JP2015208157A - wireless power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless power supply system, capable of stable power transmission without the need of a battery exchange for power reception equipment.SOLUTION: A power transmission device includes: direction control means for controlling the direction of power transmission from the power transmission device; and storage means for storing a power reception state at the power reception equipment, as information associated with the direction of power transmission controlled by the direction control means. The direction of the power transmission from the power transmission device is controlled based on the information stored in the storage means.

Description

  The present invention relates to a wireless power feeding system that performs wireless power transmission from a power transmission device to a power receiving device.

  When a plant constitutes various facilities using a wireless field device, a primary battery is usually mounted on the wireless field device and used as a power source. In the field wireless device, power is consumed mainly for data communication. Therefore, by extending the data update cycle, the frequency of data communication can be reduced and the battery life can be extended.

JP 2013-030914 A JP 2012-016087 A JP 2008-240661 A JP 2008-283804 A

  However, when the battery life is several years, it is impossible to cope with the case where it is desired to shorten the data update cycle in consideration of the battery life, for example, the communication frequency is about once every several tens of seconds. In addition, wireless field devices are inherently superior to wired devices when they are installed in places where it is difficult for people to enter and access frequently, for example, above steel towers or offshore platforms. When the battery needs to be replaced, the merit of using the wireless field device is impaired. Therefore, there is a need for a system that does not require battery replacement and enables stable and sufficient power transmission without being affected by weather or the like.

  An object of the present invention is to provide a wireless power feeding system that does not require battery replacement of a power receiving device and can stably transmit power.

The wireless power feeding system of the present invention is a wireless power feeding system that performs wireless power transmission from a power transmission device to a power receiving device, wherein the power transmission device controls a direction of power transmission from the power transmission device, and the power receiving device. Storage means for storing the power receiving state in the information associated with the direction of power transmission controlled by the direction control means, and the direction of power transmission from the power transmission device is the information stored in the storage means It is controlled based on.
According to this wireless power feeding system, the power receiving state in the power receiving device is controlled based on information associated with the direction of power transmission, so that battery replacement of the power receiving device is not necessary and stable power transmission is possible. It becomes possible.

  The power receiving device includes a power reception state transmission unit that wirelessly transmits the power reception state of the power reception device toward the power transmission device, and the power transmission device receives the power reception state wirelessly transmitted by the power reception state transmission unit. You may provide a receiving condition receiving means.

  The power reception state may be wirelessly transferred from the power reception state transmission unit to the power reception state reception unit while the power reception device receives power transmission from the power transmission device.

  The power transmission device may include a plurality of antennas, and the direction control means may control the direction of power transmission by controlling the phase of radio waves radiated from the plurality of antennas.

  The power transmission device may be housed in a case with a flameproof structure, and the case may be provided with a region that transmits radio waves radiated from the plurality of antennas.

  The case may have a cylindrical shape, and a cylindrical plane in the case may be used as the region.

  According to the wireless power feeding system of the present invention, the power receiving state in the power receiving device is controlled based on the information associated with the direction of power transmission, so that battery replacement of the power receiving device is unnecessary and stable. Power transmission is possible.

The top view which shows the structure of a wireless electric power feeding system. The block diagram which shows the structure of a power transmission apparatus. It is a figure which shows the example of mounting of a power transmission apparatus, (a) is a front view, (b) is a side view. The circuit diagram which shows the charging circuit with which a wireless field device is equipped. It is a figure which shows the example of mounting of a receiving antenna, (a) is a front view, (b) is a side view. The flowchart which shows the operation example of a power transmission apparatus.

  Hereinafter, embodiments of a wireless power feeding system according to the present invention will be described.

  FIG. 1 is a plan view showing the configuration of the wireless power feeding system of the present embodiment.

  As shown in FIG. 1, the wireless power feeding system of the present embodiment is configured to receive power connected to the wireless field devices 1A, 1B, 1C and the wireless field devices 1A, 1B, 1C arranged in one area of the plant or facility. Antennas 2, 2, 2, a power transmission device 3 that performs wireless power transmission toward the power receiving antennas 2, 2, and 2, and a wireless system device 10 that is connected to the power transmission device 3.

  Each of the field wireless devices 1A, 1B, 1C and the wireless system device 10 includes a data communication antenna 11, and can perform wireless data communication with each other via the data communication antenna 11. In FIG. 1, three wireless field devices are shown, but the number is arbitrary. A plurality of power transmission devices can also be used.

  FIG. 2 is a block diagram illustrating a configuration of the power transmission device 3.

  As shown in FIG. 2, the power transmission device 3 includes a microwave generation device 31 that generates a microwave for power transmission, a power supply 32 that supplies power to the microwave generation device 31, and a microwave generated by the microwave generation device 31. , Which outputs waves, phase shifters 34, 34,... That change the phase of microwaves applied to the power transmission antennas 4, 4,. , A control unit 35 that controls the microwave generator 31 and the phase shifters 34, 34,..., And a storage unit 36 that stores power reception information to be described later.

  In the present embodiment, the frequency of the microwave for power transmission is set to a frequency different from the data communication between the wireless field devices 1A, 1B, 1C and the wireless system device 10. Thereby, it is possible to perform power transmission and data communication simultaneously. For example, the frequency of data communication can be set to 2.45 GHz, and the frequency of microwaves for power transmission can be set to 5.77 GHz.

  FIGS. 3A and 3B are diagrams illustrating an implementation example of the power transmission device 3, in which FIG. 3A is a front view and FIG. 3B is a side view.

  As shown in FIGS. 3A and 3B, the power transmission device 3 includes a patch antenna 41, 41,... Formed on a flat substrate 42 (FIG. 3B), and a substrate. A cylindrical member 43 made of an aluminum die-casting housing 42, a pressure-resistant glass 44 fitted into the cylindrical member 43, and a leg 45 attached to the cylindrical member 43. A case with a pressure-proof explosion-proof structure is formed by the cylindrical member 43 and the pressure-resistant glass 44, and the patch antennas 41, 41,... The microwaves from the patch antennas 41, 41,...

  The spacing between adjacent patch antennas 41 is 0.5λ to 1.0λ, where λ is the wavelength of the emitted microwave. 3A shows an example in which 16 patch antennas 41, 41,... Are provided, the number thereof can be arbitrarily selected.

  In addition, the whole power transmission apparatus 3 (FIG. 2) or a part thereof can be appropriately accommodated in the case of the explosion-proof explosion-proof structure formed by the cylindrical member 43 and the pressure-resistant glass 44.

  In order to obtain a pressure-resistant explosion-proof structure, the cylindrical member 43 can be formed by a plate material having a thickness of about 7 mm, for example, and the pressure-resistant glass 44 can be formed by a glass plate having a thickness of about 10 mm, for example.

  .. (FIG. 2) is configured as a phased array with patch antennas 41, 41,..., And each of the patch antennas 41, 41,. ... By changing the phase of the microwaves radiated from the power transmission antennas 4, 4,... By the phase shifters 34, 34, 34, the radiation direction of the microwaves can be finely controlled. For example, if the phases of the microwaves radiated from all the power transmission antennas 4, 4,... Are aligned, the microwaves are radiated in the normal direction of the surface of the substrate 42. The microwave radiation direction can be changed in a direction having an angle from the direction. The microwave radiation direction can be changed in both left and right and up and down directions. In FIG. 1, the radiation range when the microwave radiation direction is swayed toward the wireless field device 1A is indicated by a solid line, and the radiation range when the microwave radiation direction is swayed toward the wireless field device 1C is indicated by a dotted line Respectively.

  The directivity of the power transmitting antennas 4, 4,... Is the power transmission output, the gain of the power receiving antenna 2, the efficiency when converting the microwave power received by the power receiving antenna 2 into the power for charging, the power transmitting antennas 4, 4,. .. To the field wireless devices 1A, 1B, 1C, etc., as appropriate, but can be, for example, about 25 to 30 dBi.

Further, for example, intermittent power transmission may be performed for the purpose of complying with Japanese radio wave protection standards of 5 mW / cm ² (average value for 6 minutes).

  In addition, since the technique which changes the radiation direction of a microwave by phase control is well-known, the detailed description is abbreviate | omitted.

  In the present embodiment, a phased array is configured by the patch antennas 41, 41,... And the microwave radiation direction is changed by controlling the phase. This makes it easier to obtain an explosion-proof structure. In addition, since the device can be made more compact as compared with the case where the rotation mechanism is provided, the cost when the device is accommodated in the pressure-resistant case to obtain the pressure-proof explosion-proof structure can be reduced. In addition, when a device having a rotation mechanism is accommodated in a case with a flameproof structure, it is necessary to use a material that transmits microwaves in a wide radiation direction as a material of the case, which makes it difficult to create the case. There is also. In this regard, in the power transmission device 3, the patch antennas 41, 41,... And the pressure-resistant glass 44 are arranged close to each other, so that the area of the pressure-resistant glass 44 can be suppressed, and most of the other strength is obtained. Or a metal that can be easily sealed.

  FIG. 4 is a circuit diagram showing a charging circuit provided in the wireless field device 1A. A similar circuit is mounted on the wireless field device 1B and the wireless field device 1C.

  As shown in FIG. 4, the wireless field device 1A includes a low-pass filter 12 for rectifying and storing microwaves radiated from the power transmitting antennas 4, 4,. A charging circuit that is composed of the λ / 4 line 14 and the capacitor 15 and charges the storage battery 16 is provided. The charged storage battery 16 functions as a power source for each circuit inside the device.

  In addition, the wireless field device 1A is provided with a charge amount detection circuit 17 for detecting the current charge amount of the storage battery based on the output voltage of the storage battery 16, for example, and the charge amount detected by the charge amount detection circuit 17 And the like are transmitted via the communication circuit 18 and the data communication antenna 11. As will be described later, this state of charge is used to control power transmission in the power transmission device 3.

  FIGS. 5A and 5B are diagrams illustrating an example of mounting the power receiving antenna 2, in which FIG. 5A is a front view and FIG. 5B is a side view.

  As shown in FIGS. 5A and 5B, the power receiving antenna 2 includes an array of patch antennas 21, 21,... Formed on a flat substrate (not shown), a patch antenna 21, Are made of aluminum die-casting, a pressure-resistant glass 23 fitted to the front surface of the case 22 so as to follow the formation surface of the patch antennas 21, 21,. And a lead wire 24 for drawing out the electric power obtained by. The electric power drawn out via the lead wire 24 is given to the low-pass filter 12 of the field wireless devices 1A, 1B, 1C (FIG. 4).

  The case 22 can be formed by a plate material having a thickness of about 7 mm, for example, and the pressure-resistant glass 23 can be formed by a glass plate having a thickness of about 10 mm, for example. In addition, since the power receiving antenna 2 does not handle large electric power, it can have an intrinsically safe explosion-proof structure.

  In order to increase the power receiving efficiency, the power receiving antenna 2 is installed so that the formation surfaces of the patch antennas 21, 21,.

  Next, the operation of the power transmission device 3 will be described.

  FIG. 6 is a flowchart illustrating an operation example of the power transmission device 3. The operation illustrated in FIG. 6 is executed based on the control of the control unit 35 (FIG. 2) of the power transmission device 3.

  Steps S1 to S8 in FIG. 6 show a series of processes for calculating the power reception state and storing it in the storage unit 36 (FIG. 2) of the power transmission device 3. This process is performed when the power receiving information described later is updated when the field wireless devices 1A, 1B, 1C are installed, when the equipment is changed, or periodically.

  In step S1 of FIG. 6, the radiation direction of the microwaves from the power transmission antennas 4, 4,.

  Next, in step S2, the phase shifters 34, 34,... Are controlled so that the microwave is radiated in the direction set in step S1, and the microwave is generated from the microwave generator 31. Thus, power transmission is executed in the direction set in step S1.

  Next, in step S3, the charging state transmitted from the wireless field devices 1A, 1B, 1C is received via the wireless system device 10. As described above, this state of charge is data indicating the amount of charge of the storage battery 16 mounted on the wireless field devices 1A, 1B, and 1C.

  Next, in step S4, it is determined whether or not a predetermined time has elapsed since the start of power transmission in the direction set in step S1, and if the determination is affirmed, the process proceeds to step S, and the determination is denied. If so, the process returns to step S2 to continue power transmission.

  In step S5, the operation of the microwave generator 31 is stopped to stop power transmission.

  Next, in step S6, based on the state of charge received in step S3, the amount of increase in the amount of charge due to power transmission for a certain period of time, that is, the amount of received power is calculated for each wireless field device 1A, 1B, 1C.

  Next, in step S7, the amount of power received calculated in step S6 is stored in the storage unit 36 as power reception information associated with the power transmission direction for each wireless field device 1A, 1B, 1C, that is, the direction set in step S1. Store.

  Next, in step S8, it is determined whether or not the processing in steps S2 to S7 has been completed for all scheduled power transmission directions. If the determination is affirmative, the processing is ended, and if the determination is negative. Return to step S1. In the latter case, the power transmission direction is changed in step S1, and the processes in steps S2 to S7 are repeated.

  As described above, in the processing of Step S1 to Step S8, power transmission is performed for a certain time while changing the direction of power transmission from the power transmission device 3, and the amount of change in the charge amount in the wireless field devices 1A, 1B, and 1C is calculated. In this processing, for example, by calculating and storing the amount of change in the charge amount while changing the power transmission direction in all of the vertical and horizontal directions, the storage unit 36 stores the unit in each wireless field device 1A, 1B, 1C. Information in which the amount of power received per hour is associated with the direction of power transmission is stored as power reception information. Accordingly, for example, it is possible to grasp the power transmission direction in which the amount of power received per unit time is maximum for each of the wireless field devices 1A, 1B, and 1C.

  It should be noted that the time for measuring the change in the charge amount with the power transmission direction as a fixed direction (a fixed time serving as a criterion for determination in step S4) is set according to the characteristics of the rechargeable battery 16 used for the field device.

  Next, steps S11 to S14 in FIG. 6 show a series of processes for performing power transmission to the wireless field devices 1A, 1B, and 1C using the power reception information stored in the storage unit 36. This process can be executed at any time after storing the power reception information in steps S1 to S8.

  In step S <b> 11 of FIG. 6, the charging state transmitted from the wireless field devices 1 </ b> A, 1 </ b> B, and 1 </ b> C is received via the wireless system device 10. As described above, this state of charge is data indicating the amount of charge of the storage battery 16 mounted on the wireless field devices 1A, 1B, and 1C.

  Next, in step S <b> 12, power reception information is acquired from the storage unit 36.

  Next, in step S13, a power transmission direction and a power transmission time are set based on the charging state of each wireless field device 1A, 1B, 1C received in step S11 and the power reception information acquired in step S12.

  Next, in step S14, the phase shifters 34, 34,... Are controlled so that the microwave is radiated in the direction set in step S13, and the microwave is generated from the microwave generator 31, Power transmission is executed for the time set in step S13 in the direction set in step S13, and the process returns to step S11.

  As described above, in the processing of Step S11 to Step S14, the power transmission direction and the power transmission time are set based on the charging state of each wireless field device at the present time and the power reception information stored in the storage unit 36, and then power transmission is performed. doing. For this reason, it is possible to perform appropriate power transmission according to the state of charge of each wireless field device, and it is possible to perform stable power transmission without causing the battery to run out of charge. The algorithm in this process can be selected arbitrarily.For example, when there is a wireless field device that is likely to run out of battery power, power is transmitted toward the direction of power transmission that maximizes the amount of power received per unit time. Thus, it is possible to reliably avoid a charge failure.

  In addition, while receiving the power reception information of each wireless field device while performing the processing of step S11 to step S14, the power reception information is updated at any time by executing a process of calculating and storing the power reception amount per unit time. You can also. In this way, by updating the power reception information in parallel with the processing of steps S11 to S14, it is possible to quickly obtain more accurate power reception information corresponding to the change in the situation.

  In the above embodiment, the amount of received power per unit time is calculated based on the change in the amount of charge for a certain time, but the method for calculating the amount of received power is arbitrary. For example, the reception intensity of microwaves in each wireless field device when receiving power transmission may be measured and converted into the amount of power received per unit time.

  In the above embodiment, the power transmission device or the like has an explosion-proof structure, but the present invention can also be applied to a device that does not have an explosion-proof structure.

  The scope of application of the present invention is not limited to the above embodiment. The present invention can be widely applied to a wireless power feeding system that performs wireless power transmission from a power transmission device to a power receiving device.

1A, 1B, 1C Wireless field device (power receiving device)
3 Power transmission device 4 Power transmission antenna (antenna)
10 Wireless system equipment (power reception status receiving means)
35 Control unit (direction control means)
36 storage unit (storage means)
17 Charge amount detection circuit (power reception state transmission means)
18 Communication circuit (power reception state transmission means)
43 Cylindrical member (case)
44 Pressure-resistant glass (case)

Claims (6)

In a wireless power feeding system that performs wireless power transmission from a power transmission device to a power receiving device,
The power transmission device is:
Direction control means for controlling the direction of power transmission from the power transmission device;
Storage means for storing a power reception state in the power receiving device as information associated with a direction of power transmission controlled by the direction control means;
With
A wireless power feeding system, wherein a direction of power transmission from the power transmission device is controlled based on the information stored in the storage unit. The power receiving device includes a power receiving state transmitting unit that wirelessly transmits the power receiving state of the power receiving device toward the power transmission device,
The wireless power feeding system according to claim 1, wherein the power transmission device includes a power reception state reception unit that receives the power reception state wirelessly transmitted by the power reception state transmission unit.   3. The wireless according to claim 2, wherein the power receiving state is wirelessly transferred from the power receiving state transmitting unit to the power receiving state receiving unit while the power receiving device receives power transmission from the power transmitting device. Power supply system. The power transmission device includes a plurality of antennas,
The wireless power feeding system according to claim 1, wherein the direction control unit controls a direction of power transmission by controlling phases of radio waves radiated from the plurality of antennas. The power transmission device is housed in a case with a flameproof structure,
The wireless power feeding system according to claim 4, wherein a region that transmits radio waves radiated from the plurality of antennas is provided in the case. The case has a cylindrical shape,
The wireless power feeding system according to claim 5, wherein a cylindrical plane in the case is used as the region.

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