JP7236959B2 - Power supply device and power supply method - Google Patents

Description

The present invention relates to a power feeding device and a power feeding method.

Conventionally, a master power transmission unit having a first power transmission device and a first power transmission antenna, and one or more slave power transmission units each having a second power transmission device and a plurality of second power transmission antennas are used to detect a power receiving device and then , detecting the direction of the first power transmission antenna when power transmission from the slave power transmission unit is stopped, and detecting the second power transmission antenna that maximizes the amount of power received by the power receiving device when power transmission is stopped from the master power transmission unit; There is a wireless power supply method that adjusts the phase of the electric wave transmitted by either the master power transmission unit or the slave power transmission unit to the phase that maximizes the amount of power received by the power receiving device (see Patent Document 1, for example).

JP 2018-098770 A

By the way, in the conventional wireless power supply method, in order to detect the second power transmission antenna, power is transmitted to all the detected power receiving devices, and in order to adjust the phase to maximize the amount of power received by the power receiving device, The process of detecting the second power transmitting antenna that maximizes is performed for all the power receiving devices that have been detected.

Therefore, there is a problem that the amount of calculation required to detect the desired antenna and phase is extremely large.

Therefore, it is an object of the present invention to provide a power feeding device and a power feeding method that reduce the number of trials and/or the amount of calculation for detecting a desired antenna and phase.

In the power feeding device according to the embodiment of the present invention, based on the received power of a device that receives power transmitted from at least one antenna element of a two-dimensional antenna grid, the received power is reduced to the first by a first Bayesian optimization process. an antenna selection unit that obtains a plurality of antenna elements in a predetermined combination when the value is equal to or greater than one predetermined value; and a complex amplitude when the device receives power transmitted from the plurality of antenna elements in the predetermined combination. a phase control unit configured to control phases of powers output from the plurality of antenna elements of the predetermined combination by a second Bayesian optimization process so as to be equal to or greater than a second predetermined value.

It is possible to provide a power feeding device and a power feeding method that reduce the number of trials and/or the amount of calculation for detecting a desired antenna and phase.

It is a figure which shows the electric power feeding apparatus 100 of embodiment. 3 is a diagram showing a configuration of a control device 140; FIG. FIG. 5 is a diagram for explaining antenna subset selection processing; FIG. 5 is a diagram for explaining antenna subset selection processing; FIG. 5 is a diagram for explaining antenna subset selection processing; FIG. 5 is a diagram for explaining antenna subset selection processing; FIG. 5 is a diagram for explaining antenna subset selection processing; FIG. 4 is a diagram showing a power supply apparatus 100 and a device 50 used in phase control processing; 5 is a diagram showing a received power vector Pt of received power received by an antenna 51 of the device 50. FIG. FIG. 4 is a diagram showing a power supply apparatus 100 and a device 50 used in phase control processing; 4 is a diagram for explaining control processing of a phase control unit 143; FIG. 4 is a diagram for explaining control processing of a phase control unit 143; FIG. 4 is a diagram for explaining control processing of a phase control unit 143; FIG. 4 is a diagram for explaining control processing of a phase control unit 143; FIG. 5 is a diagram showing a distribution represented by an objective function of the electric field distribution of received power of the device 50. FIG. FIG. 10 is a diagram showing an estimated distribution of RSSI values obtained by phase control processing using Bayesian optimization processing by a phase control unit 143; FIG. 10 is a diagram showing an estimated distribution of RSSI values obtained by phase control processing using Bayesian optimization processing by a phase control unit 143; FIG. 10 is a diagram showing an estimated distribution of RSSI values obtained by phase control processing using Bayesian optimization processing by a phase control unit 143; FIG. 10 is a diagram showing an estimated distribution of RSSI values obtained by phase control processing using Bayesian optimization processing by a phase control unit 143; FIG. 10 is a diagram showing an estimated distribution of RSSI values obtained by phase control processing using Bayesian optimization processing by a phase control unit 143; FIG. 2 shows an antenna element 111;

EMBODIMENT OF THE INVENTION Hereinafter, embodiment to which the electric power feeding apparatus of this invention and the electric power feeding method are applied is described.

<Embodiment>
FIG. 1 is a diagram showing a power supply device 100 according to an embodiment. In the following description, the XYZ coordinate system will be used. A planar view is an XY planar view.

Power supply device 100 is arranged in large-scale facilities such as smart factories, large-scale plants, distribution centers, and warehouses, for example. The power supply device 100 includes an array antenna 110, a phase shifter 120, a microwave generation source 130, and a control device 140, and supplies power (microwave power supply) to the device 50 in a contactless manner.

The device 50 has an antenna 51, a received power monitor section 52, and a charging section 53, as shown enlarged in the lower part of FIG.

Antenna 51 is an antenna for receiving power from one or more antenna elements 111 . The antenna 51 outputs the received power to the received power monitor section 52 and the charging section 53 .

The received power monitor unit 52 has a configuration in which a power detection unit is added to an IC (Integrated Circuit) portion of an RFID (Radio Frequency Identifier) tag, and an antenna 52A is connected. When power is supplied from the antenna 51, the received power monitor unit 52 receives RSSI (Received Signal Strength Indicator) representing a magnitude corresponding to the supplied power, and a received signal strength indicator stored in the internal memory of the IC. emits packet data containing IDs. The emitted packet data is received by controller 140 .

The charging unit 53 is, for example, a secondary battery or a capacitor, and charges power supplied from the antenna 51 . A load that consumes power may be connected to charging unit 53 . For example, the load may be a sensor that detects temperature, humidity, etc. In this case, the device 50 can be treated as a sensor device.

Further, when the device 50 is attached to a movable body, the electric power charged by the charging unit 53 is used as electric power for driving a power source such as a motor of the moving body as a load, a control unit, or the like. can be used.

The array antenna 110 is an example of a two-dimensional antenna grid, and includes antenna elements 111 arranged in a matrix as an example. As an example, there are 256 antenna elements 111, 16 in the X direction and 16 in the Y direction. 256 antenna elements 111 are located on the XY plane.

Each antenna element 111 is connected to a microwave generation source 130 via a power transmission cable 130A. Under the control of the control device 140 , selected antenna elements 111 out of the 256 antenna elements 111 are fed with power in the microwave band from the microwave generation source 130 . The antenna element 111 is a rectangular patch antenna in a plan view. The antenna element 111 may have a ground plate held at ground potential on the -Z direction side.

Each antenna element 111 is attached to the ceiling, pillar, or the like of a large-scale facility such as the smart factory described above. The interval between each antenna element 111 corresponds to, for example, several wavelengths of the communication frequency of the antenna element 111 . A communication frequency of the antenna element 111 is assumed to be a microwave band, for example, 915 MHz.

FIG. 1 also shows, as an example, a state in which the device 50 receives power from three antenna elements 111 out of 256 antenna elements 111 included in the array antenna 110 . This represents a state in which the three antenna elements 111 selected by the controller 140 are outputting power and the device 50 is receiving power. A set of antenna elements 111 thus selected by controller 140 is referred to as antenna subset 110A.

One phase shifter 120 is connected to each antenna element 111 and inserted between each antenna element 111 and the power transmission cable 130A. In FIG. 1, one antenna element 111 and one phase shifter 120 are enlarged for convenience of explanation.

Phase shifter 120 shifts the phase of power transmitted from microwave generation source 130 via power transmission cable 130A and outputs the power to antenna element 111 . Phase shifter 120 is an example of a phase adjuster.

A microwave source 130 is connected to 256 phase shifters 120 and supplies microwaves of a predetermined power. Microwave source 130 is an example of a radio wave source. An example microwave frequency is 915 MHz. In addition, although the form in which the power supply device 100 includes the microwave generation source 130 will be described here, it is not limited to microwaves, and radio waves of a predetermined frequency may be used.

The control device 140 is an example of a control unit, and is a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a nonvolatile memory. Wavelet Multitone (DMWT) can be used.

Control device 140 has antenna 140A and receives packet data transmitted from device 50 . The packet data includes RSSI values of radio waves that device 50 receives from some antenna elements 111 of array antenna 110 .

The control device 140 performs selection control of the antenna elements 111 to be fed, phase control in the 256 phase shifters 120, power output control of the microwave generation source 130, and predetermined control by Bayesian optimization processing. Predetermined control by Bayesian optimization processing will be described later.

FIG. 2 is a diagram showing the configuration of the control device 140. As shown in FIG. The control device 140 has a main control section 141 , an antenna selection section 142 , a phase control section 143 and a memory 144 . The main control unit 141, the antenna selection unit 142, and the phase control unit 143 represent functions of programs executed by the control device 140 as functional blocks. A memory 144 functionally represents the memory of the control device 140 .

The main control unit 141 is a processing unit that supervises the processing of the control device 140 and executes processing other than the processing executed by the antenna selection unit 142 and the phase control unit 143 . The main control unit 141 performs, for example, phase adjustment of the phase shifter 120 and power output control of the microwave generation source 130 .

The antenna selection unit 142 performs Bayesian optimization processing (first A plurality of antenna elements 111 in a predetermined combination when the received power is maximized is obtained by one example of 1-Bayesian optimization processing. A given combination of multiple antenna elements 111 constitutes an antenna subset 110A. Detailed control contents of the antenna selection unit 142 will be described later with reference to FIGS. 3 to 7. FIG. The number of multiple antenna elements 111 in the predetermined combination is the number of antenna elements 111 included in antenna subset 110A.

It should be noted that the plurality of antenna elements 111 in the predetermined combination obtained by the antenna selection unit 142 is not limited to the case where the received power is the largest, and if the received power is equal to or greater than a predetermined value (an example of the first predetermined value) good. The case in which the received power is maximized is the best mode among the cases in which the received power is equal to or greater than a predetermined value. The predetermined value may be set to an appropriate value.

The phase control unit 143 controls the complex amplitude when the device 50 receives power simultaneously transmitted from a plurality of antenna elements 111 of a predetermined combination forming the antenna subset 110A to a predetermined value (an example of a second predetermined value) or more. By Bayesian optimization processing (an example of the second Bayesian optimization processing), the phase of power output from each of the plurality of antenna elements 111 in a predetermined combination that constructs the antenna subset 110A is controlled so that Details of the control performed by the phase control unit 143 will be described later with reference to FIGS. 8 to 20. FIG.

The memory 144 stores data, programs, and the like used when the main control unit 141, the antenna selection unit 142, and the phase control unit 143 execute processing.

Control processing executed by the control device 140 will be described below. The processing executed by control device 140 mainly includes antenna subset selection processing and phase control processing.

First, antenna subset selection processing will be described with reference to FIGS. 3 to 7. FIG. Antenna subset selection processing is mainly performed by antenna selection section 142 in control device 140 . 3 to 7 are diagrams for explaining the antenna subset selection process.

FIG. 3 shows the power received by the device 50 from each antenna element 111 when the device 50 is placed at a certain XY coordinate position and power is transmitted sequentially from the 256 antenna elements 111 to the device 50. The RSSI value representing the magnitude is shown. It is assumed that the 256 antenna elements 111 have the same position in the Z direction, and that the position of the device 50 in the Z direction is constant (unchangeable).

When the device 50 is at the position X=10, Y=10, the RSSI value at the position X=10, Y=10 is maximum, as shown in FIG. shows the characteristic that the RSSI value attenuates as the distance from .

The distribution of characteristic values in which the RSSI value attenuates shown in FIG. 3 is represented by an originally unknown objective function in the Bayesian optimization processing described below. In the antenna subset selection process, the XY coordinates representing the position of the device 50 are obtained with as few trials as possible by the Bayesian optimization process without completely obtaining the objective function representing the distribution as shown in FIG.

FIG. 4 shows the magnitude corresponding to the received power that is sequentially transmitted from four antenna elements 111 out of 256 antenna elements 111 to the device 50 and that the device 50 sequentially receives from the four antenna elements 111. The RSSI values are used to show the distribution of (predicted) RSSI values determined by the Bayesian optimization process. The location of device 50 is the same as for the distribution shown in FIG.

The four antenna elements 111 may be selected from the 256 antenna elements 111 so that there is little bias. For example, the 256 antenna elements 111 are divided into four areas by dividing both the X direction and the Y direction into 1st to 8th and 9th to 16th elements, and a position near the center of each area is divided into four areas. antenna element 111 is selected.

When an estimated distribution of RSSI values is obtained by Bayesian optimization processing using four RSSI values received from the device 50 after power transmission from four antenna elements 111, the distribution shown in FIG. 4 is obtained as an example.

In the estimated distribution shown in FIG. 4, the RSSI value is high at X=10, Y=10 and its surroundings, and in the region of X=9-16 and Y=9-16.

In FIG. 5, in addition to the four antenna elements described above, the antenna elements are sequentially selected by Bayesian optimization, and trials are performed. An estimated distribution of RSSI values obtained (predicted) by Bayesian optimization processing is shown using RSSI values representing magnitudes corresponding to received power sequentially received from the antenna elements 111 of . The location of device 50 is the same as for the distribution shown in FIG.

When an estimated distribution of RSSI values is obtained by Bayesian optimization processing using six RSSI values received from the device 50 by transmitting power from the six antenna elements 111, the distribution shown in FIG. 5 is obtained as an example.

In the distribution shown in FIG. 5, the RSSI value is high around X=10 and Y=10.

6 and 7 further advance the antenna selection sequentially by Bayesian optimization, and sequentially transmit power to the device 50 from a total of 8 and 10 antenna elements 111 out of 256 antenna elements 111, respectively. 50 shows an estimated distribution of RSSI values obtained (predicted) by Bayesian optimization using RSSI values representing received power received sequentially from eight and ten antenna elements 111 . The location of device 50 is the same as for the distribution shown in FIG.

Using 8 or 10 RSSI values received from the device 50 by transmitting power from 8 and 10 antenna elements 111, and obtaining an estimated distribution of RSSI values by Bayesian optimization processing, as an example, FIG. The distribution shown in FIG. 7 is obtained.

In the distributions shown in FIGS. 6 and 7, the RSSI value is high around X=10 and Y=10.

As shown in FIGS. 4 to 7, the antenna selection unit 142 selects a predetermined number of antenna elements 111 from 256 antenna elements 111, and receives power transmitted from the selected predetermined number of antenna elements 111. Based on the received power of 50, a combination of a predetermined number of antenna elements 111 when the received power estimated value is maximized by Bayesian optimization processing is obtained as the antenna subset 110A.

When obtaining the antenna subset 110A, an appropriate number of antenna elements 111 (4 to 10 as an example here) are selected from 256 antenna elements 111, and the received power estimated value is the largest by Bayesian optimization processing. A combination of a predetermined number of antenna elements 111 in such a case may be obtained as the antenna subset 110A.

By repeating such processing multiple times, multiple antenna elements 111 that construct the antenna subset 110A can be selected with higher accuracy.

Note that the number of antenna elements 111 constructing the antenna subset 110A selected by the antenna selection unit 142 in the antenna subset selection process should be one or more.

In addition, here, a configuration has been described in which a combination of a predetermined number of antenna elements 111 when the estimated received power is the largest is obtained as the antenna subset 110A. A combination of a predetermined number of antenna elements 111 that is greater than or equal to the first predetermined value may be obtained as the antenna subset 110A.

In this way, as the Bayesian optimization process (an example of the first Bayesian optimization process), the antenna selection unit 142 performs received power of the device 50 that has received power transmitted from at least one antenna element 111 of the array antenna 110. , a predetermined combination of a plurality of antenna elements 111 (antenna subset 110A) when the received power estimated value is greater than or equal to the first predetermined value is obtained in the two-dimensional plane in which the array antenna 110 is arranged.

Next, phase control processing will be described. FIG. 8 is a diagram showing the power supply apparatus 100 and the device 50 used in phase control processing. Here, the three antenna elements 111 are distinguished as 111A, 111B, and 111C. As an example, assume that the antenna selection unit 142 selects three antenna elements 111A, 111B, and 111C in the antenna subset selection process, and the phases of power output by them are φ1, φ2, and φ3. Also, a case where φ1 is fixed at 0 degrees and the phase control unit 143 controls φ2 and φ3 will be described.

FIG. 9 is a diagram showing the received power vector Pt of the received power received by the antenna 51 of the device 50. As shown in FIG. The received power vector Pt is the sum of the vectors of the powers P1, P2, and P3 transmitted by the three antenna elements 111A, 111B, and 111C and received by the antenna 51 of the device 50 (hereinafter referred to as transmitted vectors P1, P2, and P3). be. The length of the received power vector Pt is a complex amplitude and represents the magnitude of the received power. The power transmission vector P1 has a power phase of φ1, the power transmission vector P2 has a power phase of φ2, and the power transmission vector P3 has a power phase of φ3. Note that the I axis is the real axis and the Q axis is the imaginary axis.

As shown in FIG. 9A, when the directions of the power transmission vectors P1, P2, and P3 are not aligned, the length (complex amplitude) of the power reception vector Pt becomes short, but as shown in FIG. , the power transmission vectors P1, P2, and P3 are oriented in the same direction, the length (complex amplitude) of the power reception vector Pt is long.

Therefore, the phase control unit 143 controls φ2 and φ3 so that the directions of the power transmission vectors P1, P2, and P3 are aligned to increase the complex amplitude of the power reception vector Pt.

FIG. 10 is a diagram showing the power supply apparatus 100 and the device 50 used in phase control processing. FIG. 10A shows two antenna elements 111A and 111B, and let φ1 and φ2 be the phases of power output from them, respectively. Also, a case where φ1 is fixed at 0 degrees and φ2 is controlled by the phase control unit 143 will be described. Note that the control device 140 is omitted in FIG. 10(A).

As shown in FIG. 10B, the received power vector Pt of the received power output by the two antenna elements 111A and 111B and received by the antenna 51 of the device 50 is the power P1 received by the antenna 51 of the device 50. , P2 (power transmission vectors P1, P2). The length of the received power vector Pt is a complex amplitude and represents the magnitude of the received power. The power transmission vector P1 has a power phase of φ1, and the power transmission vector P2 has a power phase of φ2. Note that the I axis is the real axis and the Q axis is the imaginary axis.

As shown in FIG. 10C, when the phase of the power transmission vector P2 is changed from 1 degree to 360 degrees, the received power changes sinusoidally, and the received power has only one peak and one trough.

Although the two antenna elements 111A and 111B have been described here, the same applies to the two antenna elements 111A and 111C.

Next, referring to FIGS. 11 to 14, the phase control unit 143 uses Bayesian optimization processing (an example of the second Bayesian optimization processing) to increase the complex amplitude of the received power vector Pt. A process for controlling the phases of the output powers of 111B and 111C will be described. 11 to 14 are diagrams for explaining control processing of the phase control unit 143. FIG.

First, as shown in FIG. 11, the phase control unit 143, in the Bayesian optimization process (an example of the second Bayesian optimization process), performs The phase φ2 (an example of the first phase) of the power output by one antenna element 111B (an example of the first antenna element) is set to α degrees (an example of the first predetermined phase) and (α+180) degrees (a first predetermined phase). 180 degrees added to the phase), and the other one antenna element 111C (an example of the second antenna element) among the three antenna elements 111A, 111B, and 111C forming the antenna subset 110A is The phase φ3 (an example of the second phase) of the power to be output is set to β degrees (an example of the second predetermined phase) and (β+180) degrees (the phase obtained by adding 180 degrees to the second predetermined phase). In FIG. 11, as an example, α=90 degrees and β=90 degrees.

The phase control unit 143 causes the main control unit 141 to adjust the phase of the phase shifter 120 and control the output of the power of the microwave generation source 130, so that φ2=α degrees, φ3=β degrees, and φ2=(α+180) degrees. φ3 = β degrees, φ2 = α degrees and φ3 = (β + 180) degrees, φ2 = (α + 180) degrees and φ3 = (β + 180) degrees at four points Q1 to Q4 (four points Q1 to Q4 indicated by black circles in Fig. 11) Sequentially set. Note that the phase φ1 of the power output from the antenna element 111A is a fixed value, such as 0 degrees. Points Q1 to Q4 are operating points specified by phases φ2 and φ3.

Further, the phase control unit 143 controls the phase φ2 of the φ2-φ3 plane defined by the phase φ2 (an example of the first phase) and the phase φ3 (an example of the second phase) shown in FIG. An area (an example of a two-dimensional search area) where the phase φ3 is 1 degree≦φ3≦360 degrees is divided into four areas A1 to A4. Note that the phases φ2 and φ3 are in increments of 1 degree.

Area A1 is an area where 1 degree≦φ2≦180 degrees and 1 degree≦φ3≦180 degrees. Area A2 is an area where 180 degrees<φ2≦360 degrees and 1 degree≦φ3≦180 degrees. Area A3 is an area where 1 degree≦φ2≦180 degrees and 180 degrees<φ3≦360 degrees. Area A4 is an area where 180 degrees<φ2≦360 degrees and 180 degrees<φ3≦360 degrees. Areas A1 to A4 are 1/4 areas of the φ2-φ3 plane where the phase φ2 is 1 degree ≤ φ2 ≤ 360 degrees and the phase φ3 is 1 degree ≤ φ3 ≤ 360 degrees (an example of a two-dimensional search region). .

The phase control unit 143 controls the power transmitted from the antenna elements 111A, 111B, and 111C in a state in which the phases φ2 and φ3 of the power output by the antenna elements 111B and 111C are sequentially set to each of the four points Q1 to Q4. The area including the phases φ2 and φ3 when the estimated value of the received power when 50 receives power is equal to or greater than a predetermined value (an example of a third predetermined value) is narrowed down to one of areas A1 to A4.

More specifically, phase control section 143 sets phases φ2 and φ3 of power output from antenna elements 111B and 111C to four points Q1 to Q4, respectively. Among the estimated values, narrow down to the area including the point that gives the largest estimated value of the received power.

The area including the point that gives the largest estimated value of received power is an example of the area including phases φ2 and φ3 when the received power is equal to or greater than a predetermined value (an example of a third predetermined value). Therefore, the area is not limited to the area including the phases φ2 and φ3 that give the largest estimated value of the received power, and any area including the phases φ2 and φ3 when the value is equal to or greater than a predetermined value (an example of the third predetermined value).

As a result, as shown in FIG. 12 as an example, the phase control unit 143 narrows down to an area A1 where 1 degree≦φ2≦180 degrees and 1 degree≦φ3≦180 degrees. In this way, if the phase obtained by adding 180 degrees to the phases φ2 and φ3 is used, the received power of the device 50 can be expressed once in each of the four areas A1 to A4 obtained by dividing the φ2-φ3 plane into four equal parts. The RSSI value can be used to obtain an estimate of the received power.

In addition, comparing the estimated values of the received power of the device 50 at the four points Q1 to Q4 on the φ2-φ3 plane, the power received by the device 50 in the four areas A1 to A4 obtained by dividing the φ2-φ3 plane into four areas. It is possible to grasp the tendency of the magnitude relationship of electric power.

Further, among the estimated values of the received power of the device 50 at the four points Q1 to Q4 respectively included in the four areas A1 to A4 obtained by dividing the φ2-φ3 plane into four areas, the largest estimated value of the received power is obtained. If the area A1 is selected, the probability of obtaining the optimum values of the phases φ2 and φ3 that makes the length of the power receiving vector Pt the longest in the area inside or near the area A1 increases. Therefore, it becomes unnecessary to search for the optimum values of the phases φ2 and φ3 for all areas A1 to A4, and the amount of calculation can be reduced.

The phase control unit 143 shifts the phase φ2 (an example of the first phase) at a pitch PH1 (an example of the first pitch) and the phase φ3 (an example of the first pitch) in the area A1 shown in FIG. An example of two phases) is swung at a pitch PH2 (an example of a second pitch), and the RSSI value representing the received power obtained by the device 50 receiving the power transmitted from the antenna elements 111A, 111B, and 111C is used to receive power. Calculate the estimated power distribution.

As a result, an estimated value of received power at each intersection of the mesh of area A1 shown in FIG. 12 is obtained. Since as many combinations of power transmission vectors P2 and P3 as the number of intersections are obtained, the phase control unit 143 adjusts the phases φ2 and φ3 of the power transmitted from the antenna elements 111B and 111C (see FIG. 8) to the phases φ2 and φ3 of each combination. to obtain an estimate of the received power using the RSSI value representing the received power of the device 50 .

Then, the phase control unit 143 selects a point Q11 (see FIG. 13) specified by the phases φ2 and φ3 that gives the largest received power estimated value (an example of the fourth predetermined value) among the obtained received power estimated values. to get Point Q11 is the operating point specified by phases φ2 and φ3.

If the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q11 are larger than the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q1, the phase control unit 143 sets the point Q11 as the center. Continue exploring. If the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q11 are equal to or smaller than the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q1, then the phase of the point Q1 The search is continued with φ2 and φ3 as the center points.

Here, a mode of acquiring the point Q11 specified by the phases φ2 and φ3 that gives the largest estimated value of the received power among the estimated values of the received power obtained from the mesh of the area A1 has been described. That is, an example of the fourth predetermined value is the largest estimated value of received power among the estimated values of received power obtained from the mesh of area A1.

However, among the estimated values of the received power obtained from the mesh of the area A1, the phases φ2 and φ3 when the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q1 are equal to or greater than a predetermined value are specified. You may acquire the point Q11 where it is made. That is, the fourth predetermined value may be a predetermined value that is larger than the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q1.

In FIG. 13, the phase control unit 143 further searches inside an area A11 centered on the point Q11. Area A11 is a region indicated by a mesh and is narrower (smaller) than area A1. Area A11 is an example of an area narrower than area A1.

The phase control unit 142 shifts the phase φ2 (an example of the first phase) at a pitch PH3 (an example of the third pitch) and shifts the phase φ3 (an example of the second phase) at a pitch PH4 (an example of the fourth phase) within the area A11. An example of the pitch), the estimated distribution of the received power is calculated using the RSSI value representing the received power obtained by the device 50 receiving the power transmitted from the antenna elements 111A, 111B, and 111C. Pitch PH3 is smaller than pitch PH1, and pitch PH4 is smaller than pitch PH2.

At this time, as many combinations of power transmission vectors P2 and P3 are obtained as the number of intersections of the mesh of area A11, the phase control unit 143 sets the phases φ2 and φ3 of the power transmitted from the antenna elements 111B and 111C (see FIG. 8). to the phases φ2, φ3 of each combination, and the RSSI value representing the received power of the device 50 is used to obtain an estimate of the received power.

As a result, an estimated value of received power at each intersection of the mesh of area A11 shown in FIG. 13 is obtained. Phase control section 143 acquires point Q12 specified by phases φ2 and φ3 that give the largest estimated value of received power among the obtained estimated values of received power. Point Q12 is the operating point identified by phases φ2 and φ3.

If the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q12 are larger than the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q11, the phase control unit 143 controls the point Q12 (see FIG. 14). ) to continue the search. If the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q12 are equal to or smaller than the received power obtained at the phases φ2 and φ3 of the point Q11, then the phases φ2 and φ3 of the point Q11 is the center point and the search is continued.

Here, a mode of obtaining the point Q12 specified by the phases φ2 and φ3 that gives the largest estimated value of the received power among the estimated values of the received power obtained from the mesh of the area A11 has been described. That is, an example of the fifth predetermined value is the largest estimated value of received power among the estimated values of received power obtained from the mesh of area A11.

However, among the estimated values of the received power obtained from the mesh of the area A11, the phases φ2 and φ3 that are larger than the estimated values of the received power obtained at the phases φ2 and φ3 of the point Q11 are specified by the phases φ2 and φ3. You may acquire the point Q12 where it is made. That is, the fifth predetermined value may be a predetermined value that is larger than the estimated values of the received power obtained at phases φ2 and φ3 at point Q11.

In FIG. 14, the phase control unit 143 further searches inside an area A12 centered on the point Q12. Area A12 is a region indicated by a mesh and is narrower (smaller) than area A11. Area A12 is an example of an area narrower than area A11.

Searching in area 12 is similar to searching in area 11 . That is, the pitch in the direction of the phases φ2 and φ3 is made smaller than the pitches PH3 and PH4, and the phase of the point Q12 at which power larger than the received power obtained at the phases φ2 and φ3 of the point Q12 is obtained in the Bayesian optimization process. φ2 and φ3 are obtained.

Next, the power transmission vector selected in the phase control process executed by the phase control unit 143 will be described. Here, power is transmitted from the antenna elements 111A, 111B, and 111C (see FIG. 8), and the phase φ1 of power transmitted by the antenna element 111A is 0 degrees as an example. That is, the power transmission vector P1 is fixed.

FIG. 15 shows the electric field distribution of the received power of the device 50, which is originally a distribution represented by an unknown objective function. In FIG. 15, the two horizontal axes indicate phases φ2 and φ3, and the vertical axis indicates normalized values (unitless) of the electric field distribution.

16 to 20 are diagrams showing estimated distributions of RSSI values obtained by phase control processing using Bayesian optimization processing by the phase control unit 143. FIG. In FIGS. 16 to 20, the two horizontal axes indicate phases φ2 and φ3, and the vertical axis indicates normalized RSSI values (without units).

FIG. 15 shows the electric field distribution when power is sequentially transmitted from 256 antenna elements 111 to the device 50, which is originally represented by an unknown objective function. The electric field distribution shown in FIG. 15 is obtained by setting the phases of the power transmission vectors P2 and P3 to 360 (degrees)×360 (degrees)=129,600 combinations of phases while the phase of the power transmission vector P1 is fixed. represents the electric field distribution of the power received by the device 50 when The optimum values of the phases φ2 and φ3 are φ2=270 degrees and φ3=200 degrees.

Further, the phases φ2 and φ3 included in 129600 combinations are, for example, the X axis in FIG. φ3≦360 degrees), the phases φ2 and φ3 corresponding to the X and Y coordinates may be proportionally divided.

FIGS. 16 to 20 show the cases where the power transmission vectors P2 and P3 have 4, 5, 6, 7, and 8 combinations of the phases φ2 and φ3, respectively, and power transmission is performed sequentially with each power transmission vector. 2 is a diagram showing an estimated distribution of received power obtained by phase control processing using Bayesian optimization processing by the phase control unit 143 based on received power sequentially received by the device 50. FIG. 4, 5, and 6 combinations of the phases φ2 and φ3 of the power transmission vectors P2 and P3 correspond to FIGS. 11, 13, and 14, respectively.

First, by sequentially transmitting power using four sets of power transmission vectors having a phase difference of 180 degrees each in the phase φ2 direction and the phase φ3 direction, as shown in FIG. The area is narrowed down to 1/4 of the area (an example of the two-dimensional search area) where the phase φ3 is 1 degree≦φ3≦360 degrees at 360 degrees. This is the same as the state narrowed down to area A1 in FIG.

Next, in the area narrowed down in FIG. 16, a virtual mesh is created at a predetermined pitch in the direction of phases φ2 and φ3, and five pairs of power transmission vectors P2 of phases φ2 and φ3 corresponding to intersections are generated. , P3 are used to transmit power from the antenna elements 111A, 111B, and 111C. In this case, the estimated distribution of the RSSI values obtained by the phase control process using the Bayesian optimization process by the phase control unit 143 using the RSSI value representing the magnitude corresponding to the received power received by the device 50 is shown in FIG. as shown in

Similarly, in the area narrowed down in FIG. 16, the antenna elements 111A, 111B, and 111C are obtained using six pairs of power transmission vectors P2 and P3 of phases φ2 and φ3 corresponding to intersection points of the virtual mesh. FIG. 18 shows the estimated distribution of RSSI values obtained by the phase control unit 143 through the Bayesian optimization process when power is transmitted from .

Similarly, when power is transmitted from the antenna elements 111A, 111B, and 111C using seven pairs of power transmission vectors P2 and P3 with phases φ2 and φ3 corresponding to intersections of the virtual mesh, the phase control unit The estimated distribution of RSSI values obtained by Bayesian optimization processing by 143 is as shown in FIG.

Similarly, when power is transmitted from the antenna elements 111A, 111B, and 111C using eight pairs of power transmission vectors P2 and P3 with phases φ2 and φ3 corresponding to the intersection points of the virtual mesh, the phase FIG. 20 shows the estimated distribution of RSSI values obtained by the control unit 143 through the Bayesian optimization process.

As described above, the area narrowed down to 1/4 shown in FIG. 16 includes the area giving the maximum RSSI value shown in FIGS. It was confirmed that the amount of calculation can be reduced by narrowing down the area with four sets of power transmission vectors having a phase difference of 1 degree.

Further, by refining the mesh in the area narrowed down in FIG. 16, the estimated distribution of RSSI values shown in FIGS. 17 to 20 could be obtained by Bayesian optimization processing. As shown in FIGS. 17 to 20, as the mesh becomes finer (as the number of pairs of power transmission vectors P2 and P3 increases), a shape closer to the shape of the distribution shown in FIG. 15 is obtained.

In the above description, the antenna subset 110A includes three antenna elements 111A, 111B, and 111C, and the two-dimensional search area with phases φ2 and φ3 is used, but the antenna subset 110A includes two antenna elements 111. In this case, the optimum value of φ2 can be found in a one-dimensional search area of only phase φ2.

In the above description, the antenna subset 110A includes three antenna elements 111A, 111B, and 111C. However, when the antenna subset 110A includes four or more antenna elements 111, the following good.

FIG. 21 is a diagram showing the antenna element 111. As shown in FIG. FIG. 21 shows nine antenna elements 111 arranged in three rows and three columns. For convenience of explanation, antenna numbers 1 to 9 are assigned to the nine antenna elements 111 . The nine antenna elements 111 are divided into the following four groups G1-G4. G1={1, 2, 5}, meaning that group G1 includes antenna elements 111 with antenna numbers 1, 2, and 5; Similarly, G2={3,5,6}, G3={4,5,7} and G4={5,8,9}.

Groups G1 to G4 all include antenna element 111 with antenna number 5 located in the center. In this way, the nine antenna elements 111 are divided into a plurality of groups so that all groups G1 to G4 include a common antenna element 111 (here, the antenna element 111 with antenna number 5). Then, the antenna element 111 with antenna number 5 is set as the reference antenna element 111 for fixing the phase φ1 like the antenna element 111A described above, and the optimum values of the phases φ2 and φ3 of the remaining two antenna elements 111 are obtained. Just do it. Such processing may be performed simultaneously for the four groups G1 to G4.

As described above, according to the embodiment, by using the Bayesian optimization process in the antenna subset selection process and the phase control process, the phases φ2 and φ3 of the power transmission vectors P2 and P3 when feeding the device 50 are optimized. The amount of calculation for calculating the value can be reduced.

More specifically, in the antenna subset selection process, the antenna selection unit 142 receives power transmitted from at least one antenna element 111 selected from the 256 antenna elements 111 of the array antenna 110. Based on the power, a predetermined combination of a plurality of antenna elements 111 when the received power is greater than or equal to the first predetermined value in the two-dimensional plane in which the array antennas 110 are arranged is obtained as the antenna subset 110A.

In the phase control process, the phase control unit 143 first narrows down the area with four sets of power transmission vectors having a phase difference of 180 degrees in the phase φ2 direction and the phase φ3 direction, and virtual create a nice mesh. Based on the estimated value of the RSSI representing the received power of the device 50 when power is transmitted from the antenna elements 111A, 111B, and 111C using a plurality of sets of power transmission vectors P2 and P3 corresponding to the intersections of the mesh, the phase control unit 143 performs the Bayesian optimization process, the optimum values of the phases φ2 and φ3 can be obtained.

That is, according to the embodiment, at least one or more antenna elements 111 included in the antenna subset 110A can be obtained from among the plurality of antenna elements 111 included in the array antenna 110 with a small amount of calculation, and further, The phase of each of the multiple antenna elements 111 included in the antenna subset 110A can be obtained with a small amount of computation.

Therefore, it is possible to provide the power feeding device 100 and the power feeding method that reduce the number of trials and/or the amount of calculation for detecting the desired antenna element 111 and phase.

In the above description, the received power monitor unit 52 of the device 50 radiates packet data containing an RSSI value representing the power received from the antenna element 111. Instead of the RSSI value, the power received by the device 50 The packet data may include data representing the amount of charge by the .

Also, if the device 50 has a camera or a light receiving unit, the packet data may include data representing the amount of light received by the device 50 instead of the RSSI value.

Also, the configuration in which the array antenna 110 includes 256 antenna elements 111 has been described above. However, for example, by mounting a plurality of (for example, about four) antenna elements 111 on a moving body such as a drone so as to be positioned on the same plane and gradually shifting the flying position of the drone, the antenna elements 111 mounted on the drone can be mounted. The positions of the four antenna elements 111 included in the array antenna 110 may be set to the positions of the 256 antenna elements 111 included in the array antenna 110, and the RSSI value obtained by the device 50 when power is transmitted from 256 points may be acquired. . In this case, a movement position selection unit may be included instead of the antenna selection unit 142 to obtain the positions of the antenna elements 111 included in the antenna subset 110A.

Although the power supply device and the power supply method according to the exemplary embodiments of the present invention have been described above, the present invention is not limited to the specifically disclosed embodiments, and is within the scope of the claims. Various modifications and changes may be made without departing from the description.

50 device 100 feeding device 110 array antenna 120 phase shifter 140 control device 142 antenna selection section 143 phase control section

Claims (10)

A predetermined combination in which the received power is greater than or equal to a first predetermined value by a first Bayesian optimization process based on the received power of a device that receives power transmitted from at least one antenna element of a two-dimensional antenna grid. an antenna selection unit for determining a plurality of antenna elements of
A second Bayesian optimization process is performed so that the complex amplitude when the device receives the power transmitted from each of the plurality of antenna elements of the predetermined combination is equal to or greater than a second predetermined value. and a phase controller that controls the phase of power output by each antenna element. The antenna selection unit, as the first Bayesian optimization process, power transmitted from one antenna element of the two-dimensional antenna grid, or at least two antenna elements of the two-dimensional antenna grid Based on the received power of the device that received the power sequentially transmitted from the predetermined combination when the received power is equal to or greater than the first predetermined value in the two-dimensional plane in which the two-dimensional antenna grid is arranged 2. The feeding device of claim 1, wherein a plurality of antenna elements are determined. When controlling the phase of the power output by each of the plurality of antenna elements in the predetermined combination by the second Bayesian optimization process, the phase control unit controls the first antenna among the plurality of antenna elements in the predetermined combination. setting a first phase at which the element outputs the power to a first predetermined phase and a phase obtained by adding 180 degrees to the first predetermined phase, and a second antenna among the plurality of antenna elements in the predetermined combination; 2 defined by the first phase and the second phase in a state where the second phase in which the element outputs the power is set to the second predetermined phase and the phase obtained by adding 180 degrees to the second predetermined phase In the dimensional search area, the area including the first phase and the second phase when the complex amplitude when the device receives power is equal to or greater than a third predetermined value is 1/4 of the two-dimensional search area. The power supply device according to claim 1, wherein the power supply device is narrowed down to . The phase control section swings the first phase at a first pitch and swings the second phase at a second pitch in the quarter area, so that the complex amplitude when the device receives power changes to the 4. The power feeding device according to claim 3, further narrowing the area including said first phase and said second phase within said 1/4 area when said value is equal to or greater than a fourth predetermined value that is greater than said three predetermined values. The phase control unit swings the first phase at a third pitch and swings the second phase at a fourth pitch in an area further narrowed within the 1/4 area, while the device is The area including the first phase and the second phase when the complex amplitude at the time of power reception is equal to or greater than a fifth predetermined value larger than the fourth predetermined value is further narrowed within the quarter area. 5. The power supply device according to claim 4, further narrowed inside the. 6. The power feeding device according to claim 5, wherein said third pitch is smaller than said first pitch, and said fourth pitch is smaller than said second pitch. The 1/4 area is any one of four areas obtained by equally dividing the two-dimensional search area having the first phase and the second phase as two axes along the two axes. The power supply device according to any one of claims 3 to 6, which is an area of . The power supply apparatus according to any one of claims 1 to 7, wherein the received power of said device is represented by an RSSI value of power received by said device or a charge amount of power received by said device. A plurality of predetermined combinations when the received amount is equal to or greater than a first predetermined value by the first Bayesian optimization processing based on the received amount of the device that received the optical signals transmitted from the plurality of elements of the two-dimensional element grid an element selection unit that obtains an element of
A second Bayesian optimization process is performed such that the complex amplitude when the device receives the optical signals transmitted from the plurality of elements of the predetermined combination is equal to or greater than a second predetermined value. and a phase controller that controls the phase of the optical signal output by each element. A plurality of predetermined combinations when the received power becomes equal to or greater than a predetermined value by the first Bayesian optimization process based on the received power of the device that received the power transmitted from at least one antenna element of the two-dimensional antenna grid. determining the antenna elements of
The plurality of antenna elements of the predetermined combination are subjected to a second Bayesian optimization process so that the complex amplitude when the device receives the power transmitted from the plurality of antenna elements of the predetermined combination is equal to or greater than a predetermined value. and controlling the phase of the power output by each.

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