Power transmission device, control method and control program

Abstract

To make an improvement for proper emission of radio waves when there is a target to be avoided for radio waves within the vicinity.SOLUTION: A power transmission device 10 comprises a transmitter / receiver 13 that transmits radio waves via an array antenna 11, a memory section 17D that stores an array response vector for each of a plurality of predetermined positions set in advance, and a controller 17 which generates weights to direct nulls to an avoidance target in radio waves based on the array response vector stored in the memory section 17D, corresponding to the location of the avoidance target for radio waves.SELECTED DRAWING: Figure 2

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 weakens the strength of radio waves reaching the position of an object when the object is within a predetermined range, without stopping power supply to the object by radio waves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-005468 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a wireless transmission system in an indoor manned environment, when a far-field null is formed from the direction of an object, a certain level of strength is required before the strength of the radio waves is reduced. However, when the wireless transmission system is used in an indoor environment, there is a possibility that a sufficient distance cannot be secured between the system and an object to be avoided by the radio waves. Conventional power transmission devices have room for improvement in terms of appropriate radiation of radio waves when an object to be avoided by the radio waves is nearby. [Means for solving the problem]

[0005] A power transmission device according to one aspect includes a transmitting unit that transmits radio waves via an array antenna, a memory unit that stores array response vectors for each of a plurality of predetermined positions, and a control unit that generates a weight for directing a null in the radio waves toward an object to be avoided based on the array response vector stored in the memory unit, which corresponds to a position of the object to be avoided for the radio waves.

[0006] A control method according to one aspect includes a storage step in which a power transmission device having a transmitting unit that transmits radio waves via an array antenna stores array response vectors for each of a plurality of predetermined positions in a storage unit, and a generation step in which a weight is generated for directing a null in the radio waves transmitted via the array antenna toward an object to be avoided based on the array response vector stored in the storage unit that corresponds to the position of the object to be avoided.

[0007] A control program according to one aspect causes a power transmission device having a transmitting unit that transmits radio waves via an array antenna to execute a storage process of storing array response vectors for each of a plurality of predetermined positions in a storage unit, and a generation process of generating weights for directing a null in the radio waves transmitted via the array antenna toward an object to be avoided, based on the array response vectors stored in the storage unit that correspond to the position of the object to be avoided. [Brief description of the drawings]

[0008] [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 illustrating an example of the configuration of the power transmitting device according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing an example of an equivalent low-pass system analysis model of an adaptive array antenna. [Figure 4] FIG. 4 is a diagram showing an example of the relationship between direction and phase in an adaptive array antenna. [Diagram 5] FIG. 5 is a diagram for explaining the relationship between the radio wave propagation environment of the power transmitting device and a plurality of predetermined positions. [Figure 6] FIG. 6 is a diagram for explaining an example of the arrangement of a plurality of antenna elements in an array antenna of a power transmitting device. [Figure 7] FIG. 7 is a diagram illustrating an example of a data structure of the predetermined position information. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of a power receiving device according to the embodiment. [Figure 9] FIG. 9 is a diagram for explaining an example of a processing procedure of the power transmitting device illustrated in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A number of embodiments according to 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.

[0010] 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 system 1 can be applied to, for example, space solar power generation. The microwave transmission type system 1 uses radio waves (microwaves) as energy transmission. A plurality of frequency bands are available for the radio waves used in the microwave transmission type system 1, and in Japan, for example, the 920 MHz band, the 2.4 GHz band, the 5.7 GHz band, and the like are included. The microwave transmission type system 1 can use a retrodirective method. In this embodiment, the system 1 makes it possible to simultaneously improve power supply efficiency appropriate to the situation and ensure safety.

[0011] 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 that transmits power wirelessly in the system 1 and is a device that can transmit radio waves for power supply. The power transmitting device 10 includes a sensor unit 15 that can detect objects to be avoided, such as human bodies, animals, plants, etc., in the vicinity of the array antenna 11. In the following description, the power transmitting device 10 may be referred to as "own device".

[0012] The power receiving device 20 is a power-supplied device in the system 1 that receives radio waves for power supply to obtain power. Examples of the power receiving device 20 include 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 20 of the present disclosure may be a mobile device.

[0013] 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.

[0014] 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 radiated from the power transmitting device 10 have a radiation pattern that makes use of not only paths toward the power receiving device 20, but also paths toward a direction different from the power receiving device 20.

[0015] (Embodiment) [Configuration of power transmitting device according to embodiment] Fig. 2 is a diagram showing an example of a configuration of a power transmitting device 10 according to an embodiment. As shown in Fig. 2, 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.

[0016] 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 radio waves 2000W including a transmission signal 2000, and receives radio waves 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 an example of an antenna, and a case where the array antenna 11 includes three or more antenna elements 11A will be described, but the number of antenna elements 11A is not limited thereto.

[0017] 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, there is no time variation in the transmission signal 2000 during the transmission period. In the case of a modulated signal, the transmission signal generating unit 12 time-varies the transmission signal 2000 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.

[0018] 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 simultaneously radiates radio waves 2000W including the transmission signal 2000 multiplied by the transmission weight (complex amplitude) from the plurality of antenna elements 11A, so that the power transmitting device 10 radiates radio waves 2000W with controlled directivity. The transmitting / receiving unit 13 is an example of a transmitting unit and a receiving unit, and the transmitting unit and the receiving unit may be configured separately.

[0019] 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.

[0020] The sensor unit 15 can acquire information capable of detecting the presence, direction, area, distance, importance, and the like of the avoidance target 5000 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 acquires information on the avoidance target 5000 present in the radio wave propagation environment using, for example, a camera, a radar such as a millimeter wave radar, a LIDAR (Laser Imaging Detection and Ranging), a ToF (Time of Flight) sensor, an infrared sensor, a human sensor, a depth 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 presence, direction, area, distance, importance, and the like of the avoidance target 5000 in the radio wave propagation environment. The sensor information may include, for example, information on the presence, direction, distance, area, position, importance, image, and the like of the avoidance target 5000.

[0021] The detection unit 16 detects information on the presence or absence, direction, area, distance, importance, etc. of an avoidance target 5000 different from the power receiving device 20 in the radio wave propagation environment based on the sensor information from the sensor unit 15. The avoidance target 5000 includes, for example, a human being, an animal, a robot, a moving object, a plant, food, and a device that transmits or receives electromagnetic waves. The detection unit 16 executes a publicly known object recognition process on an image indicated by the sensor information, and detects information on the presence or absence, the area in which the avoidance target 5000 exists, the shape, the direction of the avoidance target 5000 from the own device, the distance from the own device to the avoidance target 5000, and important parts such as the head, etc. For example, the detection unit 16 detects the direction and area of ​​the avoidance target 5000 from the array antenna 11 based on the direction and area, etc. of the avoidance target 5000 detected from the sensor information and the relative positional relationship between the sensor unit 15 and the array antenna 11. When there are multiple avoidance targets 5000, the detection unit 16 detects the direction, area, distance, importance, etc. of each of the multiple avoidance targets 5000. The detection unit 16 is electrically connected to the control unit 17, and supplies object information of the avoidance targets 5000 from the array antenna 11 to the control unit 17. The object information may include information that can identify, for example, the number of avoidance targets 5000 different from the power receiving device 20 in the radio wave propagation environment, the direction and area of ​​the avoidance targets 5000 from the array antenna 11, and the distance from the array antenna 11 to the avoidance targets 5000. Importance may be assigned to the direction and area of ​​the avoidance targets 5000. Note that the information on the area can be information that can identify the size of the avoidance targets 5000 depending on the arrangement of the multiple antenna elements 11A. For example, the area of ​​the avoidance targets 5000 when the multiple antenna elements 11A are arranged in a matrix can be set to have a vertical and horizontal angular spread, like the area 151. The area 151 of the avoidance target 5000 may be a spatial area according to the outer shape, etc., of the avoidance target 5000. For example, the area of ​​the avoidance target 5000 in a case where a plurality of antenna elements 11A are arranged side by side in the horizontal direction can be set to have a horizontal angular spread, etc., like the area 151. In this manner, the detection unit 16 of the present disclosure detects information on the number, direction, area, distance, importance, etc. of the avoidance target 5000 different from the power receiving device 20 in the radio wave propagation environment based on the sensor information from the sensor unit 15, and supplies the information to the control unit 17 as object information.

[0022] The sensor information includes, for example, information indicating the presence, direction, area, position, importance, etc. of the avoidance target 5000 from the array antenna 11. The sensor information includes, for example, identifiable information such as an area 151 including the avoidance target 5000 and a size 152, as shown in FIG. 2. The sensor information can be information that identifies the size of the avoidance target 5000 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 avoidance target 5000 can set the length and width, the position, the shape of the avoidance target 5000, etc. For example, when the multiple antenna elements 11A are arranged side by side in one direction, the size 152 of the avoidance target 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 avoidance target 5000 may be a spatial area according to the outer shape, etc. of the avoidance target 5000.

[0023] The control unit 17 generates 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 object information of the avoidance target 5000 different from the power receiving device 20, which is 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. The control unit 17 includes a storage unit 17D, and various information such as a control program and data required for weight generation is stored in the storage unit 17D.

[0024] 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.

[0025] The storage unit 17D may store various programs that cause the entire power transmission device 10 or the control unit 17 to function, and various information used by the entire power transmission device 10 or the control unit 17. In addition, the implementation form of the program is not limited to application programs such as object code compiled by a compiler and program code executed by an interpreter, and may be in the form of a program module incorporated into an operating system. Furthermore, the program may or may not be configured so that all processing is performed only by the CPU on the control board. The program used in the present disclosure may be configured so that a part or all of it is executed by another processing unit implemented on an expansion board or expansion unit added to the board as necessary.

[0026] 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 corresponding to the antenna element 11A.

[0027] At least one of the transmission signal generating unit 12, the transceiver unit 13, the estimation unit 14, the sensor unit 15, the detection unit 16, the control unit 17, the multiplication unit 18, and the like that constitute the power transmitting device 10 may be realized by one or more processors and memories. The processor may include a general-purpose processor that executes a specific function by loading a specific program, and a dedicated processor specialized for a specific process. The dedicated processor may include an application-specific IC such as an ASIC (Application Specific Integrated Circuit). The processor may include a programmable logic device (PLD), for example. The PLD may include a field-programmable gate array (FPGA). At least one of the transmission signal generating unit 12, the transceiver unit 13, the estimation unit 14, the sensor unit 15, the detection unit 16, the control unit 17, the multiplication unit 18, and the like that constitute the power transmitting device 10 may be realized by either a system-on-a-chip (SoC) in which one or more processors work together, or a system in a package (SiP). At least one of the components constituting the power transmission device 10, such as the transmission signal generating unit 12, the transceiver unit 13, the estimation unit 14, the sensor unit 15, the detection unit 16, the control unit 17, and the multiplication unit 18, may control the operation of each component of the power transmission device 10.

[0028] 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. 2 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.

[0029] [Example of weight generation in power transmission device according to embodiment] The weight generation method and the problems will be described below. Fig. 3 is a diagram showing an example of an equivalent low-pass system analysis model of an adaptive array antenna. Fig. 4 is a diagram showing an example of the relationship between direction and phase in an adaptive array antenna. 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 weight generation methods will be described in the order of the retrodirective method that does not form a null, the retrodirective method with linear constraint that forms a null, and the retrodirective method with multi-point null constraint that supports widening of the null angle, and finally the problems of the retrodirective method with multi-point null constraint will be described.

[0030] As shown in FIG. 3, 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 1).

number

[0031] 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 a, then (Equation 1) can be expressed as the inner product of complex vectors in the following (Equation 2). 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).

number

[0032] When the weight vector w and the array response vector a are expressed by concrete elements, they are given by the following (Equation 3).

number

[0033] If the array response vector a 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 a is calculated based on a prescribed signal 1000 (pilot signal) transmitted from the power receiving device 20. 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 a 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 during power transmission. ||w|| 2 = 1, the magnitude of the array response value |w H a d The optimal weight vector w that maximizes | opt can be expressed as the following (Equation 4).

number

[0035] As described above, the optimal weight vector w for retrodirective transmission is opt is the array response vector of the received pilot signal a dIt is sufficient only, and information such as the direction of the receiving point 200P is unnecessary. However, in the retro-directive method, radiation to the avoidance target 5000 different from the power receiving device 20 in the radio wave propagation environment is not considered.

[0036] Next, the simultaneous realization of the retro-directive method and a plurality (for example, M) of null formations will be described. Thereby, the power transmission device 10 can suppress radiation to the avoidance target 5000 different from the power receiving device 20 in the radio wave propagation environment. In the present disclosure, this is referred to as a retro-directive method with linear constraints.

[0037] A null means that the gain such as a direction or a 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 a i (i = 1, ···, M), the magnitude |w H a i | may be set to zero. Under this condition, the magnitude |w d of the array response value of the array response vector a H a d | is maximized. This can be formulated as an optimization problem shown in the following (Equation 5). 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 is assumed. argmax (argument of the maximum) means the set of values that achieve the maximum value. (Equation 5) is an equation for obtaining the optimal weight vector w H a d such that |w opt | is maximum.

Equation

[0038] The optimization problem of (Equation 5) has a closed-form solution. When a’ d is defined as shown in the following (Equation 6), the optimal weight vector w opt is given by the following (Equation 7).

Equation

Number

[0039] Here, A is the array response vector a1, a2, ···, a which is a matrix of M complex column vectors M arranged as shown in the following (Equation 8).

Number

[0040] Also, A + is the Moore-Penrose generalized inverse matrix of A. And A + satisfies AA + A = A, A + AA + = A + , (AA + ) H = AA + , (A + A) H = A + A. When the array response vectors a1, a2, ···, a which are complex column vectors are linearly independent, A M = (A + A) H A -1 A H holds.

[0041] For the array response value corresponding to null, the weight vector w must satisfy w H a i = 0 (i = 1, ···, M < K). Therefore, considering these as a system of homogeneous linear equations, it is expressed as the product of a matrix and a vector using the matrix A formed by arranging the M complex column vectors of the array response vectors a1, a2, ···, a M such that A H w = 0. The general solution is obtained using the Moore-Penrose generalized inverse matrix A + as w = (I - AA + ) H z = (I - AA +)z, where z is an arbitrary complex vector. The magnitude of the array response we wish to maximize is |w H a d |to w=(I-AA + ) H z=(I-AA + )z is substituted, |w H a d |=|z H (I-AA + )a d | is obtained. And, by the Cauchy-Schwarz inequality, |w H a d |=|z H (I-AA + )a d |≦||z||·||(I-AA + )a d || holds true. |w H a d | is maximized when the inequality is equal, and then z=γ(I-AA + )a d where γ is a complex constant.

[0042] The optimal weight vector w opt is the above-mentioned w=(I-AA + ) H z=(I-AA + )z, z=γ(I-AA + )a d By substituting, w opt =γ(I-AA + )a d Here, a' is given as in (Eq. 6). d =(I-AA + )a d Then, ||w opt || 2 = |γ| 2 ||a' d || 2 = 1, γ = 1 / ||a' d Therefore, the optimal weight vector w opt can be expressed as the above-mentioned (Equation 7).

[0043] 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 can be estimated from the prescribed signal 1000. However, if it is assumed that the prescribed 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 suppress radio waves traveling 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 object information of the avoidance target 5000, which is the null target, acquired using the sensor unit 15 and the detection unit 16.

[0044] As shown in Fig. 4, in a linear array in which K antenna elements 11A are arranged at equal intervals, the array response vector a 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 9). The broadside is a direction perpendicular to the direction in which the antenna elements 11A are arranged, and is the upward direction in Fig. 4. The inter-element distance from antenna element 11A #0 to antenna element 11A #k of reference point 200B is kd, and the inter-element distance from antenna element 11A #0 to antenna element 11A #K-1 of reference point 200B is (K-1)d.

number

[0045] Here, the impulse response Z is expressed by the following (Equation 10). j is the imaginary unit, and j 2 =-1, and λ is the wavelength.

number

[0046] By this, if the direction θ of the null target is known, M array response vectors a i (i=1, 2, , M) can be calculated as shown in (Equation 11) below. Note that the M directions θ are θ=θ i (i=1,2,...,M) and the impulse response Z i is the direction θ ican be obtained from the following (Equation 12).

number

number

[0047] The power transmitting device 10 can suppress radiation to an object to be avoided 5000, which is different from the power receiving device 20, in a radio wave propagation environment by using the linearly constrained retrodirective method. However, when the power transmitting device 10 forms a far-field null from the direction of the object to be avoided 5000, it takes a certain distance before the strength of the radio wave is reduced. The reason for this is that when the array antenna 11 of the power transmitting device 10 and the object to be avoided 5000 are close to each other, the distance d shown in FIG. k It is considered that the approximation of sin θ is not valid and the null performance is deteriorated. For this reason, in the present embodiment, the power transmitting device 10 provides a function for sufficiently reducing the intensity of the radio wave 2000W directed toward the avoidance target 5000, i.e., the effect on the human body, when the avoidance target 5000 is present in the vicinity of the power transmitting device 10.

[0048] [Example of radio wave propagation environment of power transmitting device according to embodiment] Fig. 5 is a diagram for explaining the relationship between the radio wave propagation environment of the power transmitting device 10 and a plurality of predetermined positions. Fig. 6 is a diagram for explaining an example of the arrangement of a plurality of antenna elements 11A in the array antenna 11 of the power transmitting device 10.

[0049] As shown in FIG. 5, the power transmitting device 10 and the power receiving device 20 are arranged in a room 4000. The room 4000 is an indoor space surrounded by walls or the like on all four sides. The power transmitting device 10 is configured to estimate characteristic values ​​of multiple paths from the power receiving device 20 to the power transmitting device 10 based on the prescribed signal 1000, and to control antenna directivity using the characteristic values ​​to transmit radio waves 2000W including a transmission signal 2000 for power supply. In the room 4000, a range indicated by an approximately circular shape with a radius of a predetermined distance centered on the power transmitting device 10 is set as a first region 4100, and a region other than the first region 4100 is set as a second region 4200. In this embodiment, the first region 4100 is described as a circular region, but the shape of the region may be other shapes such as a square, a triangle, a polygon, or an ellipse.

[0050] The power transmitting device 10 sets a plurality of different predetermined positions 400P in the first region 4100. Each of the plurality of predetermined positions 400P is located inside the first region 4100, and is set at a position with a different direction and distance from the power transmitting device 10. The power transmitting device 10 assigns a unique ID to each of the plurality of predetermined positions 400P, and stores predetermined position information capable of identifying an array response vector for each predetermined position 400P in the storage unit 17D. In this embodiment, the power transmitting device 10 arranges the plurality of predetermined positions 400P in a matrix shape at intervals based on the wavelength λ of the radio wave 2000W inside the first region 4100, but the arrangement is not limited to this. For example, the power transmitting device 10 may arrange the plurality of different predetermined positions 400P in a radial, linear, spiral, or other shape with the power transmitting device 10 at the center.

[0051] 6, the power transmitting device 10 radiates radio waves 2000W including a transmission signal 2000 for feeding power to the power receiving device 20 from the array antenna 11. The power transmitting device 10 detects an avoidance target 5000 located at a distance R inside the room 4000 by the detection unit 16. In this case, the power transmitting device 10 controls the directivity of the array antenna 11 so that a null is directed toward the avoidance target 5000.

[0052] In an example shown in FIG. 6, the array antenna 11 is arranged in a matrix shape by lining up a plurality of antenna elements 11A in a line along a first direction 111 and a second direction 112 on the plane of the substrate 110. In the array antenna 11, the range in which the plurality of antenna elements 11A are arranged has a length D in the arrangement directions of the first direction 111 and the second direction 112. The length D may be the size of the array antenna 11, the length of a diagonal line, or the like. For example, the length D may be one side if the substrate 110 is a square, or the long side or short side if the substrate 110 is a rectangle. The length D may be, for example, the length of an aperture surface of the array antenna 11, a region in which the plurality of antenna elements 11A are provided, or the like.

[0053] The power transmitting device 10 is located at a distance 2D that can be calculated from the length D of the array antenna 11 and the wavelength λ of the radio wave of 2000 W. 2 / λ is set as the predetermined distance 4300. In this embodiment, the predetermined distance 4300 is the distance to the vicinity of the boundary between the first region 410 and the second region 420 shown in Fig. 5. For example, the predetermined distance 4300 may be set as the distance to the boundary between the far field and the near field, so that the first region 4100 is the near field and the second region 4200 is the far field. The power transmitting device 10 can improve the accuracy of the radio wave 2000W by increasing the length D of the array antenna 11.

[0054] FIG. 7 is a diagram showing an example of a data structure of the predetermined position information. As shown in FIG. 7, the predetermined position information 300 has items such as the ID, direction, position, and array response vector of the predetermined position 400P. The ID item of the predetermined position 400P is set with information that can identify the predetermined position 400P. The direction item is set with information that can identify the direction of the predetermined position 400P from the power transmitting device 10. The position item is set with information that can identify the position of the predetermined position 400P in the first region 4100, the distance from the power transmitting device 10 to the predetermined position 400P, and the like. The array response vector item is set with information that can identify an array response vector for directing a null to the predetermined position 400P. For example, the array response vector is information for obtaining null performance that is estimated based on a pilot signal from the predetermined position 400P transmitted from the predetermined position 400P and then received by the power transmitting device 10. The array response vector includes, for example, information capable of identifying specific values ​​of multiple paths from the predetermined position 400P to the power transmitting device 10, propagation channel characteristics of the pilot signal, etc. The predetermined position information 300 may be configured to include information such as the amplitude and phase of the pilot signal from the predetermined position 400P.

[0055] The power transmitting device 10 can store, in the storage unit 17D, predetermined position information 300 corresponding to each of the plurality of predetermined positions 400P set inside the first region 4100. The power transmitting device 10 can calculate a transmission weighting coefficient corresponding to the predetermined position 400P by using the array response vector stored in the storage unit 17D.

[0056] [Power receiving device according to the embodiment] FIG. 8 is a diagram showing an example of the configuration of the power receiving device 20 according to the embodiment. As shown in FIG. 8, 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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, a load, etc. The load includes, for example, mechanical equipment, IoT sensors, electronic devices, lighting equipment, etc.

[0061] 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. 8 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.

[0062] [Example of Processing Procedure of Power Transmission Device According to the Embodiment] Fig. 9 is a diagram for explaining an example of a processing procedure of the power transmitting device 10 shown in Fig. 6. The processing procedure shown in Fig. 9 is executed by the power transmitting device 10 when the detection unit 16 detects an avoidance target 5000, etc. The power transmitting device 10 may store predetermined position information 300 of a plurality of predetermined positions 400P in the storage unit 17D in advance, or may store the predetermined position information 300 in the storage unit 17D when executing the predetermined procedure.

[0063] As shown in FIG. 9, when the power transmitting device 10 receives radio waves including a prescribed signal 1000 at the array antenna 11, the power transmitting device 10 outputs an array response vector a 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 a d When the process of step S100 ends, the power transmitting device 10 advances the process to step S101.

[0064] The power transmitting device 10 acquires directional information of the avoidance target 5000 (step S101). For example, the power transmitting device 10 acquires directional information capable of identifying the position and direction of the avoidance target 5000 detected by the detection unit 16, the distance R to the avoidance target 5000, and the like, based on sensor information from the sensor unit 15. For example, when the detection unit 16 detects a plurality of avoidance targets 5000, the power transmitting device 10 acquires directional information for each of the plurality of avoidance targets 5000. When the process of step S101 ends, the power transmitting device 10 advances the process to step S102.

[0065] The power transmission device 10 detects that the distance R to the avoidance target 5000 is a predetermined distance 2D 2 It is determined whether the distance 2D is greater than / λ (step S102). 2 / λ is a value calculated from the length D of the array antenna 11 and the wavelength λ of the radio wave 2000 W. In this embodiment, the predetermined distance 2D 2 / λ indicates the distance to the boundary between the first area 4100 and the second area 4200 in the room 4000. The power transmitting device 10 2 If it is determined that the difference is greater than / λ (Yes in step S102), the avoidance target 5000 exists in the second area 4200, and therefore the process proceeds to step S103.

[0066] The power transmitting device 10 calculates an array response vector that directs a null toward the avoidance target 5000 in the second region 4200 (step S103). For example, the power transmitting device 10 performs array response vectorization and matrix calculation corresponding to the null. For example, when M nulls exist, the power transmitting device 10 calculates an array response vector that directs a null toward the avoidance target 5000 in the control unit 17. M Based on the above (Eq. 11) and (Eq. 12), the array response vectorization (a1, a2, . . . , a M ) is performed. In the power transmitting device 10, the control unit 17 then performs a matrix calculation. In detail, the power transmitting device 10 performs a matrix calculation on the array response vector a i =a1,a2,...,a M Using (I-AA +) and stores the calculation 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 generates a transmission weight based on the calculated array response vector (step S104). For example, in the power transmitting device 10, the control unit 17 generates a transmission weight based on the array response vector a d and the matrix (I-AA + ) to obtain the array response vector a d The power transmitting device 10 calculates the array response vector a′ calculated by the control unit 17. d ' is normalized using (Equation 7) to obtain the optimal weight vector w opt When the process of step S104 ends, the power transmitting device 10 advances the process to step S105.

[0068] The power transmitting device 10 multiplies the transmission weight (step S105). For example, the power transmitting device 10 multiplies the transmission weight by the optimal weight vector w opt 9. Based on the weight information indicating ...

[0069] In addition, the power transmitting device 10 detects that the distance R is a predetermined distance 2D 2If it is determined that the difference is not greater than / λ (No in step S102), the avoidance target 5000 is present in the first region 4100, and the process proceeds to step S106. The power transmitting device 10 acquires an array response vector corresponding to the avoidance target 5000 in the first region 4100 from the storage unit 17D (step S106). For example, the power transmitting device 10 causes the control unit 17 to identify position information of the avoidance target 5000 in the first region 4100 based on sensor information, and acquires predetermined position information 300 corresponding to the position information from among the plurality of predetermined position information 300. In detail, the power transmitting device 10 acquires one or more pieces of predetermined position information 300 indicating a position that matches or is close to a position indicated by the position information of the avoidance target 5000 from among the plurality of predetermined position information 300. For example, when the position of the avoidance target 5000 spans a plurality of predetermined positions 400P, the power transmitting device 10 can acquire the array response vector from each of the predetermined position information 300 corresponding to those predetermined positions 400P. When the process of step S106 ends, the power transmitting device 10 advances the process to step S107.

[0070] The power transmitting device 10 generates a transmission weight based on the array response vector acquired in step S106 (step S107). For example, the power transmitting device 10 generates a transmission weight based on the array response vector acquired by the control unit 17 and the matrix (I-AA + ) to obtain the array response vector a d The power transmitting device 10 calculates the array response vector a′ calculated by the control unit 17. d ' is normalized using (Equation 7) 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 S105 already described.

[0071] The power transmitting device 10 multiplies the transmission weight (step S105). For example, the power transmitting device 10 multiplies the transmission weight by the 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. As a result, the power transmitting device 10 causes the plurality of antenna elements 11A to radiate the radio waves 2000W including the transmission signal 2000 for power supply. In this case, the radio waves 2000W are combined in a constructive manner in the power receiving device 20, but since the power transmitting device 10 can form a null toward the avoidance target 5000 in the first area 4100 close to the device itself, the radio waves 2000W are combined in a destructive manner in the avoidance target 5000. Therefore, even if the power transmitting device 10 is installed in an environment in which the distance between the radio waves 2000W and the avoidance target 5000 cannot be sufficiently secured, the radio waves 2000W can be reliably directed toward the avoidance target 5000, thereby improving safety. Then, when the process of step S105 is completed, the power transmitting device 10 ends the process procedure shown in FIG. 9.

[0072] [System operation example] 1, when an avoidance target 5000 exists in the vicinity between the power transmitting device 10 and the power receiving device 20 and in the first area 4100, the power transmitting device 10 can detect the direction, position, etc. of the avoidance target 5000 based on the sensor information of the sensor unit 15. When the power receiving device 20 emits radio waves including a prescribed signal 1000, the main paths are a path that goes directly to the power transmitting device 10 and a path that is reflected by multiple avoidance targets 5000 and goes to the power transmitting device 10. In this case, the power transmitting device 10 estimates the propagation channel characteristics of the radio waves including the prescribed signal 1000 received by the array antenna 11, and calculates an array response vector a i The power transmitting device 10 detects the direction, position, etc. of the avoidance target 5000 different from the power receiving device 20 based on the sensor information from the sensor unit 15. When the avoidance target 5000 is present in the first area 4100, the power transmitting device 10 acquires the predetermined position information 300 corresponding to the position from the storage unit 17D, and acquires an array response vector from the predetermined position information 300. The power transmitting device 10 converts the array response vector into a matrix and stores the matrix (I-AA + The power transmitting device 10 calculates the array response vector a dand the matrix (I-AA + ) to obtain the array response vector a d The power transmitting device 10 calculates the calculated array response vector a d ' is normalized using (Equation 7) to obtain the optimal weight vector w opt The power transmitting device 10 generates an optimal weight vector W opt The radio waves 2000W of the transmission signal 2000 multiplied by are radiated from the multiple antenna elements 11A of the array antenna 11. The power receiving device 20, for example, converts the received radio waves 2000W for power supply into a direct current, and uses this direct current to charge a battery or to operate using the charged power. After that, the power receiving device 20 transmits the specified signal 1000.

[0073] As described above, the power transmitting device 10 stores in advance in the storage unit 17D an array response vector suitable for the direction and position (distance) of each of a plurality of predetermined positions, and calculates a weight vector w that directs a null to the avoidance target 5000 based on the array response vector. opt can be generated. As a result, the power transmitting device 10 does not need to travel a distance until the radio wave intensity to the avoidance target 5000 in the first area 4100 near the power transmitting device itself is reduced, so that the influence of radio waves from the radio waves 2000W to the avoidance target 5000 can be reduced. Therefore, even if the avoidance target is inside the first area 4100 near the power transmitting device itself, the power transmitting device 10 can reduce the radiation of the radio waves 2000W to the avoidance target and ensure safety. Even in an installation environment where a sufficient distance cannot be ensured between the power transmitting device 10 and the avoidance target 5000, the power transmitting device 10 can reduce the intensity of the radio waves 2000W directed toward the avoidance target 5000. Even if the power transmitting device 10 is set in a narrow propagation environment where the avoidance target 5000 exists, the power transmitting device 10 can ensure null performance, so that safe wireless power transmission can be realized.

[0074] The power transmission device 10 detects that the distance R from the power transmission device 10 to the avoidance target 5000 is a predetermined distance 2D 2 / λ or less, a weight vector for directing a null to the target to be avoided 5000 in the near field in the radio waves 2000W can be generated based on the array response vector stored in the storage unit 17D. This allows the power transmitting device 10 to reduce the intensity of the radio waves 2000W directed toward the target to be avoided 5000 even if the target to be avoided 5000 exists in the near field.

[0075] The power transmission device 10 detects that the distance R from the power transmission device 10 to the avoidance target 5000 is a predetermined distance 2D 2 When it is larger than / λ, the radiated radio waves 2000W can be directed toward the power receiving device 20 based on the direction of the object to be avoided 5000, and radiation of the radio waves 2000W toward the object to be avoided 5000 can be suppressed.

[0076] Even if a plurality of avoidance targets 5000 exist in the propagation environment, the power transmitting device 10 detects the directions of the plurality of avoidance targets 5000 and calculates a weight vector W so as to direct a null to each of the plurality of avoidance targets 5000. opt In the present disclosure, the control unit 17 may generate a transmission weight such that the gain in the direction of the avoidance target 5000 is within a predetermined gain range from null. For example, when null is x [dB], the control unit 17 may generate a transmission weight such that the gain in the direction of the avoidance target 5000 is within a gain range of x [dB] to y [dB] of null.

[0077] In the above embodiment, the power transmitting device 10 has been described as having a linear array in which the antenna elements 11A of the array antenna 11 are equally spaced, but the present invention is not limited to this. i As long as it is possible to calculate the above, the arrangement of the multiple antenna elements 11A does not need to be an equally spaced linear array.

[0078] 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.

[0079] For example, in the appended claims, the function of the control unit 17 of the power transmitting device 10 may be realized as a transmission weight generating device. The transmission weight generating device may be realized, for example, by various devices and may be configured to be incorporated into the power transmitting device 10 of the above embodiment, or may be configured to provide information such as the transmission weight to the power transmitting device 10 from outside the power transmitting device 10.

[0080] [Appendix 1] A transmission weight generation device that generates a transmission weight for an antenna having a plurality of antenna elements based on a received signal transmitted from a power receiving device and information related to an object to be avoided that is different from the power receiving device, so that a strength of a radio wave transmitted to the power receiving device by the antenna having the plurality of antenna elements is equal to or less than a predetermined strength, a storage unit that stores an array response vector for each of a plurality of predetermined positions that are set in advance, a transmission weight generating device that generates a weight for directing a null in the radio wave toward the target to be avoided, based on the array response vector stored in the storage unit and corresponding to a position of the target to be avoided for the radio wave. [Appendix 2] A power receiving device; a transceiver unit that transmits a transmission signal to a power receiving device and receives a reception signal transmitted from the power receiving device by an antenna having a plurality of antenna elements; A power transmitting device having a control unit that controls the directivity of the antenna that transmits the transmission signal so that the strength of the radio wave that transmits the transmission signal to the object is equal to or less than a predetermined value based on the received signal and information about a floor object different from the power receiving device; Equipped with the power transmitting device further includes a storage unit configured to store an array response vector for each of a plurality of predetermined positions set in advance; the control unit generates a weight for directing a null in the radio waves toward the target to be avoided, based on an array response vector stored in the storage unit and corresponding to a position of the target to be avoided for the radio waves. [Explanation of symbols]

[0081] 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 20 Power receiving device 21 Antenna 22 Transmitter / receiver 23 Signal Generator 24 Power receiving section 151 areas 200B Reference point 200P receiving point 300 Predetermined location information 400P in place 1000 regulation signal 2000 Transmitted signal 2000W radio wave 4000 rooms 4100 1st area 4200 2nd area 4300 given distance 5000 Avoidance Target R Distance W opt Weight Vector

Claims

1. A transmitter that transmits radio waves via an array antenna; a storage unit that stores an array response vector for each of a plurality of predetermined positions that are set in advance; a control unit that generates a weight for directing a null in the radio wave toward the target to be avoided based on an array response vector stored in the storage unit and corresponding to a position of the target to be avoided in the radio wave; A power transmitting device comprising:

2. 2. The power transmitting device according to claim 1, wherein when a distance from the power transmitting device to the target to be avoided is equal to or shorter than a predetermined distance, the control unit generates a weight for directing a null in the radio waves to the target to be avoided based on an array response vector stored in the storage unit and corresponding to a position of the target to be avoided.

3. When the wavelength of the radio wave is λ and the length in the arrangement direction of the multiple antenna elements used in the transmission unit when they are arranged on the substrate is D, the predetermined distance is 2D ２ The power transmitting device according to claim 2 , wherein the value satisfies:

4. The power transmitting device according to claim 3 , wherein when a distance to the avoidance target is greater than the predetermined distance, the control unit generates a weight for controlling directivity based on characteristics of a propagation channel of a specified signal from the power receiving device and a target direction of the avoidance target.

5. 2. The power transmitting device according to claim 1, wherein the control unit identifies a predetermined position corresponding to a position of the object to be avoided from among a plurality of the predetermined positions, and generates the weight for directing a null from the array response vector of the identified predetermined position.

6. The power transmitting device according to claim 1 , wherein the control unit controls the transmission unit so as to supply power to a power receiving device by the radio waves.

7. A power transmitting device including a transmitting unit that transmits radio waves via an array antenna, a storage step of storing an array response vector for each of a plurality of predetermined positions in a storage unit; a generating step of generating a weight for directing a null to an object to be avoided in radio waves transmitted via an array antenna based on an array response vector stored in the storage unit and corresponding to a position of the object to be avoided; A control method comprising:

8. A power transmitting device including a transmitting unit that transmits radio waves via an array antenna, a storage step of storing an array response vector for each of a plurality of predetermined positions in a storage unit; a generating step of generating a weight for directing a null to an object to be avoided in radio waves transmitted via an array antenna based on an array response vector stored in the storage unit and corresponding to a position of the object to be avoided; A control program that executes the above.

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