Wireless power transmission system

Abstract

The wireless power transmitting device includes: a power transmitting circuit that transmits power for a load device to a wireless power receiving device; a signal transmitting circuit that transmits a control signal of the load device to the wireless power receiving device; a signal receiving circuit that obtains an estimated value of a power receiving level indicating the level of power transmitted from the wireless power transmitting device and received by the wireless power receiving device; and a control circuit. The control circuit periodically allocates a plurality of time slots for wirelessly transmitting power from the wireless power transmitting device to each wireless power receiving device to each wireless power receiving device. When the power receiving level is less than a threshold value in a first time slot allocated to a certain wireless power receiving device, the control circuit extends a second time slot that is allocated to the same wireless power receiving device before or after the first time slot.

Description

Technical Field

[0001] The present disclosure relates to a wireless power transmission system including a wireless power transmitting device and a wireless power receiving device, and also relates to the wireless power transmitting device of the wireless power transmission system. Background Art

[0002] A wireless power transmission system is known that wirelessly transmits power from a power transmission device connected to a power source to a power receiving device including a load device such as a rechargeable battery. For example, in a sensor network including a plurality of sensors, a wireless power transmission system including a wireless power transmission device and a wireless power receiving device is constructed to supply power to each sensor.

[0003] When the radio wave propagation environment around the wireless power transmitting device and / or the wireless power receiving device constantly changes due to the movement of people or objects, it is necessary to adjust the operating parameters of the wireless power transmitting device or the wireless power receiving device according to the change in the radio wave propagation environment.

[0004] Patent Document 1 discloses a power transmission device that increases power transmission output according to surrounding conditions.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-102087 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] Due to changes in the radio wave propagation environment, it may be temporarily impossible to transmit power from the wireless power transmitting device to the wireless power receiving device, resulting in the load device being unable to operate normally due to insufficient power. For example, when the load device is a sensor, the malfunction of the sensor may cause an error in the measured value, which in turn may cause other devices (e.g., manufacturing devices in a factory, etc.) that use the measured value of the sensor to malfunction. Therefore, it is required to wirelessly transmit power from the wireless power transmitting device to the wireless power receiving device so that the load device is unlikely to malfunction due to insufficient power regardless of changes in the radio wave propagation environment.

[0010] The present disclosure aims to provide a wireless power transmission device that can wirelessly transmit power to a wireless power receiving device so that a load device is unlikely to malfunction due to insufficient power. Another object of the present invention is to provide a wireless power transmission system including such a wireless power transmission device.

[0011] Technical solutions for solving technical problems

[0012] According to the wireless power transmission device involved in the aspect of the present disclosure,

[0013] The wireless power transmitting device wirelessly transmits power to at least one wireless power receiving device including a load device that operates using power from a power storage device.

[0014] The wireless power transmission device comprises:

[0015] a power transmission circuit for transmitting electric power for operating the load device to the wireless power receiving device;

[0016] a signal sending circuit, which sends a control signal for controlling the load device to the wireless power receiving device;

[0017] a signal receiving circuit that acquires an estimated value of a power receiving level indicating a level of power transmitted from the wireless power transmitting device and received by the wireless power receiving device; and

[0018] a control circuit for controlling the operation of the wireless power transmission device,

[0019] The control circuit periodically allocates a plurality of time slots for wirelessly transmitting power from the wireless power transmitting device to each of the wireless power receiving devices to each of the wireless power receiving devices.

[0020] When the power reception level is lower than a predetermined threshold value in a first time slot allocated to a wireless power receiving device, the control circuit extends a second time slot before or after the first time slot allocated to the same wireless power receiving device.

[0021] With this configuration, electric power can be wirelessly transmitted from the wireless power transmitting device to the wireless power receiving device, making it difficult for the load device to malfunction due to power shortage.

[0022] According to the wireless power transmission device involved in the aspect of the present disclosure,

[0023] The wireless power transmitting device wirelessly transmits power to at least one wireless power receiving device including a load device that operates using power from a power storage device.

[0024] The wireless power transmission device comprises:

[0025] a power transmission circuit for transmitting electric power for operating the load device to the wireless power receiving device;

[0026] a signal sending circuit, which sends a control signal for controlling the load device to the wireless power receiving device;

[0027] a signal receiving circuit that acquires an estimated value of a power receiving level indicating a level of power transmitted from the wireless power transmitting device and received by the wireless power receiving device; and

[0028] a control circuit for controlling the operation of the wireless power transmission device,

[0029] When the power reception level changes from a state where the power reception level is less than a predetermined threshold to a state where the power reception level is greater than or equal to the threshold, the control circuit waits for a predetermined standby time and then transmits a control signal for operating the load device through the signal transmission circuit.

[0030] With this configuration, electric power can be wirelessly transmitted from the wireless power transmitting device to the wireless power receiving device, making it difficult for the load device to malfunction due to power shortage.

[0031] According to an aspect of the present disclosure, a wireless power transmission system includes:

[0032] The wireless power transmission device; and

[0033] At least one wireless power receiving device includes a load device that operates using the power of the power storage device.

[0034] By providing this configuration, for example, in a sensor network including a plurality of sensors, power can be supplied to each sensor.

[0035] Effects of the Invention

[0036] According to the wireless power transmission system according to an aspect of the present disclosure, power can be wirelessly transmitted from a wireless power transmitting device to a wireless power receiving device, so that a load device is unlikely to malfunction due to power shortage. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram showing the configuration of a system including the wireless power transmission system according to the first embodiment.

[0038] Figure 2 Yes means Figure 1 A block diagram showing a structure of a wireless power transmission device 1.

[0039] Figure 3 Yes means Figure 1 A block diagram of the structure of the wireless power receiving device 2.

[0040] Figure 4 Yes means Figure 1 1 is a timing chart showing changes in the charging voltage and the state signal when the power receiving level of the wireless power receiving device 2 always exceeds the threshold value Th1.

[0041] Figure 5 Yes means Figure 1 1 is a timing chart showing an example of changes in the charging voltage and the state signal when the power receiving level of the wireless power receiving device 2 is less than the threshold value Th1.

[0042] Figure 6 Yes means Figure 1FIG. 1 is a timing chart showing another example of changes in the charging voltage and the state signal when the power receiving level of the wireless power receiving device 2 is less than the threshold value Th1 .

[0043] Figure 7 Yes means Figure 1 A sequence diagram of an example of the operation of the system.

[0044] Figure 8 It means by Figure 1 Flowchart of the sensing process executed by the power transmission control circuit 10 of the wireless power transmission device 1 .

[0045] Fig. 9 Yes means Figure 1 A sequence diagram of a modified example of the operation of the system.

[0046] Fig.10 It is a schematic diagram showing a configuration of a wireless power transmitting device 1A of a wireless power transmission system according to a modification of the first embodiment.

[0047] Fig.11 It is a schematic diagram showing a configuration of a wireless power receiving device 2A of a wireless power transmission system according to a modification of the first embodiment.

[0048] Fig.12 This is a timing chart showing the initial state of time slots allocated to the wireless power receiving devices 2 - 1 to 2 - 3 in the wireless power transmission system according to the second embodiment.

[0049] Fig.13 It means when Fig.12 1 is a timing chart showing changes in the transmitted power and the charging voltage of the wireless power receiving device 2 - 1 when the power receiving level of the wireless power receiving device 2 - 1 always exceeds the threshold value Th1 .

[0050] Fig.14 It means when Fig.12 1 is a timing chart showing changes in the transmitted power and charging voltage of the wireless power receiving device 2-2 when the power reception level of the wireless power receiving device 2-2 is lower than the threshold value Th1 in the time slot T2(2) but the length of each time slot does not change.

[0051] Fig.15 It means when Fig.12 1 is a timing chart showing changes in the transmitted power and charging voltage of the wireless power receiving device 2-2 when the power reception level of the wireless power receiving device 2-2 is lower than the threshold value Th1 in the time slot T2(2) and the previous time slot T2(1) is extended.

[0052] Fig.16 It means when Fig.121 is a timing chart showing changes in the transmitted power and charging voltage of the wireless power receiving device 2-2 when the power reception level of the wireless power receiving device 2-2 is lower than the threshold value Th1 in the time slot T2(2) and the time slot T2(3) is extended thereafter.

[0053] Fig.17 It means when Fig.12 1 is a timing chart showing changes in the lengths of the time slots allocated to the wireless power receiving devices 2-1 to 2-3 when the power reception level of the wireless power receiving device 2-2 is lower than the threshold value Th1 in the time slot T2(2).

[0054] Fig.18 It means when Fig.12 1 is a timing chart showing a modified example of changing the lengths of the time slots allocated to the wireless power receiving devices 2-1 to 2-3 when the power reception level of the wireless power receiving device 2-2 is lower than the threshold value Th1 in the time slot T2(2). DETAILED DESCRIPTION

[0055] Hereinafter, an embodiment according to one aspect of the present disclosure (hereinafter also referred to as “this embodiment”) will be described based on the drawings. In each of the drawings, the same reference numerals denote the same constituent elements.

[0056] [First embodiment]

[0057] Reference Figures 1 to 11 A wireless power transmission system according to the first embodiment will be described.

[0058] [Application example of the first embodiment]

[0059] Figure 1 It is a schematic diagram showing the configuration of a system including the wireless power transmission system according to the first embodiment. Figure 1 The wireless power transmission system includes a wireless power transmitting device 1 and at least one wireless power receiving device 2 - 1 to 2 - 3 , and power is wirelessly transmitted from the wireless power transmitting device 1 to the wireless power receiving devices 2 - 1 to 2 - 3 .

[0060] Hereinafter, the wireless power receiving devices 2-1 to 2-3 are collectively referred to as "wireless power receiving devices 2". Figure 1 , the wireless power transmission system includes three wireless power receiving devices 2, but the wireless power transmission system may include any number of wireless power receiving devices 2. In addition, the wireless power transmitting device 1 is referred to as "power transmitting device 1" and the wireless power receiving device 2 is referred to as "power receiving device 2" hereinafter.

[0061] Figure 2 Yes means Figure 11 is a block diagram of the structure of a power transmission device 1. The power transmission device 1 includes at least a power transmission control circuit 10, a power transmission circuit 12, a signal transmission circuit 13, and a signal receiving circuit 15. The power transmission control circuit 10 is a control circuit of the power transmission device 1 that controls the overall operation of the power transmission device 1. The power transmission circuit 12 transmits power for operating a sensor 23 (described later) of the power receiving device 2 to the power receiving device 2. The signal transmission circuit 13 transmits a control signal for controlling the sensor 23 to the power receiving device 2. The signal receiving circuit 15 obtains an estimated value of a power receiving level indicating the level of power transmitted from the power transmission device 1 and received by the power receiving device 2.

[0062] Figure 3 Yes means Figure 1 1 is a block diagram of the structure of the power receiving device 2. The power receiving device 2 includes at least a power storage device 22 and a sensor 23. The power storage device 22 stores the power wirelessly transmitted from the power transmitting device 1 to the power receiving device 2. The power storage device 22 includes, for example, a rechargeable battery or a capacitor. The sensor 23 is a load device that operates using the power stored in the power storage device 22.

[0063] When the power receiving level changes from less than the predetermined threshold Th1 to greater than the threshold Th1 , the power transmission control circuit 10 waits for a predetermined waiting time Tw and then transmits a control signal to operate the sensor 23 via the signal transmission circuit 13 .

[0064] When the charging voltage of the power storage device 22 is higher than the predetermined threshold value Th2, the power storage device 22 can supply the sensor 23 with power sufficient to stably operate the sensor 23. The threshold value Th1 of the power receiving level can be set such that the charging voltage of the power storage device 22 reaches the threshold value Th2 after a sufficiently long time.

[0065] For example, when an obstacle passes between the power transmission device 1 and the power receiving device 2, the radio wave is cut off, the power receiving level is reduced, and the charging voltage of the power storage device 22 is also reduced. Once the power transmission is interrupted and the charging voltage of the power storage device 22 is lower than the threshold value Th2, even if the power transmission is restarted, it takes a predetermined time determined by the time constant of the circuit for the charging voltage of the power storage device 22 to reach the threshold value Th2 or more. Therefore, the standby time Tw is set to, for example, the length of time from zero to the charging voltage of the power storage device 22 reaching the threshold value Th2 when the power receiving device 2 receives power at a standard power receiving level higher than the threshold value Th1.

[0066] According to the wireless power transmission system involved in the first embodiment, as described above, when the state where the power receiving level is less than the threshold value Th1 changes to the state where the power receiving level is greater than the threshold value Th1, after waiting for the waiting time Tw, a control signal for operating the sensor 23 is transmitted. At this time, since it is considered that the charging voltage of the power storage device 22 is greater than the threshold value Th2, the power that enables the sensor 23 to operate stably can be supplied to the sensor 23. As a result, power can be wirelessly transmitted from the power transmission device 1 to the power receiving device 2, making it difficult for the sensor 23 to malfunction due to insufficient power.

[0067] The control signal for operating the sensor 23 may include, for example, turning on the sensor 23 , measuring a predetermined physical quantity by the sensor 23 , reading out the physical quantity measured by the sensor 23 , and the like.

[0068] [Configuration Example of First Embodiment]

[0069] exist Figure 1 In the example of , the power transmission device 1 and the power receiving devices 2-1 to 2-3 are arranged in a factory equipped with a control device 3, a manufacturing device 4 and a belt conveyor 5. The belt conveyor 5 conveys a pallet 6 and a workpiece 7. The pallet 6 and the workpiece 7 are moved by the belt conveyor 5 to reach predetermined positions p1 to p3 at a predetermined time. An event that a predetermined operation is performed on the workpiece 7 at positions p1 to p3. The power receiving devices 2-1 to 2-3 are respectively arranged near the positions p1 to p3, and are respectively associated with the events performed at the positions p1 to p3. The sensor 23 of each power receiving device 2-1 to 2-3 measures a predetermined physical quantity associated with the event. The power transmission device 1 collects the measured physical quantities from each power receiving device 2-1 to 2-3 and transmits them to the control device 3. The control device 3 controls the operation of the manufacturing device 4 based on the measured physical quantities. The control device 3 is, for example, a programmable logic controller. An event that the manufacturing device 4 performs a predetermined operation (for example, a processing step such as welding) on ​​the workpiece 7.

[0070] The power transmission device 1 is connected to a control device 3 and a manufacturing device 4 as external devices.

[0071] Reference Figure 2 The power transmission device 1 includes a power transmission control circuit 10, a power supply device 11, a power transmission circuit 12, a signal transmission circuit 13, an antenna control circuit 14, a signal reception circuit 15, a circulator 16, an antenna device ANT1, an interface (I / F) circuit 17 and a display device 18.

[0072] As described above, the power transmission control circuit 10 controls the overall operation of the power transmission device 1 .

[0073] The power supply device 11 supplies electric power to be transmitted to the power receiving device 2 .

[0074] As described above, the power transmission circuit 12 transmits power for operating the sensor 23 of the power receiving device 2 to the power receiving device 2 via the circulator 16 and the antenna device ANT1. The power transmission circuit 12 generates a CW (continuous wave) wave from the power supplied from the power supply device 11, for example.

[0075] The signal transmission circuit 13 transmits a control signal for controlling the sensor 23 (for example, a readout signal of the sensor 23) to the power receiving device 2 via the circulator 16 and the antenna device ANT1. The signal receiving circuit 15 receives a response signal including a physical quantity measured by the sensor 23 from the power receiving device 2 via the antenna device ANT1 and the circulator 16, for example. In addition, as described above, the signal receiving circuit 15 acquires an estimated value of the power receiving level. As described later, the estimated value of the power receiving level may be generated by the power transmission device 1 or by the power receiving device 2, and may be received from the power receiving device 2 via the antenna device ANT1 and the circulator 16.

[0076] The antenna device ANT1 has variable directivity. The antenna device ANT1 is, for example, an array antenna having a plurality of antenna elements, and its directivity changes by individually adjusting the amplitude and phase of the signal transmitted and received by each antenna element. The antenna control circuit 14 controls the directivity of the antenna device ANT1 under the control of the power transmission control circuit 10 .

[0077] The circulator 16 combines and separates the power and signal transmitted to the power receiving device 2 via the antenna device ANT1 and the signal received from the power receiving device 2 via the antenna device ANT1 .

[0078] The interface circuit 17 is connected to the control device 3 via a wired or wireless communication line. As described later, the power transmission control circuit 10 generates a state signal indicating whether the sensor 23 can operate, and outputs the state signal to the control device 3 via the interface circuit 17. In addition, as described later, the power transmission control circuit 10 generates a readout result signal including a physical quantity measured by the sensor 23, and transmits the readout result signal to the control device 3 via the interface circuit 17.

[0079] The display device 18 displays the state of the power transmitting device 1 and the state of the power receiving device 2 communicably connected to the power transmitting device 1 (power receiving level, etc.).

[0080] Reference Figure 3 The power receiving device 2 includes a power receiving control circuit 20, a power conversion circuit 21, a power storage device 22, a sensor 23, a matching (integration) circuit 24, a circulator 25, a signal transmission circuit 26, a signal reception circuit 27, a power receiving circuit 28, an antenna device ANT2 and a switch SW.

[0081] The power reception control circuit 20 controls the overall operation of the power reception device 2 .

[0082] The antenna device ANT2 has predetermined directivity or non-directivity.

[0083] The matching circuit 24 matches the impedance of the antenna device ANT2 with the impedance of the circulator 25 and other circuits.

[0084] The circulator 25 combines and separates the power and signal transmitted from the power transmission device 1 via the antenna device ANT2 and the signal transmitted to the power transmission device 1 via the antenna device ANT2.

[0085] The signal transmission circuit 26 transmits a response signal including a physical quantity measured by the sensor 23 via the circulator 25, the matching circuit 24 and the antenna device ANT2. The signal reception circuit 27 receives a control signal for controlling the sensor 23 from the power transmission device 1 via the antenna device ANT2, the matching circuit 24 and the circulator 25.

[0086] The power receiving circuit 28 receives power for operating the sensor 23 from the power transmitting device 1 via the antenna device ANT2 , the matching circuit 24 , and the circulator 25 .

[0087] The power conversion circuit 21 converts (rectifies) the power wirelessly transmitted from the power transmission device 1 to the power receiving device 2 from AC to DC, and then steps up or steps down the DC power. The power storage device 22 stores the power wirelessly transmitted from the power transmission device 1 to the power receiving device 2 and stepped up or down by the power conversion circuit 21. The power storage device 22 includes, for example, a rechargeable battery or a capacitor.

[0088] The sensor 23 operates using the power stored in the power storage device 22 and measures a predetermined physical quantity. The sensor 23 is connected to the power receiving control circuit 20 via a switch SW that is turned on / off under the control of the power receiving control circuit 20. When the switch SW is turned on, power is supplied from the power storage device 22 to the sensor 23, and the physical quantity measured by the sensor 23 is transmitted to the power receiving control circuit 20. The physical quantity measured by the sensor 23 is wirelessly transmitted to the power transmission device 1.

[0089] In order to estimate the power receiving level, the signal transmission circuit 26 of the power receiving device 2 can wirelessly transmit a test signal, and the signal receiving circuit 15 of the power transmitting device 1 can wirelessly receive the test signal and measure the received signal strength of the test signal. The signal receiving circuit 15 of the power transmitting device 1 can directly measure the received signal strength of the test signal, or can measure the received signal strength of the amplified test signal, or can measure the power of the test signal instead of the received signal strength of the test signal.

[0090] In order to estimate the power receiving level, the signal transmission circuit 13 of the power transmission device 1 can wirelessly transmit a test signal, and the signal receiving circuit 27 of the power receiving device 2 can wirelessly receive the test signal and measure the received signal strength of the test signal. The signal receiving circuit 27 of the power receiving device 2 can directly measure the received signal strength of the test signal, or can measure the received signal strength of the amplified test signal, or can measure the power of the test signal instead of the received signal strength of the test signal.

[0091] In order to estimate the power receiving level, the signal transmission circuit 13 of the power transmission device 1 may wirelessly transmit a test signal, and the signal receiving circuit 15 of the power transmission device 1 may wirelessly receive the test signal reflected by the power receiving device 2, and measure the received signal strength of the test signal. In this case, the power receiving device 2 may be configured to selectively generate impedance mismatch in any circuit portion under the control of the power receiving control circuit 20, for example, in order to reflect the test signal transmitted from the power transmission device 1.

[0092] The test signal may be a communication signal having a predetermined format or a CW (continuous wave) wave. The test signal may be transmitted in response to a command signal generated by the power transmitting device 1 or the power receiving device 2 or may be transmitted periodically without a command signal.

[0093] In order to estimate the power receiving level, the charging voltage of the power storage device 22 may be measured.

[0094] In order to estimate the power reception level, the power supplied to the load device of the power receiving device 2 , for example, the power conversion circuit 21 , the power storage device 22 , or the sensor 23 , may be measured.

[0095] [Operation Example of First Embodiment]

[0096] In the Figure 1 The environment around the power transmission device 1 and the power receiving device 2 is different when the power transmission device 1 and the power receiving device 2 are installed in the factory and when the factory is actually operated. For example, when the power transmission device 1 and the power receiving device 2 are installed, the manufacturing device 4 and the belt conveyor 5 are stopped, but when the power transmission device 1 and the belt conveyor 5 are operated, the pallet 6 and the workpiece 7 pass near the power transmission device 1 and the power receiving device 2.

[0097] When the surrounding environment of the power transmission device 1 and the power receiving device 2 changes, the radio wave propagation environment also changes. Therefore, even if the main beam direction of the antenna device ANT1 of the power transmission device 1 is adjusted to match the position of each power receiving device 2, or the main beam direction of the antenna device ANT2 of each power receiving device 2 is adjusted to match the position of the power transmission device 1 during installation, the propagation path of the radio wave may change or be cut off during operation. As a result, the power reception level of any power receiving device 2 becomes less than the threshold value Th1, and the sensor 23 cannot be supplied with power that can stably operate. When the sensor 23 malfunctions due to insufficient power, there is a possibility that the product processed by the manufacturing device 4 is defective or the manufacturing device 4 fails.

[0098] The wireless power transmission system according to the first embodiment wirelessly transmits power from the power transmitting device 1 to the power receiving device 2 as described below, so that malfunction of the sensor 23 due to power shortage is unlikely to occur.

[0099] Figure 4 It means when Figure 1 The timing diagram of the change of the charging voltage and the state signal when the power receiving level of the power receiving device 2 always exceeds the threshold value Th1. The power transmission control circuit 10 generates a state signal indicating whether the sensor 23 can operate, that is, whether the power storage device 22 can supply the sensor 23 with power that enables the sensor 23 to operate stably, based on the power receiving level. As described above, when the power receiving level is above the threshold value Th1, the charging voltage of the power storage device 22 is above the threshold value Th2, and the sensor 23 can be supplied with power that enables the sensor 23 to operate stably. Figure 4 In the example of , the status signal is always at a high level, indicating that the sensor 23 is always able to operate (enabled).

[0100] The display device 18 can also display Figure 4 At least one of the power receiving level, charging voltage and status signal shown.

[0101] Figure 5 It means when Figure 11 is a timing diagram showing an example of changes in the charging voltage and the state signal when the power receiving level of the power receiving device 2 is less than the threshold value Th1. As described above, during factory operation, the manufacturing device 4 and the belt conveyor 5 are in operation, and the pallet 6 and the workpiece 7 pass near the power transmitting device 1 and the power receiving device 2. As a result, the propagation of the radio wave is periodically interrupted between the power transmitting device 1 and the power receiving device 2, the power receiving level is periodically less than the threshold value Th1, and the charging voltage of the power storage device 22 is also periodically less than the threshold value Th2. At this time, the power transmission control circuit 10 sets the state signal to a low level. As described above, once the power transmission is interrupted and the charging voltage of the power storage device 22 is less than the threshold value Th2, even if the power transmission is started again, it takes a predetermined time determined by the time constant of the circuit for the charging voltage of the power storage device 22 to reach more than the threshold value Th2. Therefore, when the state changes from the state where the power receiving level is less than the threshold value Th1 to the state where the power receiving level is more than the threshold value Th1, the power transmission control circuit 10 changes the state signal from a low level to a high level after the standby standby time Tw.

[0102] Figure 6 It means when Figure 1 This is another example of a timing chart showing changes in the charging voltage and the state signal when the power receiving level of the power receiving device 2 is less than the threshold value Th1. Figure 5 In the example of , when the status signal is at a high level, it indicates that the sensor 23 can be operated (enabled), and when the status signal is at a low level, it indicates that the sensor 23 cannot be operated (disabled). Figure 6 As shown, when the status signal is at a low level, it indicates that the sensor 23 can be operated (enabled), and when the status signal is at a high level, it indicates that the sensor 23 cannot be operated (disabled).

[0103] Multiple time slots for wirelessly transmitting power from the power transmitting device 1 to each power receiving device 2 are periodically allocated to each power receiving device 2. In each time slot, the following are performed in time division:

[0104] (1) Estimation of power level (i.e., transmission and reception of test signals);

[0105] (2) Wireless transmission of power; and

[0106] (3) Send and receive control signals from the control sensor 23 and the measured physical quantities. Figures 4 to 6 In order to simplify the diagram, only the wireless transmission of power is shown, and the transmission and reception of other signals are omitted.

[0107] Figure 7 Yes means Figure 1 A sequence diagram of an example of the operation of the system.

[0108] The power transmitting device 1 acquires in advance an estimated value of the power reception level of each power receiving device 2 , and sets a state signal of each power receiving device 2 based on the power reception level.

[0109] When manufacturing device 4 itself is ready for operation, manufacturing device 4 transmits a sensing request signal to control device 3 in order to operate sensor 23 of each power receiving device 2 .

[0110] Next, the control device 3 sends a read start signal to the power transmission device 1 to start reading the measured value of the sensor 23. Next, the power transmission device 1 sends a status signal to the control device 3. When the sensor 23 cannot be operated (disabled), the control device 3 repeatedly sends the read start signal to the power transmission device 1 until the sensor 23 becomes operable (enabled). When the sensor 23 is operable (enabled), the control device 3 sends a read request signal to the power transmission device 1 to request the power transmission device 1 to read the measured value of the sensor 23.

[0111] Next, the power transmission device 1 transmits a readout signal to the power receiving device 2 in order to read out the measured value of the sensor 23. Next, the power receiving device 2 transmits a response signal including the physical quantity measured by the sensor 23 to the power transmission device 1. Next, the power transmission device 1 transmits a readout result signal including the physical quantity measured by the sensor 23 to the control device 3.

[0112] Next, the control device 3 determines whether the physical quantity measured by the sensor 23 satisfies a predetermined criterion (for example, a criterion indicating that the manufacturing device 4 can operate), and sends a sensing completion signal including the result to the manufacturing device 4. Then, the control device 3 sends a control signal to the manufacturing device 4 to control the manufacturing device 4.

[0113] Figure 8 It means by Figure 1 Flowchart of the sensing process executed by the power transmission control circuit 10 of the power transmission device 1 .

[0114] In step S1, the power transmission control circuit 10 obtains an estimated value of the power reception level of each power receiving device 2 using the signal receiving circuit 15. In step S2, the power transmission control circuit 10 determines whether the power reception level is greater than or equal to the threshold value Th1, and proceeds to step S3 if "yes" and to step S12 if "no".

[0115] In step S3, the power transmission control circuit 10 determines whether the state signal is disabled, and if it is "yes", it proceeds to step S4, and if it is "no", it proceeds to step S6. If step S3 is "yes", in step S4, the power transmission control circuit 10 waits for the standby period Tw in the state where the state signal is disabled, and in step S5, the state signal is changed from disabled to enabled. On the other hand, if step S3 is "no", the power transmission control circuit 10 maintains the state signal enabled.

[0116] In step S6 , the power transmission control circuit 10 determines whether a read start signal has been received from the control device 3 , and proceeds to step S7 if the determination is “yes”, or proceeds to step S8 if the determination is “no”. In step S7 , the power transmission control circuit 10 sends a status signal to the control device 3 .

[0117] In step S8, the power transmission control circuit 10 determines whether a readout request signal is received from the control device 3. If yes, the circuit proceeds to step S9, and if no, the circuit returns to step S1. In step S9, the power transmission control circuit 10 sends a readout signal to the power receiving device 2. When the power receiving control circuit 20 receives the readout signal, it obtains the physical quantity measured by the sensor 23. In step S10, the power transmission control circuit 10 receives a response signal including the physical quantity measured by the sensor 23 from the power receiving device 2. In step S11, the power transmission control circuit 10 sends a readout result signal including the physical quantity measured by the sensor 23 to the control device 3.

[0118] If the answer is “NO” in step S2 , the power transmission control circuit 10 sets the status signal to disabled in step S12 .

[0119] According to the wireless power transmission system according to the first embodiment, by executing Figure 7 as well as Figure 8 By means of the processing, electric power can be wirelessly transmitted from the power transmitting device 1 to the power receiving device 2, making it difficult for the sensor 23 to malfunction due to insufficient power.

[0120] Fig. 9 Yes means Figure 1 A sequence diagram of a modified example of the operation of the system. Figure 1 Systematic duplication Figure 7 The control device 3 collects status signals indicating whether the sensors 23 of each power receiving device 2 can operate. Fig. 9 In order to simplify the diagram, Figure 7 In each action, actions other than those related to the generation and transmission of the status signal are omitted. When the control device 3 collects the status signals of each power receiving device 2 within a predetermined time length, it performs an automatic scheduling process for automatically determining the scheduling for the manufacturing device 4 to operate based on the collected status signals. According to the automatic scheduling process, the control device 3 extracts the time period during which the sensor 23 can operate and the time period during which the sensor 23 cannot operate from the collected status signals, and determines the scheduling for the manufacturing device 4 to operate so that the manufacturing device 4 operates during the time period during which the sensor 23 can operate.

[0121] [Modification of the first embodiment]

[0122] Fig.10 1 is a schematic diagram showing a configuration of a power transmission device 1A of a wireless power transmission system according to a modification of the first embodiment. The power transmission device 1A includes antenna devices ANT11 and ANT12 and an antenna control circuit 14A instead of Figure 2 The antenna device ANT1, the antenna control circuit 14A and the circulator 16 are provided. Instead of using the same antenna device ANT1 for transmission and reception, separate antenna devices ANT11 and ANT12 may be used. The antenna control circuit 14A controls the directivity of the antenna devices ANT11 and ANT12 under the control of the power transmission control circuit 10.

[0123] Fig.11 The power receiving device 2A is a schematic diagram showing a configuration of a wireless power transmission system according to a modification of the first embodiment. The power receiving device 2A includes antenna devices ANT21 and ANT22, a power receiving control circuit 20A, and matching circuits 24a and 24b. Figure 3 The antenna device ANT2, the power reception control circuit 20 and the matching circuit 24 are provided. Instead of using the same antenna device ANT2 for transmission and reception, separate antenna devices ANT21 and ANT22 may be used.

[0124] [Effects of the First Embodiment]

[0125] According to the wireless power transmission system involved in the first embodiment, when the state where the power receiving level is less than the threshold value Th1 changes to the state where the power receiving level is greater than the threshold value Th1, after waiting for the waiting time Tw, a control signal for operating the sensor 23 is transmitted. At this time, since it is considered that the charging voltage of the power storage device 22 is greater than the threshold value Th2, the power that can stably operate the sensor 23 can be supplied to the sensor 23. As a result, power can be wirelessly transmitted from the power transmission device 1 to the power receiving device 2, making it difficult for the sensor 23 to malfunction due to insufficient power.

[0126] The wireless power transmission system according to the first embodiment can be applied to a radio wave propagation environment in which a periodic drop in the power receiving level occurs, and can also be applied to a radio wave propagation environment in which a non-periodic drop in the power receiving level occurs.

[0127] According to the wireless power transmission system according to the first embodiment, since the sensor 23 is unlikely to malfunction, products processed by the manufacturing device 4 are unlikely to be defective, and failure of the manufacturing device 4 is unlikely to occur.

[0128] According to the wireless power transmission system according to the first embodiment, the control device 3 recognizes whether the sensor 23 of each power receiving device 2 can be operated, so the control device 3 can operate the manufacturing device 4 during the time when the sensor 23 can be operated while monitoring the environment around the manufacturing device 4 and the belt conveyor 5. As a result, the product processed by the manufacturing device 4 is less likely to be defective, and the manufacturing device 4 is less likely to fail.

[0129] According to the wireless power transmission system involved in the first embodiment, by using the display device 18 to visualize the state of the power receiving device 2 (power receiving level, etc.), for example, the designer of the factory production line can appropriately determine the operation timing of the manufacturing device 4 and the belt conveyor 5, etc. according to whether the sensor 23 of each power receiving device 2 can be operated (i.e., changes in the radio wave propagation environment).

[0130] [Second embodiment]

[0131] Reference Figures 12 to 18 A wireless power transmission system according to a second embodiment will be described.

[0132] [Application example of the second embodiment]

[0133] The wireless power transmission system according to the second embodiment has the same configuration as the wireless power transmission system according to the first embodiment, and therefore, repeated description of the configuration will be omitted.

[0134] The power transmission control circuit 10 periodically allocates a plurality of time slots for wirelessly transmitting power from the power transmission device 1 to each power receiving device 2 to each power receiving device 2. When the power reception level in the first time slot allocated to a certain power receiving device 2 is less than a predetermined threshold value Th1, the power transmission control circuit 10 extends the second time slot allocated to the same power receiving device 2 before or after the first time slot.

[0135] For example, when an obstacle passes between the power transmission device 1 and the power receiving device 2 in a time slot allocated to a certain power receiving device 2, the radio wave is cut off, the power receiving level is reduced, and the charging voltage of the power storage device 22 is also reduced. According to the wireless power transmission system involved in the second embodiment, in order to compensate for the reduction in charging voltage, other time slots allocated to the same power receiving device 2 are extended. As a result, power can be wirelessly transmitted from the power transmission device 1 to the power receiving device 2, making it difficult for the sensor 23 to malfunction due to insufficient power.

[0136] [Operation Example of Second Embodiment]

[0137] Fig.12 2 is a timing chart showing the initial state of time slots allocated to the power receiving devices 2-1 to 2-3 of the wireless power transmission system according to the second embodiment. Fig.12In the example of , time slots T1(1) and T1(2) are allocated to the power receiving device 2-1, time slots T2(1) and T2(2) are allocated to the power receiving device 2-2, and time slots T3(1) and T3(2) are allocated to the power receiving device 2-3. Fig.12 In the example of , in the time section including the time slot T2(2) allocated to the power receiving device 2-2, the power receiving level of the power receiving device 2-2 becomes lower than the threshold value Th1.

[0138] Fig.13 It means when Fig.12 This is a timing chart showing changes in the transmitted power and charging voltage of the power receiving device 2-1 when the power receiving level of the power receiving device 2-1 always exceeds the threshold value Th1. Fig.13 In the example shown in FIG. 1 , the charging voltage always exceeds the threshold value Th2.

[0139] Fig.14 It means when Fig.12 This is a timing chart showing changes in the transmitted power and charging voltage of the power receiving device 2-2 when the power receiving level of the power receiving device 2-2 becomes lower than the threshold value Th1 in the time slot T2(2) but the length of each time slot does not change. Fig.14 In the example, in the time slot T2(2) (also referred to as "first time slot") allocated to the power receiving device 2-2, the power receiving level becomes lower than the threshold Th1, so the charging voltage becomes lower than the threshold Th2. As a result, the sensor 23 may malfunction.

[0140] Fig.15 It means when Fig.12 1 is a timing chart showing changes in the transmitted power and charging voltage of the power receiving device 2-2 when the power receiving level of the power receiving device 2-2 becomes lower than the threshold value Th1 in the time slot T2(2) and the previous time slot T2(1) is extended. Fig.16 It means when Fig.12 This is a timing chart showing changes in the transmitted power and charging voltage of the power receiving device 2-2 when the power receiving level of the power receiving device 2-2 becomes lower than the threshold value Th1 in the time slot T2(2) and the time slot T2(3) is extended thereafter. Fig.15 as well as Fig.16 In the example of , in order to compensate for the decrease in charging voltage, the time slot T2(1) before the time slot T2(2) or the time slot T2(3) after the time slot T2(2) (also referred to as the "second time slot") allocated to the same power receiving device 2-2 is extended.

[0141] When the power receiving level of a certain power receiving device 2 periodically decreases, other time slots allocated to the same power receiving device 2 are extended to allow wireless power transmission from the power transmitting device 1 to the power receiving device 2 , thereby making it difficult for the sensor 23 to malfunction due to power shortage.

[0142] Fig.17 It means when Fig.12 The timing diagram of the change in the length of the time slots allocated to the power receiving devices 2-1 to 2-3 when the power receiving level of the power receiving device 2-2 becomes lower than the threshold value Th1 in the time slot T2(2). The power transmission control circuit 10 shortens the time slots T1(1) and T3(1) (referred to as "third time slots") allocated to the power receiving devices 2-1 and 2-3 other than the power receiving device 2-2 allocated the time slots T2(1) to T2(2).

[0143] Fig.18 It means when Fig.12 A timing diagram of a modified example of changing the length of the time slots allocated to the power receiving devices 2-1 to 2-3 when the power receiving level of the power receiving device 2-2 becomes lower than the threshold value Th1 in the time slot T2(2). The power transmission control circuit 10 extends the time slots T1(2) and T3(2) (referred to as "fourth time slots") allocated to the same power receiving devices 2-1 and 2-3 as the power receiving devices allocated the time slots T1(1) and T3(1) and adjacent to the time slot T2(2).

[0144] exist Fig.17 as well as Fig.18 In the example of , power transmission from the power transmitting device 1 to the power receiving device 2 - 2 may be stopped in the time slot T2 ( 2 ).

[0145] according to Fig.17 as well as Fig.18 , wireless resources for a plurality of power receiving devices 2 can be effectively utilized to wirelessly transmit power from the power transmitting device 1 to the power receiving device 2, making it difficult for the sensor 23 to malfunction due to power shortage.

[0146] [Effects of the Second Embodiment]

[0147] According to the wireless power transmission system of the second embodiment, by changing the length of the time slot allocated to each power receiving device 2, power can be wirelessly transmitted from the power transmitting device 1 to the power receiving device 2, thereby making it difficult for the sensor 23 to malfunction due to power shortage.

[0148] The features of the first embodiment and the features of the second embodiment may be combined. That is, when the power receiving level in the first time slot allocated to a certain power receiving device 2 is less than the predetermined threshold value Th1, the power transmission control circuit 10 may extend the second time slot allocated to the same power receiving device 2 before or after the first time slot, and further, when the state changes from the power receiving level less than the predetermined threshold value Th1 to the state where the power receiving level is greater than the threshold value Th1, after waiting for a predetermined standby time Tw, the signal transmission circuit 13 transmits a control signal to operate the sensor 23. In this way, power can be wirelessly transmitted from the power transmission device 1 to the power receiving device 2, making it more difficult for the sensor 23 to malfunction due to insufficient power.

[0149] [Modifications]

[0150] The antenna device ANT2 of the power receiving device 2 may have variable directivity.

[0151] The display device may be provided in another device, for example, in the control device 3 instead of in the power transmission device 1 .

[0152] The power receiving device 2 etc. may also include any other load device instead of the sensor 23 or in addition to the sensor 23. The other load device may be, for example, a lighting device, a switch or relay that controls other devices, or a signal processing circuit that outputs a signal to other devices. In this case, the power receiving device may also use the detection result of the sensor 23 as a trigger to control the other load device.

[0153] [Summarize]

[0154] The wireless power transmission device and the wireless power transmission system according to various aspects of the present disclosure can also be described as follows.

[0155] According to the wireless power transmission device 1 according to the first aspect of the present disclosure, power is wirelessly transmitted to at least one wireless power receiving device 2, the wireless power receiving device 2 including a load device that operates using power from a power storage device 22. The wireless power transmission device 1 includes: a power transmission circuit 12 that transmits power for operating the load device to the wireless power receiving device 2; a signal transmission circuit 13 that transmits a control signal for controlling the load device to the wireless power receiving device 2; a signal reception circuit 15 that acquires an estimated value of a power reception level indicating the level of power transmitted from the wireless power transmission device 1 and received by the wireless power receiving device 2; and a power transmission control circuit 10 that controls the operation of the wireless power transmission device 1. In addition, the power transmission control circuit 10 periodically allocates a plurality of time slots for wirelessly transmitting power from the wireless power transmission device 1 to each wireless power receiving device 2 to each wireless power receiving device 2. In addition, when the power reception level is less than a predetermined threshold value in a first time slot allocated to a certain wireless power receiving device 2, the power transmission control circuit 10 extends a second time slot allocated to the same wireless power receiving device 2 before or after the first time slot.

[0156] According to the wireless power transmitting device 1 involved in the second aspect of the present disclosure, in the wireless power transmitting device 1 involved in the first aspect, when wireless power is transmitted from the wireless power transmitting device 1 to multiple wireless power receiving devices 2, the power transmission control circuit 10 shortens the third time slot that is temporally adjacent to the second time slot and is allocated to other wireless power receiving devices 2 that are different from the wireless power receiving device 2 to which the first time slot and the second time slot are allocated.

[0157] According to the wireless power transmitting device 1 of the third aspect of the present disclosure, in the wireless power transmitting device 1 of the second aspect, the power transmission control circuit 10 extends the fourth time slot adjacent to the first time slot allocated to the same wireless power receiving device 2 as the wireless power receiving device 2 allocated the third time slot.

[0158] According to the wireless power transmission device 1 involved in the fourth aspect of the present disclosure, in the wireless power transmission device 1 involved in one of the first to third aspects, when the state where the power receiving level is less than a predetermined threshold value changes to the state where the power receiving level is greater than the threshold value, the power transmission control circuit 10 sends a control signal through the signal transmission circuit 13 after standing by for a predetermined standby time.

[0159] According to the wireless power transmission device 1 of the fifth aspect of the present disclosure, in the wireless power transmission device 1 of the fourth aspect, the power transmission control circuit 10 generates a state signal indicating whether the load device can operate based on the power reception level. The wireless power transmission device 1 further includes an interface circuit 17 that outputs the state signal to an external device.

[0160] The wireless power transmission device according to the sixth aspect of the present disclosure wirelessly transmits power to at least one wireless power receiving device 2, the wireless power receiving device 2 having a load device that operates using power from a power storage device 22. The wireless power transmission device 1 includes: a power transmission circuit 12 that transmits power for operating the load device to the wireless power receiving device 2; a signal transmission circuit 13 that transmits a control signal for controlling the load device to the wireless power receiving device 2; a signal reception circuit 15 that acquires an estimated value of a power reception level indicating the level of power transmitted from the wireless power transmission device 1 and received by the wireless power receiving device 2; and a power transmission control circuit 10 that controls the operation of the wireless power transmission device 1. In addition, when the state where the power reception level is less than a predetermined threshold value is changed to the state where the power reception level is greater than the threshold value, the power transmission control circuit 10 transmits a control signal for operating the load device through the signal transmission circuit 13 after waiting for a predetermined standby time.

[0161] According to the wireless power transmission device 1 of the seventh aspect of the present disclosure, in the wireless power transmission device 1 of the sixth aspect, the power transmission control circuit 10 generates a state signal indicating whether the load device can operate based on the power reception level. The wireless power transmission device 1 further includes an interface circuit 17 that outputs the state signal to an external device.

[0162] According to the eighth aspect of the present disclosure, the wireless power transmission system comprises: the wireless power transmitting device 1 according to one of the first to seventh aspects; and at least one wireless power receiving device 2 including a load device that operates using power from a power storage device 22 .

[0163] According to the wireless power transmission system of the ninth aspect of the present disclosure, in the wireless power transmission system of the eighth aspect, the wireless power receiving device 2 includes a sensor 23 for measuring a predetermined physical quantity, and wirelessly transmits the physical quantity measured by the sensor 23 to the wireless power transmitting device 1 .

[0164] Industrial Applicability

[0165] The wireless power transmission system according to aspects of the present disclosure may be used, for example, to supply power to each sensor in a sensor network including a plurality of sensors.

[0166] Description of Reference Numerals

[0167] 1.1A Wireless power transmission device (power transmission device)

[0168] 2.2A.2-1~2-3 Wireless power receiving device (power receiving device)

[0169] 3 Control device

[0170] 4. Manufacturing equipment

[0171] 5 Belt conveyor

[0172] 6 Pallets

[0173] 7 Workpiece

[0174] 10 Power transmission control circuit

[0175] 11 Power supply unit

[0176] 12 Power transmission circuit

[0177] 13 Signal transmission circuit

[0178] 14.14A Antenna control circuit

[0179] 15 Signal receiving circuit

[0180] 16 Circulator

[0181] 17 Interface (I / F) circuit

[0182] 18 Display device

[0183] 20, 20A power receiving control circuit

[0184] 21 Power conversion circuit

[0185] 22 Power storage equipment

[0186] 23 Sensors

[0187] 24 Matching Circuit

[0188] 25 Circulator

[0189] 26 Signal transmission circuit

[0190] 27 Signal receiving circuit

[0191] 28 Power receiving circuit

[0192] ANT1, ANT2, ANT2A, ANT11~ANT22 antenna devices

[0193] SW switch.

Claims

1. A wireless power transmitting device for wirelessly transmitting power to at least one wireless power receiving device, wherein the wireless power receiving device includes a load device that operates using power from a power storage device, The wireless power transmission device comprises: a power transmission circuit for transmitting electric power for operating the load device to the wireless power receiving device; A signal sending circuit, sending a control signal for controlling the load device to the wireless power receiving device; a signal receiving circuit that acquires an estimated value of a power receiving level indicating a level of power transmitted from the wireless power transmitting device and received by the wireless power receiving device; as well as a control circuit for controlling the operation of the wireless power transmission device, The control circuit periodically allocates a plurality of time slots for wirelessly transmitting power from the wireless power transmitting device to each of the wireless power receiving devices to each of the wireless power receiving devices. When the power reception level is periodically lower than a predetermined first threshold value in a first time slot allocated to a wireless power receiving device, the control circuit extends a second time slot before or after the first time slot allocated to the same wireless power receiving device.

2. The wireless power transmission device according to claim 1, wherein: When the wireless power transmitting device wirelessly transmits power to a plurality of wireless power receiving devices, the control circuit shortens a third time slot temporally adjacent to the second time slot allocated to a wireless power receiving device other than the wireless power receiving device to which the first and second time slots are allocated.

3. The wireless power transmission device according to claim 2, wherein: The control circuit extends a fourth time slot that is temporally adjacent to the first time slot and is allocated to the same wireless power receiving apparatus as the wireless power receiving apparatus to which the third time slot is allocated.

4. The wireless power transmission device according to any one of claims 1 to 3, wherein: When the state where the power receiving level is less than a predetermined first threshold value changes to the state where the power receiving level is greater than the first threshold value, the control circuit transmits the control signal through the signal transmission circuit after waiting for a predetermined standby time. The standby time is the length of time from when the wireless power receiving device receives power at the power receiving level higher than the first threshold value until the charging voltage of the wireless power receiving device reaches a second threshold value from zero. When the charging voltage of the wireless power receiving device is above the second threshold value, the load device can be supplied with power sufficient for the load device to operate stably.

5. The wireless power transmission device according to claim 4, wherein: The control circuit generates a status signal indicating whether the load device is operable based on the power receiving level. The wireless power transmitting device further includes an interface circuit that outputs the state signal to an external device.

6. A wireless power transmission system comprising: Wireless power transmission device; and at least one wireless power receiving device, the wireless power receiving device including a load device that operates using power from the power storage device, The wireless power transmission device comprises: a power transmission circuit for transmitting electric power for operating the load device to the wireless power receiving device; A signal sending circuit, sending a control signal for controlling the load device to the wireless power receiving device; a signal receiving circuit that acquires an estimated value of a power receiving level indicating a level of power transmitted from the wireless power transmitting device and received by the wireless power receiving device; as well as a control circuit for controlling the operation of the wireless power transmission device, The control circuit periodically allocates a plurality of time slots for wirelessly transmitting power from the wireless power transmitting device to each of the wireless power receiving devices to each of the wireless power receiving devices. When the power reception level is periodically lower than a predetermined first threshold value in a first time slot allocated to a wireless power receiving device, the control circuit extends a second time slot before or after the first time slot allocated to the same wireless power receiving device.

7. The wireless power transmission system according to claim 6, wherein: The wireless power receiving device includes a sensor for measuring a predetermined physical quantity, and wirelessly transmits the physical quantity measured by the sensor to the wireless power transmitting device.

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