Wireless power supply device and wireless power supply system

Abstract

To provide a wireless power supply device and a wireless power supply system capable of efficiently supplying power to a power reception device.SOLUTION: The wireless power transmission apparatus according to the present embodiment comprises a receiver configured to receive a first signal from a power reception apparatus via a plurality of antennas, and a controller configured to determine a plurality of weights to be used for the plurality of antennas based on a reception signal of the first signal, wherein the receiver is configured to receive a second signal from the power reception apparatus by reception beamforming based on the plurality of weights, and the controller is configured to determine a transmission power of a power signal to be transmitted to the power reception apparatus based on a reception power of the second signal, and transmit the power signal based on the transmission power by transmission beamforming based on the plurality of weights.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present embodiment relates to a wireless power supply device and a wireless power supply system. [Background technology]

[0002] Conventionally, there has been a method for measuring the received power at the power receiving device to prevent the power supplied to the power receiving device via microwave power from becoming excessive (for example, an input that causes output saturation or failure of the rectifier). Another method has been to measure the received power by transmitting a test beam with a weak power. There has also been a method for determining the transmission power of the power transmitting device from the radio wave strength by receiving a beacon signal transmitted from the power receiving device with the power transmitting device.

[0003] A configuration in which the power receiving device measures the received power requires a mechanism for measuring the power on the power receiving device side, which increases costs. In addition, directly measuring the received power can pose a risk of damage.

[0004] Although the method using a weak test beam is effective in preventing damage, it has the problem of reducing the power supply time efficiency due to unnecessary exchanges occurring before power transmission begins. There is also the problem of the risk of damage due to nonlinearity and variations in the input / output power characteristics of the rectifier.

[0005] In the method of receiving a beacon signal transmitted from a power receiving device by a power transmitting device, the antenna radiation characteristics differ when receiving a beacon from the power receiving device and when actually supplying power to the power receiving device (during beamforming power supply). Therefore, even if the transmission power for power supply is determined from the radio wave strength of the beacon signal, it is difficult to reduce the risk of saturation or failure of the power receiving device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5556044 [Patent Document 2] Patent No. 6864801 Summary of the Invention [Problem to be solved by the invention]

[0007] The present embodiment provides a wireless power supply device and a wireless power supply system that enable efficient power supply to a power receiving device. [Means for solving the problem]

[0008] The wireless power supply device of this embodiment includes a receiving unit that receives a first signal from a power receiving device via multiple antennas, and a control unit that determines multiple weights to be used for the multiple antennas based on the received signal of the first signal, wherein the receiving unit receives a second signal from the power receiving device using receive beamforming based on the multiple weights, and the control unit determines the transmission power of a power signal to be transmitted to the power receiving device based on the received power of the second signal, and includes a transmitting unit that transmits the power signal based on the transmission power using transmit beamforming based on the multiple weights. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing the overall configuration of a wireless power feeding system according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing an example of an operation flow of the wireless power feeding system of FIG. [Figure 3] FIG. 10 is a block diagram showing the overall configuration of a wireless power feeding system according to a second embodiment. [Figure 4] FIG. 4 is a diagram showing an example of an operation flow of the wireless power feeding system of FIG. 3. [Figure 5] FIG. 10 is a block diagram showing the overall configuration of a wireless power feeding system according to a third embodiment. [Figure 6] FIG. 6 is a diagram showing an example of an operation flow of the wireless power feeding system of FIG. 5. [Figure 7] FIG. 10 is a block diagram showing the overall configuration of a wireless power feeding system according to a fourth embodiment. [Figure 8]FIG. 10 is a block diagram showing the overall configuration of a wireless power feeding system according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present embodiment will be described below with reference to the drawings.

[0011] (First embodiment) FIG. 1 is a block diagram showing the overall configuration of a wireless power supply system according to this embodiment. 1 includes a power transmitting device 100 and a power receiving device 200, and performs wireless power transmission (wireless power feeding) using electromagnetic waves such as microwaves from the power transmitting device 100 to the power receiving device 200. In the example of FIG. 1, the wireless power feeding system includes only one power receiving device 200, but may include multiple power receiving devices 200.

[0012] The power receiving device 200 may be any device that receives power from the power transmitting device 100 and operates based on the supplied power. For example, the power receiving device 200 can be used in a sensor device attached to a robot arm, a camera for fixed-point observation, a sensor for monitoring factory processes, a device for picking up goods such as merchandise at a logistics center, a lock mechanism control device for an auto-lock door, a smartphone, and the like.

[0013] [Power receiving device 200] The power receiving device 200 includes a power receiving antenna 201, an RF-DC converter 202 (a rectifier, or a rectifier and a battery charging circuit, etc.), a signal generator 203 (a transmitter), a transmission / reception switch 204, a battery 205, a control unit 206, a communication unit 207, and a load device 208. The RF-DC converter 202, the signal generator 203, the transmission / reception switch 204, the control unit 206, and the communication unit 207 are realized by at least one of an analog circuit that performs analog signal processing and a digital circuit that performs digital signal processing. The digital circuit may be a CPU (Central Processing Unit), a DSP (Digital Signal Processor), a general-purpose processor, a microprocessor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof.

[0014] The transmission / reception switch 204 switches the connection destination of the antenna 201 between the RF-DC converter 202 and the signal generator 203. The antenna 201 is connected to the RF-DC converter 202 during reception, and to the signal generator 203 during transmission.

[0015] The signal generator 203 generates a beacon signal 250 of a predetermined frequency using an oscillator and transmits it to the power transmitting device 100 via the antenna 201. The signal generator 203 functions as a transmitter that transmits the beacon signal 250. The beacon signal 250 corresponds to an example of a predetermined first signal or second signal. The beacon signal 250 is a signal including a predetermined pattern and is used by the power transmitting device 100 to estimate a propagation path between the power receiving device 200. The signal including the predetermined pattern also includes an unmodulated signal or a signal not including data, such as an equal sine wave signal. The transmission power of the beacon signal 250 is known to the power transmitting device 100 and is, for example, predetermined. The frequency of the beacon signal 250 may be the same as or approximately the same as the frequency of the power signal transmitted from the power transmitting device 100. "Same" includes a case where there is an error of about 10%.

[0016] The RF-DC converter 202 is a rectifier that converts AC to DC. More specifically, the RF-DC converter 202 converts an AC power signal (power supply signal) 150 received by the antenna 201 from the power transmitting device 100 into DC and outputs DC power. The power supply signal 150 is a signal such as a microwave.

[0017] The storage battery 205 stores the DC power output from the RF-DC converter 202. The stored power can be used as operating power for the communication unit 207, the control unit 206, the load device 208, the RF-DC converter 202, the signal generator 203, and the transmission / reception switch 204.

[0018] The communication unit 207 communicates information with the communication unit 110 of the power transmitting device 100. For example, the communication unit 207 transmits information (beacon power information) related to the transmission power of a beacon signal to the power transmitting device 100 in accordance with an instruction from the control unit 206. The transmission power is, for example, antenna power or equivalent isotropically radiated power (EIRP).

[0019] Furthermore, the communication unit 110 transmits to the power transmitting device 100 information (optimum received power information) regarding the optimum received power of wireless power feeding received by the power receiving device 200. The optimum received power is determined according to the power conversion characteristics of the RF-DC converter 202. The optimum received power is an example of the received power desired by the power receiving device 200. The information regarding the optimum received power may be, for example, information regarding the maximum allowable power or information regarding the range of received power that the power receiving device 200 can tolerate (a power range in which a desired conversion efficiency can be obtained). Furthermore, when the communication unit 207 receives a request to transmit a beacon signal (a request to transmit a first beacon signal or a request to transmit a second beacon signal) from the power transmitting device 100, it sends the request to transmit the beacon signal to the control unit 206.

[0020] Any wireless standard may be used for the communication method used by the communication unit 207. Examples include Bluetooth Low Energy (BLE), wireless local area network (wireless LAN), and a 920 MHz band communication standard. The communication unit 207 includes a communication antenna separate from the antenna 201 and performs communication using the communication antenna. However, a configuration in which the communication unit 207 performs communication using the antenna 201 is also possible. Note that the communication destination of the communication unit 207 is not limited to the power transmitting device 100. For example, the communication unit 207 may communicate with a master device that controls multiple power receiving devices 200. In this case, the power transmitting device 100 may be the master device. Communication with the master device may be performed by the communication unit 207, or a communication unit separate from the communication unit 207 may be provided and perform communication using the separate communication unit. In this case, the communication method with the master device may be different from the communication method with the power transmitting device 100.

[0021] The control unit 206 controls the entire power receiving device 200, for example, controlling at least one or all of the signal generator 203, the RF-DC converter 202, the transmission / reception switch 204, and the communication unit 207. When a transmission request for a beacon signal (a transmission request for a first beacon signal, a transmission request for a second beacon signal) from the power transmitting device 100 is received by the communication unit 207, the control unit 206 controls the communication unit 207 to transmit the beacon signal (the first beacon signal, the second beacon signal) to the power transmitting device 100 in response to the request.

[0022] [Power transmission device 100] The power transmitting device 100 includes a plurality of antennas 102, a transmission / reception switch 103, a receiving unit 104, a transmitting unit 105, a control unit 107 (phase / amplitude detection unit), a weight setting unit 108, a high-frequency unit 109, and a communication unit 110. The transmission / reception switch 103, the receiving unit 104, the transmitting unit 105, the control unit 107, the weight setting unit 108, the high-frequency unit 109, and the communication unit 110 are realized by at least one of an analog circuit that performs analog signal processing and a digital circuit that performs digital signal processing. The digital circuit may be a CPU, a DSP, a general-purpose processor, a microprocessor, an ASIC, an FPGA, or a combination thereof.

[0023] The power transmitting device 100 operates based on power supplied from an external commercial power source or an external power storage device. However, the power transmitting device 100 may be provided with an internal storage battery and operate based on stored power in the storage battery.

[0024] The transmission / reception switch 103 switches the connection destination of the multiple antennas 102 between the receiving unit 104 and the transmitting unit 105. During reception, the multiple antennas 102 are connected to the receiving unit 104, and during transmission, they are connected to the transmitting unit 105.

[0025] The high-frequency unit 109 (signal generator) includes a local oscillator that generates a local signal, and generates a power supply signal 150 (power signal) to the power receiving device 200 using the local oscillator. The local signal is, for example, a high-frequency analog signal. The high-frequency unit 109 sends the local signal generated by the local oscillator to the transmitting unit 105 as the power supply signal 150. The high-frequency unit 109 may also send a signal obtained by amplifying the local signal using an amplifier to the transmitting unit 105 as the power supply signal 150. The high-frequency unit 109 may frequency-convert the local signal before or after amplification, and may further band-control the frequency-converted signal using a filter.

[0026] The communication unit 110 communicates information with the communication unit 207 of the power receiving device 200. For example, the communication unit 110 receives information related to the transmission power of a beacon signal from the power receiving device 200. The communication unit 110 also receives information related to the optimum reception power of wireless power supply (optimum reception power information) from the power receiving device 200. The communication unit 110 sends this received information to the control unit 107. The communication unit 110 also transmits a transmission request for a beacon signal (a transmission request for a first beacon signal, a transmission request for a second beacon signal) to the power receiving device 200 in accordance with an instruction from the control unit 107. Any wireless standard may be used by the communication unit 207. Details of the wireless standard have been described in the explanation of the power receiving device 200 and are therefore omitted here.

[0027] The receiving unit 104 receives beacon signals (first beacon signals) from the power receiving device 200 via the multiple antennas 102, and performs A / D conversion on the received beacon signals using an ADC. The receiving unit 104 may amplify and adjust the band of the received signals before or after the A / D conversion.

[0028] The control unit 107 controls the entire power transmitting device 100, for example, at least one or all of the transmission / reception switch 103, the receiving unit 104, the transmitting unit 105, the weight setting unit 108, the high frequency unit 109, and the communication unit 110.

[0029] The control unit 107 detects the phase and amplitude of the signal for each antenna 102, or detects the phase difference and amplitude difference from predetermined values ​​for the phase and amplitude, and obtains the detection result as an estimated result of the propagation path between each antenna 102 and the power receiving device 200.

[0030] The control unit 107 determines a weight for each antenna 102 for performing transmission beamforming for the power receiving device 200 based on the propagation path estimation result for each antenna 102. The control unit 107 sends the weight determined for each antenna 102 to the weight setting unit 108.

[0031] The weight setting unit 108 sets the weight for each antenna 102 received from the control unit 107 in the receiving unit 104 and the transmitting unit 105. The weight set for each antenna 102 in the receiving unit 104 and the transmitting unit 105 is the same value. Note that, before setting the weight, initial value weights may be set in the receiving unit 104 and the transmitting unit 105. The initial value may be, for example, a value that keeps the phase and amplitude the same (does not change), or may be another value.

[0032] After the weight setting unit 108 sets the weight for the receiving unit 104, the receiving unit 104 receives a beacon signal (second beacon signal) transmitted from the power receiving device 200, adjusts the phase and amplitude based on the weight set for each antenna 102, and outputs the adjusted signal to the control unit 107. Receiving a signal from the power receiving device 200 based on the weight set for each antenna 102 in this manner is called receive beamforming. In this embodiment, the phase and amplitude are adjusted for each antenna 102 based on the weight set for each antenna 102. However, a configuration in which only the phase is adjusted is also possible. In this case, amplitude adjustment may be omitted from the following description regarding phase and amplitude adjustment. The phase and amplitude adjustment based on the weight in receive beamforming may be performed in either the digital domain or the analog domain. In the digital domain, the received signal is converted from analog to digital by an ADC, and the phase and amplitude of the AD-converted signal may be adjusted based on the weight set for each antenna 102. In the analog domain, the phase and amplitude may be adjusted in the signal before AD conversion, i.e., the analog (low frequency (baseband) domain signal after high frequency / frequency conversion). In this case, a phase shifter may be used to adjust the phase, and a variable gain amplifier or a variable attenuator may be used to adjust the amplitude.

[0033] The control unit 107 combines the signals adjusted for each antenna 102 to obtain a beacon reception signal. The combination of signals can be performed in either the digital or analog domain. The control unit 107 detects the amplitude of the obtained beacon reception signal. The control unit 107 calculates the propagation loss of the beacon signal based on the difference between the detected amplitude and the transmission power of the beacon signal indicated by the beacon power information previously obtained from the power receiving device 200. The difference may be a ratio or a subtraction. Due to the symmetry of the propagation path, even when transmission beamforming is performed from the power transmitting device 100 to the power receiving device 200 with the same weight, it is considered that the same or similar propagation loss (hereinafter referred to as "same") occurs in the transmitted power supply signal (power signal). In other words, it is considered that the propagation loss during actual power transmission (power transmission using beamforming to the power receiving device 200) is the same or similar to the propagation loss calculated during the above-mentioned reception beamforming. The control unit 107 determines the transmission power of the transmission beamforming of the power supply signal, assuming that the same propagation loss occurs. As an example, the transmission power is determined by adding a value corresponding to the propagation loss to the optimum reception power desired by the power receiving device 200. This increases the possibility that the power supply signal will be received at the reception power desired by the power receiving device 200. The power obtained by subtracting the value corresponding to the propagation loss from the transmission power determined in this manner becomes the estimated value of the reception power of the power receiving device 200 during transmission beamforming.

[0034] The control unit 107 controls the high frequency unit 109 to generate a high frequency signal (power supply signal) with the determined transmission power. For example, by changing the settings of an amplifier included in the high frequency unit 109, the high frequency signal with the determined transmission power can be generated.

[0035] The transmitter 105 adjusts the phase and amplitude of the high-frequency signal supplied from the high-frequency unit 109 based on the weight for each antenna 102 to generate a transmission signal for each antenna 102, performs DA conversion on each of the generated transmission signals using a DAC, and transmits the signal from the antenna 102. The transmitter 105 may perform band adjustment, amplification, and the like on the DA-converted signal. Transmitting a signal from the transmitter 105 based on the weight for each antenna 102 in this manner is called transmit beamforming. A transmit beam having directivity toward the power receiving device 200 is formed by transmit beamforming, and the power feeding signal 150 is transmitted to the power receiving device 200. Here, adjustment of the phase, etc. (transmit beamforming) is performed in the digital domain before DA conversion. However, adjustment of the phase, etc. (transmit beamforming) may also be performed in the analog domain, specifically, after DA conversion, using a phase shifter, etc. As described above, the power feeding signal 150 transmitted from the transmitter 105 is attenuated during propagation and is received by the power receiving device 200 as optimal received power (optimal input power of the RF-DC converter 202). The received power is converted into DC power via an RF-DC converter 202, and then used to charge a storage battery 205 or to supply to a load device 208, for example.

[0036] Fig. 2 shows an example of an operation flow of the wireless power supply system of Fig. 1. The timing of execution of this operation flow may be at startup, at regular or arbitrary time intervals, or when an instruction is input by a user such as an administrator.

[0037] The communication unit 207 of the power receiving device 200 transmits the beacon power information and the optimum received power information to the power transmitting device 100 (S11). The beacon power information and the optimum received power information may be transmitted simultaneously or separately. The beacon power information and the optimum received power information may be transmitted every time the flow is executed. Alternatively, they may be transmitted only the first time.

[0038] Next, the communication unit 110 of the power transmitting device 100 transmits a beacon transmission request to the power receiving device 200 via wireless communication, requesting the transmission of a beacon signal (first beacon signal) (S12). The control unit 206 of the power receiving device 200 generates a first beacon signal using the signal generator 203, and transmits the first beacon signal from the antenna 201 (S13). The first beacon signal is received by the multiple antennas 102 of the power transmitting device 100, and the phase and amplitude of each antenna 102 are detected by the control unit 107. Note that receive beamforming is not performed when the first beacon signal is received. The phase and amplitude information for each antenna corresponds to propagation path information between the power transmitting device 100 and the power receiving device 200. Based on this propagation path information, the control unit 107 determines a weight for each antenna 102 and notifies the weight setting unit 108, and the weight setting unit 108 sets the weight for each antenna 102 in the receiving unit 104 and the transmitting unit 105 (S14).

[0039] Next, a beacon transmission request is transmitted from the communication unit 110 of the power transmitting device 100 to the power receiving device 200, requesting transmission of a beacon signal (second beacon signal) (S15). The control unit 206 of the power receiving device 200 generates a second beacon signal using the signal generator 203, and transmits the second beacon signal from the antenna 201 (S16). The second beacon signal is received by reception beamforming corresponding to the power receiving device 200 (i.e., directed toward the power receiving device 200) with a weight set for the reception unit 104. The control unit 107 detects the amplitude of the second beacon signal, and compares it with the transmission power indicated by the beacon power information to detect the propagation loss of the second beacon signal.

[0040] The control unit 107 estimates (calculates) the received power value when the power feed signal reaches the power receiving device 200 based on the propagation loss and the transmission power value of the power feed signal. If the estimated received power value exceeds the aforementioned optimal power value, the control unit 107 determines the transmission power of the power feed signal to a value that makes the received power value equal to or not exceeding the optimal power value (S17). The determined transmission power value is set in the high-frequency unit 109 (S17). This sets the high-frequency unit 109 to generate a high-frequency signal (power feed signal) with the set transmission power. Even if the estimated received power value is below the aforementioned optimal power value, the transmission power of the power feed signal may be set to a value that makes the received power value equal to or not exceeding the optimal power value, provided, however, that the transmission power of the power feed signal does not exceed a value specified by law or regulation. Here, the comparison is made with the optimal power value, but it may also be made with the maximum allowable power value or allowable power range. When comparing with the allowable power range, if the calculated received power value is within this range, the above-mentioned transmission power value for power supply (default value) may be used without change.

[0041] A transmission / reception switching request is transmitted from the communication unit 110 of the power transmitting device 100 to the power receiving device 200 (S18). Based on the transmission / reception switching request, the control unit 206 of the power receiving device 200 controls the transmission / reception switch 204 to switch the connection destination of the antenna 201 to the RF-DC converter 202. This causes the power receiving device 200 to enter a power reception standby state. The control unit 107 of the power transmitting device 100 causes the high-frequency unit 109 to generate a high-frequency signal (power supply signal) at the transmission power value. The transmission unit 105 transmits the generated high-frequency signal from the multiple antennas 102 using the set weights. That is, the power supply signal 150 is transmitted to the power receiving device 200 by transmission beamforming (S19).

[0042] 2, a beacon transmission request is transmitted to have the power receiving device 200 transmit the second beacon signal. However, a configuration is also possible in which the transmission of the beacon transmission request is omitted. For example, in response to a beacon transmission request transmitted to transmit a first beacon signal, the power receiving device 200 may transmit the first beacon signal and then, after a certain time, transmit the second beacon signal spontaneously. Alternatively, the power receiving device 200 may transmit the second beacon signal consecutively after transmitting the first beacon signal.

[0043] As described above, according to this embodiment, efficient power transmission is possible without providing the power receiving device 200 with a means for measuring received power and without causing saturation of received power or failure of the rectifier in the power receiving device 200. Furthermore, since the propagation path is estimated by receiving a beacon signal with the same weight setting as that used during actual power supply (transmission), the propagation loss during actual power transmission can be estimated with high accuracy. This allows the power receiving device 200 to transmit power that allows for highly efficient rectification operation and significantly reduces the risk of rectifier saturation or failure.

[0044] (Second embodiment) Fig. 3 is a block diagram showing the overall configuration of a wireless power supply system according to this embodiment. Elements with the same names as those in Fig. 1 are given the same reference numerals, and descriptions thereof will be omitted as appropriate, except for expanded or changed processes. The following description will focus on the differences from the first embodiment.

[0045] The power receiving device 200 includes multiple RF-DC converters. In this example, it includes an RF-DC converter 202A and an RF-DC converter 202B. However, the number of RF-DC converters may be three or more. Furthermore, the RF-DC converters 202A and 202B have different power conversion characteristics, and each has a different optimal input power.

[0046] The power receiving device 200 also includes a switch 209 that switches between the RF-DC converter 202A and the RF-DC converter 202B to be used. The switch 209 switches the connection destination of the antenna 201 between the RF-DC converters 202A and 202B. Other means may be used to switch between the RF-DC converters. The switching of the switch 209 is controlled by the control unit 206. In order to prevent the output current of the RF-DC converter 202A or 202B that is not being used from inputting (reverse flowing) into the output side of the other RF-DC converter, a backflow prevention element such as a diode may be provided on the output side of each of the RF-DC converters 202A and 202B.

[0047] Figure 4 shows an example of the operation flow of the wireless power supply system of Figure 3. The same operations as those in Figure 2 above are denoted by the same reference numerals, and explanations common to the first embodiment will be omitted as appropriate. The following description will focus on differences from the operation flow of the first embodiment.

[0048] The communication unit 207 of the power receiving device 200 transmits the beacon power information and the optimum received power information of each RF-DC converter to the power transmitting device 100 (S11A). The optimum power value information may be, for example, maximum allowable power information.

[0049] Steps S12 to S16 are the same as steps S12 to S16 in FIG. 2, and therefore a description thereof will be omitted.

[0050] In step S17, similar to step S17 in FIG. 2, the transmission power of the power supply signal is determined so that the received power value of the power receiving device 200 is equal to or does not exceed the optimal power value (or the maximum allowable power value, etc.), and the determined transmission power value is set in the high frequency unit 109 (same S17).

[0051] In the following step S20, the control unit 107 of the power transmitting device 100 compares the estimated received power with the optimal input values ​​of the RF-DC converters 202A and 202B of the power receiving device 200, and selects the RF-DC converter having the optimal input value closest to the estimated received power.

[0052] In the following step S21, the communication unit 110 transmits a switching request to the selected RF-DC converter as information indicating the selected RF-DC converter to the power receiving device 200. Upon receiving the switching request, the control unit 206 of the power receiving device 200 controls the switch 209 to switch the connection destination of the antenna 201 to the RF-DC converter indicated in the switching request.

[0053] The subsequent steps S18 and S19 are the same as steps S18 and S19 in FIG. 2, and therefore a description thereof will be omitted.

[0054] As described above, according to this embodiment, in addition to the effects of the first embodiment, by selecting an RF-DC converter according to the estimated received power of a power supply signal received by the power receiving device, more optimal RF-DC conversion according to the received power becomes possible, thereby enabling efficient power supply to the power receiving device.

[0055] (Third embodiment) Fig. 5 is a block diagram showing the overall configuration of a wireless power supply system according to this embodiment. Elements with the same names as those in Fig. 1 are given the same reference numerals, and descriptions thereof will be omitted as appropriate, except for expanded or changed processes. The following description will focus on the differences from the first embodiment.

[0056] The wireless power feeding system in Fig. 5 includes a power transmitting device 100 and a plurality of power receiving devices 200A, 200B, and 200C. The block diagram of the power transmitting device 100 and the block diagram of the power receiving devices 200A to 200C are the same as those in Fig. 1, but some operations are expanded.

[0057] The communication unit 207 in each of the power receiving devices 200A to 200C transmits to the power transmitting device 100 remaining battery level information, which is measurement information related to the remaining capacity or voltage of the storage battery 205, in addition to the beacon power information and optimal received power information in the first embodiment. The remaining battery level information may be the value of the remaining battery level (remaining energy) of the storage battery 205, or may be the ratio of the remaining battery level to the total capacity of the storage battery 205 (SOC), or may be the voltage of the storage battery 205 (for example, charging voltage or discharging voltage). Since the charging voltage or discharging voltage depends on the remaining battery level of the storage battery 205, the remaining battery level can be estimated from the voltage of the storage battery 205. Since the remaining battery level or voltage can be acquired from a measuring means provided in the storage battery 205, there is no need to add a new measuring means. Note that the remaining battery level information may be transmitted in the first embodiment.

[0058] The control unit 107 in the power transmitting device 100 generates a power supply schedule for each power receiving device based on the estimated received power of each power receiving device estimated in the same manner as in the first embodiment and the remaining battery capacity of each power receiving device. For example, the control unit 107 determines the order of power receiving devices to be supplied with power and the time (period) for power supply. The control unit 107 controls power supply to each power receiving device according to the generated power supply schedule.

[0059] Fig. 6 shows an example of the operation flow of the wireless power supply system in Fig. 5. The same operations as those in Fig. 2 of the first embodiment are denoted by the same reference numerals, and explanations common to the first embodiment will be omitted as appropriate. The following description will focus on the differences from the operation flow of the first embodiment.

[0060] The communication units 207 of the power receiving devices 200A to 200C transmit the beacon power information, the optimum received power information, and the remaining battery level information to the power transmitting device 100 (S11B).

[0061] The power transmitting device 100 sequentially performs the same processes of steps S12 to S16 as those in Fig. 2 in the first embodiment with each of the power receiving devices 200A to 200C. As a result, the propagation loss and received power due to receive beamforming are estimated for each power receiving device. Note that, for each receiving device, the weight of the antenna 102 is set to an initial value before the processes of steps S12 to S16.

[0062] The control unit 107 of the power transmitting device 100 generates a power supply schedule for each power receiving device based on the estimated value of received power and the remaining battery level value for each power receiving device (S31). Specifically, the order of power receiving devices to be supplied with power and the power supply time (period) are determined. As an example, the power supply order is determined so that power is supplied in order from the power receiving device with the lowest remaining battery level. The power supply time is set to the time required for the remaining battery level to reach a predetermined reference value. If the estimated value of received power is below a threshold (for example, when there is an obstacle between the power receiving device and the power receiving device and the radio wave conditions are poor), efficient power supply is not possible, so the power supply order may be delayed or placed last. Alternatively, the power receiving device may be excluded from the power supply targets until the estimated value of received power becomes equal to or greater than the threshold.

[0063] In the example of Fig. 6, the power receiving device 200B is selected first according to the power feeding schedule. The control unit 107 of the power transmitting device 100 sets the weight and transmission power value determined in steps S12 to S16 for the power receiving device 200B in the transmitting unit 105 and the high-frequency unit 109, respectively (S32). After this, the process is the same as in the first embodiment. That is, the power transmitting device 100 transmits a transmission / reception switching request to the power receiving device 200B (S18). Then, the power transmitting device 100 transmits a high-frequency signal (power feeding signal) generated by the high-frequency unit 109 to the power receiving device 200B by transmission beamforming using the weight set in the transmitting unit 105 (S19). After completing power feeding to the power receiving device 200B, the power transmitting device 100 repeats selecting the next power receiving device and performing the processes of steps S32, S18, and S19 according to the power feeding schedule.

[0064] As described above, according to this embodiment, the remaining battery capacity information of each power receiving device is used to optimize the power supply sequence and power supply time of the entire power supply system, thereby enabling efficient power supply. Furthermore, because the remaining battery capacity information can be obtained from a measurement means (specifically, a battery charging circuit) that the battery originally has, there is no need to add a new measurement configuration to the power receiving device, which helps prevent increases in the cost of the power receiving device.

[0065] (Fourth embodiment) Fig. 7 is a block diagram showing the overall configuration of a wireless power supply system according to this embodiment. Elements with the same names as those in Fig. 1 are given the same reference numerals, and descriptions thereof will be omitted as appropriate, except for expanded or changed processes. The following description will focus on the differences from the first embodiment.

[0066] The block diagram of the power receiving device 200 is the same as that in Fig. 1. The power transmitting device 100 is additionally provided with a notification unit 111. The notification unit 111 is controlled by the control unit 107.

[0067] After power supply from the power transmitting device 100 to the power receiving device 200 by transmit beamforming is started in the same manner as in the first embodiment, it is assumed that a situation occurs in which an object 300 is located between the power transmitting device 100 and the power receiving device 200, as shown in Fig. 7. This situation can occur due to movement of the power receiving device 200 or movement of the object 300. As an example of movement of the power receiving device 200, for example, the power receiving device 200 may be attached to the arm of a robot, and the object 300 may be located between the power receiving device 200 and the power transmitting device 100 as the arm moves. In this case, the object 300 may be a part of the robot, or may be an object different from the robot.

[0068] When an object 300 is located between the power transmitting device 100 and the power receiving device 200, the beacon signal 309 is reflected or absorbed by the object 300, causing the power of the beacon signal 309 to suddenly decrease before reaching the power transmitting device 100. When this situation occurs, the received power value estimated by the power transmitting device 100 decreases significantly. When the control unit 107 detects a sudden decrease in the received power of the beacon signal, it detects that an abnormal situation has occurred, such as the presence of an object between the power transmitting device 100 and the power receiving device 200. For example, when the received power value of the beacon signal decreases by more than a predetermined value, it detects the occurrence of an abnormal situation.

[0069] The notification unit 111 in the power transmitting device 100 transmits information notifying that an abnormal situation has occurred, in accordance with the detection result of the control unit 107. For example, the notification unit 111 displays information indicating the occurrence of an abnormal situation on a screen. If the notification unit 111 has a screen, the information may be displayed on the screen of the notification unit 111, or on the screen of another device that can communicate with the power transmitting device 100. Alternatively, the notification unit 111 may output the information indicating the occurrence of an abnormal situation by sound. A speaker that outputs sound may be provided in the notification unit 111, or may be provided in another device that can communicate with the power transmitting device 100. The destination of the information may also be a terminal provided by an administrator.

[0070] When the control unit 107 detects the occurrence of an abnormal situation, it may stop power supply to the power receiving device 200. Furthermore, when there is a power receiving device to be supplied with power other than the power receiving device 200, the power supply destination may be switched to the other power receiving device.

[0071] As described above, according to this embodiment, when an abnormality such as the presence of an object occurs, it is possible to notify a manager or the like, and to resolve the abnormality early.

[0072] (Fifth embodiment) Fig. 8 is a block diagram showing the overall configuration of a wireless power feeding system according to this embodiment. The block diagram of the power transmitting device 100 is the same as Fig. 7. The block diagram of the power receiving device 200 is the same as Fig. 1. Elements with the same names as Fig. 1 or 7 are given the same reference numerals, and descriptions thereof will be omitted as appropriate, except for expanded or changed processes. The following description will focus on the differences from the first embodiment.

[0073] The power transmitting device 100 includes a notification unit 112. The notification unit 112 is controlled by the control unit 107.

[0074] The communication unit 207 of the power receiving device 200 acquires remaining battery level information (remaining battery level, battery voltage, etc.) and transmits it to the power transmitting device 100, as in the third embodiment described above.

[0075] The power transmitting device 100 performs transmission beamforming based on the transmission power and weight determined in the same manner as in the first embodiment, and transmits a power supply signal to the power receiving device 200. The control unit 107 of the power transmitting device 100 detects the occurrence of an abnormality in the power receiving device 200 when the remaining battery level or battery voltage of the power receiving device 200 continues to be low even though the estimated received power value of the power receiving device 200 is equal to or greater than a predetermined value. For example, the occurrence of an abnormality is detected when the remaining battery level estimated from the estimated received power value and the power supply time up to now is smaller by a predetermined value or more than the remaining battery level indicated by the remaining battery level information received from the power receiving device 200. The occurrence of an abnormality is also detected when the battery voltage estimated from the estimated remaining battery level is smaller by a predetermined value or more than the battery voltage indicated by the remaining battery level information. Examples of abnormalities include a decrease in battery charging efficiency due to a failure of the RF-DC converter, and an increase in current consumption due to a failure of a load device (e.g., a sensor).

[0076] The notification unit 112 in the power transmitting device 100 transmits information notifying that an abnormal situation has occurred, in accordance with the detection result of the control unit 107. For example, the notification unit 112 displays information indicating the occurrence of the abnormal situation on a screen. If the notification unit 112 has a screen, the information may be displayed on the screen of the notification unit 112, or on the screen of another device that can communicate with the power transmitting device 100. Alternatively, the notification unit 112 may output the information indicating the occurrence of the abnormal situation by sound. The speaker that outputs the sound may be provided in the notification unit 112, or may be provided in another device that can communicate with the power transmitting device 100.

[0077] As described above, according to this embodiment, it is possible to detect an abnormality such as a failure in the RF-DC converter or the load device in the power receiving device 200. Furthermore, by notifying an administrator of the occurrence of the abnormality, it is possible to quickly resolve the abnormality.

[0078] (Application example) Although the first to fifth embodiments have shown examples in which the present invention is applied to a microwave power supply system, the present invention can also be applied to optimization of wireless communication, etc. For example, when a base station performs transmission beamforming on a terminal, it is possible to enable the terminal to receive beamformed signals from the base station with reception power suited to the terminal, while simplifying the configuration of the terminal.

[0079] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined.

[0080] This embodiment can also have the following configuration. [Item 1] a receiving unit that receives a first signal from a power receiving device via a plurality of antennas; a control unit that determines a plurality of weights to be used for the plurality of antennas based on a received signal of the first signal; Equipped with the receiving unit receives a second signal from the power receiving device by receiving beamforming based on the plurality of weights; the control unit determines a transmission power of a power signal to be transmitted to the power receiving device based on the received power of the second signal; a transmitting unit that transmits the power signal based on the transmission power by transmission beamforming based on the plurality of weights, Wireless power supply device. [Item 2] the control unit calculates a propagation loss between the power receiving device and the power receiving apparatus based on the transmission power of the first signal and the reception power of the second signal, and determines the transmission power of the power signal based on the calculated propagation loss. Item 1. The wireless power supply device according to item 1. [Item 3] the control unit estimates a received power of the power signal at the power receiving device based on the calculated propagation loss, and selects a rectifier to be used for rectifying the power signal from among a plurality of rectifiers in the power receiving device based on the estimated value of the received power; a communication unit that transmits instruction information instructing use of the selected rectifier; Item 2. The wireless power supply device according to item 2. [Item 4] the plurality of rectifiers have different power conversion efficiency characteristics between input power and output power, the control unit selects the rectifier based on the power conversion efficiency characteristics of the plurality of rectifiers. Item 3. The wireless power supply device according to item 3. [Item 5] the control unit selects the rectifier to be used by the power receiving device based on correspondence information that associates an estimated value of received power of the power signal in the power receiving device with a rectifier to be used. Item 3. The wireless power supply device according to item 3. [Item 6] a communication unit for receiving measurement information related to a remaining capacity or a voltage of a storage battery that is charged based on the power signal in each of the plurality of power receiving devices; the control unit calculates a propagation loss between the power receiving device and the power receiving apparatus based on a transmission power of the first signal and a reception power of the second signal, and estimates a reception power of the power signal at the power receiving apparatus based on the calculated propagation loss; the control unit determines an order of the power receiving devices to which the power signals are to be transmitted based on the received measurement information and an estimated value of the received power of the power signals at each power receiving device. Item 1. The wireless power supply device according to item 1. [Item 7] the control unit determines the plurality of weights by estimating a propagation path between the antenna and the power receiving device based on an amplitude and a phase of a received signal of the first signal for each antenna. Item 1. The wireless power supply device according to item 1. [Item 8] the control unit detects deterioration of a radio wave propagation environment between the power receiving device and the power receiving apparatus based on a plurality of results of estimating the propagation path; a notification unit that outputs notification information indicating the deterioration of the propagation environment, Item 7. The wireless power supply device according to item 7. [Item 9] The deterioration of the propagation environment includes the presence of an obstacle to radio wave propagation between the power receiving device and the power receiving apparatus. Item 9. The wireless power supply device according to item 8. [Item 10] a communication unit that receives measurement information related to a remaining capacity or a voltage of a storage battery that is charged based on the power signal in the power receiving device; the control unit calculates a propagation loss between the power receiving device and the power receiving apparatus based on a transmission power of the first signal and a reception power of the second signal, and estimates a reception power of the power signal at the power receiving apparatus based on the calculated propagation loss; the control unit detects an occurrence of an abnormality in the power receiving device based on the measurement information and an estimated value of received power of the power signal in the power receiving device; a notification unit that outputs information indicating the occurrence of the detected abnormality; Item 1. The wireless power supply device according to item 1. [Item 11] The abnormality includes an abnormality in a rectifier that rectifies the power signal in the power receiving device, or an increase in current consumption of a load device that consumes power from the storage battery in the power receiving device. Item 11. The wireless power supply device according to item 10. [Item 12] the first signal and the second signal are beacon signals; Item 1. The wireless power supply device according to item 1. [Item 13] a power receiving device; a wireless power supply device; the power receiving device includes a control unit that controls transmission of a first signal and a second signal via an antenna; The wireless power supply device a receiving unit that receives a first signal from the power receiving device via a plurality of antennas; a control unit that determines a plurality of weights to be used for the plurality of antennas based on a received signal of the first signal; Equipped with the receiving unit receives a second signal from the power receiving device by receiving beamforming based on the plurality of weights; the control unit determines a transmission power of a power signal to be transmitted to the power receiving device based on the received power of the second signal; the wireless power supply device includes a transmitter that transmits the power signal based on the transmission power by transmission beamforming based on the plurality of weights; the power receiving device includes a rectifier that receives the power signal via the antenna and rectifies the power signal; Wireless power supply system. [Explanation of symbols]

[0081] 100 Power transmission device 102 Antenna 103 Transmit / Receive Switch 104 Receiving unit 105 Transmitter 107 Control section (phase / amplitude detection section) 108 Weight setting section 109 High Frequency Section 110 Communications Department 111 Notification Department 112 Notification Department 150 Power supply signal (power signal) 200 Powered Device 200A power receiving device 200B Powered Device 200C Powered Device 201 Antenna 202 RF-DC converter 202A RF-DC Converter 203 Signal Generator 204 Transmission / reception switch 205 Storage battery 206 Control Unit 207 Communications Department 208 Load device 209 Switch 250 Beacon Signal 300 objects 202A RF-DC Converter 202B RF-DC Converter 309 Beacon Signal

Claims

1. a receiving unit that receives a first signal from a power receiving device via a plurality of antennas; a control unit that determines a plurality of weights to be used for the plurality of antennas based on a received signal of the first signal; Equipped with The receiver performs receive beamforming based on the plurality of weights. receiving a second signal from the power receiving device by the control unit determines a transmission power of a power signal to be transmitted to the power receiving device based on the received power of the second signal; a transmitting unit that transmits the power signal based on the transmission power by transmission beamforming based on the plurality of weights, Wireless power supply device.

2. the control unit calculates a propagation loss between the power receiving device and the power receiving apparatus based on the transmission power of the first signal and the reception power of the second signal, and determines the transmission power of the power signal based on the calculated propagation loss. The wireless power supply device according to claim 1 .

3. the control unit estimates a received power of the power signal at the power receiving device based on the calculated propagation loss, and selects a rectifier to be used for rectifying the power signal from among a plurality of rectifiers in the power receiving device based on the estimated value of the received power; a communication unit that transmits instruction information instructing use of the selected rectifier; The wireless power supply device according to claim 2 .

4. the plurality of rectifiers each have a different power conversion efficiency characteristic between input power and output power, the control unit selects the rectifier based on the power conversion efficiency characteristics of the plurality of rectifiers. The wireless power supply device according to claim 3 .

5. the control unit selects the rectifier to be used by the power receiving device based on correspondence information that associates an estimated value of received power of the power signal in the power receiving device with a rectifier to be used. The wireless power supply device according to claim 3 .

6. a communication unit for receiving measurement information related to a remaining capacity or a voltage of a storage battery that is charged based on the power signal in each of the plurality of power receiving devices; the control unit calculates a propagation loss between the power receiving device and the power receiving apparatus based on a transmission power of the first signal and a reception power of the second signal, and estimates a reception power of the power signal at the power receiving apparatus based on the calculated propagation loss; the control unit determines an order of the power receiving devices to which the power signals are to be transmitted based on the received measurement information and an estimated value of the received power of the power signals at each power receiving device. The wireless power supply device according to claim 1 .

7. the control unit determines the plurality of weights by estimating a propagation path between the antenna and the power receiving device for each antenna based on an amplitude and a phase of a received signal of the first signal for each antenna. The wireless power supply device according to claim 1 .

8. the control unit detects deterioration of a radio wave propagation environment between the power receiving device and the power receiving apparatus based on a plurality of results of estimating the propagation path; a notification unit that outputs notification information indicating the deterioration of the propagation environment, The wireless power supply device according to claim 7.

9. The deterioration of the propagation environment includes the presence of an obstacle to radio wave propagation between the power receiving device and the power receiving apparatus. The wireless power supply device according to claim 8.

10. a communication unit that receives measurement information related to a remaining capacity or a voltage of a storage battery that is charged based on the power signal in the power receiving device; the control unit calculates a propagation loss between the power receiving device and the power receiving apparatus based on a transmission power of the first signal and a reception power of the second signal, and estimates a reception power of the power signal at the power receiving apparatus based on the calculated propagation loss; the control unit detects an occurrence of an abnormality in the power receiving device based on the measurement information and an estimated value of received power of the power signal in the power receiving device; a notification unit that outputs information indicating the occurrence of the detected abnormality; The wireless power supply device according to claim 1 .

11. The abnormality includes an abnormality in a rectifier that rectifies the power signal in the power receiving device, or an increase in current consumption of a load device that consumes power from the storage battery in the power receiving device. The wireless power supply device according to claim 10.

12. the first signal and the second signal are beacon signals; The wireless power supply device according to claim 1 .

13. a power receiving device; a wireless power supply device; the power receiving device includes a control unit that controls transmission of a first signal and a second signal via an antenna; The wireless power supply device a receiving unit that receives a first signal from the power receiving device via a plurality of antennas; a control unit that determines a plurality of weights to be used for the plurality of antennas based on a received signal of the first signal; Equipped with the receiving unit receives a second signal from the power receiving device by receiving beamforming based on the plurality of weights; the control unit determines a transmission power of a power signal to be transmitted to the power receiving device based on the received power of the second signal; the wireless power supply device includes a transmitter that transmits the power signal based on the transmission power by transmission beamforming based on the plurality of weights; the power receiving device includes a rectifier that receives the power signal via the antenna and rectifies the power signal; Wireless power supply system.

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