WO2013160978A1 - Power reception device, power transmission system, program, and power reception method - Google Patents

Description

Power receiving apparatus, power transmission system, program, and power receiving method

The present invention relates to a power receiving device, a power transmission system, a program, and a power receiving method.

A power receiving device (hereinafter referred to as a wireless power receiving device) that receives AC power provided wirelessly and converts it into DC power has been developed. In the wireless power receiving apparatus, the value of received power may change. For example, when a power transmission device that transmits wireless power (hereinafter referred to as a wireless power transmission device) is movable, the distance between the wireless power transmission device and the wireless power reception device changes. Therefore, it is desirable that the wireless power receiving apparatus can follow the change in the input power value.

The conversion efficiency when converting AC power received by the wireless power receiving device into DC power depends on the value of power input to the rectifier that performs power conversion. Therefore, in order for the wireless power receiving apparatus to follow the change in the input power value, a decrease in power conversion efficiency in the rectifier described above becomes a problem. Therefore, in the rectifier, it is a problem to obtain high power conversion efficiency even when the input power value changes. *

For example, there is a technique described in Patent Document 1 for the above problem. This is a technique in which a plurality of antennas and a plurality of rectifiers are provided in a wireless power receiving apparatus, and the connection state between the antenna and the rectifier is switched based on a current value measured between the rectifier and the load.

As another example, there is a technique described in Patent Document 2. This is a technique for switching the impedance in a matching circuit that matches the received power and the power input to the rectifier, based on the current value measured between the rectifier and the load in the wireless power receiver.

As another example, there is a technique described in Patent Document 3. This is a technique of having a plurality of rectifiers in a wireless power receiving apparatus and changing the number of rectifiers used for power conversion based on the value of received power.

JP 2011-114949 A JP 2011-45161 A Japanese Patent No. 3385472

Wireless power receiving devices are required to reduce cost and size. For example, when the technique described in Patent Literature 1 is used, the cost and the size of the wireless power receiving apparatus increase. This is because it is necessary to use a plurality of antennas and rectifiers. Further, when the technique described in Patent Document 3 is used, there arises a problem of an increase in cost and an increase in size. This is because a plurality of rectifiers are necessary and a distribution circuit that distributes the received power to the plurality of rectifiers is necessary.

Furthermore, even when the input power value changes greatly in a short time, the wireless power receiving apparatus is required to follow the change. For example, when the technique described in Patent Document 1 and the technique described in Patent Document 2 are used, when the input power value changes greatly in a short time, it is difficult to follow the change. This is because the power value is measured after the rectifier performs power conversion.

Although there are two problems as described above, it is difficult to solve both of the two problems with the technique described in the prior art document.

An object of the present invention is to provide a power receiving device, a power transmission system, a program, and a power receiving method that are small in size and low in cost, and that can obtain high power conversion efficiency even when the value of input power changes greatly in a short time. There is to do.

The power receiving device provided by the present invention includes a power receiving means for receiving AC power transmitted wirelessly, a rectifying means for converting the received AC power into DC power, and matching the output of the power receiving means with the input of the rectifying means. A matching means; a control means for controlling the rectifying means; and a power measuring means for measuring power, wherein the rectifying means has a variable impedance, and the control means is based on a value of the power W measured by the power measuring means. Then, the impedance of the rectifying means is controlled, and the measuring point of the power measuring means is a power receiving device between the power receiving means and the rectifying means.

The power transmission system provided by the present invention is a power transmission system including a power transmission device that transmits AC power wirelessly and a power reception device that receives the AC power transmitted wirelessly, and the power reception device includes: Receiving means for receiving the AC power transmitted wirelessly; rectifying means for converting the received AC power into DC power; matching means for matching the output of the power receiving means and the input of the rectifying means; A control means for controlling the rectification means; and a power measurement means for measuring power, wherein the impedance of the rectification means is variable, and the rectification means is based on the value of the power W measured by the power measurement means by the control means. The power transmission system is a power receiving device that controls the impedance of the power receiving means and the measuring point of the power measuring means is between the power receiving means and the rectifying means.

The program provided by the present invention is a program for causing a computer to function as a control device for a power receiving device, wherein the power receiving device receives power from a wireless device and receives the AC power. Rectifying means for converting the power into DC power, matching means for matching the output of the power receiving means and the input of the rectifying means, control means for controlling the rectifying means, and power measuring means for measuring power, A power receiving device in which impedance is variable and a measuring point of the power measuring unit is between the power receiving unit and the rectifying unit, and a function of reading a value of the power W measured by the power measuring unit into the computer; , A program that has a function of determining an impedance to be set in the rectifying means based on the value of the electric power W.

The power receiving method provided by the present invention is a power receiving method in a power receiving device that receives AC power transmitted wirelessly, the power receiving device receiving power that receives AC power transmitted wirelessly, Rectification means for converting the received AC power into DC power, matching means for matching the output of the power reception means and the input of the rectification means, control means for controlling the rectification means, and power measurement means for measuring power An impedance of the rectifying means is variable, a power receiving device in which a measurement point of the power measuring means is between the power receiving means and the rectifying means, the power receiving means receiving AC power, and the power A step of measuring the power by the measuring means, a step of reading the value of the power W measured by the power measuring means by the control means, and the value of the power by the control means. A power receiving method including the step of determining the impedance to be set in the rectifying means Zui.

According to the present invention, the power receiving device can be reduced in size and cost, and the change can be followed even when the input power value changes greatly in a short time.

The above-described object and other objects, features, and advantages will be further clarified by a preferred embodiment described below and the following drawings attached thereto.

1 is a block diagram illustrating a configuration of a power transmission system according to a first embodiment. It is a block diagram showing the internal structure of a control part. It is a block diagram showing the internal structure of an electric power measurement part. It is a block diagram showing the internal structure of a rectification | straightening part. It is a graph showing the relationship between the reflection coefficient between a matching part and a rectification | straightening part, and power conversion efficiency. It is a block diagram showing the structure of the electric power transmission system concerning Embodiment 2. FIG. It is a flowchart showing operation | movement of the program which a control apparatus hold | maintains. It is a block diagram showing the structure of the electric power transmission system concerning Embodiment 3.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

In the following description, each component of each device indicates a functional unit block, not a hardware unit configuration. Each component of each device includes a CPU, memory, a program that realizes the components of this figure loaded in the memory, a storage medium such as a hard disk that stores the program, and a network connection interface. It is realized by any combination of software and software. There are various modifications of the implementation method and apparatus.

[Embodiment 1]
FIG. 1 illustrates a configuration of the power transmission system according to the first embodiment. The power transmission system according to the first embodiment includes a power receiving device 1000, a power transmitting device 2000, and a load 4000. An example of the load 4000 is a rechargeable battery. The power receiving apparatus 1000 receives AC power AC transmitted by the power transmitting apparatus 2000 wirelessly, converts it to DC power DC, and outputs the DC power DC to the load 4000. The power receiving apparatus 1000 includes a power receiving unit 1020, a matching unit 1040, a rectifying unit 1060, a power measuring unit 1080, and a control unit 1100. Power reception unit 1020 receives AC power AC transmitted wirelessly from power transmission device 2000 and outputs the AC power AC to matching unit 1040. The matching unit 1040 matches the output impedance of the power receiving unit 1020 and the input impedance of the rectifying unit 1060. The rectifying unit 1060 receives the AC power AC from the matching unit 1040 and converts it into DC power DC, and then outputs the DC power DC to the load 4000. Load 4000 operates with DC power DC received from rectifier 1060. The power measuring unit 1080 measures the value of the power W of the AC power AC. The control unit 1100 controls the impedance of the rectifying unit 1060 by changing the value of the voltage applied to the rectifying unit 1060 based on the value of the power W.

The measurement point P of the power measuring unit 1080 is between the power receiving unit 1020 and the rectifying unit 1060. The measurement point P may be located between the power receiving unit 1020 and the matching unit 1040 or between the matching unit 1040 and the rectifying unit 1060. In FIG. 1, as an example, a measurement point P is provided between the power receiving unit 1020 and the matching unit 1040.

FIG. 2 shows an example of the internal configuration of the control unit 1100. The control unit 1100 includes an impedance determination circuit 1101 and a data ROM 1102.

The control unit 1100 in the configuration of FIG. 2 controls the impedance of the rectifying unit 1060 by increasing the value V of the voltage applied to the rectifying unit 1060 as the value of the power W measured by the power measuring unit 1080 increases. An example of a specific operation is as follows. First, the data ROM 1102 holds in advance W1 as a threshold relating to the value of the power W and VL and VH as voltage values to be applied to the rectifying unit 1060. The impedance determination circuit 1101 reads the value of the power W measured by the power measurement unit 1080. Next, the impedance determination circuit 1101 compares the value of the power W with the threshold value W1, and determines the voltage V to be applied to the rectifying unit 1060. Specifically, the value of the voltage V is VL when the value of power W ≦ W1, and VH when the value of power W> W1. Then, the impedance of the rectifying unit 1060 is changed by applying the voltage V having the magnitude determined above to the rectifying unit 1060.

FIG. 3 shows an example of the internal configuration of the power measurement unit 1080. The power measurement unit 1080 includes a power measurement circuit 1081 and a power value storage RAM 1082.

The specific operation in which the power measuring unit 1080 in the configuration of FIG. 3 measures the value of the power W of the AC power AC is as follows. First, the power measurement circuit 1081 measures the power at the measurement point P to obtain the value of the power W. Then, the power measurement circuit 1081 stores the value of the power W in the power value storage RAM 1082. In this case, the control unit 1100 reads the value of the power W from the power value storage RAM 1082 to obtain the value of the power W.

FIG. 4 shows an example of the internal configuration of the rectification unit 1060. The rectifying unit 1060 includes a three-terminal device 1061, a power reflecting element 1062, and a capacitor 1063. The three-terminal device 1061 includes a terminal G that is a gate terminal, a terminal S that is a source terminal, and a terminal D that is a drain terminal.

4, the impedance of the rectifying unit 1060 is determined by the magnitude of the voltage V applied to the terminal G of the three-terminal device 1061. In this case, the control unit 1100 changes the impedance of the rectifying unit 1060 by changing the voltage V applied to the terminal G of the three-terminal device 1061.

The reflection coefficient between the matching unit 1040 and the three-terminal device 1061 is preferably 0.3 or less. This is because as the reflection coefficient increases, the power output from the matching unit 1040 to the rectifying unit 1060 decreases, and as a result, the power conversion efficiency decreases as shown in FIG.

In order to obtain a rectifying action with the same polarity when rectifying AC power, it is desirable that all impedances set in the rectifying unit 1060 have the same polarity. If the polarity at which the rectifying action is obtained changes when the impedance is changed, the reflection coefficient between the matching unit 1040 and the rectifying unit 1060 increases, and the power input to the rectifying unit 1060 decreases. is there.

Thus, according to this embodiment, since it is not necessary to have a plurality of rectifying units 1060 and power receiving units 1020, the power receiving apparatus 1000 can be reduced in size and cost. Furthermore, when the measurement point P is between the power receiving unit 1020 and the rectifying unit 1060 and the value of the received AC power W can be measured at an early stage, the value of the power received greatly fluctuates in a short time It becomes possible to follow.

[Embodiment 2]
FIG. 6 illustrates a configuration of the power transmission system according to the second embodiment. The second embodiment includes a power transmission device 2000, a power reception device 1000, and a load 4000. The control unit 1100 according to the second embodiment includes a data ROM 1102, a CPU 1103, and a program ROM 1104. The program ROM 1104 records a program for realizing the flow shown in FIG. The control unit 1100 reads the value of the power W measured by the power measurement unit 1080 and changes the impedance of the rectification unit 1060 based on the value. 6, the functional blocks to which the same reference numerals as those in FIG. 1 are assigned have the same functions as the functional blocks in the first embodiment.

The control unit 1100 controls the impedance of the rectifying unit 1060 by executing a program recorded in the program ROM 1104. Specifically, first, the CPU 1103 reads the program for realizing step S102 from the program ROM 1104 and executes it, thereby reading the value of the power W measured by the power measuring unit 1080. Then, the CPU 1103 reads out and executes the program for realizing step S104 from the program ROM 1104, thereby determining the impedance to be set in the rectifying unit 1060 from the value of the power W. A specific method for determining the impedance of the rectifying unit 1060 is as follows as an example. First, the data ROM 1102 previously stores a list of threshold values (hereinafter referred to as threshold list) W1, W2,... Wn regarding the value of power W, and a list of voltage values (hereinafter referred to as voltage value list) V1 applied to the rectifying unit 1060. V2,... Vn + 1 are held. Here, n is an integer of 1 or more, and Wn + 1> Wn and Vn + 1> Vn. The CPU 1103 reads the value of the power W measured by the power measurement unit 1080. Next, the CPU 1103 determines the voltage V to be applied to the rectifying unit 1060 by referring to the threshold value list and the voltage value list held by the data ROM 1102 based on the value of the power W. Specifically, the value of the voltage V is V1 if the value of the power W <W1, Wm-1 ≦ the value of the power W <Wm (2 ≦ m ≦ n), Vm, and the value of the power W ≧ Wn. In this case, Vn + 1 is set. Then, the impedance of the rectifying unit 1060 is changed by applying the voltage V having the magnitude determined above to the rectifying unit 1060.

According to the present embodiment, for the same reason as in the first embodiment, the power receiving apparatus 1000 can be reduced in size and cost, and can be followed even when the magnitude of the power received greatly changes in a short time. . Furthermore, since the impedance of the rectifying unit 1060 is determined using a program, the impedance value can be determined more flexibly.

[Embodiment 3]
FIG. 8 illustrates a configuration of the power transmission system according to the third embodiment. The third embodiment includes a power transmission device 2000, a power reception device 1000, and a control device 5000. Control device 5000 reads the value of power W measured by power measurement unit 1080 and changes the impedance of rectification unit 1060 based on the read value of power W. In FIG. 8, the functional blocks to which the same reference numerals as those in FIG. 1 or FIG. 2 are assigned have the same functions as the functional blocks in the first or second embodiment.

The control device 5000 includes a control unit 1100 (not shown) as an example. The control unit 1100 controls the impedance of the rectifying unit 1060 by performing the same operation as the control unit 1100 described in the first embodiment or the second embodiment.

According to the present embodiment, for the same reason as in the first embodiment, the power receiving apparatus 1000 can be reduced in size and cost, and can be followed even when the magnitude of the power received greatly changes in a short time. . Since the control device 5000 that performs impedance control is provided outside the power receiving device 1000, the power receiving device 1000 can be further reduced in size.

As described above, the embodiments of the present invention have been described with reference to the drawings. However, these are exemplifications of the present invention, and various configurations other than the above can be adopted.

This application claims priority based on Japanese Patent Application No. 2012-097365 filed on April 23, 2012, the entire disclosure of which is incorporated herein.

(Appendix 1)
Power receiving means for receiving AC power transmitted wirelessly, rectifying means for converting the received AC power into DC power, matching means for matching the output of the power receiving means and the input of the rectifying means, and the rectifying means Control means for controlling the power, and power measuring means for measuring the power,
The rectifying means has a variable impedance,
The control means controls the impedance of the rectifying means based on the value of the power W measured by the power measuring means,
The power receiving device according to claim 1, wherein a measuring point of the power measuring means is between the power receiving means and the rectifying means.
(Appendix 2)
The power receiving apparatus according to appendix 1, wherein all impedances set in the rectifying means have the same polarity.
(Appendix 3)
The rectifying means comprises a three-terminal device,
The control means controls the voltage V applied to the first terminal of the three-terminal device based on the value of the power W,
The power receiving device according to appendix 1 or 2, wherein the impedance of the rectifying means is switched according to the magnitude of the voltage V.
(Appendix 4)
The power receiving apparatus according to appendix 3, wherein the control means increases the voltage V as the value of the power W increases.
(Appendix 5)
The power receiving apparatus according to appendix 3 or 4, wherein the matching means and the three-terminal device have a reflection coefficient of 0.3 or less.
(Appendix 6)
A power transmission system including a power transmission device that wirelessly transmits AC power and a power reception device that receives the AC power transmitted wirelessly,
The power receiving device is:
Power receiving means for receiving the AC power transmitted wirelessly, rectifying means for converting the received AC power into DC power, matching means for matching the output of the power receiving means and the input of the rectifying means, and the rectification A control means for controlling the means, and a power measuring means for measuring the power,
The impedance of the rectifying means is variable,
Based on the value of the power measured by the power measuring means, the control means controls the impedance of the rectifying means,
The power measuring device is a power receiving device in which the measuring point of the power measuring device is between the power receiving device and the rectifying device;
Power transmission system characterized by
(Appendix 7)
The power transmission system according to appendix 6, wherein all the impedances set by the rectifying means have the same polarity.
(Appendix 8)
The power transmission system according to appendix 6 or 7,
The rectifying means has a three-terminal device,
The power transmission system, wherein the control unit determines an impedance of the rectifying unit by determining a voltage V to be applied to the three-terminal device.
(Appendix 9)
The power transmission system according to appendix 8, wherein the control means increases the voltage V as the value of the power W increases.
(Appendix 10)
A program for causing a computer to function as a control device for a power receiving device,
The power receiving device includes power receiving means for receiving AC power transmitted wirelessly, rectifying means for converting the received AC power into DC power, and matching for matching the output of the power receiving means and the input of the rectifying means. Means, a control means for controlling the rectifying means, and a power measuring means for measuring power, wherein the impedance of the rectifying means is variable, and a measurement point of the power measuring means is between the power receiving means and the rectifying means. A power receiving device in
In the computer,
A function of reading the value of the power W measured by the power measuring means;
A function of determining an impedance to be set in the rectifying means based on the value of the power W;
A program to give
(Appendix 11)
The program according to claim 10, wherein all impedances set in the rectifying means have the same polarity.
(Appendix 12)
The program according to appendix 10 or 11,
The rectifying means comprises a three-terminal device;
The program for determining the impedance of the rectifying means to be given to the computer determines the impedance by determining the voltage V applied to the three-terminal device.
(Appendix 13)
The program according to claim 12, wherein the function of determining the impedance of the rectifying means provided to the computer increases the voltage V as the value of the power W increases.
(Appendix 14)
A power receiving method in a power receiving device for receiving AC power transmitted wirelessly,
The power receiving device includes a power receiving unit that receives the AC power transmitted wirelessly, a rectifying unit that converts the received AC power into DC power, and an alignment that matches an output of the power receiving unit and an input of the rectifying unit. Means, a control means for controlling the rectifying means, and a power measuring means for measuring power, wherein the impedance of the rectifying means is variable, and a measurement point of the power measuring means is between the power receiving means and the rectifying means. A power receiving device in
The power receiving method is
The power receiving means receiving AC power;
The power measuring means measuring power;
Reading the value of the power W measured by the power measuring means by the control means;
Determining the impedance that the control means sets in the rectifying means based on the value of the power W;
A method of receiving power.
(Appendix 15)
15. The power receiving method according to claim 14, wherein all impedances set in the rectifying means have the same polarity.
(Appendix 16)
The power receiving method according to appendix 14 or 15,
The rectifying means comprises a three-terminal device;
The step of determining the impedance set in the rectifying means is a step of determining the impedance by determining a voltage V to be applied to the three-terminal device.
(Appendix 17)
The power receiving method according to supplementary note 16, wherein the step of determining the impedance to be set in the rectifying means is a step of increasing the voltage V as the power W increases.

Claims (8)

Power receiving means for receiving AC power transmitted wirelessly, rectifying means for converting the received AC power into DC power, matching means for matching the output of the power receiving means and the input of the rectifying means, and the rectifying means Control means for controlling the power, and power measuring means for measuring the power,
The rectifying means has a variable impedance,
The control means controls the impedance of the rectifying means based on the value of the power W measured by the power measuring means,
The measuring point of the power measuring means is between the power receiving means and the rectifying means;
A power receiving device characterized by the above. The power receiving device according to claim 1, wherein all impedances set in the rectifying means have the same polarity. The rectifying means comprises a three-terminal device,
The control means controls the voltage V applied to the first terminal of the three-terminal device based on the value of the power W,
The power receiving device according to claim 1 or 2, wherein the impedance of the rectifying means is switched depending on the magnitude of the voltage V. 4. The power receiving apparatus according to claim 3, wherein the control means increases the voltage V as the value of the electric power W increases. The power receiving device according to claim 3 or 4, wherein a reflection coefficient of the matching means and the three-terminal device is 0.3 or less. A power transmission system including a power transmission device that wirelessly transmits AC power and a power reception device that receives the AC power transmitted wirelessly,
The power receiving device is:
Power receiving means for receiving the AC power transmitted wirelessly; Rectifying means for converting the received AC power into DC power; Matching means for matching the output of the power receiving means and the input of the rectifying means; and the rectification A control means for controlling the means, and a power measuring means for measuring the power,
The impedance of the rectifying means is variable,
Based on the value of the power measured by the power measuring means, the control means controls the impedance of the rectifying means,
A power receiving device in which a measuring point of the power measuring means is between the power receiving means and the rectifying means;
A power transmission system characterized by that. A program for causing a computer to function as a control device for a power receiving device,
The power receiving device includes power receiving means for receiving AC power transmitted wirelessly, rectifying means for converting the received AC power into DC power, and matching for matching the output of the power receiving means and the input of the rectifying means. Means, a control means for controlling the rectifying means, and a power measuring means for measuring power, wherein the impedance of the rectifying means is variable, and a measurement point of the power measuring means is between the power receiving means and the rectifying means. A power receiving device in
In the computer,
A function of reading the value of the power W measured by the power measuring means;
A function of determining an impedance to be set in the rectifying means based on the value of the power W;
A program to give A power receiving method in a power receiving device for receiving AC power transmitted wirelessly,
The power receiving device includes power receiving means for receiving AC power transmitted wirelessly, rectifying means for converting the received AC power into DC power, and matching for matching the output of the power receiving means and the input of the rectifying means. Means, a control means for controlling the rectifying means, and a power measuring means for measuring power, wherein the impedance of the rectifying means is variable, and a measurement point of the power measuring means is between the power receiving means and the rectifying means. A power receiving device in
The power receiving method is:
The power receiving means receiving AC power;
The power measuring means measuring power;
Reading the value of the power W measured by the power measuring means by the control means;
Determining the impedance that the control means sets in the rectifying means based on the value of the power W;
A method of receiving power.

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