Power transmission equipment and power transmission method

Abstract

To provide a power transmission device and a power transmission method that achieves wireless power transmission over a wide power transmission range while suppressing electromagnetic wave leakage and preventing a drop in transmission efficiency.SOLUTION: A power transmission device includes a power transmission portion in which plurality of power transmission coils are arranged side by side on a plane, a detection portion that detects, for each of the power transmission coils, that a power transmission target is placed on the coil, and a control portion that controls power transmission to a power receiving coil provided in a power transmission target object, and the control portion transmits power to the coil while the detection portion detects that the power transmission target object is placed on any one of the plurality of power transmission coils.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wireless power transmission device and a power transmission method for a driving battery of an autonomous mobile body.

Background Art

[0002] Wireless power supply that supplies power wirelessly has been put into practical use. Wireless power supply is suitable for supplying power to a battery provided in a mobile body that can autonomously return to a home position, rather than plug-in charging that requires manual operation.

[0003] However, in wireless power supply, if the positions of the power receiving coil and the power transmitting coil are misaligned, a high coupling coefficient cannot be maintained and the transmission efficiency decreases. Alignment of the power transmitting coil and the power receiving coil during power supply to an autonomous mobile body is more difficult than that which can be aligned manually, such as an automobile driven by a human or a smartphone used by a human. Moreover, even if there are multiple power supply targets, it is desirable to be able to supply power simultaneously.

[0004] In order to solve the problem of misalignment in wireless power supply, Patent Document 1 proposes wireless power supply using a plurality of coils (Patent Document 1 etc.). Patent Document 1 discloses preparing a plurality of antennas for transmitting and receiving radio waves to be converted into electric power, and using an antenna that can transmit and receive radio waves efficiently.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] To address the positional misalignment issues described above, it is desirable to use a power transmission device with a transmission range that is sufficiently wider than the area of ​​the receiving coil. Furthermore, in order to enable simultaneous power supply even when there are multiple power transmission targets using a single control means, a wide transmission range is desirable.

[0007] When a single large transmitting coil (antenna) can cover a transmission range significantly larger than the area of ​​the receiving coil, the dimensional ratio between the transmitting and receiving coils becomes skewed. As the size of the transmitting coil increases, leakage electromagnetic fields become more likely to be a problem. In addition to leakage electromagnetic fields, the skewed dimensional ratio makes it difficult to maintain a high coupling coefficient, thus reducing power transmission efficiency.

[0008] When achieving a sufficiently wide power transmission range by arranging multiple transmission coils, a process is required to determine which transmission coil is intended to output power only from the corresponding location. Patent Document 1 describes testing the transmission and reception of radio waves with multiple antennas and selecting the antenna that can efficiently transmit and receive radio waves. However, the process to reach this selection is complex, and sequentially energizing and testing multiple antennas does not suppress leakage electromagnetic fields.

[0009] In a configuration with multiple transmitting coils arranged in a row, a detection unit may be placed on each coil to detect the location of the device to be energized in order to determine which coil to energize. In this case, each detection unit is more likely to be affected by electromagnetic waves from nearby coils, so it is desirable to provide an appropriate distance between the multiple coils and the detection unit for each coil. Providing an appropriate distance increases the area within the power transmission range where charging is impossible or difficult. There is a possibility that it will happen.

[0010] It is also possible to equip each of the multiple transmission coils in a row with a wireless communication device, communicate with the wireless communication device mounted on the mobile object to be powered, and select the transmission coil corresponding to the wireless communication device that has successfully paired to transmit power. However, when multiple transmission coils are arranged in close proximity, there are technical challenges such as how to select the coil carrying the object to be powered using wireless communication in a simple configuration.

[0011] The present invention aims to provide a power transmission device and a power transmission method that enable wireless power transmission over a wide transmission range while suppressing electromagnetic wave leakage and preventing a decrease in transmission efficiency. [Means for solving the problem]

[0012] A power transmission device according to one embodiment of the present disclosure includes a power transmission unit having a plurality of power transmission coils arranged in parallel on a plane, a detection unit for each of the power transmission coils that detects when an object to be powered is placed on the coil, and a control unit that controls the power transmission to a power receiving coil provided on the object to be powered, wherein the control unit transmits power to the coil while the detection unit detects that the object to be powered is placed on one of the plurality of power transmission coils.

[0013] A power transmission method according to one embodiment of the present disclosure detects for each of a plurality of power transmission coils arranged side by side on a plane that an object to be powered is placed on the coil, and transmits power to the coil while the object to be powered is detecting that it is placed on one of the coils of the plurality of power transmission coils.

[0014] In the power transmission device and power transmission method of this disclosure, the detection unit for detecting the object to be powered is positioned within a power transmission range in which multiple power transmission coils are arranged, in a manner that suppresses the influence of electromagnetic waves from the coils. [Effects of the Invention]

[0015] According to the present disclosure, among a sufficiently wide power transmission support range, it is possible to realize without trouble the output only from the power transmission side coil corresponding to the location where the power transmission object is placed.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic diagram of a power transmission device. [Figure 2] It is a schematic cross-sectional view of the power transmission device. [Figure 3] It is a block diagram showing the configuration of the power transmission device. [Figure 4] It is a schematic diagram of a power transmission device when a flexible container is used. [Figure 5] It is a flowchart showing an example of a processing procedure by the power transmission device. [Figure 6] It is a schematic diagram of the power transmission device in Modification 1. [Figure 7] It is a schematic diagram of the power transmission device in Modification 2. [Figure 8] It is a flowchart showing an example of a processing procedure by the power transmission device of the second embodiment. [Figure 9] It is a schematic diagram of the power transmission device of the second embodiment. [Figure 10] It is a schematic diagram of another power transmission device of the second embodiment.

Modes for Carrying Out the Invention

[0017] The present disclosure will be specifically described with reference to the drawings showing its embodiments. In the following embodiments, the power transmission device of the present disclosure will be described.

[0018] (First Embodiment) FIG. 1 is a schematic diagram of the power transmission device 1, FIG. 2 is a schematic cross-sectional view of the power transmission device 1, and FIG. 3 is a block diagram showing the configuration of the power transmission device 1. In FIG. 1 and FIG. 2, and in the following description, as an object to be powered from the power transmission device 1, a drone D equipped with a power receiving coil and a battery is taken as an example, but the object to be powered is not limited thereto. For example, the object to be powered may be a portable device such as a smartphone. For example, the object to be powered may be a portable device such as a smartphone.

[0019] The power transmission device 1 includes a power transmission unit 10, a detection unit 11, a power supply unit 12, and a control unit 13 within a housing 14. The housing 14 has a flat plate shape. The housing 14 houses the power transmission unit 10, which has multiple coils 100 arranged on a plane. The power transmission device 1 is divided into multiple segments S, each corresponding to one of the multiple coils 100. Each of the multiple segments S is provided with a detection unit 11 that detects the presence of an object above the coil 100.

[0020] The detection unit 11 is located below the power transmission unit 10, and is designed to reduce the influence of electromagnetic waves from the coil 100 of the power transmission unit 10. As shown in Figure 2, it is preferable that a shield 101 made of a magnetic material is provided between the coil 100 and the detection unit 11 for each segment to return the electromagnetic field back to the power transmission coil 100. The shield 101 does not need to be provided if it does not interfere with detection in the detection unit 11.

[0021] The power supply unit 12 is located below or to the side of the power transmission unit 10. The power supply unit 12 is connected to each segment, i.e., to each of the coils 100 of the power transmission unit 10. The power supply unit 12 can supply power to each of the coils 100 individually.

[0022] The control unit 13 is connected to the power supply unit 12 and the detection unit 11 of each segment S. The control unit 13 can identify the detection result of the detection unit 11 for each segment S. The control unit 13 controls the switching of the individual power supply to the coil 100 of each segment S by the power supply unit 12, from ON to OFF, according to the detection result of the detection unit 11.

[0023] The housing 14 is configured such that the detection unit 11 can detect when an object to be powered is placed on its upper surface for each segment S. For example, as shown in Figure 1, the housing 14 is divided into sections along its longitudinal direction on its upper surface. In this case, the presence of an object to be powered on the upper surface of the housing 14 can be detected for each segment S by the change in its weight. In other examples, the housing 14 may be configured such that its upper surface is made of a flexible material, and a downward force acts only where the drone D to be powered is placed, allowing the detection unit 11 to detect it. Figure 4 is a schematic diagram of the power transmission device 1 when a flexible housing 14 is used.

[0024] The control unit 13 of the power transmission device 1 switches the power supply from the power supply unit 12 to the coil 100 ON for segments S on which the detection unit 11 determines that an object to be powered is placed, and switches the power supply OFF if it determines that no object to be powered is placed on the segment S.

[0025] The control unit 13 of the power transmission device 1 includes a processor 130, a memory 131, and an input / output circuit 132. The processor 130, memory 131, and input / output circuit 132 may be integrated on a single board to form a microcontroller, or they may be implemented as separate components.

[0026] The processor 130 uses power supplied from the power supply unit 12 to read and execute the program P1 stored in the memory 131, thereby realizing the control processing described later. The processor 130 can input and output signals from the detection unit 11 via the input / output circuit 132.

[0027] Memory 131 uses non-volatile memory. Program (program product) P1 is stored in memory 131. Program P1 is incorporated into memory 131 during the manufacturing of the power transmission device 1. Program P1 is recorded on a recording medium readable by the computer (processor), and the processor 130 reads it and stores it in memory 131. It may also be something that has been memorized.

[0028] The input / output circuit 132 is a circuit that receives a signal from the detection unit 11 and outputs a control signal to the power supply unit 12.

[0029] Each detection unit 11 provided for each segment S is, in one example, a load sensor. It outputs the load applied to the segment S. The detection unit 11 is not limited to detecting load. The detection unit 11 may also use a light intensity sensor that detects when the segment S is covered with an object to be powered.

[0030] The power transmission control in power transmission device 1 will be explained with reference to a flowchart. Figure 5 is a flowchart showing an example of the processing procedure by power transmission device 1.

[0031] The control unit 13 of the power transmission device 1 refers to the output from the detection unit 11 for each segment (step S101). Based on the output from the detection unit 11, the control unit 13 determines whether or not a power transmission target is present on any of the segments S (step S102).

[0032] If it is determined in step S102 that there is a target for power transmission (S102: YES), the control unit 13 turns on the power supply from the power supply unit 12 to the coil 100 of the target segment S (step S103).

[0033] In step S102, the control unit 13 determines, based on the output from the detection unit 11, whether the load on segment S falls within the range of loads that include the weight of the powered object, which is included in the setting information stored in memory 131 beforehand. This prevents the unit from turning on the power supply to an object that is not the target object if it happens to be placed on segment S.

[0034] If it is determined in step S102 that there is no device to be powered (S102: NO), the control unit 13 proceeds to step S104.

[0035] The control unit 13 determines, based on the output from the detection unit 11, whether or not the power supply target has left any of the segments S (step S104). If it is determined in step S104 that the power supply target has left (S104: YES), the control unit 13 turns OFF the power supply from the power supply unit 12 to the coil of the target segment (step S105) and terminates the process.

[0036] In step S104, the control unit 13 determines, based on the output from the detection unit 11, whether or not the load applied to segment S falls within the range of "no power transmission target" included in the setting information stored in memory 131 beforehand.

[0037] In step S104, if it is determined that the recipient of the power supply is not far away (S104: NO ), the control unit 13 terminates the process.

[0038] With the configuration of the power transmission device 1 in the first embodiment, it is possible to energize only the necessary power transmission coil 100 without using a sensor affected by electromagnetic waves between the power transmission coil 100 and the power receiving coil of the power recipient, and with a simple configuration. Furthermore, as shown in Figure 1, the control unit 13 can switch the power supply to the power transmission coil 100 ON and OFF for each segment S while providing a sufficiently wide power transmission range. As a result, it is possible to supply power simultaneously even if there are multiple power recipients, while clearing the problem of leakage electromagnetic fields.

[0039] In the first embodiment, the control unit 13, based on the output from the detection unit 11, uses the program P1 The system is configured to control the supply of power to the target power transmission coil 100. However, it may also be implemented mechanically, that is, by configuring a circuit that turns on the power supply when the output from the detection unit 11 exceeds a predetermined value.

[0040] (Variation 1) Figure 6 is a schematic diagram of the power transmission device 1 in Modification 1. In Modification 1, the upper surface of the housing 14 is divided into segments, and a retractable retractable body such as a spring is provided between the power transmission coil and the detection unit 11. In Modification 1, as shown in Figure 6, when the object to be powered is placed on a segment, the segment itself sinks vertically. This increases the likelihood that the object to be powered will fit within the segment.

[0041] (Modification 2) Figure 7 is a schematic diagram of the power transmission device 1 in Modification 2. In Modification 2, partitions 141 are provided on the upper surface of the housing 14 between segments S so that the object to be transmitted does not straddle the segments S. The partitions 141 are made of resin, for example, and are erected along the boundaries of the segments S. In Modification 2, as shown in Figure 7, the partitions 141 have a tapered surface, and even if the object to be transmitted is placed on the partitions 141, there is a higher possibility that it will slide and fall into the segments S.

[0042] (Second Embodiment) As shown in Figure 1, the power transmission device 1 of the first embodiment was controlled assuming that the object to be transmitted would not straddle any segments. In the second embodiment, even if the object to be transmitted spans multiple segments and rests on the power transmission device 1, the appropriate power transmission coil 100 is selected to conduct the power appropriately.

[0043] The hardware configuration of the power transmission device 1 in the second embodiment is the same as that of the hardware configuration in the first embodiment. Therefore, among the components of the power transmission device 1 in the second embodiment that are common with the power transmission device 1 in the first embodiment, the same reference numerals are used and detailed descriptions are omitted. The control contents of the power transmission device 1 in the second embodiment will be described below with reference to a flowchart.

[0044] Figure 8 is a flowchart showing an example of the processing procedure by the power transmission device 1 of the second embodiment.

[0045] The control unit 13 of the power transmission device 1 refers to the output from the detection unit 11 for each segment (step S201). Based on the output from the detection unit 11, the control unit 13 identifies the segment that will be subjected to a predetermined range of load when the weight of the power transmission target is placed on it (step S202). The control unit 13 turns on the power supply from the power supply unit 12 to the coil 100 of the identified segment S (step S203).

[0046] The control unit 13 identifies, in addition to the segment S identified in step S202, multiple adjacent segments S on which the load of the power transmission target is applied (step S204). In step S204, the control unit 13 adds the weights applied to each of the adjacent segments S and determines whether the sum is within the range of the load including the weight of the power transmission target. The control unit 13 determines and identifies whether the sum is within the range of the load including the weight of the power transmission target.

[0047] In step S204, the control unit 13 may determine the ratio of the weights applied to each adjacent segment, for example, as 2:8.

[0048] The control unit 13 controls each of the coils 100 of the multiple segments S identified in step S204 Power is turned ON from the power supply unit 12 to the segment (step S205). If the weight ratio to the multiple segments S is determined in step S204, the control unit 13 may adjust the strength of the output from the power transmission coil 100 according to the ratio.

[0049] The control unit 13 turns off the power supply to the power transmission coils 100 for segments S other than those identified in steps S202 and S204 (step S206), and terminates the process.

[0050] In the configuration of the power transmission device 1 of the second embodiment, it is possible to energize only the necessary power transmission coil 100 without using a sensor that is affected by electromagnetic waves between the power transmission coil 100 and the power receiving coil to be transmitted, and with a simple configuration.

[0051] Figure 9 is a schematic diagram of the power transmission device 1 of the second embodiment. In the second embodiment, even if the power to be transmitted spans multiple segments S as shown in Figure 9, power can be supplied while suppressing electromagnetic wave leakage by turning on only the necessary coils 100.

[0052] Furthermore, in the case of the power transmission device 1 capable of performing the processing shown in the second embodiment, the power transmission unit 10 may have a configuration in which the power transmission coils 100 are more densely packed. Figure 10 is a schematic diagram of another example of the power transmission device 1 of the second embodiment. In the power transmission device 1 shown in Figure 10, the segments S are divided in a honeycomb shape. In the example shown in Figure 10, each segment S is provided with a power transmission coil 100 and a detection unit 11 that detects the presence of an object above the coil 100. The control unit 13 can individually supply power to each of the multiple coils 100 from the power supply unit 12. As a result, even if the object to be powered is placed across multiple segments S as shown in Figure 10, it is possible to supply power while suppressing electromagnetic wave leakage by turning on only the necessary coils 100.

[0053] The embodiments disclosed above are illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, and all modifications within the meaning and scope equivalent to the claims are included. [Explanation of Symbols]

[0054] 1. Power transmission equipment 10 Power transmission section 100 coils 101 Shield 11 Detection unit 12 Power supply section 13 Control Unit 130 processors 131 memory 132 Input / Output Circuits 14 containment units S segment D Drone P1 Program

Claims

1. A power transmission unit in which multiple power transmission coils are arranged side by side on a plane, Each of the aforementioned power transmission coils is provided with a detection unit that detects when the object to be transmitted is placed on top of the coil, A control unit that controls the transmission of power to a receiving coil provided in the object to be powered, Equipped with, The detection unit is a sensor that detects load and is provided below each of the multiple power transmission coils. An electromagnetic shielding material is provided between the detection unit and the coil to return the electromagnetic field from the coil back to the coil. The control unit transmits power to the coil while the detection unit detects that the object to be powered is placed on one of the coils of the plurality of power transmission coils. Power transmission equipment.

2. The control unit transmits power to the multiple power transmission coils while the detection unit detects that the object to be powered is placed across the multiple power transmission coils. The power transmission device according to claim 1.

3. For each of the multiple power transmission coils arranged side by side on a plane, a sensor located below each of the multiple power transmission coils detects when the object to be transmitted is placed on top of the coil, An electromagnetic shielding material is provided between the sensor and the coil to return the electromagnetic field from the coil back to the coil. While detecting that the object to be powered is placed on one of the coils of the plurality of power transmission coils, power is supplied to the coil. Power transmission method.

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