Power transmission device, control method, and control program

Abstract

To improve a radio wave emitted from a power transmission device when a structure with high reflectance is present inside a room.SOLUTION: A power transmission device 10 comprises: a transmission and reception unit 13 that transmits a transmission wave to a power reception device; and a control unit 17 that, when the transmission wave is reflected on a reflecting object and reaches a first position of an object different from the power reception device, reduces the field intensity of the transmission wave at a second position of the reflecting object, compared with the intensity of the transmission wave when the transmission wave is reflected on the reflecting object and does not reach the first position of the object different from the power reception device.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present application relates to a power transmitting device, a control method, and a control program. [Background technology]

[0002] In wireless power supply using an array antenna, a retrodirective method is sometimes used. In the retrodirective method, a pilot signal is transmitted from a power receiving device prior to power transmission, and the power transmitting device estimates the radio wave propagation channel characteristics of the pilot signal and generates a transmission weight based on the estimation, thereby controlling the antenna directivity. Patent Document 1 discloses a wireless power supply device that calculates a propagation coefficient between multiple antenna elements and an antenna of a device to be powered, and adjusts the phase and amplitude of a power supply signal for each of the multiple antenna elements based on the propagation coefficient.

[0003] Cited Document 2 discloses a technology for supplying power to wireless devices such as actuators that require large power by an open-space wireless power distribution method while complying with the radio wave protection guidelines. Cited Document 3 discloses a leakage electromagnetic wave control system that prevents people from entering the range of leakage electromagnetic waves in a space where people are present. Cited Document 4 discloses a wireless power supply device that weakens the strength of radio waves reaching the position of an object without stopping power supply by radio waves to the object when the object is within a predetermined range. In addition, Non-Patent Document 1 describes the effectiveness in a multipath environment where reflected waves exist and an out-of-line-of-sight environment where a shield exists. In this document, the method is called a multipath retrodirective method. And, a technology is described in which a pilot signal propagating from a power receiving device to a power transmitting device does not pass through the human body even when a person is present in the usage environment, so that the pilot signal is not radiated from the power transmitting device to the human body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-10485 A [Patent Document 2] JP 2010-233430 A [Patent Document 3] JP 2014-217093 A [Patent Document 4] JP 2020-005468 A [Non-patent literature]

[0005] [Non-Patent Document 1] Taichi Sasaki, Naoki Shinohara, “Study on Multipath Retrodirective for Efficient and Safe Indoor Microwave Power Transmission,” 2019 IEEE Wireless Power Transfer Conference(WPTC), 2019 Summary of the Invention [Problem to be solved by the invention]

[0006] In the retrodirective method, when a human being is present between the power receiving device and the power transmitting device, the pilot signal transmitted by the power receiving device is significantly attenuated by the human body, and therefore, when the antenna directivity is controlled based on the radio wave propagation channel characteristics of the pilot signal, the strength of the radio waves radiated from the power transmitting device toward the human body is weakened, and it is considered to be safe for the human body. However, when there is a highly reflective structure such as a metal plate indoors, the reflected waves that pass through the structure may hit an object to be avoided, and there is room for improvement in the appropriate radiation of radio waves from the power transmitting device. [Means for solving the problem]

[0007] A power transmission device in one aspect includes a transmitting unit that transmits a transmission wave to a power receiving device, and a control unit that, when the transmission wave is reflected by a reflecting object and reaches a first position on an object other than the power receiving device, reduces the radio wave intensity of the transmission wave at a second position on the reflecting object to an intensity lower than the intensity of the transmission wave when the transmission wave is not reflected by the reflecting object and reaches the first position on an object other than the power receiving device.

[0008] In one aspect, a control method is provided in which a power transmitting device having a transceiver unit that transmits a transmission wave to a power receiving device reduces the radio wave intensity of the transmission wave at a second position of a reflecting object when the transmission wave is reflected by a reflecting object and reaches a first position of an object other than the power receiving device, compared to the intensity of the transmission wave when the transmission wave is not reflected by a reflecting object and reaches the first position of an object other than the power receiving device.

[0009] A control program in one aspect includes a power transmitting device having a transceiver unit that transmits a transmission wave to a power receiving device, and when the transmission wave is reflected by a reflecting object and reaches a first position of an object other than the power receiving device, the radio wave intensity of the transmission wave at a second position of the reflecting object is reduced compared to the intensity of the transmission wave when the transmission wave is not reflected by the reflecting object and reaches the first position of the object other than the power receiving device. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram for explaining an overview of a wireless power transmission system according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the results of calculating, by computer simulation, the intensity distribution of radio waves radiated by a reference power transmitting device in a conventional retrodirective system. [Diagram 3] FIG. 3 is a diagram for explaining another problem caused by radio waves emitted by a reference power transmitting device in a conventional retrodirective system. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of the power transmitting device according to the first embodiment. [Diagram 5]FIG. 5 is a diagram showing an example of an equivalent low-pass system analysis model of an adaptive array antenna. [Figure 6] FIG. 6 is a diagram showing an example of an adaptive array antenna and its directivity. [Figure 7] FIG. 7 is a diagram illustrating an example of the configuration of the power receiving device according to the first embodiment. [Figure 8] FIG. 8 is a diagram for explaining an example of control of the power transmitting device. [Figure 9] FIG. 9 is a flowchart illustrating an example of a processing procedure executed by the power transmitting device. [Figure 10] FIG. 10 is a diagram illustrating an example of a configuration of a power transmitting device according to a modified example of the first embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of a configuration of a power transmitting device according to a modified example of the first embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of a configuration of a power transmitting device according to the second embodiment. [Figure 13] FIG. 13 is a diagram showing an example of vectorization when differential coefficients are constrained. [Figure 14] FIG. 14 is a diagram illustrating an example of a configuration of a power transmitting device according to the third embodiment. [Figure 15] FIG. 15 is a diagram showing an example of vectorization in the multi-point null constraint method. [Figure 16] FIG. 16 is a diagram showing an example of vectorization in the differential coefficient constraint method. [Figure 17] FIG. 17 is a diagram illustrating an example of null depth processing in the preprocessing unit. [Figure 18] FIG. 18 is a diagram illustrating another example of processing of the null depth in the preprocessing unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A number of embodiments for carrying out the present application will be described in detail with reference to the drawings. Note that the present invention is not limited to the following description. Furthermore, the components in the following description include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. In the following description, similar components may be given the same reference numerals. Furthermore, duplicated descriptions may be omitted.

[0012] FIG. 1 is a diagram for explaining an outline of a wireless power transmission system according to an embodiment. The system 1 shown in FIG. 1 includes, for example, a wireless power transmission system capable of microwave transmission type (space transmission type) wireless power transmission. Wireless power transmission is a mechanism that allows power to be transmitted without using, for example, a cable or a plug. The microwave transmission type system 1 can use a retrodirective method. The microwave transmission type system 1 uses radio waves (microwaves) as energy transmission. The frequency of the radio waves used in the microwave transmission type system 1 can be in a plurality of frequency bands, including, for example, the 920 MHz band, the 2.4 GHz band, and the 5.7 GHz band in Japan. In this embodiment, the system 1 makes it possible to simultaneously improve power supply efficiency appropriate to the situation and ensure safety. The system 1 can also be applied to, for example, space solar power generation. The radio waves used in the wireless power transmission system of the present disclosure are not limited to microwaves, and radio waves in other frequency bands may be used as appropriate.

[0013] In the example shown in FIG. 1, the system 1 uses a multipath retrodirective method. The system 1 includes a power transmitting device 10 and a power receiving device 20. The system 1 transmits power from the power transmitting device 10 to the power receiving device 20 using multiple paths (propagation channels). The power transmitting device 10 is a transmission device in the system 1 that transmits power wirelessly and is a device capable of transmitting radio waves for power supply. The power transmitting device 10 includes a sensor unit 15 that can detect an object such as a human body in the vicinity of the array antenna 11. In the following description, the power transmitting device 10 may be referred to as "own device".

[0014] The power receiving device 20 is a power-supplied device in the system 1 that receives radio waves for power supply to obtain power. The power receiving device 20 includes, for example, a smartphone, a tablet terminal, an IoT (Internet of Things) sensor, a notebook personal computer, a drone, an electric car, an electric bicycle, a game machine, and the like. In this manner, the power receiving device of the present disclosure may be a mobile device. The power receiving device of the present disclosure may include a device that is usually used without being moved, such as a base station, a traffic light, or a vending machine.

[0015] In scene C1, the power receiving device 20 can transmit a prescribed signal 1000 determined between the power receiving device 20 and the power transmitting device 10. The prescribed signal 1000 includes, for example, a beacon, a pilot signal, and the like. The power receiving device 20 can transmit the prescribed signal 1000, for example, at a transmission period. The power receiving device 20 can transmit the prescribed signal 1000 by emitting radio waves including the prescribed signal 1000. On the other hand, when the power transmitting device 10 receives the prescribed signal 1000, it estimates characteristic values ​​(array response vectors) of multiple paths from the power receiving device 20 to the power transmitting device 10 based on the prescribed signal 1000. The power transmitting device 10 calculates a weighting coefficient for transmission using the estimated array response vector for the power receiving device 20.

[0016] In scene C2, the power transmitting device 10 performs directivity control by multiplying each antenna by a weighting coefficient, and radiates radio waves including a transmission signal 2000 for power supply. Directivity control means, for example, controlling the relationship between the radiation direction and radiation intensity of radio waves. If the frequencies of the prescribed signal 1000 and the transmission signal 2000 are the same and time fluctuations in the propagation path are ignored, the characteristics of the multiple paths from the power transmitting device 10 to the power receiving device 20 match the characteristics from the power receiving device 20 to the power transmitting device 10. As a result, the radio waves 2000W for power supply radiated from the power transmitting device 10 have a radiation pattern that makes use of not only paths directly toward the power receiving device 20, but also paths heading in a direction different from the power receiving device 20.

[0017] FIG. 2 is a diagram showing an example of the result of calculating the intensity distribution of radio waves emitted by the reference power transmitting device 100A in the conventional retrodirective method by computer simulation. The intensity distribution 3000 shown in FIG. 2 shows the intensity distribution when the reference power transmitting device 100A and the power receiving device 20 are placed in a room 4000, an object 5000 whose physical properties are similar to a human body is placed, and radio waves 2000W including a transmission signal 2000 are emitted from the reference power transmitting device 100A in the retrodirective method. The reference power transmitting device 100A is configured to estimate the characteristic values ​​of multiple paths from the power receiving device 20 to the power transmitting device 10 based on the specified signal 1000, control the antenna directivity using the characteristic values, and transmit radio waves 2000W including a transmission signal 2000 for power supply, similar to the power transmitting device 10 according to the present embodiment. The room 4000 is a room of 3m×3m×3m with walls made of concrete. The object 5000 is disposed between the reference power transmitting device 100A and the power receiving device 20, at a position shifted to the left from a straight line connecting the reference power transmitting device 100A and the power receiving device 20. The object 5000 has physical properties such as a relative dielectric constant of 35.4 and a conductivity of 5.17, for example.

[0018] 2, the intensity distribution 3000 shows that the radio wave 2000W-1 traveling directly from the reference power transmitting device 100A to the power receiving device 20 and the radio wave 2000W-2 traveling from the reference power transmitting device 100A to the object 5000 have high intensities. In other words, the intensity distribution 3000 is considered to indicate that the reference power transmitting device 100A receives the specified signal 1000 directly from the power receiving device 20 and also receives the specified signal 1000 reflected by the object 5000.

[0019] FIG. 3 is a diagram for explaining another problem caused by radio waves emitted by the reference power transmitting device 100A in the conventional retrodirective method. In an example shown in FIG. 3, the reference power transmitting device 100A and the power receiving device 20 are arranged in a room 4000, an object 5000 to be avoided from being irradiated and a reflecting object 6000 are arranged, and radio waves 2000W including a transmission signal 2000 are emitted from the reference power transmitting device 100A toward the power receiving device 20 in the retrodirective method. The object 5000 may include, for example, a human being, an animal, a robot, a moving object, a plant, food, a device that transmits or receives electromagnetic waves, and the like. The reflecting object 6000 includes a reflecting plate that, when receiving the radio waves 2000W, reflects the radio waves 2000W at a predetermined angle and emits them. The reflecting object 6000 includes, for example, a door, a whiteboard, a metasurface reflecting plate (RIS: Reconfigurable Intelligent Surface), a metal plate, a mirror, and the like. The metasurface reflector is configured to reflect 2000W of incident radio waves by changing their direction of travel to the desired direction.

[0020] A part of the radio waves 2000W, radio waves 2000W-3, travels toward the reflecting object 6000, and the reflected waves 2100W reflected by the reflecting object 6000 travel toward the object 5000 whose irradiation is to be avoided. In this way, if a reflecting object 6000 with high reflectivity, such as a metal plate, is present inside the room 4000 (indoors), there is a possibility that the reflected waves 2100W that have passed through the reflecting object 6000 will reach the object 5000.

[0021] In the present disclosure, the system 1 provides a technology for reducing the impact on the human body in the multipath retrodirective method when a specified signal 1000 from a power receiving device 20 is reflected off a human body and reaches a power transmitting device 10, and when a reflective object 6000 is present indoors.

[0022] (Embodiment 1) [Configuration of power transmission device according to embodiment 1] Fig. 4 is a diagram illustrating an example of the configuration of the power transmitting device 10 according to the first embodiment. Fig. 5 is a diagram illustrating an example of an equivalent low-pass system analysis model of an adaptive array antenna. Fig. 6 is a diagram illustrating an example of an adaptive array antenna and its directivity.

[0023] As shown in FIG. 4, the power transmitting device 10 includes an array antenna 11, a transmission signal generating unit 12, a transmitting / receiving unit 13, an estimating unit 14, a sensor unit 15, a detecting unit 16, a control unit 17, and a multiplying unit 18.

[0024] The array antenna 11 is configured to be capable of directivity control (beam forming). The array antenna 11 includes a plurality of antenna elements 11A. For example, the array antenna 11 is configured such that each of the plurality of antenna elements 11A radiates the same radio wave, and the phase and power intensity of each element are adjusted to strengthen the radio wave in a specific direction and to weaken the radio wave by canceling each other out in another direction. The array antenna 11 radiates a radio wave including a transmission signal 2000 and receives a radio wave including a prescribed signal 1000 from the power receiving device 20. The array antenna 11 supplies the received signal to the transmitting / receiving unit 13. In this embodiment, for the sake of simplicity, the array antenna 11 is described as including three or more antenna elements 11A, but the number of antenna elements 11A is not limited to this.

[0025] The transmission signal generating unit 12 generates a transmission signal 2000 for power supply to be transmitted to the power receiving device 20. The transmission signal 2000 is a signal for emitting radio waves 2000W capable of supplying power. For example, the transmission signal 2000 may be a baseband signal. The transmission signal 2000 may be, for example, an unmodulated signal or a modulated signal. In the case of an unmodulated signal in the baseband, the transmission signal 2000 does not vary with time during the transmission period. In the case of a modulated signal in the baseband, the transmission signal generating unit 12 varies the transmission signal 2000 with time during the transmission period. The transmission signal generating unit 12 includes, for example, stopping the transmission signal 2000 at the timing of receiving the specified signal 1000. The transmission signal generating unit 12 is electrically connected to the multiplier unit 18 and supplies the generated transmission signal 2000 to the multiplier unit 18.

[0026] The transmitting / receiving unit 13 has a plurality of transmitting / receiving circuits 13A electrically connected to each of the plurality of antenna elements 11A of the array antenna 11. The transmitting / receiving circuit 13A is electrically connected to the estimating unit 14, the multiplying unit 18, and the like. The transmitting / receiving circuit 13A extracts a reception signal received by the antenna element 11A and supplies it to the estimating unit 14. The transmitting / receiving circuit 13A causes the antenna element 11A to radiate a transmission signal 2000 multiplied by a transmission weight in the multiplying unit 18. The transmission weight includes, for example, a weighting coefficient capable of adjusting the amplitude and phase. The transmitting / receiving unit 13 causes the plurality of antenna elements 11A to simultaneously radiate radio waves 2000W including the transmission signal 2000 multiplied by a transmission weight (complex amplitude). As a result, the power transmitting device 10 radiates radio waves 2000W with controlled directivity. The transmitting / receiving unit 13 functions as a transmitting unit.

[0027] The estimation unit 14 estimates a propagation channel characteristic (impulse response) from a reference signal 1000 included in a received signal received by the multiple antenna elements 11A. The propagation channel characteristic (impulse response) includes, for example, an amplitude characteristic and a phase characteristic. The array response vector indicates, for example, channel characteristics for the number of antennas. The array response vector includes, for example, a vector in which the propagation channel characteristic (impulse response) for each of the multiple antenna elements 11A is arranged. The array response vector in the receiving process is also called a receiving response vector. The estimation unit 14 estimates the receiving response vector using a known algorithm, for example, as disclosed in Japanese Patent Application Laid-Open No. 2002-43995. The estimation unit 14 supplies vector data of the array response vector to the control unit 17.

[0028] The sensor unit 15 can obtain information capable of detecting the presence, direction, and the like of an object 5000 and a reflecting object 6000 different from the power receiving device 20 in the radio wave propagation environment of the power transmitting device 10. The radio wave propagation environment includes, for example, a space in which radio waves 2000W are propagated between the power transmitting device 10 and the power receiving device 20. The sensor unit 15 obtains information on the object 5000 and the reflecting object 6000 present in the radio wave propagation environment using, for example, a camera, a LIDAR (Laser Imaging Detection and Ranging), a radar such as a millimeter wave radar, a ToF (Time of Flight) sensor, an infrared sensor, a human presence sensor, and the like. The sensor unit 15 may be provided outside the power transmitting device 10. The sensor unit 15 is electrically connected to the detection unit 16, and supplies the detection unit 16 with sensor information capable of detecting the direction, position, and the like of the object 5000 and the reflecting object 6000 in the radio wave propagation environment. The sensor information includes, for example, information on the presence / absence, distance, position, image, etc. of the object 5000 and the reflecting object 6000. The direction of the reflecting object 6000 may include the direction in which the normal direction of the surface of the reflecting object 6000 faces. The sensor unit 15 may acquire, as information on the object 5000 and the reflecting object 6000, their three-dimensional coordinates or their direction and distance.

[0029] The detection unit 16 detects information on the presence, position, and direction of an object 5000 and a reflecting object 6000 different from the power receiving device 20 in a radio wave propagation environment based on the sensor information from the sensor unit 15. When a plurality of objects 5000 and reflecting objects 6000 exist, the detection unit 16 detects the positions and directions of the plurality of objects 5000 and reflecting objects 6000. For example, the detection unit 16 executes a publicly known object recognition process on an image indicated by the sensor information, extracts the object 5000 and the reflecting object 6000 from the sensor information, detects the positions, etc. of the extracted object 5000 and reflecting object 6000, and detects the directions of the object 5000 and the reflecting object 6000 from the array antenna 11. For example, the detection unit 16 detects the positions and directions of the object 5000 and the reflecting object 6000 from the array antenna 11 based on the positions, etc. of the object 5000 and the reflecting object 6000 indicated by the sensor information and the relative positional relationship between the sensor unit 15 and the array antenna 11. The detection unit 16 is electrically connected to the control unit 17, and supplies the control unit 17 with position information indicating the positions of the object 5000 and the reflecting object 6000 from the array antenna 11, and directional information indicating the directions. The position information includes, for example, information indicating the three-dimensional coordinates of the object 5000 and the reflecting object 6000. The directional information includes, for example, information indicating the directions of the object 5000 and the reflecting object 6000 from the array antenna 11. The detection unit 16 of the present disclosure may detect information regarding the positions and directions of the object 5000 and the reflecting object 6000 different from the power receiving device 20 in the radio wave propagation environment, based on sensor information including position information, directional information, distance information, etc., such as GPS information of the object 5000 and the reflecting object 6000, from the sensor unit 15.

[0030] The control unit 17 has a function of generating weights for power transmission based on the array response vector for the power receiving device 20, which is the estimation result of the estimation unit 14, and the position information and direction information of the object 5000 and the reflecting object 6000, which are the detection result of the detection unit 16. For example, a ZF (Zero-Forcing) algorithm or an MMSE (Minimum Mean Square Error) algorithm used in MIMO can be used as a method for generating the weights. The control unit 17 is electrically connected to the multiplication unit 18, and supplies weight information indicating the weights for power transmission to the multiplication unit 18. In the following description, for the sake of simplicity, a case will be described in which a plurality of antenna elements 11A of the array antenna 11 are arranged at equal intervals in the horizontal direction. The control unit 17 may be capable of determining whether or not the transmitted radio wave is reflected by the reflecting object 6000 and reaches the object 5000 different from the power receiving device 20, based on information on the presence, position, and direction of the object 5000 different from the power receiving device 20 and the reflecting object 6000 in the radio wave propagation environment detected by the detection unit 16.

[0031] As shown in FIG. 5, the adaptive array antenna transmits a complex amplitude w k Complex conjugate w of (weight) k * After multiplying by, radio waves of 2000 W are emitted simultaneously from K antenna elements 11A. * When a character has an asterisk (*) on its right side, it means the complex conjugate. Weight w k where k=0, ,K-1. At the receiving point 200P, a composite signal of 2000W of radio waves radiated from K antenna elements 11A is observed. At this time, the amplitude and phase change for each propagation channel. Therefore, the impulse response of the propagation channel between the antenna elements 11A #0 to #K-1 and the receiving point 200P is expressed as Z k (complex number), the analytical array antenna characteristics are given by the following (Equation 11).

number

[0032] In this disclosure, the analytical array antenna characteristic is referred to as the array response value AR. If the weight vector is W and the array response vector is V, then (Equation 11) can be expressed as the inner product of complex vectors as shown in the following (Equation 12). Note that in this disclosure, (·) H When an "H" is written on the right side of a letter, it means complex conjugate transpose (Hermitian transpose). AR=W H V...(Formula 12) When the weight vector W and the array response vector V are expressed by concrete elements, they are given by the following (Equation 13).

number

[0033] If the array response vector V is known, then the array response value AR at the receiving point 200P can be controlled by providing an appropriate weight vector W. When determining the weight vector W, it is necessary to ensure that the square of the norm of the weight vector W is 1 (||W|| 2 = 1).

[0034] In the retrodirective system 1, an array response vector V d and use this to find the optimal weight vector W opt If we ignore the time variation of the propagation channel, the array response vector V d can be regarded as an array response vector from the power transmitting device 10 to the power receiving device 20. However, the pilot signal has the same frequency as the radio wave used for power transmission. ||W|| 2 = 1, the magnitude of the array response value |W H V d The optimal weight vector W that maximizes | opt can be expressed as the following (Equation 14).

number

[0035] As described above, the optimal weight vector W for the retro-directive transmission opt only needs the array response vector V of the received pilot signal d and does not require information such as the direction of the receiving point 200P.

[0036] Next, the simultaneous realization of the retro-directive method and multiple (for example, M) null formations will be described.

[0037] A null means that the gain such as the direction or point becomes zero in the directivity of the array antenna 11. To form a null with the array antenna 11, for the array response vector V i (i = 1, ···, M), the magnitude |W H V i | of the array response value may be set to zero. Under this condition, the magnitude |W d V H V d | of the array response value of the array response vector V is maximized. This can be formulated as an optimization problem shown in the following (Equation 15). In the present disclosure, this is referred to as a retro-directive method with linear constraints. Here, K is the number of antenna elements 11A. M is the number of nulls. Since the degree of freedom is K - 1, M < K. argmax (argument of the maximum) means the set of values that achieve the maximum value. (Equation 15) is an equation for obtaining the optimal weight vector W for which |W H V d | becomes maximum. opt

Equation

[0038] The optimization problem of (Equation 15) has a closed-form solution. If (Equation 16) is defined as follows, the optimal weight vector W opt is given by (Equation 17).

Equation

Math

[0039] Here, A is a matrix shown in (Equation 18) formed by arranging the M complex column vectors, i.e., array response vectors V1, V2, ···, V M .

Math

[0040] The array response value corresponding to the null must satisfy W H V i = 0 (i = 1, ···, M < K). Therefore, considering these as a system of homogeneous linear equations, it can be expressed as the product of a matrix and a vector, i.e., A M W = 0 using the matrix A formed by arranging the M complex column vectors, i.e., array response vectors V1, V2, ···, V H . The general solution is given by W=(I - AA + ) + z=(I - AA H )z using the Moore - Penrose generalized inverse matrix A + . z is an arbitrary complex vector. The magnitude of the array response value to be maximized, |W H Vd |W=(I-AA + ) H z=(I-AA + )z, |W H V d |=|z H (I-AA + )V d | is obtained. And, by the Cauchy-Schwarz inequality, |W H V d |=|z H (I-AA + )V d |≦||z||·||(I-AA + )V d || holds true. |W H V d | is maximized when the inequality is equal, and then z=α(I-AA + )V d where α is a complex constant.

[0041] The optimal weight vector W opt is the above-mentioned W=(I-AA + ) H z=(I-AA + )z, z=α(I-AA + )V d By substituting, W opt =α(I-AA + )V d Here, V' is given as in (Equation 16). d =(I-AA + )V d Then, ||W opt || 2 = |α| 2 ||V' d || 2 = 1, α = 1 / ||V' d Therefore, the optimal weight vector W opt can be expressed as (Equation 17) above.

[0042] Next, an example of a method for calculating an array response vector corresponding to a null will be described. The array response vector between the power transmitting device 10 and the power receiving device 20 is estimated from the specified signal 1000. However, if it is assumed that the specified signal 1000 is not transmitted from the target to which the null is to be directed, it is necessary to calculate the array response vector by another method. In the present disclosure, the purpose is to avoid radio waves going directly from the power transmitting device 10 to the target to which the null is to be directed, and the array response vector is calculated from the directions of the object 5000 and the reflecting object 6000, which are the null targets, acquired by the sensor unit 15.

[0043] As shown in Fig. 6, in a linear array in which K antenna elements 11A are arranged at equal intervals, the array response vector in the far field radiated in a direction rotated clockwise by θ (-π / 2<θ<π / 2) from the broadside is given by the following (Equation 19). The broadside is a direction perpendicular to the direction in which the antenna elements 11A are arranged, and is the upward direction in Fig. 6. The inter-element distance from antenna element 11A #0 to antenna element 11A #k of reference point 200B is kd. The inter-element distance from antenna element 11A #0 to antenna element 11A #K-1 is (K-1)d.

number

[0044] Here, the impulse response Z is expressed by (Equation 20).

number

number

number

[0045] The control unit 17 determines the direction θ of the null object. i Array response vector V corresponding to null from i is derived using (Equation 21) and (Equation 22), and then the matrix (I-AA + The control unit 17 calculates the calculated matrix (I-AA + ) and the array response vector V corresponding to the power receiving device 20 d From this, the magnitude of the array response value |W H V d The optimal weight vector W that maximizes | opt Generally, the matrix (I-AA + ) and the array response vector V d Therefore, the control unit 17 calculates the matrix (I-AA + ) can be stored in the memory unit 17D.

[0046] 4, the storage unit 17D may include any non-transitory storage medium such as a semiconductor storage medium and a magnetic storage medium. The storage unit 17D may include a combination of a storage medium such as a memory card, an optical disk, or a magneto-optical disk, and a storage medium reader. The storage unit 17D may include a storage device used as a temporary storage area such as a RAM. The storage unit 17D may be provided outside the control unit 17.

[0047] The memory unit 17D stores a control program 171 that causes the power transmitting device 10 to set the radio wave intensity of the radio waves 2000W (transmitted wave) at a first position to a first intensity based on a first position of an object 5000 different from the power receiving device 20 and a second position of a reflecting object 6000 having a reflectivity equal to or higher than a predetermined value, and to set the radio wave intensity of the radio waves 2000W at the second position to a second intensity that is lower when the radio waves 2000W are reflected by the reflecting object 6000 and reach the first position than when the radio waves 2000W are reflected by the reflecting object 6000 and do not reach the first position.

[0048] The reflective object 6000 of the present disclosure may be a mirror, iron, aluminum or other metals, wood, plastic, glass, ice or other materials, or any combination thereof. The reflective object 6000 of the present disclosure may be a home appliance, a PC, a TV, a display, a printer or other arbitrary device, or furniture such as a cabinet, a desk, a chair, or tableware. The reflective object 6000 of the present disclosure may be a living thing such as a person, an animal, or a plant. The reflectance of the present disclosure may be defined as the ratio of the energy of the radio wave incident on the object to the radio wave reflected from the object. The reflectance of the reflective object 6000 may be the reflectance with respect to the center frequency of the band of the incident radio wave. The reflectance of the predetermined value or more of the present disclosure may be, for example, a relatively high reflectance such as 0.7 with emphasis on the power supply efficiency, or may be a medium reflectance such as 0.5 from the balance between the power supply efficiency and reducing the influence of the power supply radio wave on objects other than the power receiving device (for example, the human body). In addition, when it is desired to avoid the influence of the power supply radio wave on objects other than the power receiving device as much as possible, the reflectance of the predetermined value or more of the present disclosure may be 0.3 or more. In the present disclosure, the influence of a transmitted radio wave such as a power supply radio wave on an object such as a human body may be determined in consideration of the strength of the radio wave, the characteristics of the object, the transmission time, etc. In the present disclosure, the strength and transmission time of the transmitted radio wave for an object such as a human body may be determined based on the influence of a transmitted radio wave such as a power supply radio wave on an object such as a human body.

[0049] The control unit 17 has a function of determining the radio wave intensity of the radio wave 2000W at the first position as a first intensity based on a first position of the object 5000 different from the power receiving device 20 and a second position of the reflecting object 6000 having a reflectance equal to or higher than a predetermined value, and determining the radio wave intensity of the radio wave 2000W-3 at the second position as a second intensity when the radio wave 2000W is reflected by the reflecting object 6000 and reaches the first position. The control unit 17 may determine the second intensity as the intensity when a null is formed. The control unit 17 determines the second intensity as the intensity when the radio wave 2000W (transmitted wave) output from the device is reflected by the reflecting object 6000 according to the law of reflection and reaches the position of the object 5000, and the radio wave 2000W is reflected by the reflecting object 6000 and reaches the first position of the object 5000. The law of reflection includes, for example, that the angle of incidence and the angle of reflection with respect to the reflecting surface are equal in reflection.

[0050] When the radio wave 2000W is reflected by the reflecting object 6000 and reaches the first position, the control unit 17 may virtually arrange an irradiation avoidance target at a position symmetrical with respect to the reflecting surface of the reflecting object 6000. When the irradiation avoidance target virtually arranged at a position symmetrical with respect to the reflecting surface of the reflecting object 6000 is set as the virtual irradiation avoidance target, the control unit 17 may direct a null in this direction when the power transmitting device 10, the reflecting object 6000, and the virtual irradiation avoidance target are aligned on a straight line. The control unit 17 may determine whether the transmitted radio wave is reflected by the reflecting object 6000 and reaches the object 5000 different from the power receiving device 20 using the law of reflection based on the information on the presence, position, and direction of the object 5000 different from the power receiving device 20 and the reflecting object 6000 detected by the detection unit 16 in the radio wave propagation environment. Based on information regarding the presence, position, and direction of an object 5000 other than the power receiving device 20 and a reflecting object 6000 in the radio wave propagation environment detected by the detection unit 16, the control unit 17 may determine that the transmitted wave will reach the object 5000 other than the power receiving device 20 when a virtual straight line extending in the direction of the main lobe of the transmitted radio wave 2000W is reflected by the reflecting object 6000 in accordance with the reflection law and reaches the object 5000 other than the power receiving device 20.

[0051] Furthermore, the control unit 17 may reduce the radio wave intensity of the transmission wave at the second position of the reflecting object 6000 when the radio wave intensity at the first position of the object 5000 is equal to or greater than a predetermined intensity. In this case, the radio wave intensity may be determined in consideration of the effect of the radio wave on the human body. The control unit 17 may direct a null in the direction of the reflecting object 6000 when the radio wave 2000W is reflected by the reflecting object 6000 and reaches the first position. The control unit 17 may transmit the electromagnetic wave using null formation conditions that direct the null to the position and direction of the reflecting object 6000 when the radio wave 2000W is reflected by the reflecting object 6000 and reaches the first position. When the radio waves 2000W are reflected by the reflecting object 6000 and reach a first position, the control unit 17 may use null formation conditions to direct the null toward the position and direction of the reflecting object 6000, and may control the antenna transmission conditions to transmit the radio waves 2000W to the power transmitting device 10 so that the power receiving device 20 is powered by the transmitted radio waves or so that the power receiving device 20 is powered by the transmitted radio waves with maximum efficiency.

[0052] The control unit 17 judges whether the radio wave 2000W (transmitted wave) is reflected by the reflecting object 6000 and reaches the first position of the object 5000 by using information on the relative position and direction of the own device and the reflecting object 6000. The control unit 17 includes, for example, judging whether the radio wave 2000W is reflected by the reflecting object 6000 and reaches the first position by using information on the relative position and direction of the own device and the reflecting object 6000 stored in advance in the storage unit 17D. The control unit 17 may, for example, use information on the relative position and direction of the own device and the reflecting object 6000 detected by the detection unit 16 to judge whether the radio wave 2000W is reflected by the reflecting object 6000 and reaches the first position of the object 5000. The control unit 17 may set the second intensity based on the reflectance of the reflecting object 6000. The control unit 17 includes, for example, determining the reflectance of the reflecting object 6000 stored in advance in the storage unit 17D. The control unit 17 may determine the reflectance of the reflective object 6000 using machine learning, for example, from an image of the reflective object 6000 or the like.

[0053] The multiplier 18 multiplies the transmission signal 2000 from the transmission signal generator 12 by a weight for each of the antenna elements 11A based on the weight information of the controller 17. The multiplier 18 has, for example, a multiplier. The multiplier 18 supplies the transmission signal 2000 multiplied by the weight corresponding to the antenna element 11A to the transmission / reception circuit 13A of the antenna element 11A.

[0054] An example of the functional configuration of the power transmitting device 10 according to the present embodiment has been described above. Note that the above configuration described with reference to Fig. 4 is merely an example, and the functional configuration of the power transmitting device 10 according to the present embodiment is not limited to this example. The functional configuration of the power transmitting device 10 according to the present embodiment can be flexibly modified according to the specifications and operation.

[0055] [Power receiving device according to embodiment 1] FIG. 7 is a diagram showing an example of the configuration of the power receiving device 20 according to the first embodiment. As shown in FIG. 7, the power receiving device 20 includes an antenna 21, a transmitting / receiving unit 22, a signal generating unit 23, and a power receiving unit 24. The power receiving device 20 of the present disclosure may be a mobile device. For example, such a power receiving device 20 may be a mobile battery, a smartphone, a camera, a vibration sensor, a biosensor, a temperature sensor, an alarm, or other device mounted on a moving object such as a drone or a car, an autonomous vehicle, a vibration sensor, a biosensor, a temperature sensor, an alarm, or the like whose installation position is variable. In the present disclosure, since the power receiving device 20 is a mobile device, the characteristics of the propagation channel based on the prescribed signal may change depending on the position of the power receiving device 20.

[0056] The antenna 21 is electrically connected to the transmitting / receiving unit 22. The antenna 21 is a power receiving antenna capable of receiving radio waves 2000W from the power transmitting device 10. For example, a patch antenna, a dipole antenna, a parabolic antenna, or the like can be used as the antenna 21. For example, the antenna 21 emits radio waves including a specified signal 1000, and receives radio waves 2000W including a transmission signal 2000 from the power transmitting device 10. The antenna 21 supplies a reception signal of the received radio waves 2000W to the transmitting / receiving unit 22.

[0057] The transmitting / receiving unit 22 is electrically connected to the signal generating unit 23 and the power receiving unit 24. The transmitting / receiving unit 22 causes the antenna 21 to radiate radio waves including the specified signal 1000 from the signal generating unit 23. The transmitting / receiving unit 22 supplies the power receiving unit 24 with a reception signal of the radio waves received by the antenna 21.

[0058] The signal generating unit 23 generates a specified signal 1000. The signal generating unit 23 causes the antenna 21 to emit radio waves including the specified signal 1000 via the transmitting / receiving unit 22. The signal generating unit 23 can generate the specified signal 1000 based on a transmission period. The signal generating unit 23 may be configured to generate a signal different from the specified signal 1000.

[0059] The power receiving unit 24 converts the radio waves of 2000 W received by the antenna 21 into a direct current and receives power using this direct current. The power receiving unit 24 converts the radio waves into a direct current using, for example, a known rectifier circuit. The power receiving unit 24 supplies the received power to, for example, a battery or load compatible with Qi (an international standard for wireless power supply). The load includes, for example, mechanical equipment, an IoT (Internet of Things) sensor, electronic equipment, lighting equipment, and the like.

[0060] An example of the functional configuration of the power receiving device 20 according to the present embodiment has been described above. Note that the above configuration described with reference to Fig. 7 is merely an example, and the functional configuration of the power receiving device 20 according to the present embodiment is not limited to this example. The functional configuration of the power receiving device 20 according to the present embodiment can be flexibly modified according to the specifications and operation.

[0061] [Example of control of power transmission device according to embodiment 1] FIG. 8 is a diagram for explaining a control example of the power transmitting device 10. In the following description, the system 1 arranges the power transmitting device 10 and the power receiving device 20 in a room 4000 so as to face each other as shown in FIG. 8. In the room 4000, an object 5000 to be avoided from being irradiated is present at a first position P10, and a reflective object 6000 is present at a second position P20. Note that the power transmitting device 10, the object 5000 to be avoided from being irradiated, and the reflective object 6000 may not be present in the room 4000. The room 4000 may have a window. In the present disclosure, the room 4000 may be a non-moving structure such as a room or a factory, or a part thereof, or a movable structure such as an automobile, a bus, or an airplane, or a part thereof. In the present disclosure, the room 4000 may be a structure such as an office, a living room, a factory, a building, a hospital, a school, an automobile, a bus, or an airplane, or a part thereof. The first position P10 and the second position P20 are positions shifted to the left and right from the straight line connecting the power transmitting device 10 and the power receiving device 20. When the power transmitting device 10 detects the position, direction, etc. of the object 5000 using the detection unit 16, the power transmitting device 10 grasps the relative position between the object 5000 and the array antenna 11. The system 1 wirelessly supplies power to the power receiving device 20 by emitting radio waves 2000W including a transmission signal 2000 from the power transmitting device 10 toward the power receiving device 20 in a retrodirective manner. The power receiving device 20 is a power-receiving device in the system 1 that receives radio waves for power supply to obtain power. The power receiving device 20 includes, for example, a smartphone, a tablet terminal, an IoT (Internet of Things) sensor, a notebook personal computer, a drone, an electric car, an electric bicycle, a game machine, and the like. In this way, the power receiving device of the present disclosure may be a mobile device. The power receiving device 20 of the present disclosure may include a device that is usually used without being moved, such as a base station, a traffic light, or a vending machine.

[0062] In this embodiment, the power transmitting device 10 stores in advance in the storage unit 17D environmental information capable of identifying the relative position and direction of the reflecting object 6000 and the array antenna 11 in the room 4000. The environmental information includes, for example, information on the position, direction, distance from the power transmitting device itself, the reflecting surface (reflection area), and the reflection angle of the reflecting surface from the power transmitting device itself. The power transmitting device 10 determines the presence or absence of the reflecting object 6000 around the power transmitting device itself by referring to the environmental information, but may also determine the reflecting object 6000 based on the detection result of the detection unit 16.

[0063] Fig. 9 is a flowchart showing an example of a processing procedure executed by the power transmitting device 10. The processing procedure shown in Fig. 9 is realized by the control unit 17 executing the control program 171 stored in the storage unit 17D. The processing procedure shown in Fig. 9 is a procedure for dealing with the case where an object 5000 and a reflective object 6000 are present around the power transmitting device 10.

[0064] 8, in the system 1, the power receiving device 20 transmits a prescribed signal 1000. In this case, as shown in FIG. 9, when the power transmitting device 10 receives a radio wave including the prescribed signal 1000 at the array antenna 11, the power transmitting device 10 transmits an array response vector V d For example, the power transmitting device 10 estimates the propagation channel characteristics of the reference signal 1000 included in the received signals received by the multiple antenna elements 11A in the estimation unit 14, and estimates the array response vector V d When the process of step S101 ends, the power transmitting device 10 advances the process to step S102.

[0065] The power transmitting device 10 recognizes the reflective object 6000 (step S102). For example, the power transmitting device 10 checks the presence or absence of the reflective object 6000 in the radio wave propagation environment based on the sensor information from the sensor unit 15 using the detection unit 16, and recognizes the relative position and direction of the reflective object 6000 and the array antenna 11 in the room 4000 based on the environmental information in the storage unit 17D. The power transmitting device 10 may recognize the relative position of the reflective object 6000, the reflective surface 6100, and the like from the sensor information using machine learning. After storing information indicating the recognition result in the storage unit 17D, the power transmitting device 10 advances the process to step S103.

[0066] The power transmitting device 10 recognizes the object 5000 to be avoided from being irradiated (step S103). For example, the power transmitting device 10 recognizes the relative position and direction of the object 5000 different from the power receiving device 20 in the radio wave propagation environment based on the sensor information from the sensor unit 15 using the detection unit 16, and stores information indicating the recognition result in the storage unit 17D. When the process of step S103 ends, the power transmitting device 10 advances the process to step S104.

[0067] The power transmitting device 10 virtually places the object 5000 to be avoided from being irradiated at a position of planar symmetry with respect to the reflecting surface 6100 of the reflecting object 6000 (step S104). For example, as shown in scene C1 of Fig. 8, the power transmitting device 10 sets an symmetry axis 6200 passing through the reflecting surface 6100 of the reflecting object 6000 in the room 4000, and places a virtual object 5000A virtually representing the object 5000 at a position of planar symmetry with the symmetry axis 6200 as a center. When the power transmitting device 10 finishes the process of step S104 shown in Fig. 9, the process proceeds to step S105.

[0068] The power transmitting device 10 determines whether or not to reduce the radio wave intensity to the reflecting object 6000 (step S105). For example, as shown in scene C1 of Fig. 8, when the power transmitting device 10, the reflecting object 6000, and the virtual object 5000A are aligned in a straight line inside the room 4000, the reflected wave 2100W reflected by the reflecting surface 6100 of the reflecting object 6000 heads toward the object 5000. Also, as shown in scene C2 of Fig. 8, when the power transmitting device 10, the reflecting object 6000, and the virtual object 5000A are not aligned in a straight line inside the room 4000, the reflected wave 2100W reflected by the reflecting surface 6100 of the reflecting object 6000 does not head toward the object 5000. When the power transmitting device 10, the reflecting object 6000, and the virtual object 5000A are aligned in a straight line, the power transmitting device 10 determines to reduce the radio wave intensity to the reflecting object 6000.

[0069] The power transmitting device 10 may reduce the radio wave intensity of the transmission wave at the second position P20 of the reflecting object 6000 when the radio wave intensity at the first position P10 of the object 5000 is equal to or greater than a predetermined intensity. In this case, the radio wave intensity may be determined in consideration of the influence of radio waves on the human body. That is, when the radio wave intensity at the first position P10 of the object 5000 is lower than a predetermined intensity, the control unit 17 of the power transmitting device 10 prioritizes the efficiency of power supply to the power receiving device 20 without reducing the radio wave intensity at the second position P20 of the reflecting object 6000. On the other hand, when the radio wave intensity at the first position P10 of the object 5000 is equal to or greater than a predetermined intensity, the control unit 17 of the power transmitting device 10 reduces the radio wave intensity at the second position P20 of the reflecting object 6000 to reduce the influence of the transmission radio wave from the object 5000.

[0070] When the power transmitting device 10 determines to reduce the radio wave intensity to the reflecting object 6000 (Yes in step S105), the process proceeds to step S106. The power transmitting device 10 determines the radio wave intensity of the object 5000 as the first intensity and the radio wave intensity of the reflecting object 6000 as the second intensity (step S106). In this embodiment, the power transmitting device 10 may determine the first intensity and the second intensity so that the gain of a direction, a point, etc. becomes zero, that is, a null is directed in the directivity of the array antenna 11. The power transmitting device 10 may determine the first intensity and the second intensity based on an effect on a human body when the object 5000 is a human body or the like. The power transmitting device 10 may determine the first intensity and the second intensity based on a distance from the power transmitting device 10 to the object 5000 where the transmitted radio wave reaches. When the process of step S106 is completed, the power transmitting device 10 proceeds to step S107. In other words, the control unit 17 of the power transmitting device 10 may transmit a first transmission wave toward the position of the reflecting object 6000, and when the first transmission wave is reflected by the reflecting object 6000 and reaches a first position of an object 5000 other than the power receiving device 20, the control unit 17 may transmit a second transmission wave toward the reflecting object 6000, the second transmission wave having a radio wave intensity lower than that of the first transmission wave.

[0071] The power transmitting device 10 performs array response vectorization and matrix calculation corresponding to the determined radio wave intensity to generate transmission weights (step S107). For example, the power transmitting device 10 performs array response vectorization and matrix calculation corresponding to null in the control unit 17. For example, when the detection unit 16 detects M objects 5000 and reflecting objects 6000 as null targets, the power transmitting device 10 generates transmission weights based on the directions θ1, θ2,...,θ of the multiple objects 5000 and reflecting objects 6000. M In detail, the power transmitting device 10 detects the directions θ1, θ2, . . . , θ of the object 5000 and the reflecting object 6000. M Based on the above (Eq. 21) and (Eq. 22), the array response vectorization (V1, V2, . . . , V M The power transmitting device 10 calculates the array response vector V i = V1, V2, . . . , V M Using (I-AA+ ), and the calculation result is stored in the storage unit 17D. M The power transmitting device 10 calculates the array response vector V d and the matrix (I-AA + ) to obtain the array response vector V d The power transmitting device 10 calculates the calculated array response vector V d ' is normalized using the above (Equation 17) to obtain the optimal weight vector W opt When the process of step S107 ends, the power transmitting device 10 advances the process to step S108.

[0072] The power transmitting device 10 multiplies the transmission weight and emits radio waves of 2000 W (step S108). For example, the power transmitting device 10 multiplies the generated optimal weight vector W opt Based on the weight information indicating the weight information, the power transmitting device 10 multiplies the transmission signal 2000 for power supply from the transmission signal generating unit 12 by the weight for each of the plurality of antenna elements 11A and supplies the result to the transmitting / receiving circuit 13A. In this way, the power transmitting device 10 causes the plurality of antenna elements 11A to radiate radio waves 2000W including the transmission signal 2000 for power supply. For example, as shown in scene C1 of FIG. 8, the power transmitting device 10 directs nulls in a direction D1 of the object 5000 and a direction D2 of the reflecting object 6000, so that the radio waves 2000W are constructively combined in the power receiving device 20, but are destructively combined in the object 5000 and the reflecting object 6000. Returning to FIG. 9, when the process of step S108 is completed, the power transmitting device 10 ends the process procedure shown in FIG. 9.

[0073] Furthermore, when the power transmitting device 10 determines not to reduce the radio wave intensity to the reflective object 6000 (No in step S105), the process proceeds to step S109. The power transmitting device 10 determines the radio wave intensity of the object 5000 to be the first intensity (step S109). That is, the power transmitting device 10 changes only the radio wave intensity of the object 5000, and does not change the radio wave intensity of the reflective object 6000. In this embodiment, the power transmitting device 10 determines the first intensity so that the gain of a direction, point, etc. becomes zero in the directivity of the array antenna 11, that is, so as to point to a null. When the process of step S109 is completed, the power transmitting device 10 proceeds to step S107.

[0074] The power transmitting device 10 generates a transmission weight by performing array response vectorization and matrix calculation corresponding to the determined radio wave intensity (step S107). In this case, the control unit 17 of the power transmitting device 10 determines the directions θ1, θ2, . . . , θ M Based on the above (Eq. 21) and (Eq. 22), the array response vectorization (V1, V2, . . . , V M The power transmitting device 10 calculates the array response vector V i = V1, V2, . . . , V M Using (I-AA + ) and stores the calculation result in the storage unit 17D. d and the matrix (I-AA + ) to obtain the array response vector V d The power transmitting device 10 calculates the calculated array response vector V d ' is normalized using the above (Equation 17) to obtain the optimal weight vector W opt When the process of step S107 ends, the power transmitting device 10 advances the process to step S108.

[0075] The power transmitting device 10 multiplies the transmission weight and emits radio waves of 2000 W (step S108). For example, the power transmitting device 10 multiplies the generated optimal weight vector W optBased on the weight information indicating the weight information, the power transmitting device 10 multiplies the transmission signal 2000 for power supply from the transmission signal generating unit 12 by the weight for each of the plurality of antenna elements 11A and supplies the result to the transmission / reception circuit 13A. As a result, the power transmitting device 10 radiates radio waves 2000W including the transmission signal 2000 for power supply from the plurality of antenna elements 11A. For example, as shown in scene C2 of FIG. 8, the power transmitting device 10 directs a null only in the direction D1 of the object 5000, so that the radio waves 2000W are combined constructively in the power receiving device 20, but are combined destructively in the object 5000. In addition, the radio waves 2000W emitted by the power transmitting device 10 head toward the reflecting object 6000, and the reflected waves 2100W reflected by the reflecting object head toward the power receiving device 20, thereby increasing the amount of power received by the power receiving device 20. Returning to FIG. 9, when the process of step S108 is completed, the power transmitting device 10 ends the process procedure shown in FIG. 9.

[0076] As described above, the power transmitting device 10 can set the radio wave intensity of the radio wave 2000W (transmitted wave) at the first position P10 to a first intensity based on the first position P10 of the object 5000 different from the power receiving device 20 and the second position P20 of the reflecting object 6000 having a reflectance equal to or higher than a predetermined value, and set the radio wave intensity of the radio wave 2000W at the second position P20 to a second intensity that is lower than the case where the radio wave 2000W is reflected by the reflecting object 6000 and does not reach the first position P10. As a result, when the reflected wave 2100W that has passed through the reflecting object 6000 having a high reflectance hits the object 5000 to be avoided from being irradiated, the power transmitting device 10 can suppress the radiation of the radio wave 2000W toward the object 5000 by directing a null toward the reflecting object 6000. As a result, the power transmitting device 10 can suppress the radio waves 2000W directed toward the human body even in an environment where radio waves including the specified signal 1000 from the power receiving device 20 are reflected and reach the human body and where a reflective object 6000 is present, thereby realizing safe wireless power transmission.

[0077] When the radio waves 2000W output from the power transmitting device 10 reach the position of the object 5000 as a result of being reflected by the reflecting object 6000 of the metasurface reflector, the radio waves 2000W can be reflected by the reflecting object 6000 and reach the first position P10. This allows the power transmitting device 10 to estimate the reflection direction from the traveling direction of the radio waves 2000W incident on the reflecting surface 6100 of the reflecting object 6000 and the characteristics of the reflecting object 6000.

[0078] When radio waves 2000W output from the power transmitting device 10 are reflected by the reflecting object 6000 according to the law of reflection and reach the position of the object 5000, the power transmitting device 10 determines that the radio waves 2000W are reflected by the reflecting object 6000 and reach the first position P10. This allows the power transmitting device 10 to grasp the reflection of the radio waves 2000W by the reflecting object 6000 according to the law of reflection, thereby simplifying the processing and preventing the device configuration from becoming complicated.

[0079] Based on the received signal from the power receiving device 20 and information on the object 5000 and the reflecting object 6000, the power transmitting device 10 can control the directivity of the array antenna 11 that transmits the radio waves 2000W so that the radio wave intensity of the radio waves 2000W at the first position P10 of the object 5000 is a first intensity and the electromagnetic intensity of the radio waves 2000W at the second position P20 of the reflecting object 6000 is a second intensity. As a result, even if the power transmitting device 10 receives the specified signal 1000 from the direction of the object 5000, it can direct the radiated radio waves 2000W in the direction of the power receiving device 20, thereby suppressing the radiation of the radio waves 2000W toward the object 5000.

[0080] [Modification of the power transmitting device according to the first embodiment] 10 and 11 are diagrams showing an example of the configuration of the power transmitting device 10 according to a modification of the first embodiment. As shown in FIG. 10, the power transmitting device 10 may have the sensor unit 15 and the detection unit 16 provided in the electronic device 30 outside the power transmitting device 10. In this case, the power transmitting device 10 may be configured to be able to receive data from the electronic device 30 and may acquire a detection result of the object 5000 from the electronic device 30. As shown in FIG. 11, the power transmitting device 10 may have only the sensor unit 15 provided outside the device. In this case, the power transmitting device 10 may be configured to be able to acquire sensor information and the like from the external sensor unit 15 and the detection unit 16 may detect the object 5000 based on the sensor information and the like from the sensor unit 15.

[0081] (Embodiment 2) [Configuration of power transmission device according to embodiment 2] In the second embodiment, similarly to the first embodiment, the system 1 includes a power transmitting device 10 and a power receiving device 20. The power receiving device 20 has the same configuration as the power receiving device 20 in the first embodiment.

[0082] Fig. 12 is a diagram illustrating an example of the configuration of a power transmitting device 10 according to embodiment 2. Fig. 13 is a diagram illustrating an example of vectorization when differential coefficients are constrained.

[0083] As shown in FIG. 12, the power transmitting device 10 includes an array antenna 11, a transmission signal generating unit 12, a transmitting / receiving unit 13, an estimating unit 14, a sensor unit 15, a detecting unit 16, a control unit 17, and a multiplying unit 18.

[0084] The sensor unit 15 can obtain information capable of detecting the presence, direction, area, etc. of the object 5000 and the reflecting object 6000 different from the power receiving device 20 in the radio wave propagation environment of the power transmitting device 10. The radio wave propagation environment includes, for example, a space in which radio waves 2000W are propagated between the power transmitting device 10 and the power receiving device 20. The area of ​​the object 5000 and the reflecting object 6000 includes, for example, information on the area of ​​the object 5000 and the reflecting object 6000 in the radio wave propagation environment and the angular spread of the object 5000 and the reflecting object 6000 from the own device. The sensor unit 15 obtains information on the object 5000 and the reflecting object 6000 present in the radio wave propagation environment using, for example, a camera, a radar such as a millimeter wave radar, a LIDAR, a ToF sensor, an infrared sensor, a human sensor, a depth sensor, etc. The sensor unit 15 may be provided outside the power transmitting device 10. The sensor unit 15 is electrically connected to the detection unit 16, and supplies sensor information capable of detecting the direction, position, area, etc. of the object 5000 and the reflective object 6000 in the radio wave propagation environment to the detection unit 16. The sensor information includes, for example, information on the presence / absence, distance, position, image, etc. of the object 5000 and the reflective object 6000.

[0085] The detection unit 16 detects information on the presence, position, direction, and area of ​​the object 5000 and the reflecting object 6000 different from the power receiving device 20 in the radio wave propagation environment based on the sensor information from the sensor unit 15. When multiple objects 5000 and reflecting objects 6000 exist, the detection unit 16 detects the positions, directions, and areas of the multiple objects 5000 and the reflecting objects 6000. For example, the detection unit 16 executes a publicly known object recognition process on an image indicated by the sensor information, extracts the object 5000 and the reflecting object 6000 from the sensor information, detects the position, direction, area, etc. of the object 5000 and the reflecting object 6000, and detects the direction, area, etc. of the object 5000 and the reflecting object 6000 from the array antenna 11. For example, the detection unit 16 detects the direction, area, position, etc. of the object 5000 and the reflecting object 6000 from the array antenna 11 based on the direction, position, area, etc. of the object 5000 and the reflecting object 6000 indicated by the sensor information and the relative positional relationship between the sensor unit 15 and the array antenna 11. The detection unit 16 is electrically connected to the control unit 17 and supplies the control unit 17 with position information indicating the relative positions of the object 5000 and the reflecting object 6000 from the array antenna 11 and directional information capable of identifying the direction, area, etc. The detection unit 16 of the present disclosure may detect information regarding the position and direction of the object 5000 and the reflecting object 6000 different from the power receiving device 20 in the radio wave propagation environment based on sensor information from the sensor unit 15 including position information, directional information, distance information, etc. of the object 5000 and the reflecting object 6000.

[0086] The directional information includes, for example, information indicating the direction, area, etc. of the object 5000 and the reflecting object 6000 from the array antenna 11. The directional information includes, for example, identifiable information such as the area including the object 5000 and the reflecting object 6000, the size, etc. The directional information can be information that can identify the size of the object 5000 and the reflecting object 6000 set according to the arrangement of the multiple antenna elements 11A. For example, when the multiple antenna elements 11A are arranged in a matrix, the area 151 of the object 5000 can set the length and width, the position, the shape of the object 5000, etc. For example, when the multiple antenna elements 11A are arranged in one direction, the size 152 of the object 5000 can set the length and distance in one direction such as width and height, the angle range from the own aircraft, etc. The area 151 of the object 5000 may be a spatial area according to the outer shape, etc. of the object 5000. The area and size of the reflecting object 6000 can be set in the same way as the object 5000.

[0087] The control unit 17 has a function of generating weights for power transmission based on the array response vector for the power receiving device 20, which is the estimation result of the estimation unit 14, and directional information of the object 5000 and the reflecting object 6000 from the detection unit 16. For example, a ZF (Zero-Forcing) algorithm or an MMSE (Minimum Mean Square Error) algorithm used in MIMO can be used to generate the weights. The control unit 17 is electrically connected to the multiplication unit 18, and supplies weight information indicating the weights for power transmission to the multiplication unit 18. In the following description, for the sake of simplicity, a case will be described in which a plurality of antenna elements 11A of the array antenna 11 are arranged at equal intervals in the horizontal direction.

[0088] The control unit 17 widens the null. The object 5000 and the reflecting object 6000 that are the null targets have a spread, and it is desirable to widen the null in accordance with the areas of the object 5000 and the reflecting object 6000. A number of methods can be used to widen the null. For example, the multiple null constraints method, the derivative constraints method, and the like can be used to widen the null.

[0089] The multi-point null constraint method is a method for widening the null angle by forming nulls in multiple directions in the vicinity of the null target, rather than in one direction, according to the size of the null target. For example, the array response vector V i is the orientation of the null object, θ i The calculation is performed using (Equation 21) and (Equation 22) from the above, but a wide angle is achieved by giving multiple directions near the null as the directions of the null target according to the size of the null target.

[0090] The differential coefficient constraint method is a method that uses the continuity of the array response value in the θ direction to flatten the differential coefficients. Details of the differential coefficient constraint method are explained below. By substituting (Equation 19) and (Equation 20) into (Equation 11) and (Equation 12) above, the array response value of the K-element equally spaced linear array in the θ direction can be obtained by (Equation 223).

number

[0091] W H Let V = D(θ). D(θ) is called the array response function or array factor. D(θ) is a continuous function of θ and can be differentiated with respect to θ. Also, a graph of this absolute value |D(θ)| will show the directional pattern of the array antenna.

[0092] In (Eq. 223), θ = θ i (i=1, ,M) is substituted into D(θ i ) is θ i is the array response value in the direction. Also, since (Eq. 223) is differentiable, θ = θi θ=θ i +Δθ array response value D(θ i +Δθ) is L i Using the next approximation formula, this can be expressed as (Equation 224) below.

number

[0093] In (Eq. 224), the derivative D (l) (θ i )(l=1,...,L i ) is zero, then D(θ i +Δθ) ≒ D(θ i ) and θ i Neighborhood θ i +Δθ can make the array response values ​​similar. This is called null (D(θ i )=0) is the broadening of the null by the derivative constraint, and the order of the approximation formula is L i In this disclosure, the (l) on the right side of each character indicates the order of differentiation.

[0094] Derivative constraint D (l) (θ i )=0(l=1, ,L i ) is equivalent to the following (Equation 225).

number

[0095] So, the diagonal matrix Q l If we express it as (Equation 226) below, (Equation 225) can be expressed as (Equation 227) below. Note that (Equation 226) and (Equation 227) are for l=1, ,L i It is. Q l =diag[0 l 1 l (K-1) l ]...(Formula 226) W H (Q l V i )=0...(Formula 227)

[0096] Combining the following (Equation 228) and (Equation 229) into one, the constraint condition of the l-th order differential coefficient is given by the following (Equation 230). Note that (Equation 229) holds for l = 1, ···, L i where l = 0, ···, L in (Equation 230). i V i (l) is different from the array response vector, but can be treated in the same way as the constraint condition of (Equation 215) from (Equation 230). Therefore, in the present disclosure, V in (Equation 230) i (l) is referred to as the constraint vector. V i (0) = V i ···(Equation 228) V i (l) = Q l V i ···(Equation 229) W H V i (l) = 0 ···(Equation 230)

[0097] Under the constraint condition of (Equation 230), the optimization problem of maximizing the magnitude |W d V H V d | of the array response value of the array response vector V can be formulated as the following (Equation 231).

Equation

[0098] Here, K is the number of antenna elements 11A, and M is the number of nulls. The number of nulls is the number of the object 5000 and the reflected object 6000 detected by the detection unit 16. L1, L2, ···, L M are numbers that determine the degree of angular broadening of each null, which is referred to as the wide angle in the present disclosure. The wide angle is determined according to the regions of the object 5000 and the reflected object 6000 detected by the detection unit 16, and the constraint vector is added by the wide angle. Since the degree of freedom is K - 1, M + L1 + L2 + ··· + L M < K is set. Also, the array response vector Vi (l) (l=0, ,K-1) are linearly independent.

[0099] As can be seen from the comparison of the above (Formula 15) and (Formula 231), it is possible to widen the null angle while following the algorithm of the linearly constrained retrodirective method. In this disclosure, this is called the differential coefficient constrained retrodirective method.

[0100] The control unit 17 generates transmission weights so that nulls are directed toward the directions and areas of the object 5000 and the reflecting object 6000 based on the propagation channel characteristics of the prescribed signal 1000 and the detection results of the directions and areas of the object 5000 and the reflecting object 6000 detected by the detection unit 16. In order to generate the transmission weights, for example, the control unit 17 i Determine.

[0101] For example, the control unit 17 may i Using the above (Eq. 21) and (Eq. 22), the array response vector V i For example, the control unit 17 calculates the direction θ of the null target as shown in FIG. i and the region δ i The information shown in Table 170 is applied to the wide-angle L i Find the area δ i contains information about the area, size, etc. of the object 5000 and the reflecting object 6000. i is a wide-angle parameter, and the area δ of the object 5000 and the reflecting object 6000 i Not only the direction θ i Since the direction θ also depends on the direction θ, the direction θ may be calculated using the table 170 or may be calculated using machine learning or the like. In this embodiment, the table 170 is stored in the storage unit 17D. i and the region δ i From wide angle L i This is a lookup table that derives the

[0102] The control unit 17 determines the wide angle L i and the array response vector V iTherefore, by vectorizing using the above (equation 226), (equation 228), and (equation 229), the constraint vector V i (l) (l=0,...,L i The control unit 17 calculates the constraint vector V i (l) Using the above, the magnitude of the array response value |W H V d The optimal weight vector W that maximizes | opt is determined by the above-mentioned (Equation 231). i can be set for each null target. The power transmitting device 10 can calculate the matrix calculated from the direction and region to which the null is directed and the propagation channel characteristics of the prescribed signal 1000 independently.

[0103] An example of the functional configuration of the power transmitting device 10 according to the second embodiment has been described above. Note that the above configuration described with reference to Fig. 12 is merely an example, and the functional configuration of the power transmitting device 10 according to the present embodiment is not limited to this example. The functional configuration of the power transmitting device 10 according to the present embodiment can be flexibly modified according to the specifications and operation.

[0104] [Example of control of power transmission device according to embodiment 2] A control example of the power transmitting device according to the second embodiment will be described with reference to Figs. 8 and 9 described above. As shown in Fig. 8, the system 1 arranges the power transmitting device 10 and the power receiving device 20 in a room 4000 so as to face each other. In the room 4000, an object 5000 to be avoided from being irradiated is present at a first position P10, and a reflective object 6000 is present at a second position P20. The first position P10 and the second position P20 are positions shifted to the left and right from a straight line connecting the power transmitting device 10 and the power receiving device 20. When the power transmitting device 10 detects the position, direction, area, etc. of the object 5000 using the detection unit 16, the power transmitting device 10 grasps the relative position between the object 5000 and the array antenna 11. The system 1 wirelessly supplies power to the power receiving device 20 by emitting radio waves 2000W including a transmission signal 2000 from the power transmitting device 10 toward the power receiving device 20 in a retrodirective manner.

[0105] 8, in the system 1, the power receiving device 20 transmits a prescribed signal 1000. In this case, as shown in FIG. 9, when the power transmitting device 10 receives a radio wave including the prescribed signal 1000 at the array antenna 11, the power transmitting device 10 transmits an array response vector V d For example, the power transmitting device 10 estimates the propagation channel characteristics of the reference signal 1000 included in the received signals received by the multiple antenna elements 11A in the estimation unit 14, and estimates the array response vector V d When the process of step S101 ends, the power transmitting device 10 advances the process to step S102.

[0106] The power transmitting device 10 recognizes the reflective object 6000 (step S102). For example, the power transmitting device 10 checks the presence or absence of a reflective object 6000 in the radio wave propagation environment based on the sensor information from the sensor unit 15 using the detection unit 16, and detects the relative direction, position, and area of ​​the reflective object 6000 and the array antenna 11 in the room 4000 based on the environmental information in the storage unit 17D. The power transmitting device 10 may recognize the relative position, reflective surface 6100, area, and the like of the reflective object 6000 from the sensor information using machine learning. For example, when the detection unit 16 detects M reflecting objects 6000, the power transmitting device 10 detects the directions θ1, θ2,..., θ of the multiple reflecting objects 6000. M Then, the power transmitting device 10 detects the regions δ1, δ2, . . . , δ of the multiple reflecting objects 6000. M The power transmitting device 10 detects the directions θ1, θ2, . . . , θ of the detected reflecting object 6000. M and areas δ1,δ2,...,δ M The power transmitting device 10 stores the information indicating the recognition result in the storage unit 17D. After storing the information indicating the recognition result in the storage unit 17D, the power transmitting device 10 advances the process to step S103.

[0107] The power transmitting device 10 recognizes the object 5000 to be avoided from being irradiated (step S103). For example, the power transmitting device 10 recognizes the relative position, direction, and area of ​​the object 5000 different from the power receiving device 20 in the radio wave propagation environment based on the sensor information from the sensor unit 15 using the detection unit 16, and stores information indicating the recognition result in the storage unit 17D. For example, when the detection unit 16 detects M objects 5000 as null targets, the power transmitting device 10 stores information indicating the directions θ1, θ2, . . . , θ of the multiple objects 5000. M Then, the power transmitting device 10 detects the regions δ1, δ2, . . . , δ of the plurality of objects 5000. M The power transmitting device 10 detects the directions θ1, θ2, . . . , θ M and areas δ1,δ2,...,δ M The power transmitting device 10 stores the result in the storage unit 17D. When the process of step S103 ends, the power transmitting device 10 advances the process to step S104.

[0108] The power transmitting device 10 virtually places the object 5000 to be avoided from being irradiated at a position of planar symmetry with respect to the reflecting surface 6100 of the reflecting object 6000 (step S104). For example, as shown in scene C1 of Fig. 8, the power transmitting device 10 sets an symmetry axis 6200 passing through the reflecting surface 6100 of the reflecting object 6000 in the room 4000, and places a virtual object 5000A virtually representing the object 5000 at a position of planar symmetry with the symmetry axis 6200 as a center. When the power transmitting device 10 finishes the process of step S104 shown in Fig. 9, the process proceeds to step S105.

[0109] The power transmitting device 10 determines whether or not to reduce the radio wave intensity to the reflecting object 6000 (step S105). When the power transmitting device 10 determines to reduce the radio wave intensity to the reflecting object 6000 (Yes in step S105), the process proceeds to step S106. The power transmitting device 10 determines the radio wave intensity of the object 5000 to be a first intensity and the radio wave intensity of the reflecting object 6000 to be a second intensity (step S106). In this embodiment, the power transmitting device 10 determines the first intensity and the second intensity so that the gain of a direction, point, etc. becomes zero in the directivity of the array antenna 11, that is, so as to point to a null. When the process of step S106 is completed, the power transmitting device 10 proceeds to step S107.

[0110] The power transmitting device 10 performs array response vectorization and matrix calculation corresponding to the determined radio wave intensity to generate transmission weights (step S107). For example, the power transmitting device 10 performs array response vectorization and matrix calculation corresponding to null in the control unit 17. For example, when the detection unit 16 detects M objects 5000 and reflecting objects 6000 as null targets, the power transmitting device 10 generates transmission weights based on the directions θ1, θ2,...,θ of the multiple objects 5000 and reflecting objects 6000. M In detail, the power transmitting device 10 detects a direction θ i and the region δ i The information shown in Table 170 is applied to the wide-angle L i Search for wide angle L i and the array response vector V i Therefore, by vectorizing using the above (equation 226), (equation 228), and (equation 229), the constraint vector V corresponding to the null is obtained. i (l) (l=0,...,L i Then, the power transmitting device 10 obtains a constraint vector V i (l) Using (I-AA + ) matrix operation, and the operation result is stored in the storage unit 17D. (0) ,···,V1 (L1) ,V2 (0) ,···,V2 (L2) ,···,V M (0) ,···,VM (LM) In the power transmitting device 10, the control unit 17 calculates the array response vector V d and (I-AA + ) to obtain the array response vector V d Then, the power transmitting device 10 calculates the calculated array response vector V d ' is normalized using (Equation 17) to obtain the optimal weight vector W opt When the process of step S107 ends, the power transmitting device 10 advances the process to step S108.

[0111] The power transmitting device 10 multiplies the transmission weight and emits radio waves of 2000 W (step S108). For example, the power transmitting device 10 multiplies the generated optimal weight vector W opt Based on the weight information indicating the weight information, the power transmitting device 10 multiplies the transmission signal 2000 for power supply from the transmission signal generating unit 12 by the weight for each of the plurality of antenna elements 11A and supplies the result to the transmitting / receiving circuit 13A. In this way, the power transmitting device 10 causes the plurality of antenna elements 11A to radiate radio waves 2000W including the transmission signal 2000 for power supply. For example, as shown in scene C1 of FIG. 8, the power transmitting device 10 directs nulls in a direction D1 of the object 5000 and a direction D2 of the reflecting object 6000, so that the radio waves 2000W are constructively combined in the power receiving device 20, but are destructively combined in the object 5000 and the reflecting object 6000. Returning to FIG. 9, when the process of step S108 is completed, the power transmitting device 10 ends the process procedure shown in FIG. 9.

[0112] Furthermore, when the power transmitting device 10 determines not to reduce the radio wave intensity to the reflective object 6000 (No in step S105), the process proceeds to step S109. The power transmitting device 10 determines the radio wave intensity of the object 5000 to be the first intensity (step S109). That is, the power transmitting device 10 changes only the radio wave intensity of the object 5000, and does not change the radio wave intensity of the reflective object 6000. In this embodiment, the power transmitting device 10 determines the first intensity so that the gain of a direction, point, etc. becomes zero in the directivity of the array antenna 11, that is, so as to point to a null. When the process of step S109 is completed, the power transmitting device 10 proceeds to step S107.

[0113] The power transmitting device 10 generates a transmission weight by performing array response vectorization and matrix calculation corresponding to the determined radio wave intensity (step S107). M In detail, the power transmitting device 10 detects a direction θ i and the region δ i The information shown in Table 170 is applied to the wide-angle L i Search for wide angle L i and the array response vector V i Therefore, by vectorizing using the above (equation 226), (equation 228), and (equation 229), the constraint vector V corresponding to the null is obtained. i (l) (l=0,...,L i Then, the power transmitting device 10 obtains a constraint vector V i (l) Using (I-AA + ) matrix operation, and the operation result is stored in the storage unit 17D. (0) ,···,V1 (L1) ,V2 (0) ,···,V2 (L2) ,···,V M (0) ,···,V M (LM) In the power transmitting device 10, the control unit 17 calculates the array response vector V d and (I-AA +) to obtain the array response vector V d Then, the power transmitting device 10 calculates the calculated array response vector V d ' is normalized using (Equation 217) to obtain the optimal weight vector W opt When the process of step S107 ends, the power transmitting device 10 advances the process to step S108.

[0114] The power transmitting device 10 multiplies the transmission weight and emits radio waves of 2000 W (step S108). For example, the power transmitting device 10 multiplies the generated optimal weight vector W opt Based on the weight information indicating the weight information, the power transmitting device 10 multiplies the transmission signal 2000 for power supply from the transmission signal generating unit 12 by the weight for each of the plurality of antenna elements 11A and supplies the result to the transmission / reception circuit 13A. As a result, the power transmitting device 10 radiates radio waves 2000W including the transmission signal 2000 for power supply from the plurality of antenna elements 11A. For example, as shown in scene C2 of FIG. 8, the power transmitting device 10 directs a null only in the direction D1 of the object 5000, so that the radio waves 2000W are combined constructively in the power receiving device 20, but are combined destructively in the object 5000. In addition, the radio waves 2000W emitted by the power transmitting device 10 head toward the reflecting object 6000, and the reflected waves 2100W reflected by the reflecting object head toward the power receiving device 20, thereby increasing the amount of power received by the power receiving device 20. Returning to FIG. 9, when the process of step S108 is completed, the power transmitting device 10 ends the process procedure shown in FIG. 9.

[0115] As described above, the power transmitting device 10 can set the radio wave intensity of the radio wave 2000W (transmitted wave) at the first position P10 to a first intensity based on the first position P10 of the object 5000 different from the power receiving device 20 and the second position P20 of the reflecting object 6000 having a reflectance equal to or higher than a predetermined value, and set the radio wave intensity of the radio wave 2000W at the second position P20 to a second intensity that is lower than the case where the radio wave 2000W is reflected by the reflecting object 6000 and does not reach the first position P10. As a result, when the reflected wave 2100W that has passed through the reflecting object 6000 having a high reflectance hits the object 5000 to be avoided from being irradiated, the power transmitting device 10 can suppress the radiation of the radio wave 2000W toward the object 5000 by directing a null toward the reflecting object 6000. As a result, the power transmitting device 10 can suppress the radio waves 2000W directed toward the human body even in an environment where radio waves including the specified signal 1000 from the power receiving device 20 are reflected and reach the human body and where a reflective object 6000 is present, thereby realizing safe wireless power transmission.

[0116] Based on the received signal from the power receiving device 20 and the size of the area 151 in which the object 5000 exists, the power transmitting device 10 can control the directivity of the array antenna 11 that transmits the radio waves 2000W so that the radio wave intensity of the radio waves 2000W at the first position P10 of the object 5000 is a first intensity and the electromagnetic intensity of the radio waves 2000W at the second position P20 is a second intensity. As a result, even if the power transmitting device 10 receives the specified signal 1000 from the direction of the object 5000, it can direct the radiated radio waves 2000W toward the power receiving device 20, and can suppress the radiation of the radio waves 2000W toward the object 5000 and the reflecting object 6000 by forming a wide-angle null in the area of ​​the object 5000 and the reflecting object 6000.

[0117] Even if a plurality of objects 5000 are present in the propagation environment, the power transmitting device 10 detects the directions and regions of the plurality of objects 5000 and calculates a weight vector W so as to direct a null to each of the plurality of objects 5000. opt can be generated.

[0118] The power transmitting device 10 may limit the direction and area of ​​the object 5000 and the reflecting object 6000 under specific conditions. For example, if the object 5000 is a human, the detection unit 16 may limit the direction and area relative to the human to the head by publicly known object recognition processing for the image indicated by the sensor information. For example, in the case of the reflecting object 6000, the detection unit 16 may limit the direction and area relative to the reflecting surface 6100 by publicly known object recognition processing for the image indicated by the sensor information.

[0119] (Embodiment 3) [Configuration of power transmission device according to embodiment 3] In the third embodiment, similarly to the first embodiment, the system 1 includes a power transmitting device 10 and a power receiving device 20. The power receiving device 20 has the same configuration as the power receiving device 20 in the first embodiment.

[0120] Fig. 14 is a diagram illustrating an example of a configuration of a power transmitting device 10 according to embodiment 3. As illustrated in Fig. 14, the power transmitting device 10 includes an array antenna 11, a transmission signal generating unit 12, a transmitting / receiving unit 13, an estimating unit 14, a sensor unit 15, a detecting unit 16, a control unit 17, a multiplying unit 18, and a preprocessing unit 19.

[0121] The sensor unit 15 can obtain information capable of detecting the presence, position, area, distance (depth), etc. of the object 5000 and the reflecting object 6000 different from the power receiving device 20 in the radio wave propagation environment of the power transmitting device 10. The radio wave propagation environment includes, for example, a space in which radio waves 2000W are propagated between the power transmitting device 10 and the power receiving device 20. The area of ​​the object 5000 and the reflecting object 6000 includes, for example, information on the area of ​​the object 5000 and the reflecting object 6000 in the radio wave propagation environment, the angle, angle spread, and distance of the object 5000 and the reflecting object 6000 from the own device. The sensor unit 15 obtains information on the object 5000 present in the radio wave propagation environment using, for example, a camera, a radar such as a LIDAR or a millimeter wave radar, a ToF sensor, an infrared sensor, a human sensor, a depth sensor, etc. The sensor unit 15 may be provided outside the power transmitting device 10. The sensor unit 15 is electrically connected to the detection unit 16, and supplies the detection unit 16 with sensor information capable of detecting at least the direction and distance of the object 5000 and the reflecting object 6000 in the radio wave propagation environment. The sensor information includes, for example, information on the presence / absence, distance, position, image, etc. of the object 5000 and the reflecting object 6000. In this manner, the detection unit 16 of the present disclosure detects information on the positions of the object 5000 and the reflecting object 6000 different from the power receiving device 20 in the radio wave propagation environment based on the sensor information from the sensor unit 15 including position information such as GPS information of the object 5000, direction information, distance information, etc.

[0122] The detection unit 16 detects information on the presence / absence, position, direction, area, and distance of an object 5000 and a reflecting object 6000 different from the power receiving device 20 in a radio wave propagation environment based on the sensor information from the sensor unit 15. When a plurality of objects 5000 and reflecting objects 6000 exist, the detection unit 16 detects the positions, directions, areas, distances, etc. of the plurality of objects 5000 and reflecting objects 6000. For example, the detection unit 16 executes a publicly known object recognition process on an image indicated by the sensor information, extracts the object 5000 and the reflecting object 6000 from the sensor information, and detects the presence / absence, shape, area in which the object exists in the radio wave propagation environment, and the direction and distance of the object 5000 and the reflecting object 6000 from the array antenna 11. For example, the detection unit 16 detects the direction, area, position, distance, etc. of the object 5000 and the reflecting object 6000 from the array antenna 11 based on the direction, position, area, distance, etc. of the object 5000 and the reflecting object 6000 indicated by the sensor information and the relative positional relationship between the sensor unit 15 and the array antenna 11. The detection unit 16 is electrically connected to the pre-processing unit 19 and supplies the pre-processing unit 19 with position information indicating the relative positions of the object 5000 and the reflecting object 6000 from the array antenna 11 and directional information capable of identifying the relative direction, area, distance, etc. The detection unit 16 of the present disclosure may detect information regarding the position, direction, and distance of the object 5000 and the reflecting object 6000 different from the power receiving device 20 in the radio wave propagation environment based on sensor information from the sensor unit 15 including position information, directional information, distance information, etc. of the object 5000 and the reflecting object 6000 such as GPS information.

[0123] The directional information includes, for example, information indicating the direction, area, distance, etc. of the object 5000 and the reflecting object 6000 from the array antenna 11. The directional information includes, for example, identifiable information such as the area 151 including the object 5000, the size 152, the distance 153, etc., and the area including the reflecting object 6000 or the reflecting surface 6100, the size, the distance, etc. The directional information can be information that can identify the size of the object 5000 and the reflecting object 6000 set according to the arrangement of the multiple antenna elements 11A. For example, when the multiple antenna elements 11A are arranged in a matrix, the area 151 of the object 5000 can set the length and width, the position, the shape of the object 5000, etc. For example, when the multiple antenna elements 11A are arranged in one direction, the size 152 of the object 5000 can set the length and distance in one direction such as width and height, the angle range from the aircraft, etc. The distance 153 of the object 5000 can be set as the shortest, longest, average, or other distance, depth, etc. from the sensor unit 15 to the object 5000. The area 151 of the object 5000 may be a spatial area according to the outer shape, etc. of the object 5000. The area and size of the reflective object 6000 can be set in the same way as the object 5000.

[0124] The pre-processing unit 19 performs a process of vectorization and generating the magnitude of the null depth as identifiable information based on the direction information from the detection unit 16. When widening the null angle according to the size of the object 5000 and the reflecting object 6000, the pre-processing unit 19 can perform vectorization using, for example, at least one of a multi-point null constraint method and a differential coefficient constraint method. The processing of the pre-processing unit 19 will be described later. The pre-processing unit 19 performs pre-processing related to the generation of weights and supplies the processing result to the control unit 17.

[0125] The control unit 17 generates weights for power transmission from the results of calculation in the preprocessing unit 19 based on the array response vector for the power receiving device 20, which is the estimation result of the estimation unit 14, and the direction information of the detection unit 16. For example, a ZF (Zero-Forcing) algorithm or an MMSE (Minimum Mean Square Error) algorithm used in MIMO can be used as a method for generating the weights. The control unit 17 is electrically connected to the multiplication unit 18, and supplies weight information indicating the weights for power transmission to the multiplication unit 18. In the following description, for the sake of simplicity, a case will be described in which a plurality of antenna elements 11A of the array antenna 11 are arranged at equal intervals in the horizontal direction.

[0126] The control unit 17 widens the null. The object 5000 and the reflecting object 6000 that are the null targets have a spread, and it is desirable to widen the null in accordance with the areas of the object 5000 and the reflecting object 6000. A number of methods can be used to widen the null. For example, the multiple null constraints method, the derivative constraints method, and the like can be used to widen the null.

[0127] The multi-point null constraint method is a method for widening the null angle by forming nulls in multiple directions in the vicinity of the null target, rather than in one direction, according to the size of the null target. For example, the array response vector V i is the orientation of the null object, θ i The calculation is performed using (Equation 21) and (Equation 22) from the above, but a wide angle is achieved by giving multiple directions near the null as the directions of the null target according to the size of the null target.

[0128] The differential coefficient constraint method is a method for smoothing the differential coefficients by using the continuity of the array response value in the θ direction. The differential coefficient constraint method will be described in detail below.

[0129] The array response value of an equally spaced linear array of K antenna elements 11A in the θ direction for an array response vector V(θ) is a function of θ, and is represented as D(θ). By substituting (Equation 19) and (Equation 20) into (Equation 11) and (Equation 12) above, D(θ) is given by the following (Equation 323).

number

[0130] D(θ) is called the array response function or array factor. D(θ) is a continuous function of θ and can be differentiated with respect to θ. The absolute value |D(θ)| shown in a graph represents the directional pattern of the array antenna.

[0131] In (Eq. 323), θ = θ i (i=1, ,M) is substituted into D(θ i ) is θ i is the array response value in the direction. Also, since (Eq. 323) is differentiable, θ = θ i θ=θ i +Δθ array response value D(θ i +Δθ) is L i Using the next approximation formula, this can be expressed as (Equation 324) below.

number

[0132] In (Equation 324), the derivative D (l) (θ i )(l=1,...,L i ) is zero, then D(θ i +Δθ) ≒ D(θ i ) and θ i Neighborhood θ i +Δθ can make the array response values ​​similar. This is called null (D(θ i )=0) is the broadening of the null by the derivative constraint, and the order of the approximation formula is L i In this disclosure, the degree of widening can be controlled by L i is referred to as the wide angle. In this disclosure, the derivative D(l) (θ i The (l) on the right side of the square indicates the order of differentiation.

[0133] The null direction is θ i (i=1, ,M), the order of the approximation is L i Then, the differential coefficient constraint condition is expressed as follows (Equation 325). However, (Equation 325) is for l=1, ,L i In addition, V i (l) The (l) on the right hand side is not the order of differentiation, but merely an index. D (l) (θ i )=W H V (l) (θ i )=0...(Formula 325)

[0134] (Equation 325) is equivalent to the following (Equation 326). However, (Equation 326) is for l=1, ,L i Here, Q l is a diagonal matrix and is given by the following (Equation 327). Note that the conversion of the differential coefficient constraint condition will be described later. W H (Q l V i )=W H (Q l V(θ i ))=0 ···(Formula 326) Q l =diag[0 l 1 l (K-1) l ]...(Formula 327)

[0135] Therefore, the array response vector V i As V i (l) =Q l V i By adding the following, the null can be made wider by the differential coefficient constraint. Here, l=1, ,L i It is. i (l) is not actually an array response vector, but V in (Eq. 15) in this case.i It is inappropriate to call V in (Equation 15) an array response vector. Therefore, in the following, we will use V in (Equation 15) as a vector that gives the constraint condition. i is sometimes called the constraint vector.

[0136] As described above, in order to widen the angle of the null, the number of constraint vectors must be increased. This makes the constraints on the weight vector W stricter, and the array response value |W H V d On the other hand, when the distance between the power transmitting device 10 and the object 5000 and the reflecting object 6000 is large, it is not necessary to form a deep null, and it is expected that the power supply to the power receiving device 20 can be improved by controlling the null depth. An example of a method for controlling the null depth will be described below.

[0137] The optimization problem in which some of the constraints of the above-mentioned (Equation 15) are changed can be formulated as the following conditional equation (Equation 328). In detail, (Equation 328) is the W H V i = 0, |W H V i | 2 =|ε i | 2 has been changed to.

number

[0138] Here, K is the number of antenna elements 11A, and M is the number of nulls. The number of nulls M includes a number according to the area of ​​the object 5000 detected by the detection unit 16 and the reflecting object 6000.

[0139] The optimal weight vector W in (Eq. 328) opt is given by the following (Equation 329) using the above (Equation 16).

number

[0140] Here, V'd =(I-AA + )V d , V ε =(A + ) H ε. A is a set of M complex sequence constraint vectors V1, V2, . . . , V M A is a matrix of + is the generalized Moore-Penrose inverse of A. Also, ε=[ε1ε2 ε M ] T and ε i Absolute value of |ε i | is given by (Equation 328). In this disclosure, (·) T When a letter has a superscript "T" like this, it means transposition. i The argument of the vector (A + V d ) to obtain the array response value |W H V d | can be maximized. Note that α in (Equation 329) is given by the following (Equation 330).

number

[0141] The weight vector W and the constraint vector V are calculated by (Eq. 329) and (Eq. 330). i The magnitude of the dot product of |W H V i | to |ε i |, but compared to the above (Equation 16) and (Equation 17), V ε This becomes more complicated because it requires the calculation of α.

[0142] The above-mentioned (Equation 328) can be simplified by making it into an approximate solution. An example of how to find the approximate solution will be described below.

[0143] The square of the norm of the weight vector W is 1 (||W||=1), and ||V d Since || is known, |W H V d Maximizing | is |W H V d| / (||W||·||V d This is equivalent to making W / ||W||≒V d / ||V d That is, W ≒ γV d γ is a proportionality constant. H V i | 2 =|ε i | 2 W H V i ≒ 0. As a result, the optimization problem of (Equation 328) can be approximately thought of as the following conditional equation (Equation 331). In (Equation 331), ≒ means that the value on the left side and the value on the right side should be as close as possible.

number

[0144] The optimal weight vector W in (Eq. 331) opt When the following (Equation 332) is defined, it is given by the following (Equation 333). Note that the null depth control using an approximate solution will be described later.

number

number

[0145] where A' is a set of M complex column vectors α1V1,α2V2,...,α M V M The matrix A'=[α1V1α2V2··· α M V M α i (i=1, ,M) is V i The weighting coefficient for the absolute value |ε i α instead of | iBy using the above, the null depth can be controlled. In this way, the algorithm for controlling the null depth may be obtained from an exact solution or may use an approximate solution. In addition, the algorithm for controlling the null depth can be used to widen the null angle whether it is obtained from an exact solution or using an approximate solution.

[0146] The control unit 17 generates a transmission weight so that the null is directed toward the area of ​​the object 5000 and the reflecting object 6000, based on the propagation channel characteristics of the prescribed signal 1000 and the results of calculations performed in the pre-processing unit 19 based on directional information that can identify the direction, area, and distance of the object 5000 and the reflecting object 6000 detected by the detection unit 16. When directing the null toward the area, the constraint vector V i is V i (l) (l=0,...,L i )

[0147] 15 is a diagram showing an example of vectorization in the multi-point null constraint method. When the multi-point null constraint method is used, the pre-processing unit 19 calculates a direction θ i and the region δ i Using (Eq. 321) and (Eq. 322), the array response vector V i (l) (l=0,...,L i In detail, the pre-processing unit 19 calculates the direction θ of the object 5000 and the reflecting object 6000. i and the region δ i to the minimum value θ in that direction min i and the maximum value θ max i The control unit 17 determines θ min From θ max Covering direction θ (0) i , ,θ (Li) i The step size is determined by the direction θ of the object 5000 and the reflecting object 6000. i The angle θ of the object 5000 and the reflecting object 6000 may be constant regardless of the angle θ of the object 5000 and the reflecting object 6000. i The pre-processing unit 19 may change the direction θ (0)i , ,θ (Li) i Using (Eq. 321) and (Eq. 322), the constraint vector V i (l) (l=0,...,L i In this disclosure, the order of the approximation formula L i is called the wide angle as a measure of the degree of widening, but the above L i Also sometimes called wide angle.

[0148] 16 is a diagram showing an example of vectorization in the differential coefficient constraint method. When the differential coefficient constraint method is used, the pre-processing unit 19 calculates a vector in a direction θ i and the region δ i Using (Eq. 321) and (Eq. 322), etc., we obtain the array response vector V i (l) (l=0,...,L i In detail, the pre-processing unit 19 calculates the direction θ i and the area δ of the object 5000 and the reflecting object 6000 i From wide angle L i Find the wide angle L i is the area δ i Not only the direction θ i Therefore, the preprocessing unit 19 determines the wide angle L i By using tables and machine learning to derive the wide-angle L i Request.

[0149] In the example shown in FIG. 16, the pre-processing unit 19 detects a direction θ i and the region δ i The information shown in Table 170 is applied to the wide-angle L i Find the area δ i For example, the table 170 includes information on the area, distance, etc. of the object 5000 and the reflecting object 6000. i and the region δ i From wide angle L i The preprocessing unit 19 calculates the wide angle L iand the array response vector V i Therefore, by vectorizing using the above (Equation 325), (Equation 326), and (Equation 327), the constraint vector V i (l) (l=0,...,L i ) where V i (0) =V i Let us assume that.

[0150] FIG. 17 is a diagram showing an example of processing of the null depth by the pre-processing unit 19. The example shown in FIG. 17 shows a processing example in which the pre-processing unit 19 uses the above-mentioned (Equation 328). As shown in FIG. 17, the pre-processing unit 19 can perform processing regarding the magnitude of the null depth. In the case of the above-mentioned (Equation 328), the distance d i The pre-processing unit 19 estimates the attenuation of the intensity of the radio wave of 2000 W based on the results of the previous measurement. i and absolute value |ε i Using the table of |, the absolute value |ε i Calculate the absolute value of |ε i For example, taking into account the directivity of the antenna element itself, the direction θ of the object 5000 and the reflecting object 6000 i It may be changed every time.

[0151] In the case of the multi-point null constraint method shown in 19A of FIG. 17, the preprocessing unit 19 calculates the distances d1, d2, . . . , d M and wide angles L1, L2, . . ., L M For example, a process is performed to obtain a vector P1 that indicates the magnitude of the null depth for the same null object with the same value by using the vectors [|ε1|,|ε1|,...,|ε1|,|ε2|,|ε2|,...,|ε2|,....|ε M |,|ε M |,...,|ε M |] T It is.

[0152] In the case of the derivative constraint method shown in 19B of FIG. 17, the preprocessing unit 19 calculates the distances d1, d2, . . . , d M and wide angles L1, L2, . . ., L MUsing V i (0) The magnitude of the null depth corresponding to |ε i | and V i (l) (l=1,...,L i ), the magnitude of the null depth corresponding to the vector P2 is set to zero, and a process is performed to obtain a vector P2 indicating the magnitude of the null depth. For example, the vector P2 is [|ε1|,0,···,0,|ε2|,0,···,0,···.|ε M |,0,···,0] T It is.

[0153] When the power transmission device 10 uses the above-mentioned (Equation 328), the preprocessing unit 19 calculates the obtained constraint vector V i (l) Using (I-AA + ), A + The above matrix operations are performed to calculate vectors P1 and P2 indicating the magnitude of the null depth, and the operation results are stored in the storage unit 17D and supplied to the control unit 17.

[0154] FIG. 18 is a diagram showing another example of processing of the null depth by the pre-processing unit 19. The example shown in FIG. 18 shows a processing example in which the pre-processing unit 19 uses the above-mentioned (Equation 331). As shown in FIG. 18, the pre-processing unit 19 can process the magnitude of the null depth. In the case of the above-mentioned (Equation 331), the pre-processing unit 19 calculates the distance d i and weighting factor α i Using the table, the weighting coefficient α i The weighting coefficient α i For example, taking into account the directivity of the antenna element itself, the direction θ of the object 5000 i It may be changed every time.

[0155] In the case of the multi-point null constraint method shown in 19C of FIG. 18, the preprocessing unit 19 calculates the distances d1, d2, . . . , d M and wide angles L1, L2, . . ., L MA process is performed to obtain a vector P3 that indicates the magnitude of the null depth with the same value for the same null object using the vector P3. For example, the vector P3 is expressed as [α1,α1,···,α1,α2,α2,···,α2,···.α M ,α M ,...,α M ] T It is.

[0156] In the case of the derivative constraint method shown in 19D of FIG. 18, the preprocessing unit 19 calculates the distances d1, d2, . . . , d M and wide angles L1, L2, . . ., L M Using V i (0) The size of the null depth corresponding to i And V i (l) (l=1,...,L i ), the magnitude of the null depth corresponding to the vector P4 is set to a fixed value (α0>>1), and a process is performed to obtain a vector P4 indicating the magnitude of the null depth. M ,α0,···,α0] T It is.

[0157] When the power transmission device 10 uses the above-mentioned (Equation 331), the preprocessing unit 19 calculates the obtained constraint vector V i (l) Using vectors P3 and P4, which indicate the magnitude of the null depth, (I-A'(I+A' H A') -1 A' H ) and stores the calculation result in the storage unit 17D and supplies it to the control unit 17.

[0158] The control unit 17 calculates the array response vector V d Using the information stored in the storage unit 17D, the optimal weight vector W opt is calculated using the above-mentioned (Equation 329) or (Equation 333).

[0159] The control unit 17 can store weight information capable of identifying a weight vector suitable for the generated direction, area, and distance in the storage unit 17D. i can be set for each null target. The power transmitting device 10 can calculate a matrix or vector calculated from the direction, area, and distance to which the null is directed, and the propagation channel characteristics of the prescribed signal 1000, independently.

[0160] An example of the functional configuration of the power transmitting device 10 according to the third embodiment has been described above. Note that the above configuration described with reference to Fig. 14 is merely an example, and the functional configuration of the power transmitting device 10 according to the present embodiment is not limited to this example. The functional configuration of the power transmitting device 10 according to the present embodiment can be flexibly modified according to the specifications and operation.

[0161] [Example of control of power transmission device according to embodiment 3] A control example of the power transmitting device according to the third embodiment will be described with reference to Figs. 8 and 9 described above. As shown in Fig. 8, the system 1 arranges the power transmitting device 10 and the power receiving device 20 in a room 4000 so as to face each other. In the room 4000, an object 5000 to be avoided from being irradiated is present at a first position P10, and a reflective object 6000 is present at a second position P20. The first position P10 and the second position P20 are positions shifted to the left and right from a straight line connecting the power transmitting device 10 and the power receiving device 20. When the power transmitting device 10 detects the position, direction, area, distance, etc. of the object 5000 using the detection unit 16, the power transmitting device 10 grasps the relative position between the object 5000 and the array antenna 11. The system 1 wirelessly supplies power to the power receiving device 20 by emitting radio waves 2000W including a transmission signal 2000 from the power transmitting device 10 toward the power receiving device 20 in a retrodirective manner.

[0162] 8, in the system 1, the power receiving device 20 transmits a prescribed signal 1000. In this case, as shown in FIG. 9, when the power transmitting device 10 receives a radio wave including the prescribed signal 1000 at the array antenna 11, the power transmitting device 10 transmits an array response vector V dFor example, the power transmitting device 10 estimates the propagation channel characteristics of the reference signal 1000 included in the received signals received by the multiple antenna elements 11A in the estimation unit 14, and estimates the array response vector V d When the process of step S101 ends, the power transmitting device 10 advances the process to step S102.

[0163] The power transmitting device 10 recognizes the reflective object 6000 (step S102). For example, the power transmitting device 10 checks the presence or absence of a reflective object 6000 in the radio wave propagation environment based on the sensor information from the sensor unit 15 using the detection unit 16, and detects the relative direction, position, area, and distance between the reflective object 6000 and the array antenna 11 in the room 4000 based on the environmental information in the storage unit 17D. The power transmitting device 10 may recognize the relative position, reflective surface 6100, area, etc. of the reflective object 6000 from the sensor information using machine learning. For example, when the detection unit 16 detects M reflecting objects 6000, the power transmitting device 10 detects the directions θ1, θ2,..., θ of the multiple reflecting objects 6000. M The power transmitting device 10 detects the regions δ1, δ2, . . . , δ of the multiple reflecting objects 6000. M The power transmitting device 10 detects distances d1, d2, . . . , d M The power transmitting device 10 detects the directions θ1, θ2, . . . , θ M , the regions δ1, δ2, , δ M and distances d1, d2, . . . , d M The power transmitting device 10 stores the information indicating the recognition result in the storage unit 17D. After storing the information indicating the recognition result in the storage unit 17D, the power transmitting device 10 advances the process to step S103.

[0164] The power transmitting device 10 recognizes the object 5000 to be avoided from being irradiated (step S103). For example, the power transmitting device 10 recognizes the relative position, direction, and area of ​​the object 5000 different from the power receiving device 20 in the radio wave propagation environment based on the sensor information from the sensor unit 15 using the detection unit 16, and stores information indicating the recognition result in the storage unit 17D. For example, when the detection unit 16 detects M objects 5000 as null targets, the power transmitting device 10 stores information indicating the directions θ1, θ2, . . . , θ of the multiple objects 5000. M The power transmitting device 10 detects the regions δ1, δ2, . . . , δ of the multiple objects 5000. M The power transmitting device 10 detects distances d1, d2, . . . , d M The power transmitting device 10 detects the directions θ1, θ2, . . . , θ M , the regions δ1, δ2, , δ M and distances d1, d2, . . . , d M The power transmitting device 10 stores the result in the storage unit 17D. When the process of step S103 ends, the power transmitting device 10 advances the process to step S104.

[0165] The power transmitting device 10 virtually places the object 5000 to be avoided from being irradiated at a position of planar symmetry with respect to the reflecting surface 6100 of the reflecting object 6000 (step S104). For example, as shown in scene C1 of Fig. 8, the power transmitting device 10 sets an symmetry axis 6200 passing through the reflecting surface 6100 of the reflecting object 6000 in the room 4000, and places a virtual object 5000A virtually representing the object 5000 at a position of planar symmetry with the symmetry axis 6200 as a center. When the power transmitting device 10 finishes the process of step S104 shown in Fig. 9, the process proceeds to step S105.

[0166] The power transmitting device 10 determines whether or not to reduce the radio wave intensity to the reflecting object 6000 (step S105). When the power transmitting device 10 determines to reduce the radio wave intensity to the reflecting object 6000 (Yes in step S105), the process proceeds to step S106. The power transmitting device 10 determines the radio wave intensity of the object 5000 to be a first intensity and the radio wave intensity of the reflecting object 6000 to be a second intensity (step S106). In this embodiment, the power transmitting device 10 determines the first intensity and the second intensity so that the gain of a direction, point, etc. becomes zero in the directivity of the array antenna 11, that is, so as to point to a null. When the process of step S106 is completed, the power transmitting device 10 proceeds to step S107.

[0167] The power transmitting device 10 performs array response vectorization and matrix calculation corresponding to the determined radio wave intensity to generate a transmission weight (step S107). For example, the power transmitting device 10 performs the pre-processing unit 19 to calculate the transmission weight in the direction θ i and the region δ i The information shown in Table 170 is applied to the wide-angle L i Search for wide angle L i and the array response vector V i By vectorizing from and, the constraint vector V corresponding to the null is obtained. i (l) (l=0,...,L i The power transmission device 10 calculates a constraint vector V corresponding to the null in the pre-processing unit 19. i (l) Using (I-AA + ), A + The matrix calculation is performed and the calculation result is stored in the storage unit 17D. (0) 1,...,V (L1) 1,V (0) 2,...,V (L2) 2,...,V (0) M ,···,V (LM) M The power transmitting device 10 calculates the distance d of the object 5000 and the reflecting object 6000 from the detection unit 16 by the pre-processing unit 19. i The wide angle L obtained iBased on this, the location corresponding to the differential coefficient constraint is set to zero, and a vector P2 indicating the magnitude of the null depth is calculated and stored in the storage unit 17D. + ) and the array response vector V d For example, the power transmitting device 10 accumulates (I-AA + ) and the array response vector V d Add up the vector V d The power transmitting device 10 calculates the (A + ) and the array response vector V d Multiplying the vector (A + V d ) and vector P2 and vector (A + V d The power transmitting device 10 generates a vector ε based on (A + ) and vector ε, vector V ε Generate a vector V d ' and vector V ε The power transmitting device 10 calculates the coefficient α based on the vector V d ' and vector V ε Based on and coefficient α, the optimal weight vector W opt = αV d '+V ε When the process of step S107 ends, the power transmitting device 10 advances the process to step S108.

[0168] The power transmitting device 10 multiplies the transmission weight and emits radio waves of 2000 W (step S108). For example, the power transmitting device 10 multiplies the generated optimal weight vector W optBased on the weight information indicating the weight information, the power transmitting device 10 multiplies the transmission signal 2000 for power supply from the transmission signal generating unit 12 by the weight for each of the plurality of antenna elements 11A and supplies the result to the transmitting / receiving circuit 13A. In this way, the power transmitting device 10 causes the plurality of antenna elements 11A to radiate radio waves 2000W including the transmission signal 2000 for power supply. For example, as shown in scene C1 of FIG. 8, the power transmitting device 10 directs nulls in a direction D1 of the object 5000 and a direction D2 of the reflecting object 6000, so that the radio waves 2000W are constructively combined in the power receiving device 20, but are destructively combined in the object 5000 and the reflecting object 6000. Returning to FIG. 9, when the process of step S108 is completed, the power transmitting device 10 ends the process procedure shown in FIG. 9.

[0169] Furthermore, when the power transmitting device 10 determines not to reduce the radio wave intensity to the reflective object 6000 (No in step S105), the process proceeds to step S109. The power transmitting device 10 determines the radio wave intensity of the object 5000 to be the first intensity (step S109). That is, the power transmitting device 10 changes only the radio wave intensity of the object 5000, and does not change the radio wave intensity of the reflective object 6000. In this embodiment, the power transmitting device 10 determines the first intensity so that the gain of a direction, point, etc. becomes zero in the directivity of the array antenna 11, that is, so as to point to a null. When the process of step S109 is completed, the power transmitting device 10 proceeds to step S107.

[0170] The power transmitting device 10 performs array response vectorization and matrix calculation corresponding to the determined radio wave intensity to generate a transmission weight (step S107). In this case, the power transmitting device 10 performs the pre-processing unit 19 to calculate the direction θ i and the region δ i The information shown in Table 170 is applied to the wide-angle L i Search for wide angle L i and the array response vector V i By vectorizing from and, the constraint vector V corresponding to the null is obtained. i (l) (l=0,...,L i The power transmission device 10 calculates a constraint vector V corresponding to the null in the pre-processing unit 19. i (l)Using (I-AA + ), A + The matrix calculation is performed and the calculation result is stored in the storage unit 17D. (0) 1,...,V (L1) 1,V (0) 2,...,V (L2) 2,...,V (0) M ,···,V (LM) M The power transmitting device 10 calculates the distance d i The wide angle L obtained i Based on this, the location corresponding to the differential coefficient constraint is set to zero, and a vector P2 indicating the magnitude of the null depth is calculated and stored in the storage unit 17D. + ) and the array response vector V d For example, the power transmitting device 10 accumulates (I-AA + ) and the array response vector V d Add up the vector V d The power transmitting device 10 calculates the (A + ) and the array response vector V d Multiplying the vector (A + V d ) and vector P2 and vector (A + V d The power transmitting device 10 generates a vector ε based on (A + ) and vector ε, vector V ε Generate a vector V d ' and vector V ε The power transmitting device 10 calculates the coefficient α based on the vector V d ' and vector V ε Based on and coefficient α, the optimal weight vector W opt = αV d '+V ε When the process of step S107 ends, the power transmitting device 10 advances the process to step S108.

[0171] The power transmitting device 10 multiplies the transmission weight and emits radio waves of 2000 W (step S108). For example, the power transmitting device 10 multiplies the generated optimal weight vector W opt Based on the weight information indicating the weight information, the power transmitting device 10 multiplies the transmission signal 2000 for power supply from the transmission signal generating unit 12 by the weight for each of the plurality of antenna elements 11A and supplies the result to the transmission / reception circuit 13A. As a result, the power transmitting device 10 radiates radio waves 2000W including the transmission signal 2000 for power supply from the plurality of antenna elements 11A. For example, as shown in scene C2 of FIG. 8, the power transmitting device 10 directs a null only in the direction D1 of the object 5000, so that the radio waves 2000W are combined constructively in the power receiving device 20, but are combined destructively in the object 5000. In addition, the radio waves 2000W emitted by the power transmitting device 10 head toward the reflecting object 6000, and the reflected waves 2100W reflected by the reflecting object head toward the power receiving device 20, thereby increasing the amount of power received by the power receiving device 20. Returning to FIG. 9, when the process of step S108 is completed, the power transmitting device 10 ends the process procedure shown in FIG. 9.

[0172] As described above, the power transmitting device 10 can set the radio wave intensity of the radio wave 2000W (transmitted wave) at the first position P10 to a first intensity based on the first position P10 of the object 5000 different from the power receiving device 20 and the second position P20 of the reflecting object 6000 having a reflectance equal to or higher than a predetermined value, and set the radio wave intensity of the radio wave 2000W at the second position P20 to a second intensity that is lower than the case where the radio wave 2000W is reflected by the reflecting object 6000 and does not reach the first position P10. As a result, when the reflected wave 2100W that has passed through the reflecting object 6000 having a high reflectance hits the object 5000 to be avoided from being irradiated, the power transmitting device 10 can suppress the radiation of the radio wave 2000W toward the object 5000 by directing a null toward the reflecting object 6000. As a result, the power transmitting device 10 can suppress the radio waves 2000W directed toward the human body even in an environment where radio waves including the specified signal 1000 from the power receiving device 20 are reflected and reach the human body and where a reflective object 6000 is present, thereby realizing safe wireless power transmission.

[0173] The power transmitting device 10 can control the directivity of the array antenna 11 that transmits the radio waves 2000W based on the received signal from the power receiving device 20 and the distances to the object 5000 and the reflecting object 6000 so that the radio wave intensity of the radio waves 2000W at the first position P10 of the object 5000 is a first intensity and the electromagnetic intensity of the radio waves 2000W at the second position P20 of the reflecting object 6000 is a second intensity. As a result, even if the power transmitting device 10 receives the specified signal 1000 from the direction of the object 5000, the radiated radio waves 2000W can be reinforced in the power receiving device 20, and the radiation of the radio waves 2000W toward the object 5000 can be suppressed by forming a null with a wide angle and a null depth controlled according to the area and distance of the object 5000 and the reflecting object 6000.

[0174] [Modification of the embodiment] The above-mentioned power transmitting device 10 may be configured such that the control unit 17 determines whether the radio wave 2000W (transmitted wave) is reflected by the reflecting object 6000 and reaches the first position P10 of the object 5000, using information on the relative position and direction between the power transmitting device 10 itself and the reflecting object 6000, which is stored in advance in the storage unit 17D. This allows the power transmitting device 10 to determine whether the radio wave 2000W (transmitted wave) is reflected by the reflecting object 6000 and reaches the first position P10 of the object 5000, using information on the relative position and direction between the power transmitting device 10 itself and the reflecting object 6000, thereby simplifying the process of determining the reflecting object 6000 and the device configuration.

[0175] Furthermore, the above-described power transmitting device 10 may store in the storage unit 17D radio wave intensity information that enables the control unit 17 to determine radio wave intensity based on the reflectance of the reflective object 6000. The radio wave intensity information includes, for example, information indicating the relationship between the reflectance of the reflective object 6000 and the radio wave intensity. The radio wave intensity information includes, for example, information indicating that the reflective object 6000 is not determined to be a reflective object when the reflectance is 0.0 to 0.3. The radio wave intensity information includes, for example, information indicating that the radio wave intensity is gradually decreased to 60% when the reflectance is 0.3 to 0.5, to 40% when the reflectance is 0.5 to 0.7, and to 20% when the reflectance is 0.7 to 1.0. The control unit 17 may acquire the reflectance of the reflective object 6000, identify the radio wave intensity from the reflectance and the radio wave intensity information, and determine the radio wave intensity as a second intensity that is the radio wave intensity of radio waves of 2000 W at the reflective object 6000. This allows the power transmitting device 10 to adjust the electromagnetic strength of the radio waves 2000 W depending on the reflectivity of the reflective object 6000 , and therefore allows the power supply radio waves 2000 W to be emitted with a radio wave strength suitable for the reflective object 6000 .

[0176] Characteristic embodiments have been described in order to fully and clearly disclose the technology according to the attached claims. However, the attached claims should not be limited to the above-mentioned embodiments, but should be configured to embody all modifications and alternative configurations that a person skilled in the art can create within the scope of the basic matters shown in this specification. The contents of this disclosure can be modified and amended by a person skilled in the art based on this disclosure. Therefore, these modifications and amendments are included in the scope of this disclosure. For example, in each embodiment, each functional unit, each means, each step, etc. can be added to other embodiments so as not to be logically contradictory, or can be replaced with each functional unit, each means, each step, etc. of other embodiments. In each embodiment, multiple functional units, each means, each step, etc. can be combined into one or divided. In addition, each embodiment of the present disclosure described above is not limited to being faithfully implemented to each of the embodiments described respectively, and can be implemented by combining each feature or omitting a part as appropriate. [Explanation of symbols]

[0177] 1 System 10 Power transmission equipment 11 Array Antenna 11A Antenna element 12 Transmission signal generator 13 Transmitter / receiver 14 Estimation part 15 Sensor section 16 Detection section 17 Control section 17D Storage section 18 Multiplication section 19 Pretreatment section 20 Power receiving device 21 Antenna 22 Transmitter / receiver 23 Signal Generator 24 Power receiving section 200B Reference point 200P receiving point 1000 regulation signal 2000 Transmitted signal 2000W radio wave 4000 rooms 5000 objects 6000 reflective object P10 1st position P20 2nd position

Claims

1. A transmission unit that transmits a transmission wave to the power receiving device; When the transmission wave is reflected by a reflecting object and reaches a first position of an object other than the power receiving device, than the intensity of the transmission wave when the transmission wave is reflected by a reflecting object and does not reach a first position of an object other than the power receiving device, A control unit that reduces the radio wave intensity of the transmission wave at a second position of the reflecting object.

2. The control unit transmits a first transmission wave to the second position; The power transmitting device according to claim 1, wherein when the transmission wave is reflected by a reflecting object and reaches the first position of an object other than the power receiving device, the transmission wave at the second position is a second transmission wave having a radio wave intensity lower than that of the first transmission wave.

3. The power transmitting device according to claim 1 , wherein the reflecting object comprises a metasurface reflector capable of changing the direction of propagation of incident radio waves to a desired direction and reflecting the waves.

4. The power transmitting device according to claim 1 , wherein the control unit receives a regulation signal transmitted from the power receiving device at the transmission unit, and transmits the transmission wave toward the power receiving device based on the regulation signal.

5. The power transmitting device according to claim 1 , wherein the control unit determines whether the transmission wave is reflected by the reflecting object and reaches the first position by using information on a relative position and direction between the transmission unit and the reflecting object.

6. The power transmission device of claim 1, wherein the control unit determines whether the transmission wave is reflected by the reflecting object and reaches the first position using information on the relative position and direction of the transmission unit and the reflecting object that is pre-stored in a memory unit.

7. A detection unit for detecting a relative position and direction of the reflecting object, The power transmission device of claim 1 , wherein the control unit uses information on the relative position and direction of the transmission unit and the reflecting object detected by the detection unit to determine whether the transmission wave is reflected by the reflecting object and reaches the first position.

8. The power transmitting device according to claim 1 , wherein the control unit sets the intensity based on a reflectance of the reflective object.

9. The power transmitting device according to claim 1 , wherein the control unit reduces the radio wave intensity of the transmission wave at the second position by forming a null of the transmission wave in a direction of the reflecting object.

10. The power transmitting device according to claim 1 , wherein the control unit reduces the radio wave intensity of the transmission wave at the second position of the reflecting object when the radio wave intensity at the first position is equal to or greater than a predetermined intensity.

11. a power transmitting device including a transceiver unit for transmitting a transmission wave to a power receiving device, When the transmission wave is reflected by a reflecting object and reaches a first position of an object other than the power receiving device, than the intensity of the transmission wave when the transmission wave is reflected by a reflecting object and does not reach a first position of an object other than the power receiving device, The control method includes reducing the radio wave intensity of the transmission wave at the second position of the reflecting object.

12. A power transmitting device including a transceiver unit for transmitting a transmission wave to a power receiving device, When the transmission wave is reflected by a reflecting object and reaches a first position of an object other than the power receiving device, than the intensity of the transmission wave when the transmission wave is reflected by a reflecting object and does not reach a first position of an object other than the power receiving device, A control program for reducing the radio wave intensity of the transmission wave at the second position of the reflecting object.

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