JP7554060B2 - Wireless power transmission system and power wave path change method - Google Patents

Description

This disclosure relates to a wireless power transmission system and a method for changing the path of a power wave.

In recent years, as the IoT advances, there is a demand to collect various information using a large number of information terminals, including sensors. However, as the number of such information terminals increases, it may become difficult to supply power to the terminals. Patent Document 1 discloses a power supply system that utilizes wireless power transmission technology. The power supply system of Patent Document 1 includes a structure entirely surrounded by an electromagnetic wave reflecting member, a power receiver disposed inside the structure, and another power receiver disposed inside the structure. The power receiver is a unit that transmits radio waves at a resonant frequency, assuming that the wireless power transmission system is a waveguide resonator. The power receiver is disposed inside the structure, and uses a reactance element and an impedance variable probe to match the impedance between the transmission path between the power transmitter and the power receiver. This makes it possible to improve the power received by the power receiver.

JP 2019-41529 A

However, the conventional technology of Patent Document 1 is based on the premise that there are no obstacles such as metal bodies or insulators in the space in which the power supply system is placed. Therefore, if the power receiver is placed adjacent to an obstacle in the space, it is difficult to obtain an optimal impedance between the power receiver and the power transmitter. Therefore, the conventional technology has room for improvement in terms of increasing the received power of the power receiver.

Non-limiting examples of the present disclosure contribute to providing a wireless power transmission system and a method for changing the power wave path that can improve the received power at a power receiver.

A wireless power transmission system according to one embodiment of the present disclosure includes a power transmitter that radiates a power wave, a power receiver that receives the power wave, and a propagation path changing unit that changes the propagation path of the power wave from the power transmitter to the power receiver, and the propagation path changing unit changes the position of an antenna that radiates the power wave at a constant or random period .

A method for changing a power wave path according to one embodiment of the present disclosure includes the steps of radiating a power wave from a power transmitter, receiving the power wave with a power receiver, and changing the position of an antenna radiating the power wave at a constant or random period , scattering the power wave radiated from the power transmitter, or moving the power receiver to change the receiving position of the power wave , and changing the orientation of the antenna radiating the power wave at a constant or random period, thereby changing the propagation path of the power wave from the power transmitter to the power receiver.

According to one embodiment of the present disclosure, a wireless power transmission system and a method for changing the power wave path can be constructed that can improve the received power at a power receiver.

Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and/or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them need be provided to obtain one or more identical features.

FIG. 1 illustrates an example of the configuration of a wireless power transmission system 100 according to an embodiment of the present disclosure. FIG. 2 shows an example of the configuration of a power transmitter/receiver 103. FIG. 1 is a diagram showing a configuration example of a propagation path changing unit 1 included in a wireless power transmission system 100 according to a first modified example of an embodiment of the present disclosure. FIG. 13 is a diagram illustrating a configuration example of a wireless power transmission system 100 according to a second modified example of an embodiment of the present disclosure. FIG. 13 is a diagram illustrating a configuration example of a wireless power transmission system 100 according to a third modified example of an embodiment of the present disclosure. FIG. 1 is a diagram showing a configuration example of a power receiver 104 according to an embodiment of the present disclosure. 1 is a flowchart for explaining an operation of the power receiver 104 according to an embodiment of the present disclosure. FIG. 1 is a diagram illustrating a configuration of a modified example of a power receiver 104 according to an embodiment of the present disclosure. FIG. 1 shows a semi-closed space 102 for evaluating changes in the amount of received power. FIG. 1 is a diagram for explaining the evaluation results of the amount of received power.

A preferred embodiment of the present disclosure will be described in detail below with reference to the attached drawings. Note that in this specification and drawings, components having substantially the same functions are designated by the same reference numerals to avoid redundant description.

[Embodiment]
<Configuration example of wireless power transmission system 100>
1 is a diagram illustrating an example of a configuration of a wireless power transmission system 100 according to an embodiment of the present disclosure. The wireless power transmission system 100 includes a power transmitter/receiver 103 and a plurality of power receivers 104. The wireless power transmission system 100 is disposed in a semi-closed space 102 surrounded by a wall of a building or the like.

The power transmitter/receiver 103 not only functions as a power transmitter that transmits (radiates) radio waves 105 into the semi-closed space 102, but also has a function of receiving radio waves (reflected waves) radiated from the power receiver 104. The power transmitter/receiver 103 supplies power to each of the multiple power receivers 104 by radiating radio waves 105. The power receiver 104 receives the radio waves 105 radiated from the antenna 201. The power receiver 104 converts the received radio waves into DC power and supplies it to, for example, a sensor used in IoT (Internet of Things).

<Power transmitter/receiver 103>
Next, a configuration example of the power transmitter/receiver 103 will be described with reference to Fig. 2. Fig. 2 is a diagram showing a configuration example of the power transmitter/receiver 103.

The power transmitter/receiver 103 includes an oscillator 202, an antenna 201, a ball mechanism 203, and a three-axis stage 204. The ball mechanism 203 and the three-axis stage 204 constitute a propagation path change unit 1 that changes the propagation path of radio waves 105 from the power transmitter/receiver 103 to the multiple power receivers 104.

The oscillator 202 includes electrical circuits such as a memory, a CPU (Central Processing Unit), and a communication device, and the electrical circuits generate high-frequency power (power waves), control the amount of high-frequency power transmitted, and switch the frequency band of the high-frequency power. The oscillator 202 also has a function of inputting information contained in the radio waves emitted from the power receiver 104. The frequency band of the high-frequency power is a microwave band such as the 900 MHz band, the 2.45 GHz band, or the 5.8 GHz band. These frequency bands are selected according to the distance from the power transmitter/receiver 103 to the power receiver 104, the size of the power transmitter/receiver 103, etc.

The antenna 201 radiates the high-frequency power generated by the oscillator 202 as radio waves 105 into the semi-closed space 102. The types of antenna 201 include, for example, directional antennas and omnidirectional antennas. A directional antenna is used when it is necessary to transmit radio waves 105 over a long distance in a specific direction, and an omnidirectional antenna is used when it is necessary to transmit radio waves 105 over a wide area in a short distance. For example, a flat patch antenna in which a dielectric substrate is sandwiched between a GND plate and an antenna is used as a directional antenna. For omnidirectional antennas, a dipole antenna or a monopole antenna in which an electric conductor is extended in a straight line is used.

The ball mechanism 203 is a radiation direction changer that changes the radio wave radiation direction of the antenna 201 by rotating the antenna 201 around, for example, two orthogonal axes. The rotation speed and amount of rotation of the antenna 201 by the ball mechanism 203 can be set arbitrarily. By changing the radiation direction of the radio waves 105, it is possible to change the radio wave environment in the semi-closed space 102.

The three-axis stage 204 is a radiation position changer that changes the radio wave radiation position of the antenna 201 by, for example, moving the ball mechanism 203 in three mutually perpendicular axial directions. The speed and amount of movement of the ball mechanism 203 and the antenna 201 by the three-axis stage 204 can be set arbitrarily.

Next, the operation of the wireless power transmission system 100 will be described. When a high-frequency signal is radiated into the semi-closed space 102 as radio waves 105, for example, the ball mechanism 203 changes the radio wave radiation direction of the antenna 201 at regular or random intervals, and the three-axis stage 204 changes the position of the antenna 201 at regular or random intervals.

This changes the radio wave emission direction and radio wave emission position, and therefore the phase of the multiple radio waves 105 received by the power receiver 104 can be changed. As a result, the point at which the radio waves generated by the superposition of the radio waves 105 cancel each other out moves, reducing the probability that the power receiver 104 will not be able to receive power.

In addition, even if multiple power receivers 104 are placed near obstacles in the semi-closed space 102 due to changes in the radio wave environment in the semi-closed space 102, it is possible to stably supply power to each of the multiple power receivers 104 without adjusting the impedance of the multiple power receivers 104. The obstacles are, for example, windows made of an insulating material (polycarbonate, glass, etc.) and devices with metal housings.

In addition, by changing the radio wave environment within the semi-closed space 102, the number of locations within the semi-closed space 102 where power cannot be supplied can be reduced, allowing each power receiver 104 to continue operating. In addition, because each power receiver 104 can continue operating, the work of wiring power to the power receiver 104, the work of charging the power receiver 104, the work of replacing the batteries in the power receiver 104, etc. can be reduced.

FIG. 3 is a diagram showing an example of the configuration of the propagation path change unit 1 provided in the wireless power transmission system 100 according to the first modified example of the embodiment of the present disclosure. The propagation path change unit 1 is disposed on the front side of the power transmitter/receiver 103, and is a mechanism for scattering the radio waves 105 emitted from the power transmitter/receiver 103. The propagation path change unit 1 includes a three-axis stage 204, a rotation mechanism 302 disposed on the three-axis stage 204, and a reflector 301 that rotates by the rotation mechanism 302.

The rotation mechanism 302 is a motor or the like that rotates the reflector 301 in order to change the radiation direction of the radio waves 105 emitted from the antenna 201, and is disposed on the three-axis stage 204. The reflector 301 is a radiation direction changer that changes (scatters) the radiation direction of the radio waves 105 emitted from the antenna 201. For example, it is composed of multiple blades made of a dielectric or metal. The reflector 301 is disposed, for example, in front of the antenna 201, at a certain distance from the antenna 201.

By placing the reflector 301 in front of the antenna 201, the radio waves 105 emitted from the antenna 201 are reflected by the reflector 301 and radiated (scattered) in various directions. This makes it possible to change the radio wave environment within the semi-closed space 102.

According to the wireless power transmission system 100 of the first modified example, even if the position of the existing antenna 201 cannot be changed, the reflector 301 can rotate to scatter the radio waves 105, thereby changing the radio wave environment in the semi-closed space 102.

The rotation mechanism 302 can also change the rotation speed of the reflector 301 in a constant or random cycle, for example, to finely change the radio wave environment in the semi-closed space 102. This makes it possible to finely change the radio wave environment in the semi-closed space 102.

The three-axis stage 204 may also be operated while the rotation mechanism 302 is rotating. This changes the position of the reflector 301, making it possible to more finely change the radio wave environment in the semi-closed space 102.

Figure 4 is a diagram showing a configuration example of a wireless power transmission system 100 according to a second modified example of an embodiment of the present disclosure. The wireless power transmission system 100 according to the second modified example includes a propagation path change unit 1 that changes the reception position of radio waves 105 by moving multiple power receivers 104.

The propagation path change unit 1 is, for example, the building interior (ceiling, floor, walls) that forms the semi-closed space 102, or a drive mechanism that movably attaches the receiver 104 to the building interior. FIG. 4 shows an example in which a wall functions as the propagation path change unit 1. The wall can be moved, for example, at a constant or random period, to change the position of the receiver 104 placed on the wall. This changes the receiving position and receiving direction of the receiver 104, and changes the phase of the multiple radio waves 105 received by each receiver 104. As a result, it is possible to suppress a decrease in radio wave intensity caused by the multiple radio waves 105 canceling each other out.

In addition, even if the position of the power transmitter/receiver 103 cannot be changed, or if space cannot be secured between the power transmitter/receiver 103 and the power receiver 104 to place a reflector 301 or the like shown in FIG. 3, a stable power supply to each power receiver 104 is possible.

The propagation path change unit 1 may be configured to change the reflection position, reflection direction, etc. of the radio wave 105 radiated from the power transmitter/receiver 103. For example, a metal structure may be placed on a wall or the like as the propagation path change unit 1, and moved at a constant or random interval using a drive mechanism to change the reflection position, etc. of the radio wave 105 radiated from the power transmitter/receiver 103.

Fig. 5 is a diagram showing an example of the configuration of a wireless power transmission system 100 according to a third modified example of an embodiment of the present disclosure. The receiver 104 of the third modified example has a function of generating power receiving state information 503 indicating the power receiving state of the receiver 104 based on the received radio waves 105, and radiating the power receiving state information 503 into the semi-closed space 102 by including it in a reflected wave 502. The power receiving state information 503 includes, for example, information regarding the radio wave intensity of the radio waves 105, the power supplied to the receiver 104, etc.

The antenna 201 that receives the reflected wave 502 extracts the power receiving state information 503 contained in the reflected wave 502 and inputs it to the oscillator 202. Based on the power receiving state information 503, the oscillator 202 determines, for example, whether the amount of power supplied to the power receiver 104 is insufficient relative to the amount of power consumed by a load (such as a sensor that operates with the power supplied to the power receiver 104) connected to the power receiver 104. The oscillator 202 then controls the operation of the mechanical control mechanism 505 that constitutes the propagation path change unit 1 according to the determination result. The mechanical control mechanism 505 is, for example, the three-axis stage 204 described above.

For example, when the received power of the three power receivers A, B, and C is insufficient for the power consumption of the load, the oscillator 202 determines that it is necessary to increase the received power of the power receiver A. The oscillator 202 performs feedback control 504 on the mechanical control mechanism 505 so as to increase the received power of the power receiver A. The feedback control 504 causes the mechanical control mechanism 505 to change the position of the antenna 201, thereby changing the radiation direction, radiation position, etc. of the radio waves 105 radiated from the antenna 201 toward the power receiver A.

In addition, in the feedback control 504, the movement range of the antenna 201 may be limited, or the antenna 201 may be moved at a fixed or random interval within the limited movement range so that power receivers B, C, and other devices other than the power receiver A can also secure an adequate amount of power.

In addition, the object to be controlled by the feedback control 504 is not limited to the mechanical control mechanism 505, but may be the propagation path change unit 1 shown in Figures 2 to 4.

Next, a configuration example of the power receiver 104 will be described with reference to FIG. 6. FIG. 6 is a diagram showing a configuration example of the power receiver 104 according to an embodiment of the present disclosure. The power receiver 104 shown in FIG. 6 includes an antenna 401, a rectifier unit 402, a control unit 403, a power storage unit 405, and a switch unit 406.

The antenna 401 has a function of receiving radio waves 105 emitted from the power transmitter/receiver 103, inputting the received radio waves 105 to the rectifier 402 as high-frequency power, and radiating the radio waves 105 into a semi-closed space as reflected waves 502. The type of the antenna 401 is the same as that of the antenna 201 described above, and may be, for example, a directional antenna or an omnidirectional antenna.

The rectifier 402 converts the radio waves 105 received by the antenna 401 into DC power. The rectifier 402 is composed of, for example, a rectifier diode, an impedance matching circuit, a filter circuit, etc.

The control unit 403 controls the supply of radio waves 105 received by the antenna 401 to the load 404, controls charging of the power storage unit 405 by the radio waves 105, controls discharging of the power storage unit 405, and controls switching of the switch unit 406.

The load 404 is, for example, a sensor used in the Internet of Things (IoT). However, the load 404 is not limited to this.

The power storage unit 405 is a storage means for storing the power required to drive the control unit 403. The power storage unit 405 is, for example, a secondary battery. The power storage unit 405 stores the DC power output from the rectification unit 402 under charging control by the control unit 403. Furthermore, when the power consumption of the load 404 exceeds the DC power output from the rectification unit 402, the power storage unit 405 supplies the stored power to the load 404 under discharging control by the control unit 403.

The switch unit 406 is a switching means for switching the antenna 401 to an open or grounded state in the reflection mode, and for connecting the antenna 401 to the load 404 in the power supply mode.

The reflection mode is a mode in which the antenna 401 totally reflects the radio waves 105 received in phase or totally reflects the radio waves 105 in opposite phase by switching the impedance of the circuit side as seen from the antenna 401.

The power supply mode is a mode in which the rectifier 402 supplies DC power from the rectifier 402 to the load 404 with the rectifier 402 connected to the load 404 via the switch 406.

Open circuit refers to a state in which the antenna 401 is not connected to either the GND 407 or the load 404, and the impedance of the circuit connected to the antenna 401 is infinite.

Grounding refers to a state in which the impedance of the circuit connected to the antenna 401 becomes zero by connecting the antenna 401 to GND 407.

The rectification unit 402, the control unit 403, the power storage unit 405, and the switch unit 406 constitute the phase change unit 610. The phase change unit 610 changes the phase of the power wave received by the antenna 401, and radiates the power wave after the phase change from the antenna 401 as a reflected wave 502.

In addition, in the power receiver 104, a switch unit 406 is provided on the output side of the rectifier unit 402, so power loss can be reduced compared to when the switch unit 406 is provided between the antenna 401 and the rectifier unit 402.

Next, the operation of the power receiver 104 will be described with reference to FIG. 7. FIG. 7 is a flowchart for explaining the operation of the power receiver 104 according to an embodiment of the present disclosure.

First, the control unit 403 switches the connection destination of the switch unit 406 to the load 404 side using the power stored in the power storage unit 405, thereby setting the device in power supply mode (step S1). As a result, the radio waves 105 received by the antenna 601 are converted to DC power by the rectification unit 402 and supplied to the load 404. In the power supply mode, the control unit 403 charges the power storage unit 405 at the same time as supplying power to the load 404.

The control unit 403 determines whether sufficient power is being supplied to the load 404 in the power supply mode (step S2).

For example, if the power consumption of the load 404 exceeds the power converted by the rectifier 402, the controller 403 determines that sufficient power is not being supplied to the load 404 (step S2, NO), and repeats the processing from step S1 onward.

For example, if the power consumption of the load 404 is less than the power converted by the rectifier unit 402, the control unit 403 determines that sufficient power is being supplied to the load 404 (step S2, YES) and executes the processing of step S3.

Next, the control unit 403 uses the power stored in the power storage unit 405 to set the switch unit 406 to the reflective mode (step S3).

The control unit 403 controls the switch unit 406 to alternately switch the antenna 401 between an open state and a grounded state (step S4). This switching operation causes the radio waves 105 received when the antenna 401 is open to be totally reflected in phase, and causes the radio waves 105 received when the antenna 401 is grounded to be totally reflected in the opposite phase. The totally reflected radio waves 105 are radiated toward the semi-closed space as reflected waves 502. The reflected waves 502 radiated into the semi-closed space are received by one or more power receivers 104 present around the power receiver 104. The one or more power receivers 104 receive the reflected waves 502 and the radio waves 105 radiated from the power transmitter/receiver 103, and rectify them in the rectifier unit 402 to supply power to the load 404 and to the power storage unit 405.

The control unit 403 may control the switch unit 406 to alternate between open and grounded at a constant or random cycle. This allows a reflected wave 502 whose phase changes over time (phase modulation) to be transmitted, and the phase of the reflected wave 502 received by one or more power receivers 104 changes over time. For example, even if the position of the power receiver 104 changes, efficient power supply is possible without adjusting the impedance between the power receiver 104 that emits the reflected wave 502 and the power receiver 104 that receives the reflected wave 502.

The switching operation of the switch unit 406 reduces the stored power of the power storage unit 405, so the control unit 403 monitors whether the power storage unit 405 is in a state requiring charging (step S5).

For example, when the charge rate of the power storage unit 405 is equal to or higher than a predetermined value (e.g., 30%), or when a certain period of time has not elapsed since the power storage unit 405 started to discharge, the control unit 403 determines that the power storage unit 405 does not require charging (step S5, NO), and repeats the processing from step S3 onward.

For example, when the charge rate of the power storage unit 405 falls below a predetermined value (e.g., 30%) or a certain time has elapsed since the power storage unit 405 started to discharge, the control unit 403 determines that the power storage unit 405 needs to be charged (step S5, YES). In this case, the control unit 403 executes the process of step S1 to set the power storage unit 405 in the power supply mode.

These processes may be performed in all of the multiple power receivers 104, or in a portion (one or more) of the multiple power receivers 104.

By executing these processes in all of the multiple receivers 104, radio waves 105 of stable strength can be received at any point within the semi-closed space.

By executing these processes in some of the multiple receivers 104, the power consumed by the switching operation of the switch unit 406, etc. is reduced, so that the power consumption of the entire wireless power transmission system 100 is reduced, and radio waves 105 of a more stable strength can be received compared to when these processes are not executed.

In addition, these processes may be executed by all or some of the multiple power receivers 104 in synchronization with each other, or may be executed asynchronously.

By having all or some of the multiple receivers 104 execute these processes in synchronization with each other, it is possible to receive radio waves 105 with a more stable strength than if these processes were not executed.

By having all or some of the multiple receivers 104 execute these processes asynchronously, the circuitry and control required for synchronization is no longer necessary, simplifying the configuration of the receivers 104 and improving reliability, while allowing radio waves 105 of stable strength to be received at any point within the semi-closed space.

By equipping some or all of the multiple power receivers 104 with a random number generator that randomly generates a switching clock for the switch unit 406, for example, it is possible to make the switching timing of the switch unit 406 asynchronous. This eliminates the need to centrally control the multiple power receivers 104, and allows a radio wave environment with stable strength to be created with a simple configuration.

Figure 8 is a diagram showing the configuration of a modified example of the power receiver 104 according to the embodiment of the present disclosure. In the power receiver 104 shown in Figure 8, the switch unit 406 and the rectifier unit 402 are arranged in reverse. By arranging the switch unit 406 on the input side of the rectifier unit 402, the switching operation is performed by the switch unit 406 connected to the antenna 401, improving the transmission efficiency of the reflected wave 502.

The phase change unit 610 according to this embodiment may be configured to include an impedance change unit instead of the switch unit 406. The impedance change unit is configured, for example, with a variable capacitor, a variable coil, a variable resistor, a phase shifter, etc., and changes the complex impedance of the circuit to which the antenna 401 is connected over time. By changing the impedance between the antenna 401 and GND 407, it is possible to alternate between a first state in which the antenna 401 is connected to GND 407 and a second state in which the antenna 401 is released from GND 407.

Next, we will explain the simulation results of the received power with reference to Figures 9 and 10.

Figure 9 is a diagram showing a semi-closed space 102 for evaluating changes in the amount of received power. In Figure 9, the X-axis direction, the Y-axis direction, and the Z-axis direction represent directions parallel to the X-axis, the Y-axis, and the Z-axis, respectively. The X-axis direction and the Y-axis direction are mutually orthogonal. The X-axis direction and the Z-axis direction are mutually orthogonal. The Y-axis direction and the Z-axis direction are mutually orthogonal. The XY plane represents an imaginary plane parallel to the X-axis direction and the Y-axis direction. The XZ plane represents an imaginary plane parallel to the X-axis direction and the Z-axis direction. The YZ plane represents an imaginary plane parallel to the Y-axis direction and the Z-axis direction.

The semi-closed space 102 is, for example, a space in which two XY planes and two XZ planes are radio wave reflecting surfaces (surfaces that reflect radio waves 105) and two YZ planes are radio wave non-reflecting surfaces (surfaces that do not reflect radio waves 105). In the semi-closed space 102, a power transmitter/receiver 103 and two power receivers 104 (a first power receiver 104-1 and a second power receiver 104-2) according to the present embodiment are arranged.

The width A of the semi-closed space 102 in the X-axis direction is 3 [m], the height B of the semi-closed space 102 in the Z-axis direction is 1 [m], and the depth C of the semi-closed space 102 in the Y-axis direction is 1 [m]. The distance X in the X-axis direction from the power transmitter/receiver 103 to the two power receivers 104 (the first power receiver 104-1 and the second power receiver 104-2) is 2 [m]. The distance Y in the Y-axis direction from the first power receiver 104-1 to the second power receiver 104-2 is 0.325 [m]. A dipole antenna operating at a center frequency of 920 MHz is used as the antenna 401 of each of the first power receiver 104-1 and the second power receiver 104-2.

In the simulation of the received power, the switch unit 406, which switches between ground (GND connection) and short circuit (load connection), was modeled, and the S parameters of the second power receiver 104-2 were obtained by simulation when the first power receiver 104-1 switched between ideally reflecting the power wave and absorbing the power wave, and the change in the amount of received power was evaluated.

Figure 10 is a diagram for explaining the evaluation results of the amount of received power. Figure 10 shows the evaluation results of the amount of received power in the second power receiver 104-2 when the first power receiver 104-1 performs a power reflection operation in the semi-closed space 102 in Figure 9. The vertical axis of Figure 10 represents the S parameter, and the horizontal axis of Figure 10 represents the frequency.

The dotted line represents the S-parameter 1202 of the second power receiver 104-2 when the switch section 406 of each of the second power receiver 104-2 and the first power receiver 104-1 is in a state in which it ideally absorbs the power wave.

The solid line shows the S-parameter 1203 of the first power receiver 104-1 when the switch section 406 of the first power receiver 104-1 is in a state where it ideally reflects the power wave and the switch section 406 of the second power receiver 104-2 is in a state where it ideally absorbs the power wave.

When the second power receiver 104-2 performs a power reflection operation, the amount of power received by the first power receiver 104-1 can be calculated from the difference between S parameter 1202 and S parameter 1203.

For example, at the antenna center frequency of 920 MHz, the difference between S-parameter 1203 and S-parameter 1202 is 1.4 dB. This indicates that the received power of the second power receiver 104-2 is approximately 1.5 times the received power before the first power receiver 104-1 started its power reflection operation. Figure 10 shows that the received power is improved by using a power receiver 104 with a power reflection function in the semi-closed space 102.

As described above, the power receiver 104 according to this embodiment can radiate reflected waves 502 to the surrounding power receivers 104 by switching from a power supply state in which power is supplied to a load to a reflection state in which the power wave is reflected, thereby increasing the amount of power supplied to the surrounding power receivers 104.

In addition, according to the wireless power transmission system 100 of this embodiment, the power transmitter/receiver 103 does not need to control the direction of radiation of the radio waves 105 for each of the multiple power receivers 104. Therefore, the directivity of the radio waves 105 is increased, and the amount of power supplied to the surrounding power receivers 104 can be increased while suppressing radio wave interference with surrounding devices and effects on the human body.

In addition, since there is no need to control the direction of radiation of radio waves 105, there is no need for a function to avoid radio wave interference with peripheral devices, and this simplifies the configuration of the power transmitter/receiver 103, suppressing increases in the manufacturing costs of the power transmitter/receiver 103 and improving reliability.

In addition, since there is no need to control the radiation direction of the radio waves 105, the increase in power density in the radiation direction of the radio waves 105 can be suppressed, so the wireless power transmission system 100 can be constructed without being restricted by regulations such as the Radio Law.

In addition, by emitting reflected waves 502 from a specific power receiver 104 to surrounding power receivers 104, it is possible to prevent the radio waves 105 from being reflected by a wall or the like and not reaching the specific power receiver 104. It is also possible to prevent the radio waves 105 from passing through window glass in a building and not reaching the specific power receiver 104.

For example, it is understood that the following aspects also fall within the technical scope of this disclosure:

(1) A wireless power transmission system includes a power transmitter that emits a power wave, a power receiver that receives the power wave, and a propagation path change unit that changes the propagation path of the power wave from the power transmitter to the power receiver.

(2) The propagation path change unit changes the orientation of the antenna that radiates the power wave.

(3) The propagation path change unit changes the orientation of the antenna at regular or random intervals.

(4) The propagation path change unit changes the position of the antenna that radiates the power wave.

(5) The propagation path change unit changes the position of the antenna at regular or random intervals.

(6) The propagation path change unit scatters the power wave radiated from the power transmitter.

(7) The propagation path change unit is provided on a wall that forms a space in which the power transmitter and the power receiver are arranged, and scatters the power wave radiated from the power transmitter.

(8) The propagation path change unit changes the receiving position of the power wave by moving the power receiver.

(9) The power transmitter feedback controls the propagation path change unit based on power receiving state information indicating the power receiving state of the power receiver.

(10) The power receiver includes a receiving antenna that receives a power wave radiated from either the power transmitter or the propagation path change unit, and a phase change unit that changes the phase of the power wave received by the receiving antenna and radiates the power wave after the phase change from the receiving antenna as a reflected wave.

(11) The phase change unit includes a rectifier that rectifies the power wave received by the receiving antenna, and a switch unit that is connected to the output side of the rectifier and alternates between a first state in which the receiving antenna is connected to ground and a second state in which the receiving antenna is disconnected from the ground.

(12) The phase change unit includes a switch unit that alternates between a first state in which the receiving antenna is connected to ground and a second state in which the receiving antenna is disconnected from the ground, and a rectifier unit that inputs the power wave received by the receiving antenna via the switch unit and rectifies it.

(13) The method for changing the path of an electric power wave includes the steps of radiating an electric power wave from an electric power transmitter, receiving the electric power wave with an electric power receiver, and changing the propagation path of the electric power wave from the electric power transmitter to the electric power receiver.

An embodiment of the present disclosure is suitable for a wireless power transmission system.

1: Propagation path change unit 100: Wireless power transmission system 102: Semi-closed space 103: Power transmitter/receiver 104: Power receiver 104-1: First power receiver 104-2: Second power receiver 105: Radio wave 201: Antenna 202: Oscillator 203: Ball mechanism 204: Three-axis stage 301: Reflector 302: Rotation mechanism 401: Antenna 402: Rectifier 403: Control unit 404: Load 405: Power storage unit 406: Switch unit 407: GND
502: Reflected wave 503: Power receiving state information 504: Feedback control 505: Mechanical control mechanism 610: Phase change unit

Claims (9)

A power transmitter that emits power waves;
A power receiver for receiving the power wave;
A propagation path changing unit that changes a propagation path of the electric power wave from the electric power transmitter to the electric power receiver,
The propagation path change unit changes a position of an antenna that radiates the power wave at a constant period or at a random period.
Wireless power transmission system. A power transmitter that emits power waves;
A power receiver for receiving the power wave;
A propagation path changing unit that changes a propagation path of the electric power wave from the electric power transmitter to the electric power receiver,
The propagation path change unit scatters the power wave radiated from the power transmitter.
Wireless power transmission system. The propagation path change unit is provided on a wall that forms a space in which the power transmitter and the power receiver are disposed.
The wireless power transmission system according to claim 2 . A power transmitter that emits power waves;
A power receiver for receiving the power wave;
A propagation path changing unit that changes a propagation path of the electric power wave from the electric power transmitter to the electric power receiver,
The propagation path change unit changes a receiving position of the electric power wave by moving the electric power receiver , and changes a direction of an antenna that radiates the electric power wave at a constant period or at a random period .
Wireless power transmission system. The wireless power transmission system according to claim 1 , wherein the power transmitter feedback-controls the propagation path changing unit based on power receiving state information indicating a power receiving state of the power receiver. 6. The wireless power transmission system according to claim 1 , wherein the power receiver comprises: a receiving antenna that receives an electric power wave radiated from either the power transmitter or the propagation path change unit; and a phase change unit that changes a phase of the electric power wave received by the receiving antenna and radiates the phase-changed electric power wave from the receiving antenna as a reflected wave. 7. The wireless power transmission system according to claim 6, wherein the phase change unit comprises: a rectifier unit that rectifies the power wave received by the receiving antenna; and a switch unit that is connected to an output side of the rectifier unit and that alternates between a first state in which the receiving antenna is connected to ground and a second state in which the receiving antenna is disconnected from the ground. The phase change unit includes a switch unit that alternates between a first state in which the receiving antenna is connected to ground and a second state in which the receiving antenna is disconnected from the ground, and a rectifier unit that inputs a power wave received by the receiving antenna via the switch unit and rectifies the power wave.
The wireless power transmission system according to claim 6 . emitting a power wave from a power transmitter;
receiving the power wave with a power receiver;
a step of changing a position of an antenna that radiates the electric power wave at a constant or random period , scattering the electric power wave radiated from the electric power transmitter, or moving the electric power receiver to change a receiving position of the electric power wave , and changing an orientation of the antenna that radiates the electric power wave at a constant or random period , thereby changing a propagation path of the electric power wave from the electric power transmitter to the electric power receiver;
The power wave path changing method includes:

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