Power receiving device, control method, and program

Abstract

To perform power transmission with high efficiency without waiting time for communication with a power receiving device and power transmission even when radio waves of a plurality of power transmission devices interfere with one another.SOLUTION: A power transmitting device for wirelessly transmitting electric power to a power receiving device includes communication means for wirelessly communicating with a first power receiving device, power transmitting means for transmitting electric power to the first power receiving device, detecting means for detecting a second transmitting device which wirelessly transmitting electric power to a second power receiving device, and control means for performing wireless communication with the second power transmitting device when the second power transmitting device is detected, and performing control such that power transmission is performed at same timing as the second power transmitting device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wireless power transmission and reception technology using microwaves. [Background technology]

[0002] The space-transmission type wireless power transmission system proposed by the Ministry of Internal Affairs and Communications, described in Non-Patent Document 1, is expected to be deployed in a wide range of markets by transmitting power using the 2.4 GHz frequency band used for wireless LANs, etc.

[0003] Patent Document 1 describes a technology for improving power supply efficiency by performing wireless power supply using a frequency different from the frequency used for wireless communication and performing wireless communication and wireless power supply at the same time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent application 2019-097302 publication [Non-patent literature]

[0005] [Non-Patent Document 1] Draft Report of the Working Group on Wireless Power Transmission Systems (as of 4:00 PM, May 20, 2020) Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 describes a system in which there is one power transmitting device and one power receiving device, and does not describe a system in which there are multiple power transmitting devices and multiple power receiving devices. In addition, when radio waves from multiple power transmitting devices using the same frequency interfere with each other, if radio waves transmitted by another power transmitting device are detected by carrier sense, a standby time occurs in communication with the power receiving device and in power transmission by the power transmitting device in order to avoid interference between radio waves at the same frequency, resulting in a decrease in power transmission efficiency.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to realize a technology that can transmit power with high efficiency without causing waiting time for communication with a power receiving device and power transmission, even in cases where radio waves from multiple power transmitting devices interfere with each other. [Means for solving the problem]

[0008] In order to solve the above problems and achieve the object, the present invention provides a power transmission device that transmits power wirelessly to a power receiving device, comprising: a communication means for wirelessly communicating with a first power receiving device; a power transmission means for transmitting power to the first power receiving device; a detection means for detecting a second power transmission device that transmits power wirelessly to a second power receiving device; and a control means for, when the second power transmission device is detected, performing wireless communication with the second power transmission device and controlling the power transmission to be performed at the same timing as the second power transmission device. [Effects of the Invention]

[0009] According to the present invention, even in the case where radio waves from a plurality of power transmitting devices interfere with each other, it is possible to perform highly efficient power transmission without generating a standby time for communication with a power receiving device and power transmission. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a block diagram showing the configuration of a power transmitting device and a power receiving device according to the embodiment. [Figure 2] 1A and 1B are diagrams illustrating examples of wireless communication and wireless power transmission and reception when a plurality of power transmitting devices and a plurality of power receiving devices exist according to an embodiment of the present invention; [Figure 3] 10 is a time chart illustrating a conventional procedure for wireless communication and wireless power transmission and reception when a plurality of power transmitting devices and a plurality of power receiving devices are present; [Figure 4] 4 is a time chart illustrating the procedure of wireless communication and wireless power transmission and reception when a plurality of power transmitting devices and a plurality of power receiving devices are present according to the present embodiment; [Figure 5]10 is a flowchart illustrating a procedure for wireless communication and wireless power transmission and reception of one power transmission device when there are a plurality of power transmission devices and a plurality of power reception devices according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] <Explanation of the Issues> First, referring to Figures 2 and 3, the issues of communication and power transmission when there are multiple power transmitting devices and multiple power receiving devices will be explained using an example of a case where radio waves from multiple power transmitting devices using the same frequency interfere with each other.

[0013] Fig. 2 is a diagram illustrating a communication format when multiple power transmitting devices and multiple power receiving devices that perform wireless communication exist in the same space. Here, the same space means that a second pair of power transmitting devices and power receiving devices exists within the reach of a carrier wave (carrier) that a first pair of power transmitting devices and power receiving devices use for wireless communication. Fig. 3 is a time chart illustrating the procedure for communication and power transmission between each pair of power transmitting devices and power receiving devices when multiple power transmitting devices and multiple power receiving devices that perform wireless communication exist in the same space.

[0014] 2, a first power transmitting device 110 and a first power receiving device 210 form a first pair 11 and perform wireless communication and wireless power transmission and reception. Similarly, a second power transmitting device 120 and a second power receiving device 220 form a second pair 12 and perform wireless communication and wireless power transmission and reception.

[0015] In addition, the frequency bands used by the power transmitting device and power receiving device in each pair for wireless communication and wireless power transmission and reception are the 2.4 GHz and 5.0 GHz bands used for wireless LAN, etc., and the same frequencies are used for wireless communication and wireless power transmission and reception.

[0016] 3, when the first pair 11 and the second pair 12 are not in the same space, the first power transmitting device 110 performs wireless power transmission and reception by communicating information related to wireless power transmission and reception with the first power receiving device 210. The same applies to the second pair 12.

[0017] On the other hand, when the first pair 11 and the second pair 12 exist in the same space, the second pair 12 detects the carrier of the first pair 11 before starting wireless communication, and is in a state where wireless communication is not possible for the second pair 12 while the first pair 11 is transmitting and receiving wireless power, as shown in Fig. 3. Therefore, when another pair exists in the same space, if the second pair 12 detects the carrier of the other pair, a waiting time occurs in the communication and power transmission of the first pair, and power transmission efficiency decreases.

[0018] In this embodiment, even when radio waves from a plurality of power transmitting devices interfere with each other, there is no waiting time for communication with a power receiving device and power transmission, and power transmission can be performed with high efficiency.

[0019] <Device Configuration> First, with reference to FIG. 1, the configuration of a power transmitting device 100 and a power receiving device 200 according to this embodiment will be described.

[0020] The power transmitting device 100 is a charging device that can operate using power that is constantly supplied from a power outlet in a factory or at home, etc. The power transmitting device 100 transmits power to the power receiving device 200 wirelessly.

[0021] The power receiving device 200 is an electronic device that receives power wirelessly transmitted from the power transmitting device 100. The power receiving device 200 can be carried by a user and can operate as an imaging device such as a digital camera, a mobile phone such as a smartphone, a tablet device, a mobile game console, or other portable terminal powered by a rechargeable battery.

[0022] The power receiving device 200 has a wireless communication function and a wireless charging function. The wireless communication method is, for example, Wi-Fi (registered trademark).

[0023] <Configuration of Power Transmission Device 100> Next, the configuration of the power transmission device 100 of this embodiment will be described with reference to FIG. 1(a).

[0024] 1(a) is a block diagram showing the configuration of a power transmitting device 100 according to this embodiment. In the following description, the external device is, for example, a power receiving device 200, but is not limited to this.

[0025] The control unit 101 has a memory that stores programs for controlling each component of the power transmission device 100, and a processor such as a CPU or MPU that controls each component of the power transmission device 100 by executing the programs stored in the memory.

[0026] The control unit 101 controls a power transmission control unit 102, a wireless communication control unit 104, and a switching unit 106, which will be described later.

[0027] The power transmission control unit 102 executes control related to wireless power transmission, and transmits radio waves to an external device via the power transmission resonant circuit 103 and the antenna 107 .

[0028] The power transmission resonant circuit 103 is a circuit including elements such as a coil and a capacitor, and is designed to resonate at frequencies in the 2.4 GHz band or 5.0 GHz band used in Wi-Fi (registered trademark), for example.

[0029] The wireless communication control unit 104 executes control related to wireless communication, and performs wireless communication with an external device via a communication resonant circuit 105 and an antenna 107 .

[0030] The communication resonant circuit 105 is a circuit including elements such as a coil and a capacitor, and similar to the power transmission resonant circuit 103, is designed to resonate in frequency bands such as the 2.4 GHz band and the 5.0 GHz band used in Wi-Fi (registered trademark).

[0031] The switching unit 106 is a switch that switches the connection destination of the antenna 107 between the power transmission resonant circuit 103 and the communication resonant circuit 105 .

[0032] The antenna 107 includes an antenna element and is capable of transmitting and receiving radio waves to and from an external device. The antenna 107 also includes a configuration capable of converting electric power into radio waves and transmitting the electric power to the power receiving device 200.

[0033] The power transmitting device 100 can transmit radio waves to an external device by connecting the antenna 107 and the power transmitting resonant circuit 103 with the switching unit 106. In addition, the power transmitting device 100 can perform wireless communication with an external device by connecting the antenna 107 and the communication resonant circuit 105 with the switching unit 106.

[0034] The movement detection unit 108 detects that the power transmitting device 100 has moved, and outputs the detection result to the control unit 101.

[0035] <Configuration of Power Receiving Device 200> Next, the configuration of the power receiving device 200 of this embodiment will be described with reference to FIG. 1(b).

[0036] 1(b) is a block diagram showing the configuration of the power receiving device 200 of this embodiment. In the following description, the external device is, for example, the power transmitting device 100, but is not limited to this.

[0037] The control unit 201 has a memory that stores programs for controlling each component of the power receiving device 200, and a processor such as a CPU or MPU that controls each component of the power receiving device 200 by executing the programs stored in the memory.

[0038] The control unit 201 controls a charging circuit 206, a wireless communication control unit 209, and a switching unit 203, which will be described later.

[0039] The battery 207 is a power source that supplies power for operating the power receiving device 200. The battery 207 is, for example, a rechargeable battery such as a lithium ion battery. The battery 207 supplies power to each component of the power receiving device 200.

[0040] The antenna 202 includes an antenna element and is capable of transmitting and receiving radio waves to and from an external device. The antenna 202 also includes a configuration capable of receiving power that is converted into radio waves from the power transmitting device 100 and transmitted.

[0041] The switching unit 203 is a switch that switches the connection destination of the antenna 202 between a power receiving resonant circuit 204 and a communication resonant circuit 208, which will be described later.

[0042] The power receiving resonant circuit 204 is a circuit including elements such as a coil and a capacitor, and is designed to resonate at frequencies in the 2.4 GHz band or 5.0 GHz band used in Wi-Fi (registered trademark), for example.

[0043] The rectifier circuit 205 converts the voltage of the power output from the power receiving resonant circuit 204, rectifies it to a DC voltage that allows each component of the power receiving device 200 to operate, and outputs it to the charging circuit 206 in the subsequent stage.

[0044] The charging circuit 206 supplies power to the battery 207 to charge the battery 207. The charging circuit 206 converts the DC voltage output from the rectifier circuit 205 into a predetermined voltage for charging the battery 207, and supplies the power to the battery 207.

[0045] The communication resonant circuit 208 is a circuit including elements such as a coil and a capacitor, and similar to the power receiving resonant circuit 204, is designed to resonate at frequencies in the 2.4 GHz band or 5.0 GHz band used in Wi-Fi (registered trademark), for example.

[0046] The wireless communication control unit 209 executes control relating to wireless communication, and performs wireless communication with external devices via the communication resonant circuit 208 and the antenna 202 .

[0047] The power receiving device 200 can receive radio waves from an external device by connecting the antenna 202 and the power receiving resonant circuit 204 with the switching unit 203. In addition, the power receiving device 200 can perform wireless communication with the external device by connecting the antenna 202 and the communication resonant circuit 208 with the switching unit 203.

[0048] <Control Operation> Next, with reference to FIGS. 2, 4 and 5, the operation of wireless communication and wireless power transmission and reception when there are a plurality of power transmission devices and a plurality of power reception devices of this embodiment will be described.

[0049] 2 is a diagram illustrating an example of wireless communication and wireless power transmission and reception when multiple power transmission devices and multiple power reception devices of this embodiment exist in the same space. Here, it is assumed that the first power transmission device 110 and the first power reception device 210, and the second power transmission device 120 and the second power reception device 220 have already completed wireless pairing and are in a wirelessly connected state.

[0050] It is also assumed that the first power transmission device 110 and the second power transmission device 120 have already completed wireless pairing and are in a state where they can be connected to each other.

[0051] FIG. 4 is a time chart illustrating the procedure of wireless communication and wireless power transmission and reception between the first pair 11 and the second pair 12 when a plurality of power transmitting devices and a plurality of power receiving devices are present in the same space according to this embodiment.

[0052] FIG. 5 is a flowchart illustrating a procedure for wireless communication and wireless power transmission and reception by the first power transmission device 110 in the case where a plurality of power transmission devices and a plurality of power reception devices exist in the same space according to this embodiment.

[0053] 5 is realized by the control unit 101 of the first power transmitting device 110 executing a program stored in a memory to control each component of the first power transmitting device 110. In the following description, for ease of understanding, the subject of operations will be the first power transmitting device 110, not the control unit 101.

[0054] In step S501, the first power transmitting device 110 determines whether or not connection with the first power receiving device 210 has been completed. In this embodiment, as described above, wireless pairing has already been completed and the first power transmitting device 110 is in a wirelessly connected state. If the first power transmitting device 110 determines that connection with the first power receiving device 210 has been completed, the process proceeds to step S502.

[0055] In step S502, the first power transmitting device 110 determines whether the first pair 11 and the second pair 12 are present in the same space based on whether the carrier output from the second power transmitting device 120 is detected. If the first power transmitting device 110 determines that the carrier output from the second power transmitting device 120 is not detected and that the first pair 11 and the second pair 12 are not present in the same space, the first power transmitting device 110 proceeds to step S503. If the carrier output from the second power transmitting device 120 is not detected and the first pair 11 and the second pair 12 are not present in the same space, the first power transmitting device 110 performs wireless communication and wireless power transmission / reception operations for when the first pair 11 and the second pair 12 are not present in the same space, as shown in FIG. The operation of wireless communication and wireless power transmission and reception when the first pair 11 and the second pair 12 shown in Figure 4 are not in the same space is similar to the operation of wireless communication and wireless power transmission and reception when the first pair 11 and the second pair 12 described in Figure 3 are not in the same space.

[0056] In step S503, the first power transmitting device 110 communicates power transmission and reception parameters 11A with the first power receiving device 210. The power transmission and reception parameters 11A include required power information derived from the remaining capacity of the battery 207 of the first power receiving device 210, etc.

[0057] In step S504, the first power transmitting device 110 determines whether or not power transmission to the first power receiving device 210 is necessary, based on the power transmission and reception parameters 11A received in step S503. If the first power transmitting device 110 determines that power transmission to the first power receiving device 210 is necessary, the process proceeds to step S505. On the other hand, if the first power transmitting device 110 determines that power transmission to the first power receiving device 210 is not necessary because the battery 207 is fully charged, for example, the first power transmitting device 110 ends the process.

[0058] In step S505, the first power transmitting apparatus 110 transmits the necessary power to the first power receiving apparatus 210.

[0059] In step S506, the first power transmission device 110 stops power transmission after a predetermined time has elapsed since the start of power transmission in step S505, and the process returns to step S502.

[0060] In step S502, if the first power transmitting device 110 determines that the carrier output from the second power transmitting device 120 has been detected and that the first pair 11 and the second pair 12 exist in the same space, the process proceeds to step S507. If the carrier output from the second power transmitting device 120 has been detected and the first pair 11 and the second pair 12 exist in the same space, the first power transmitting device 110 executes the wireless communication and wireless power transmission / reception operations when the first pair 11 and the second pair 12 exist in the same space as shown in FIG.

[0061] In step S507, the first power transmission device 110 establishes a connection with the second power transmission device 120.

[0062] In step S508, the first power transmission device 110 determines whether a connection with the second power transmission device 120 has been established. If the first power transmission device 110 determines that a connection with the second power transmission device 120 has been established, the process proceeds to step S509. If the first power transmission device 110 determines that a connection with the second power transmission device 120 has not been established, the process proceeds to step S503, and the first power transmission device 110 performs wireless communication and wireless power transmission / reception operations for when the first pair 11 and the second pair 12 described in FIG. 3 are not present in the same space.

[0063] In step S509, the first power transmitting device 110 communicates the power transmission and receiving parameters 11A with the first power receiving device 210. Here, the power transmission and receiving parameters 11A may be acquired in wireless communication of the first pair 11 at a timing before step S508, for example, at timing t1 in Fig. 4. Furthermore, by making the communication range between the first power transmitting device 110 and the second power transmitting device 120 wider than the power transmission range of the first power transmitting device 110, when the second power transmitting device 120 is present within the power transmission range of the first power transmitting device 110, the first power transmitting device 110 and the second power transmitting device 120 can reliably communicate with each other.

[0064] In step S510, the first power transmission device 110 communicates with the second power transmission device 120 and acquires the power transmission and reception parameters 12A communicated by the second pair 12. The timing at which the power transmission and reception parameters 12A are acquired corresponds to the timing t3 after the second pair 12 has performed wireless communication in FIG.

[0065] In step S511, the first power transmitting device 110 determines whether or not power transmission to the first power receiving device 210 and the second power receiving device 220 is necessary, based on the power transmission and reception parameters 11 acquired from the first power receiving device 210 in step S509 and the power transmission and reception parameters 12 acquired from the second power transmitting device 120 in step S510. If the first power transmitting device 110 determines that power transmission to the first power receiving device 210 and the second power receiving device 220 is necessary, the process proceeds to step S512. If the first power transmitting device 110 determines that power transmission to the first power receiving device 210 and the second power receiving device 220 is not necessary because the battery 207 is fully charged, for example, the first power transmitting device 110 ends the process.

[0066] In step S512, the first power transmission device 110 synchronizes the power transmission timing with the second power transmission device 120. The power transmission timing needs to be synchronized once, but if there is a possibility that the synchronization timing may be out of sync, the synchronization may be performed periodically.

[0067] In step S513, the first power transmission device 110 starts power transmission at the same timing as the second power transmission device 120. The power transmission timing here corresponds to the timing of wireless power transmission of the first pair 11 and wireless power transmission and reception of the second pair 12, which start at timing t4 in Fig. 4. By synchronizing the power transmission timing between the first power transmission device 110 and the second power transmission device 120 in this way, the second power transmission device 120 does not need to wait for power transmission while the first power transmission device 110 is transmitting power, and highly efficient power transmission can be performed when there are multiple power transmission devices and multiple power receiving devices, as in the first pair 11 and the second pair 12.

[0068] In step S514, after a predetermined time has elapsed since the first power transmission device 110 started transmitting power at the same time as the second power transmission device 120 in step S513, the first power transmission device 110 stops transmitting power at the same time as the second power transmission device 120, and the process returns to step S502. Here, for example, if the first power transmission device 110 is moving, it is highly likely that the first power transmission device 110 is approaching the second power transmission device 120. Therefore, when the movement detection unit 108 detects that the first power transmission device 110 has moved, the power transmission time may be shortened to make it easier to detect the second power transmission device 120.

[0069] In this embodiment, an example of two pairs, a first pair 11 and a second pair 12, has been described as a case where there are multiple power transmitting devices and multiple power receiving devices, but this is not limited to this, and there may be three or more pairs.

[0070] As described above, according to this embodiment, even in cases where radio waves from multiple power transmitting devices interfere with each other, power can be transmitted with high efficiency without causing any waiting time for communication with the power receiving device and power transmission.

[0071] [Other embodiments] The present invention can also be realized by supplying a program that realizes one or more functions of each embodiment to a system or device via a network or storage medium, and having one or more processors in the computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0072] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0073] 100... power transmitting device, 101... control unit, 102... power transmission control unit, 103... power transmission resonant circuit, 104... wireless communication control unit, 105... communication resonant circuit, 106... switching unit, 107... antenna, 108... movement detection unit, 200... power receiving device

Claims

1. A power transmitting device that wirelessly transmits power to a power receiving device, a communication means for wirelessly communicating with the first power receiving device; power transmission means for transmitting power to the first power receiving device; a detection means for detecting a second power transmitting device that wirelessly transmits power to a second power receiving device; A power transmission device characterized by having a control means that, when the second power transmission device is detected, performs wireless communication with the second power transmission device and controls the power transmission to be performed at the same timing as the second power transmission device.

2. The power transmission device described in claim 1, characterized in that the detection means detects a carrier through which the second power transmission device, which is located within the reach of the carrier through which communication with the first power receiving device, communicates with the second power receiving device, and when the detection means detects the carrier through which communication between the second power transmission device and the second power receiving device is detected, performs wireless communication with the second power transmission device.

3. The power transmission device described in claim 1 or 2, characterized in that when the detection means does not detect the carrier through which the second power transmission device and the second power receiving device communicate, the control means obtains information regarding power transmission and reception from the first power receiving device and determines whether power transmission is necessary based on the information.

4. The power transmission device described in claim 1 or 2, characterized in that when the detection means detects a carrier through which the second power transmission device and the second power receiving device communicate, the control means acquires information regarding power transmission and reception from the first power receiving device and the second power transmission device, and determines whether power transmission is necessary based on the information.

5. The power transmission device according to any one of claims 1 to 4, characterized in that a plurality of the second power transmission devices and a plurality of the second power receiving devices are present within the reach of a carrier for communication with the first power receiving device.

6. The power transmission device according to any one of claims 1 to 5, characterized in that the control means periodically communicates with the second power transmission device and starts and stops power transmission at the same timing as the second power transmission device.

7. The power transmission device according to claim 1 , wherein a communication range with the second power transmission device is wider than a power transmission range of the power transmission device.

8. The power transmission device further includes a movement detection unit that detects that the power transmission device has moved, The power transmission device according to claim 1 , wherein the control unit shortens the power transmission time when the power transmission device is moved compared to when the power transmission device is not moved.

9. A control method for a power transmitting device that wirelessly transmits power to a power receiving device, comprising: The power transmission device is a communication means for wirelessly communicating with the first power receiving device; a power transmitting means for transmitting power to the first power receiving device, The control method includes: detecting a second power transmitting apparatus that wirelessly transmits power to a second power receiving apparatus; A control method characterized by comprising a step of, when the second power transmission device is detected, performing wireless communication with the second power transmission device and controlling the transmission of power at the same timing as the second power transmission device.

10. A program for causing a computer to function as the control means for the power transmitting device according to any one of claims 1 to 8.

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