 does not transmit radio waves having a frequency other than the beacon frequency.

As shown in FIGS. 5 and 6, the power transmission device 20 does not amplify the received signal for communication use even if it receives a signal for communication use other than the beacon. Further, even if the power transmission device 20 receives a signal for communication use other than the beacon, the power transmission device 20 does not transmit the received signal for communication use. Therefore, the power transmission device 20 can suppress the influence of interference by the power transmission device 20 on the communication terminal that transmits / receives signals for communication purposes other than the beacon.

Further, in the power transmission device 20 of the wireless power transmission system 1 configured in this way, the path length of the first path and the path length of the second path are substantially the same, and the first antenna wiring length and the second antenna wiring The length is almost the same. Therefore, the power transmission device 20 is a van-atter array and does not require signal processing for forming a power transmission beam in the direction of arrival of the beacon. Upon receiving the beacon, the power transmission device 20 can automatically and in a short time form a power transmission beam in the direction of arrival of the beacon. Therefore, even when the wireless power transmission system 1 is required to follow the power transmission beam to the power receiver such as wireless power transmission to the drone at high speed, if the drone has the power receiving device 10 built-in, the wireless power transmission system 1 can be used. Appropriate wireless power transmission can be performed.

Further, since the power transmission device 20 of the wireless power transmission system 1 configured in this way is a van-atter array, it does not require a signal processing unit or a phase shifter. Therefore, the wireless power transmission system 1 configured in this way can reduce the size of the power transmission device 20. Further, the wireless power transmission system 1 configured in this way can reduce the cost related to the power transmission device 20.

Further, in the power transmission device 20 of the wireless power transmission system 1 configured in this way, only the power for amplifying the beacon is required. Therefore, the power transmission device 20 of the wireless power transmission system 1 configured in this way can reduce the power consumption.

Further, the power transmission device 20 of the wireless power transmission system 1 configured in this way does not amplify radio waves having a frequency other than the beacon frequency. Therefore, the power transmission device 20 of the wireless power transmission system 1 configured in this way can reduce the power consumption.

(Flowchart in the first embodiment)
FIG. 7 is a flowchart showing an example of a processing flow in the wireless power transmission system 1 of the first embodiment.

The power receiving device 10 transmits a beacon (step S101). The power transmission device 20 receives the beacon (step S102). Specifically, the beacon reaches the u-antenna element 201-u, and the beacon is received by the u-antenna element 201-u.

The power transmission device 20 amplifies the beacon (step S103). Specifically, the beacon received by the u-antenna element 201-u passes through the u-filter 203-u, and the radio wave transmitted through the u-th filter 203-u is amplified by the u-amplifier 204-u.

The power transmission device 20 emits radio waves after being amplified by the u-th amplifier 204-u (step S104). Specifically, the radio wave after being amplified by the first amplifier 204-1 is radiated from the second antenna element 201-2. Specifically, the radio wave after being amplified by the second amplifier 204-2 is radiated from the first antenna element 201-1.

The power receiving device 10 receives the radio wave radiated from the power transmitting device 20 (step S105). Specifically, the power receiving device 10 receives the radio wave radiated by the power transmitting device 20 in step S104.

The wireless power transmission system 1 configured in this way includes a power receiving device 10 and a power transmitting device 20. The power transmission device 20 includes a first filter 203-1, a second filter 203-2, a first amplifier 204-1 and a second amplifier 204-2, and has a path length of the first path and a second path. The path lengths of the above are substantially the same, and the wiring length of the first antenna and the wiring length of the second antenna are substantially the same. Therefore, the wireless power transmission system 1 configured in this way is a compact power transmitter capable of power saving and high-speed tracking of the power transmission beam even in an environment where wireless communication and wireless power transmission are used at the same time. It is possible to provide a technology that can be realized with a simple structure.

(Modified example of the first embodiment)
The power transmission device 20 does not necessarily have to include only one high frequency circuit 200. The power transmission device 20 may include a plurality of high frequency circuits 200. In such a case, the power transmission device 20 includes two or more first antenna elements 201-1 and the same number of second antenna elements 201-2 as the first antenna element 201-1. All of the first antenna element 211-1 and the second antenna element 201-2 are located at equal intervals in an array shape. The first antenna element 201-1 and the second antenna element 201-2 included in each high frequency circuit 200 are located at positions symmetrical with respect to the center of the array.

In the power transmission device 20, the antenna elements may be arranged not only in a linear array shape but also in a plane array shape.

(Second Embodiment)
FIG. 8 is a diagram showing an example of the system configuration of the wireless power transmission system 1a of the second embodiment. The wireless power transmission system 1a includes a power receiving device 10 and a power transmitting device 20a.
Hereinafter, those having the same functions as the wireless power transmission system 1 will be designated by the same reference numerals as those in FIG. 1, and the description thereof will be omitted.

FIG. 9 is a diagram showing an example of the functional configuration of the power transmission device 20a according to the second embodiment.
The power transmission device 20a includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and functions as a device by executing a program. The power transmission device 20a functions as a device including the high frequency circuit 200a and the oscillator 205 by executing the program.

The high frequency circuit 200a includes a first antenna element 201a-1, a second antenna element 201a-2, a first circulator 202a-1, a second circulator 202a-2, a first mixer 206-1, and a second mixer 206-2. , A first filter 203a-1, a second filter 203a-2, a first amplifier 204a-1, and a second amplifier 204a-2.

The u-antenna element 201a-u receives the beacon and radio waves other than the beacon. The u-th antenna element 201a-u radiates radio waves.

The u-th circulator 202a-u (u is an integer of 1 or more and 2 or less) is a circulator of an electronic component. The u-th circulator 202a-u includes three or more ports including three ports, a first port, a second port, and a third port. The connection destinations of the first port, the second port, and the third port are different from each other.

Specifically, the first terminal of the u-circulator 202a-u is connected to the u-antenna element 201a-u. The second terminal of the u-th circulator 202a-u is connected to the u-th mixer 206-u. The third terminal of the u-th circulator 202a-u is connected to the u-amplifier 204a-u. The u-th circulator 202a-u outputs the beacon received by the u-antenna element 201a-u to the u-th mixer 206-u.

The oscillator 205 outputs a sine wave having a frequency twice the frequency of the beacon. Specifically, the oscillator 205 outputs the frequency of the beacon as f _r, the sine wave represented by the following formula (5) to the u mixer 206-u. Hereinafter, the sine wave output by the oscillator 205 is referred to as an oscillator sine wave.

Incidentally, f _r represents the frequency of the radio wave received by the first u antenna elements 201a-u. t represents the elapsed time from a predetermined time.

The u-th mixer 206-u mixes the radio wave output by the u-circulator 202a-u to the u-mixer 206-u and the oscillator sine wave to generate a mixed radio wave. The mixed radio wave is a radio wave obtained by mixing a radio wave output by the u-circulator 202a-u to the u-mixer 206-u and an oscillator sine wave. Specifically, the mixed radio wave is a radio wave represented by the following formulas (6) and (7).

Equation (6) represents a waveform of a mixed radio wave in which a radio wave having a beacon frequency and an oscillator sine wave are mixed. Incidentally, the radio wave of the frequency of the beacon is a radio wave of the waveform of _{cos (2πf r t + φ)} . Equation (7) represents a waveform of a mixed radio wave in which a radio wave having a frequency other than the beacon frequency and an oscillator sine wave are mixed. Hereinafter, for the sake of brevity, it is assumed that the radio wave of the beacon frequency is only the beacon.

Note that φ represents the phase of the radio wave received by the u-th antenna element 201a-u. f _n represents a frequency other than the beacon frequency.

The u-th filter 203a-u transmits radio waves of the beacon frequency and does not transmit radio waves of frequencies other than the beacon frequency. The u-th filter 203a-u may be any filter as long as it transmits radio waves of the beacon frequency and does not transmit radio waves of frequencies other than the beacon frequency. The u-th filter 203a-u may be, for example, a band pass filter (BPF) that transmits radio waves having a beacon frequency. The u-th filter 203a-u may be, for example, a low-pass filter (LPF) that transmits radio waves having a beacon frequency.

The radio waves input to the u-th filter 203a-u are represented by the equations (6) and (7). Therefore, the radio wave represented by the equation (7) does not pass through the u-th filter 203a-u. Further, the radio wave represented by the first term on the right side of the equation (6) does not pass through the u-filter 203a-u. Therefore, the radio wave output by the u-filter 203a-u is the radio wave represented by the second term on the right side of the equation (6), and is a radio wave having a waveform phase-conjugated to the beacon waveform. Hereinafter, the radio wave output by the u-th filter 203a-u is referred to as a u-phase conjugated beacon. Specifically, the u-top-conjugated beacon is a radio wave represented by the following equation (8).

The u-th filter 203-u is connected to the u-th mixer 206-u and the u-amplifier 204a-u.

The u-th amplifier 204a-u amplifies the amplitude of the radio wave transmitted through the u-th filter 203a-u. Hereinafter, the u-th phase-conjugated beacon after amplification by the u-amplifier 204a-u is referred to as a u-amplified top-conjugated beacon. When the u-amplifier 204a-u increases the amplitude of the u-th phase conjugated beacon by A times, the u-th amplified phase-conjugated beacon is specifically a radio wave represented by the following equation (9).

The u-amplifier 204a-u is connected to the u-filter 203a-u and the third terminal of the u-th circulator 202a-u.

(About the propagation path)
The propagation path of the radio wave received by the power transmission device 20a in the power transmission device 20a will be described.

The propagation path of the radio wave received by the u-antenna element 201a-u will be described. The radio wave received by the u-antenna element 201a-u propagates to the u-circulator 202a-u. The radio wave propagated to the u-th circulator 202a-u propagates from the u-th circulator 202a-u to the u-th mixer 206-u. The radio wave propagated to the u-th mixer 206-u is mixed with the oscillator sine wave by the u-mixer 206-u.

The radio waves mixed by the u-th mixer 206-u propagate from the u-mixer 206-u to the u-filter 203a-u. Of the radio waves propagated to the u-th filter 203a-u, only the radio waves having the beacon frequency pass through the u-filter 203a-u. The radio wave transmitted through the u-th filter 203a-u propagates from the u-th filter 203a-u to the u-amplifier 204a-u. The radio wave propagated to the u amplifier 204a-u is amplified by the u amplifier 204a-u.

The radio wave amplified by the u-th amplifier 204a-u propagates from the u-amplifier 204a-u to the u-th circulator 202a-u. The radio wave propagated from the u amplifier 204a-u to the u circulator 202a-u propagates from the u circulator 202a-u to the u antenna element 201a-u and is radiated from the u antenna element 201a-u.

(Wiring length)
Here, the length of the wiring between each functional unit included in the power transmission device 20a will be described. In the power transmission device 20a, the length of the wiring connecting the u-antenna element 201a-u and the u-th circulator 202a-u is the same regardless of u. The length of the wiring connecting the u-th circulator 202a-u and the u-th mixer 206-u is the same regardless of u. The length of the wiring connecting the u-th mixer 206-u and the u-filter 203a-u is the same regardless of u. The length of the wiring connecting the u-th filter 203a-u and the u-amplifier 204a-u is the same regardless of u. The length of the wiring connecting the u-th amplifier 204a-u and the u-th circulator 202a-u is the same regardless of u. Further, the length of the wiring connecting the oscillator 205 and the u-th mixer 206-u is the same regardless of u. Therefore, the time from the reception of the beacon by the u-antenna element 201a-u to the emission of the u-amplified top-conjugated beacon by the u-antenna element 201a-u is the same regardless of u. That is, the third elapsed time and the fourth elapsed time are the same. The third elapsed time is the time from when the first antenna element 201a-1 receives the beacon to when the first antenna element 201a-1 emits the first amplified phase conjugate beacon. The fourth elapsed time is the time from when the second antenna element 201a-2 receives the beacon until the second antenna element 201a-2 emits the second amplified phase conjugate beacon.

Hereinafter, the time from the reception of the beacon by the u-antenna element 201a-u to the emission of the u-amplified top-conjugated beacon by the u-antenna element 201a-u is the same regardless of u. It is called time identity.

(About radio waves emitted by the power transmitter 20a)
Since the power transmitting device 20a has time identity, the first amplified phase conjugate beacon and the second amplified phase conjugate beacon propagate in the power receiving device 10 (that is, the beacon) as in the power transmitting device 20. (Direction of arrival) will be strengthened in phase with each other. Since the first amplified phase conjugated beacon and the second amplified phase conjugated beacon strengthen each other in the same phase, a beam (power transmission beam) propagating toward the power receiving device 10 is formed.

The power transmission device 20a configured in this way includes a first filter 203a-1 and a second filter 203a-2. Therefore, the power transmission device 20a configured in this way can amplify the radio wave of the beacon without amplifying the radio wave other than the beacon.

The reason why the radio waves other than the beacon are not amplified and the radio waves of the beacon are amplified by providing the first filter 203a-1 and the second filter 203a-2 will be described.

Even if the power transmitting device 20a receives radio waves having a frequency other than the beacon frequency, the received radio waves having a frequency other than the beacon frequency are cut by the first filter 203a-1 or the second filter 203a-2. To. Therefore, radio waves having a frequency other than the beacon frequency may be amplified by the first amplifier 204a-1 or the second amplifier 204a-2, and may be re-radiated from the first antenna element 201a-1 or the second antenna element 201a-2. It will not be done. Therefore, the power transmitting device 20a does not amplify radio waves having a frequency other than the beacon frequency and transmit the radio waves to the power receiving device 10.

10 to 13 show a change in the frequency spectrum from the reception of the radio wave to the radiation of the power transmission device 20a.
FIG. 10 is a diagram showing an example of the frequency spectrum of the radio wave received by the power transmission device 20a in the second embodiment.
FIG. 10 shows that the power transmission device 20a receives radio waves having a frequency of f _n and radio waves having a frequency of _fr as radio waves. Radio waves of frequency f _n are beacons. Radio waves with a frequency of _fr are radio waves other than beacons. Figure 10 shows that the intensity of the radio wave of frequency f _n to receive the power transmission device 20a is strength E0.

FIG. 11 is a diagram showing an example of the frequency spectrum of the radio waves mixed by the u-th mixer 206-u in the second embodiment.
11, the second u mixer 206-u, the frequency _{f r,} the frequency _{(2 × f r -f n)} , the radio frequency _{(2 × f r + f n} ) and frequency (3 × _{f r)} is generated Indicates that.

FIG. 12 is a diagram showing an example of the frequency spectrum of the radio wave after passing through the u-filter 203a-u in the second embodiment.
Figure 12 shows that only radio waves of the frequency _{f r} is transmitted through the first u filter 203a-u.

FIG. 13 is a diagram showing an example of the frequency spectrum of the radio wave transmitted by the power transmission device 20a in the second embodiment.
Figure 13 shows that the radio frequency power transmitter 20a transmits it strength a frequency f _r strength E0 more. FIG. 13 shows that the power transmission device 20a transmits the amplified beacon. Further, FIG. 13 shows that the power transmission device 20a does not transmit radio waves having a frequency other than the beacon frequency.

As shown in FIGS. 10 to 13, the power transmission device 20a does not amplify the received signal for communication use even if it receives a signal for communication use other than the beacon. Further, even if the power transmission device 20a receives a signal for communication use other than the beacon, the power transmission device 20a does not transmit the received signal for communication use. Therefore, the power transmission device 20a can suppress the influence of interference by the power transmission device 20a on the communication terminal that transmits / receives signals for communication purposes other than the beacon.

The power transmission device 20a configured in this way generates a signal that is phase-conjugated to the radio wave received by the u-th mixer 206-u. Therefore, the power transmission device 20a is a pong array. Since the power transmission device 20a is a pong array, no signal processing is required to form a beam in the direction of arrival of the beacon. Therefore, in the wireless power transmission system 1a, when the power transmission device 20a receives the beacon, the power transmission beam can be automatically formed in a short time with respect to the arrival direction of the beacon.

The wireless power transmission system 1a configured in this way includes a power receiving device 10 and a power transmitting device 20a. Therefore, even when the wireless power transmission system 1a is required to follow the power transmission beam to the power receiver such as wireless power transmission to the drone at high speed, if the drone has the power receiving device 10 built-in, Appropriate wireless power transmission can be performed.

Further, since the power transmission device 20a of the wireless power transmission system 1a configured in this way is a pong array, it requires an oscillator, a mixer, and a filter, but it requires a signal processing unit such as a phased array and a phase shift. Does not require a vessel. Therefore, the wireless power transmission system 1a configured in this way can reduce the size of the power transmission device 20a. Further, the wireless power transmission system 1a configured in this way can reduce the cost related to the power transmission device 20a. Further, the wireless power transmission system 1a configured in this way can reduce the power consumed by the power transmission device 20a.

(Flowchart in the second embodiment)
FIG. 14 is a flowchart showing an example of a processing flow in the wireless power transmission system 1a of the second embodiment.

The power receiving device 10 transmits a beacon (step S201). The power transmission device 20a receives the beacon (step S202). Specifically, the beacon reaches the u-antenna element 201a-u, and the beacon is received by the u-antenna element 201a-u.

The power transmission device 20a mixes the beacon and the oscillator sine wave (step S203). Specifically, the u-th mixer 206-u mixes the oscillator sine wave with the beacon received by the u-antenna element 201a-u to generate a mixed radio wave.

The power transmission device 20a amplifies radio waves having a beacon frequency (step S204). Specifically, of the mixed radio waves generated by the u-mixer 206-u, the radio waves that have passed through the u-filter 203a-u are amplified by the u-amplifier 204a-u.

The power transmission device 20a radiates radio waves after being amplified by the u-th amplifier 204a-u (step S205). Specifically, the radio wave after being amplified by the u-amplifier 204a-u is radiated from the u-antenna element 201a-u.

The power receiving device 10 receives the radio wave radiated from the power transmitting device 20a (step S206). Specifically, the power receiving device 10 receives the radio wave radiated by the power transmitting device 20a in step S205.

The wireless power transmission system 1 configured in this way includes a power receiving device 10 and a power transmitting device 20. The power transmission device 20 includes a first filter 203-1, a second filter 203-2, a first amplifier 204-1 and a second amplifier 204-2, and has a path length of the first path and a second path. The path lengths of the above are substantially the same, and the wiring length of the first antenna and the wiring length of the second antenna are substantially the same. Therefore, the wireless power transmission system 1 configured in this way is a compact power transmitter capable of power saving and high-speed tracking of the power transmission beam even in an environment where wireless communication and wireless power transmission are used at the same time. It is possible to provide a technology that can be realized with a simple structure.

(Modified example of the second embodiment)
The power transmission device 20a does not necessarily have to include only one high frequency circuit 200a. The power transmission device 20a may include a plurality of high frequency circuits 200a. In such a case, the power transmission device 20a includes two or more first antenna elements 201a-1 and the same number of second antenna elements 201a-2 as the first antenna element 201a-1. All of the first antenna element 201a-1 and the second antenna element 201a-2 are located at equal intervals in an array shape. The first antenna element 201a-1 and the second antenna element 201a-2 included in each high-frequency circuit 200a are located symmetrically with respect to the center of the array.

In the power transmission device 20a, the antenna elements may be arranged not only in a linear array shape but also in a plane array shape.

(Application example of the first embodiment and the second embodiment)
FIG. 15 is a diagram showing an application example of the wireless power transmission system 1 or 1a of the embodiment.
In FIG. 15, the communication terminal 100D is a device in which a communication terminal and a power receiver are integrally configured, and is an example of the power receiving device 10. The communication terminal 200D is a communication terminal that does not have a power receiver. In FIG. 15, the power transmitter 300D is an example of the power transmitter 20 or 20a.

FIG. 15 shows that the power transmitter 300D forms a power transmission beam only in the direction of arrival of the beacon and does not form a power formation beam in the direction of arrival of the signal for communication use.

The power transmission device 20 and the power transmission device 20a are examples of wireless power transmission devices. Note that steps S101 and S201 are examples of transmission steps. Note that steps S102 and S202 are examples of the first receiving step. Note that steps S103 and S204 are examples of amplification steps. Note that steps S104 and S205 are examples of radiation steps. Note that steps S105 and S206 are examples of the second reception step. The radio waves radiated in steps S104 and S205 are examples of radio waves having an amplitude or more of the beacon.

All or part of the functions of the power receiving device 10 and the power transmitting devices 20 and 20a are hardware such as ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), and FPGA (Field Programmable Gate Array). It may be realized by using hardware. The program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a flexible disk, a magneto-optical disk, a portable medium such as a ROM or a CD-ROM, or a storage device such as a hard disk built in a computer system. The program may be transmitted over a telecommunication line.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and the design and the like within a range not deviating from the gist of the present invention are also included.

1, 1a ... wireless power transmission system, 10 ... power receiving device, 101 ... receiving unit, 102 ... power conversion unit, 103 ... transmitting unit, 20, 20a ... power transmitting device, 201, 201a ... antenna element, 202, 202a ... Circulator, 203, 203a ... Filter, 204, 204a ... Amplifier, 205 ... Antenna, 206 ... Mixer

Claims (8)

A power receiving device including a receiving unit that receives radio waves, a power conversion unit that converts radio waves received by the receiving unit into electric power, and a transmitting unit that transmits a beacon that is a radio wave having a predetermined waveform.
A power transmission device that receives the beacon and emits a radio wave having the same frequency as the beacon and radiating a radio wave having an amplitude equal to or higher than the amplitude of the beacon, and a van-atter array or a pong array.
With
The power transmission device is
A filter that transmits radio waves of the beacon frequency and does not transmit radio waves of frequencies other than the beacon frequency.
An amplifier that amplifies the radio waves that have passed through the filter,
To prepare
Wireless power transfer system. The power transmitting device includes two antenna elements that receive the beacon.
One of the two antenna elements is used as the first antenna element, and the other is used as the second antenna element.
The power transmission device includes, as the filter, a u-filter that transmits the beacon received by the u-antenna element (u is 1 or 2).
The power transmission device includes, as the amplifier, a u-amplifier that amplifies the beacon that has passed through the u-th filter.
The beacon amplified by the first amplifier is emitted from the second antenna element.
The beacon amplified by the second amplifier is emitted from the first antenna element.
The time from when the first antenna element receives the beacon to when the second antenna element emits the amplified beacon is defined as the first elapsed time, and the second antenna element receives the beacon. The first elapsed time and the second elapsed time are the same, with the time from when the first antenna element emits the amplified beacon as the second elapsed time.
The wireless power transmission system according to claim 1. A circuit including the u-antenna element, the u-filter, and the u-amplifier is used as a high-frequency circuit.
The power transmission device includes a plurality of the high frequency circuits.
The wireless power transmission system according to claim 2. The power transmitting device includes two antenna elements that receive the beacon.
The power transmitter further comprises an oscillator that outputs an oscillator sine wave, which is a sine wave having a frequency twice the frequency of the beacon.
With one of the two antenna elements as the first antenna element and the other as the second antenna element, the power transmitter further comprises the beacon and the oscillator received by the u antenna element (u is 1 or 2). A u-th mixer that generates a radio wave having a waveform phase-coupled to the waveform of the beacon by mixing with a sine wave is provided.
The power transmitting device includes, as the filter, a u-filter that transmits radio waves of the beacon frequency received by the u-antenna element (u is 1 or 2).
The power transmission device includes, as the amplifier, a u-amplifier that amplifies the radio wave that has passed through the u-th filter.
The radio wave amplified by the u-amplifier is used as the u-amplified phase-conjugated beacon, and the u-amplified phase-conjugated beacon is radiated from the u-antenna element.
The time from when the first antenna element receives the beacon to when the first antenna element emits the first amplified phase conjugate beacon is the time from when the second antenna element receives the beacon to the first. It is the same as the time until the two antenna elements emit the second amplified phase conjugate beacon.
The wireless power transmission system according to claim 1. A circuit including the u-antenna element, the u-mixer, the u-filter, and the u-amplifier is used as a high-frequency circuit.
The power transmission device includes a plurality of the high frequency circuits.
The wireless power transmission system according to claim 4. A power transmission method performed by the wireless power transmission system according to claim 1.
A transmission step in which the power receiving device included in the wireless power transmission system transmits a beacon which is a radio wave having a predetermined waveform, and
The first reception step in which the power transmission device included in the wireless power transmission system receives the beacon,
An amplification step in which the power transmission device amplifies a radio wave having a frequency of the beacon.
A radiation step in which the power transmission device emits the radio wave amplified in the amplification step,
A second receiving step in which the power receiving device receives the radio wave radiated in the radiating step, and
A wireless power transmission method having. It is equipped with two antenna elements that receive beacons that are radio waves with a predetermined waveform.
One of the two antenna elements is used as the first antenna element, and the other is used as the second antenna element.
A u-th filter that transmits the beacon received by the u-th antenna element (u is 1 or 2) and
A u-amplifier that amplifies the beacon that has passed through the u-th filter,
With
The beacon amplified by the first amplifier is emitted from the second antenna element.
The beacon amplified by the second amplifier is emitted from the first antenna element.
The time from when the first antenna element receives the beacon to when the second antenna element emits the amplified beacon is defined as the first elapsed time, and the second antenna element receives the beacon. The first elapsed time and the second elapsed time are the same, with the time from when the first antenna element emits the amplified beacon as the second elapsed time.
Wireless power transmission device. It is equipped with two antenna elements that receive beacons that are radio waves with a predetermined waveform.
An oscillator that outputs a sine wave that is twice the frequency of the beacon.
By using one of the two antenna elements as the first antenna element and the other as the second antenna element, the beacon received by the u antenna element (u is 1 or 2) and the oscillator sine wave are mixed. A u-th mixer that generates radio waves with a waveform that is phase-coupled to the waveform of the beacon, and
A u-filter that transmits radio waves of the beacon frequency received by the u-antenna element (u is 1 or 2) and
A u-amplifier that amplifies the radio waves that have passed through the u-th filter,
With
The radio wave amplified by the u-amplifier is used as the u-amplified top-conjugated beacon, and the u-amplified top-conjugated beacon is radiated from the u antenna element.
The time from when the first antenna element receives the beacon to when the first antenna element emits the first amplified phase conjugate beacon is the time from when the second antenna element receives the beacon to the first. It is the same as the time until the two antenna elements emit the second amplified phase conjugate beacon.
Wireless power transmission device.

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