JP7368412B2 - Wireless power transmission device, wireless power supply system, and wireless power supply method - Google Patents

Description

The present invention relates to a wireless power transmission device, a wireless power supply system, and a wireless power supply method.

2. Description of the Related Art Conventionally, wireless power supply systems have been known in which power is wirelessly transmitted from a wireless power transmitting device to a wireless power receiving device in a non-contact (wireless) manner, and the power received by the wireless power receiving device is supplied to a battery or the like.

In the wireless power supply system, it is known that the amount of power received by the wireless power receiving device changes depending on the power supply state. For example, the amount of power received per unit time changes depending on the position, distance, etc. of the wireless power transmitting device and the wireless power receiving device. Further, for example, the amount of power received varies depending on whether there is another object such as a shield between the wireless power transmitting device and the wireless power receiving device.

As described above, since the amount of received power changes depending on the power supply state, techniques for efficient power supply processing are known. For example, in Patent Document 1, a wireless power transmitting device supplies power to a wireless power receiving device according to a set power, receives the received amount of power from the wireless power receiving device, and has a power receiving rate that is a ratio of the received power to the set power. This document describes a technology for calculating the power receiving rate and controlling on/off of power transmission based on the calculated power reception rate.

Japanese Patent Application Publication No. 2014-150636

By the way, as described above, there is a known problem that occurs when the amount of power received changes depending on the power supply state between the wireless power transmitting device and the wireless power receiving device.

For example, when the distance between the wireless power transmitting device and the wireless power receiving device is short (see Figure 3, details will be described later), the power reception The amount of electricity used increases. If the distance between the wireless power transmitting device and the wireless power receiving device approaches while power is being transmitted from the wireless power transmitting device to the wireless power receiving device, the amount of power received by the wireless power receiving device increases. In the wireless power receiving device, if the amount of power required does not change, the increased amount of power is not used for power supply, but is converted into heat and consumed. At this time, there was a problem in that the generated heat may have an adverse effect on the wireless power transmission device.

To solve this problem, it is necessary to control the time during which the wireless power transmitting device continuously transmits power, taking into account the amount of heat generated by the wireless power receiving device. In this case, as the amount of power received by the wireless power receiving device changes as described above, the amount of heat generated also changes. An example of a method is to perform control to shorten the length of ``. However, by shortening the continuous power transmission time, the total power supply time required to supply the necessary amount of power may become longer.

On the other hand, if the distance between the wireless power transmitting device and the wireless power receiving device increases while power is being transmitted from the wireless power transmitting device to the wireless power receiving device, the amount of power received by the wireless power receiving device decreases. In this case, in the wireless power receiving device, the amount of heat generated is reduced or no heat is generated, so that the continuous power transmission time can be extended. However, as mentioned above, the distance between the wireless power transmitting device and the wireless power receiving device may become close again, so it is not always possible to shorten the continuous power transmitting time by controlling the continuous power transmitting time by taking the maximum amount of heat generation into consideration. There were times when I couldn't do it. Therefore, a problem may arise in which the processing efficiency of wireless power supply decreases.

The technique described in Patent Document 1 aims to perform highly efficient power supply processing, but even if the technique described in Patent Document 1 is used, there are cases where processing efficiency cannot be sufficiently improved.

An object of the present invention is to provide a wireless power transmission device, a wireless power supply system, and a wireless power supply method that can improve the processing efficiency of wireless power supply.

In order to achieve the above object, a wireless power transmission device of the present invention includes a power transmission unit that wirelessly transmits power to a wireless power receiving device, and receives desired transmission power information indicating power that the wireless power receiving device desires to transmit. time information that is predetermined for power supply efficiency, which is a ratio of received power received by the wireless power receiving device to transmitted power according to the desired transmitted power information received by the power transmission side communication unit and the power transmission side communication unit; a control unit that controls the power transmission time by the power transmission unit using the power transmission unit; The control unit receives time information and power feeding efficiency information representing the power feeding efficiency, and derives a second continuous power transmission time based on the power feeding efficiency, and calculates the first continuous power transmission time and the second continuous power transmission time. The shorter time is used as the time information. The wireless power transmission device of the present invention also includes: a power transmission unit that wirelessly transmits power to the wireless power reception device; a power transmission side communication unit that receives desired transmission power information indicating power that the wireless power reception device desires to transmit; The power transmission is performed using time information predetermined for the power supply efficiency, which is the ratio of the power received by the wireless power receiving device to the power transmitted according to the desired power transmission information received by the power transmission side communication unit. a control unit that controls the power transmission time by the wireless power receiving device; Receiving received power information representing electric power, the control unit derives the power feeding efficiency using the received power represented by the received power information received by the power transmission communication unit, and calculates the power feeding efficiency based on the power feeding efficiency. A second continuous power transmission time is derived, and the shorter one of the first continuous power transmission time and the second continuous power transmission time is used as the time information.

Further, in order to achieve the above object, a wireless power supply system of the present invention is a wireless power supply system including a wireless power transmission device and a wireless power reception device, the wireless power transmission device wirelessly transmitting power to the wireless power reception device. a power transmitting unit that transmits power, a power transmitting side communication unit that receives desired transmitted power information representing the power that the wireless power receiving device desires to transmit, and a power transmitting side communication unit that receives desired transmitted power information indicating the power that the wireless power receiving device desires to transmit, and the wireless power receiving device receives power for transmitted power according to the desired transmitted power information. The power transmission side communication unit further includes a control unit that controls the power transmission time of the power transmission unit using time information predetermined for power supply efficiency that is a ratio of received power, and the power transmission side communication unit further includes The controller receives continuous power transmission time information representing a first continuous power transmission time during which power is continuously transmitted from , and power feeding efficiency information representing the power feeding efficiency, and derives a second continuous power transmission time based on the power feeding efficiency. The wireless power receiving device uses a shorter one of the first continuous power transmission time and the second continuous power transmission time as the time information, and the wireless power receiving device wirelessly receives power from the wireless power transmitting device. , a power reception side communication unit that transmits desired transmission power information representing power desired to be transmitted, and a derivation unit that derives power feeding efficiency that is a ratio of received power received by the power reception unit to transmitted power.

Furthermore, in order to achieve the above object, the wireless power supply method of the present invention wirelessly transmits power to a wireless power receiving device, and receives desired transmitted power information indicating power that the wireless power receiving device desires to transmit. When controlling power transmission time using time information predetermined for power supply efficiency, which is a ratio of received power received by the wireless power receiving device to transmitted power according to the desired transmitted power information, Further, continuous power transmission time information representing a first continuous power transmission time during which power is continuously transmitted from the wireless power receiving device and power feeding efficiency information representing the power feeding efficiency are received, and a second continuous power transmission time is derived based on the power feeding efficiency. The method further includes a process of using the shorter of the first continuous power transmission time and the second continuous power transmission time as the time information .

According to the present invention, it is possible to improve the processing efficiency of wireless power supply.

FIG. 1 is a configuration diagram schematically illustrating an example of a wireless power feeding system according to a first embodiment. 2 is a flowchart illustrating an example of a power transmission control process executed by a wireless power transmission device and a power reception control process executed by a wireless power reception device in controlling a power supply operation in the wireless power supply system of the first embodiment. FIG. 3 is an explanatory diagram illustrating an example of a power feeding state in which the distance between the wireless power transmitting device and the wireless power receiving device is short. FIG. 3 is an explanatory diagram illustrating an example of a power feeding state in which the distance between the wireless power transmitting device and the wireless power receiving device is long. FIG. 2 is an explanatory diagram illustrating information representing a correspondence relationship between power feeding efficiency and continuous power transmission time, which is stored in advance in the microcomputer of the wireless power transmission device of the first embodiment. FIG. 2 is an explanatory diagram illustrating information representing a correspondence relationship between power feeding efficiency and continuous power transmission time, which is stored in advance in the microcomputer of the wireless power receiving device according to the first embodiment. 12 is a flowchart illustrating an example of a power transmission control process executed by a wireless power transmission apparatus and a power reception control process executed by a wireless power reception apparatus in controlling a power supply operation in a wireless power supply system according to a second embodiment. 12 is a flowchart illustrating an example of a power transmission control process executed by a wireless power transmission apparatus and a power reception control process executed by a wireless power reception apparatus in controlling a power supply operation in a wireless power supply system according to a third embodiment. FIG. 7 is a configuration diagram schematically showing a modification of the wireless power feeding system in each embodiment. When the power supply control information is the transmitted power value per unit time and continuous power transmission time, information representing the correspondence relationship stored in advance in the microcomputer of the wireless power transmitting device and correspondence stored in advance in the microcomputer of the wireless power receiving device It is an explanatory diagram explaining information showing a relationship.

Each embodiment will be described in detail below with reference to the drawings.

[First embodiment]
First, the configuration of the wireless power supply system of this embodiment will be explained. FIG. 1 shows a schematic configuration diagram of an example of a wireless power supply system 10 according to the present embodiment.

As shown in FIG. 1, the wireless power feeding system 10 of this embodiment includes a wireless power transmitting device 12 including a coil antenna 22 and a wireless power receiving device 14 including a coil antenna 32.

In the wireless power supply system 10 of the present embodiment, power is supplied wirelessly from the wireless power transmission device 12 to the wireless power receiving device 14 in a contactless (wireless) manner. In the wireless power supply system 10 of this embodiment, a case will be described in which an electromagnetic induction method is used as an example of wireless power supply. In the wireless power feeding system 10 of the present embodiment, when feeding power, the wireless power transmitting device 12 generates magnetic flux by passing an alternating current through the coil antenna 22. As a result, the magnetic flux passing through the coil antenna 32 of the wireless power receiving device 14 changes, and an alternating current also flows through the coil antenna 32.

Furthermore, the wireless power supply system 10 of the present embodiment performs data communication between the wireless power transmitting device 12 and the wireless power receiving device 14 using short-range wireless communication. Examples of the short-range wireless communication performed by the wireless power supply system 10 include near-field wireless communication using NFC (Near Field Communication). The coil antenna 22 of the wireless power transmitting device 12 and the coil antenna 32 of the wireless power receiving device 14 have the functions of both an antenna used for wireless communication and an antenna used for wireless power feeding. The wireless power transmitting device 12 and the wireless power receiving device 14 are capable of switching between power feeding and information communication using a coil antenna 22 and a coil antenna 32.

The wireless power transmission device 12 includes a power transmission and communication unit (hereinafter referred to as “power transmission/communication unit”) 20, a coil antenna 22, and a microcomputer (hereinafter referred to as “microcomputer”) 24.

The microcomputer 24 controls power transmission and communication by the power transmission/communication unit 20. Although the details will be described later, the microcomputer 24 of this embodiment stores in advance information 25 (hereinafter simply referred to as "information") representing the correspondence between power feeding efficiency and continuous power transmission time. The power transmission/communication unit 20 controls power supply based on the referenced continuous power transmission time. The microcomputer 24 of this embodiment is an example of the control unit of the present invention. Further, the continuous power transmission time of this embodiment is an example of power supply control information of the present invention.

A power supply voltage is input to the power transmission/communication unit 20 , and power is transmitted (supplied) by flowing an alternating current to the coil antenna 22 under the control of the microcomputer 24 . Further, as described above, the power transmission/communication unit 20 of this embodiment performs wireless communication using the coil antenna 22 under the control of the microcomputer 24. The power transmission/communication unit 20 of this embodiment is an example of the power transmission unit and the power transmission side communication unit of the present invention.

On the other hand, the wireless power receiving device 14 includes a power receiving/communication unit 30, a coil antenna 32, a resistive element 33, a microcomputer 34, an ADC (Analog-to-Digital Converter) 36, and an ADC 38.

The microcomputer 34 controls power reception and communication by the power reception/communication unit 30. Although the details will be described later, the microcomputer 34 of this embodiment stores in advance information (hereinafter simply referred to as "information") 35 representing the correspondence between power feeding efficiency and continuous power transmission time. The power receiving /communication unit 30 controls power supply based on the referenced continuous power transmission time. The microcomputer 34 of this embodiment is an example of the derivation unit of the present invention.

The power reception/communication unit 30 receives the power transmitted (power supplied) from the wireless power transmission device 12 by changing the magnetic flux density passing through the coil antenna 32 due to the induced electromotive force and causing an alternating current to flow through the coil antenna 32. Further, as described above, the power receiving /communication unit 30 of this embodiment performs wireless communication using the coil antenna 32 under the control of the microcomputer 34. The power reception/communication unit 30 of this embodiment is an example of a power reception unit and a power reception side communication unit of the present invention.

Power received by the power receiving/communication unit 30 is output to the battery 18 via the resistive element 33. The battery 18 of this embodiment is, for example, a secondary battery such as a lithium ion battery. Note that the battery 18 is not particularly limited as long as it can be charged by supplied power.

The ADC 36 of this embodiment detects the voltage before passing through the resistance element 33. On the other hand, the ADC 38 detects the voltage after passing through the resistance element 33. The voltages detected by the ADC 36 and ADC 38 are output to the microcomputer 34. When the current passes through the resistance element 33, a voltage drop occurs, so the microcomputer 34 can derive the value of the current flowing through the resistance element 33 based on the voltage detected by the ADC 36 and the voltage detected by the ADC 38. The received (supplied) power can be derived.

Next, control of the power feeding operation in the wireless power feeding system 10 of this embodiment will be explained. In the wireless power feeding system 10 of this embodiment, when feeding power, the wireless power transmitting device 12 executes a power transmission control process, an example of which is shown in FIG. 2, and the wireless power receiving device 14 executes a power reception control process.

Note that before executing the power transmission control process and the power reception control process shown in FIG. , it is preferable to confirm through a predetermined confirmation process that it is possible to supply power to the wireless power receiving device 14. Note that, for example, when the wireless power transmitting device 12 and the wireless power receiving device 14 are physically connected to a connection part having a special shape in order to supply power, the wireless power transmitting device 12 and the wireless power receiving device 14 may be inappropriately combined. If it is assumed that this is not the case, the confirmation process may be omitted.

In the wireless power transmission device 12, the microcomputer 24 executes the power transmission control process shown in FIG. 2 by executing the power transmission control program.

In step S100, the microcomputer 24 notifies the wireless power receiving device 14 of the value of the transmitted power (“transmitted power value”). Note that in the wireless power supply system 10 of the present embodiment, the value of the transmitted power per unit time for transmitting power from the wireless power transmitting device 12 is determined in advance.

In the next step S102, the microcomputer 24 causes the power transmission/communication unit 20 to start transmitting power according to the notified transmitted power value. Although details will be described later, in response to the power transmission, the wireless power receiving device 14 starts receiving power (see step S202 in FIG. 2).

In the next step S104, the microcomputer 24 determines whether the continuous power transmission time has elapsed. Specifically, the microcomputer 24 determines whether or not the continuous power transmission time has elapsed since the start of power transmission, based on the continuous power transmission time set in a storage unit (not shown).

Generally, the power received by the wireless power receiving device 14 changes depending on the positional relationship between the coil antenna 22 of the wireless power transmitting device 12 and the coil antenna 32 of the wireless power receiving device 14, the coupling state, and the like. For example, the amount of power received by the wireless power receiving device 14 changes depending on the distance between the coil antenna 22 of the wireless power transmitting device 12 and the coil antenna 32 of the wireless power receiving device 14. In the example of the power feeding state shown in FIG. 3, the distance between the coil antenna 22 and the coil antenna 32 is shorter (closer) than in the example of the power feeding state shown in FIG. In this case, the amount of power received by the wireless power receiving device 14 is larger in the power supply state shown in FIG. 3 than in the power supply state shown in FIG.

In the wireless power receiving device 14, when the amount of power received increases, the increased amount of power is not used for power supply, but is converted into heat and consumed. At this time, in order to prevent the generated heat from having an adverse effect on the wireless power receiving device 14, the continuous power transmission time of the wireless power transmitting device 12 is determined in consideration of the amount of heat generated in the wireless power receiving device 14.

In the wireless power supply system 10 of this embodiment, when step S104 is executed for the first time after starting the present power transmission control process, the wireless power transmission device 12 and the wireless power reception device 14 check the power supply state, more specifically, the power supply efficiency. is unknown. Therefore, in the wireless power supply system 10 of the present embodiment, the continuous power transmission time that takes into account the maximum amount of heat generated by the wireless power receiving device 14 is set in advance as the initial continuous power transmission time. In this embodiment, the period from when power transmission is first started to when power transmission is first stopped corresponds to the initial continuous power transmission time.

Until the continuous power transmission time elapses, a negative determination is made in the process of step S104, and the power transmission operation continues. On the other hand, if the continuous power transmission time has elapsed, the process in step S104 becomes an affirmative determination, and the process moves to step S106.

In step S106, the microcomputer 24 stops power transmission. Although details will be described later, when power transmission is stopped, the wireless power receiving device 14 notifies the wireless power transmitting device 12 of the measurement result of the received power (see step S204 in FIG. 2).

Therefore, in the next step S108, the microcomputer 24 receives the received power measurement result from the wireless power receiving device 14.

In the next step S110, the microcomputer 24 determines whether to end this power transmission control process, that is, whether to end power supply. For example, a predetermined power supply end condition is met, such as when a predetermined amount of power is transmitted, or when information indicating that charging is completed is received from the wireless power receiving device 14 together with the received power measurement result in step S108. In this case, the determination in step S110 is affirmative, and the present power transmission control process ends. On the other hand, if the predetermined power supply termination condition is not satisfied, the determination in step S110 becomes a negative determination, and the process moves to step S112.

In step S112, the microcomputer 24 derives power feeding efficiency based on the transmitted power value transmitted to the wireless power receiving device 14 and the received power measurement result. In the present embodiment, as an example, the microcomputer 24 derives the ratio (%) of the received power (received power measurement result) to the transmitted power as the power feeding efficiency.

As described above, the power received by the wireless power receiving device 14 changes depending on the positional relationship between the coil antenna 22 of the wireless power transmitting device 12 and the coil antenna 32 of the wireless power receiving device 14, the coupling state, etc. Efficiency also changes. As the received power increases, the power feeding efficiency derived by the microcomputer 24 also increases. For example, in the power feeding state shown in FIG. 3, the power received by the wireless power receiving device 14 is greater than in the power feeding state shown in FIG. 4, and the power feeding efficiency derived by the microcomputer 24 is also greater.

In the next step S114, the microcomputer 24 derives the continuous power transmission time on the power transmission side according to the power supply efficiency derived in the above step S112 . In this embodiment, as an example, the microcomputer 24 derives the continuous power transmission time on the power transmission side according to the power feeding efficiency, based on the information 25, an example of which is shown in FIG. As shown in FIG. 5, the information 25 is information representing the correspondence between power supply efficiency and continuous power transmission time. The correspondence relationship between power supply efficiency and continuous power transmission time may be obtained experimentally in advance, but in this embodiment, as an example, the lower the power supply efficiency derived by the microcomputer 24, the longer the continuous power transmission time becomes. .

On the other hand, although the details will be described later, the continuous power transmission time on the power receiving side is similarly derived in the wireless power receiving device 14, and is notified to the wireless power transmitting device 12 (see steps S212 and S214 in FIG. 2).

Therefore, in the next step S116, the microcomputer 24 receives the power receiving side continuous power transmission time from the wireless power receiving device 14.

In the next step S118, the microcomputer 24 determines whether the length of the continuous power transmission time on the power transmitting side is greater than or equal to the length of the continuous power transmission time on the power receiving side (power transmitting side≧power receiving side). If the length of the continuous power transmission time on the power transmitting side is greater than or equal to the length of the continuous power transmission time on the power receiving side, an affirmative determination is made in the process of step S118, and the process moves to step S120.

In step S120, the microcomputer 24 sets the receiving side continuous power transmission time as the continuous power transmission time, and then returns to step S100. Through the process of this step, when the process of step S104 is executed next, a determination is made based on the continuous power transmission time on the power receiving side.

On the other hand, if the length of the continuous power transmission time on the power transmitting side is less than the length of the continuous power transmission time on the power receiving side (power transmitting side<power receiving side), a negative determination is made in the process of step S118, and the process moves to step S122.

In step S122, the microcomputer 24 sets the power transmission side continuous power transmission time as the continuous power transmission time, and then returns to step S100. Through the process of this step, when the process of step S104 is executed next, a determination is made based on the continuous power transmission time on the power transmission side.

In this way, the microcomputer 24 of the wireless power transmission device 12 of the present embodiment executes the power transmission control process until the power supply ends, specifically, until an affirmative determination is made in step S110. In this embodiment, when the microcomputer 24 ends the power transmission control process, it sets the continuous power transmission time set in the storage unit (not shown) as the initial continuous power transmission time.

On the other hand, in the wireless power receiving device 14, the microcomputer 24 executes the power receiving control process shown in FIG. 2 by executing the power receiving control program.

In step S200, the microcomputer 34 receives the transmitted power value notified from the wireless power transmitting device 12 through the process in step S100 of the power transmission control process.

Then, since power transmission is started by the process in step S102 of the power transmission control process, the microcomputer 34 receives power and measures the received power in the next step S202.

In the next step S204, the microcomputer 34 determines whether power transmission from the wireless power transmission device 12 has stopped. The method for the microcomputer 34 to determine whether power transmission has stopped is not particularly limited. In the present embodiment, the microcomputer 34 determines that power transmission has stopped, for example, when a predetermined power transmission stop condition is satisfied. Note that the predetermined power transmission stop condition is not particularly limited, but may be, for example, not receiving power even after a predetermined time has elapsed. If the predetermined power transmission stop condition is not met, the determination in step S204 is negative, and the process returns to step S202. On the other hand, if the predetermined power transmission stop condition is satisfied, the determination in step S204 becomes an affirmative determination, and the process moves to step S206.

In step S206, the microcomputer 34 notifies the wireless power transmission device 12 of the measurement result of the received power. Note that the microcomputer 34 may also notify the wireless power transmission device 12 of information indicating that charging is completed, such as when the amount of charge of the battery 18 reaches a predetermined amount of charge.

In the next step S208, the microcomputer 34 determines whether to end the main power reception control process, that is, whether to end the power supply. For example, if a predetermined power supply termination condition is met, such as when the charge amount of the battery 18 reaches a predetermined charge amount or when a predetermined amount of power is received, the determination in step S208 becomes an affirmative determination, and the power is received. Control processing ends. On the other hand, if the predetermined power supply termination condition is not satisfied, the determination in step S208 becomes a negative determination, and the process moves to step S210.

In step S210, the microcomputer 34 derives power feeding efficiency based on the transmitted power value received in step S200 and the received power measurement result. The method for deriving the power feeding efficiency is the same as in step S114 of the power transmission control process.

In the next step S212, the microcomputer 34 derives the continuous power transmission time on the receiving side according to the power feeding efficiency derived in the above step S210. In the present embodiment, as an example, the microcomputer 34 derives the continuous power transmission time on the receiving side according to the power feeding efficiency, based on the information 35, an example of which is shown in FIG. As shown in FIG. 6, the information 35, like the information 25 shown in FIG. 5, is information representing the correspondence between power feeding efficiency and continuous power transmission time. Note that the information 25 and the information 35 may be the same or different. Similar to the information 25, the information 35 of this embodiment is such that the correspondence between power feeding efficiency and continuous power transmission time may be obtained experimentally in advance. The lower the power supply efficiency, the longer the continuous power transmission time.

In the next step S214, the microcomputer 34 notifies the wireless power transmission device 12 of the continuous power transmission time on the receiving side derived in step S212. In this embodiment, if the power supply has not ended, power is transmitted from the wireless power transmission device 12 again, so after executing step S214, the process returns to step S200 and the main power reception control process is repeated.

[Second embodiment]
In the wireless power supply system 10 of the first embodiment, the wireless power transmission device 12 notifies the wireless power reception device 14 of the transmitted power value, so that the wireless power transmission device 12 and the wireless power reception device 14 recognize the transmitted power. . In this embodiment, a mode in which the wireless power transmitting device 12 and the wireless power receiving device 14 recognize the amount of transmitted power is different will be described.

Since the configuration of the wireless power supply system 10 is the same as that of the first embodiment, the description thereof will be omitted, and the control of the power supply operation in the wireless power supply system 10 of this embodiment will be described. In the wireless power feeding system 10 of the present embodiment, when feeding power, the wireless power transmitting device 12 executes a power transmission control process, an example of which is shown in FIG. 7, and the wireless power receiving device 14 executes a power reception control process.

The power reception control process executed in the wireless power reception device 14 of the present embodiment shown in FIG. 7 replaces the process in step S200 of the power reception control process (see FIG. 2) executed in the wireless power reception device 14 of the first embodiment , is different in that the process of step S201 is executed.

In step S201, the microcomputer 34 notifies the wireless power transmission device 12 of the desired transmission power value (“desired transmission power value”). Note that the desired transmitted power is not particularly limited, and may be determined in advance, or may be derived by the microcomputer 34 according to the amount of charge of the battery 18.

In this way, in order to notify the desired transmission power value, the wireless power receiving device 14 of this embodiment can derive the power feeding efficiency using the desired transmission power in the process of step S210.

On the other hand, the power transmission control process executed in the wireless power transmission device 12 of the present embodiment shown in FIG. 7 is the process of step S100 of the power transmission control process (see FIG. 2) executed in the wireless power transmission device 12 of the first embodiment. The difference is that the process of step S101 is executed instead of .

In step S101, the microcomputer 24 receives the desired transmission power value from the wireless power receiving device 14. Thereby, in the next step S102, the microcomputer 24 starts transmitting power based on the desired transmission power value.

In this way, in the wireless power supply system 10 of the present embodiment, the wireless power transmitting device 12 notifies the wireless power receiving device 14 of the desired transmitted power value, and the wireless power receiving device 14 transmits the transmitted power according to the notified desired transmitted power value. Power is transmitted to the wireless power transmission device 12. Therefore, the wireless power transmitting device 12 and the wireless power receiving device 14 can recognize the transmitted power according to the desired transmitted power value.

[Third embodiment]
In the wireless power supply system 10 of each of the embodiments described above, a mode has been described in which both the wireless power transmission device 12 and the wireless power reception device 14 derive the power supply efficiency. In contrast, in this embodiment, a case will be described in which only the wireless power receiving device 14 derives the power feeding efficiency.

Since the configuration of the wireless power supply system 10 is the same as that of the first embodiment, the description thereof will be omitted, and the control of the power supply operation in the wireless power supply system 10 of this embodiment will be described. In the wireless power feeding system 10 of this embodiment, when feeding power, the wireless power transmitting device 12 executes a power transmission control process, an example of which is shown in FIG. 8, and the wireless power receiving device 14 executes a power reception control process.

The power reception control process executed in the wireless power reception device 14 of the present embodiment shown in FIG. 8 includes the process of step S206 of the power reception control process (see FIG. 2) executed in the wireless power reception device 14 of the first embodiment. They are different in that they cannot be used. Therefore, the wireless power receiving device 14 of this embodiment does not notify the wireless power transmitting device 12 of the received power measurement result.

Further, the power reception control process executed in the wireless power receiving device 14 of the present embodiment includes steps S210 and S212 of the power reception control process (see FIG. 2) executed in the wireless power receiving device 14 of the first embodiment. The difference is that the process of step S211 is executed.

In step S211, the microcomputer 34 notifies the wireless power transmission device 12 of the power feeding efficiency derived in step S210 (“power feeding efficiency derivation result”).

On the other hand, the power transmission control process executed in the wireless power transmission device 12 of the present embodiment shown in FIG. 8 is the process of step S108 of the power transmission control process (see FIG. 2) executed in the wireless power transmission device 12 of the first embodiment. It is different in that it does not include Therefore, the wireless power receiving device 14 of this embodiment does not receive the received power measurement result from the wireless power transmitting device 12.

Further, the power transmission control process executed in the wireless power transmission device 12 of the present embodiment is performed in step S113 instead of the process in step S112 of the power transmission control process (see FIG. 2) executed in the wireless power transmission device 12 of the first embodiment. They are different in that they perform the same processing.

In step S113, the microcomputer 24 receives the power feeding efficiency derivation result from the wireless power receiving device 14. Thereby, in the next step S114, the microcomputer 24 derives the power transmission side continuous power transmission time using the power supply efficiency according to the received power supply efficiency derivation result.

In this way, in the wireless power supply system 10 of the present embodiment, only the wireless power receiving device 14 derives the power feeding efficiency, so the wireless power transmitting device 12 and the wireless power receiving device 14 can share the same power feeding efficiency. Therefore, for example, the power feeding efficiency derived by the wireless power transmitting device 12 and the power feeding efficiency derived by the wireless power receiving device 14 will not differ due to an error or the like.

Therefore, according to the wireless power supply system 10 of this embodiment, transmitted power can be controlled more accurately.

Note that it goes without saying that this embodiment may be combined with the second embodiment described above. In this case, instead of step S100 of the power transmission control process shown in FIG. 8, step S101 (see FIG. 7) of the power transmission control process of the second embodiment may be executed. Furthermore, instead of step S200 of the power reception control process shown in FIG. 8, step S201 (see FIG. 7) of the power reception control process of the second embodiment may be executed.

As described above, the wireless power transmission device 12 of the wireless power supply system 10 of each embodiment described above includes the power transmission/communication unit 20, and the power transmission/communication unit 20 wirelessly transmits power to the wireless power receiving device 14. Further, the power transmission/communication unit 20 transmits transmission power information representing the power to be transmitted, or receives desired transmission power information representing the power that the wireless power reception device 14 desires to transmit, with the wireless power reception device 14 . The wireless power transmitting device 12 also transmits the transmitted power according to the transmitted power information transmitted by the power transmitting/communication unit 20 or the desired transmitted power information received by the power transmitting/communicating unit 20, and the received power received by the wireless power receiving device 14, The microcomputer 24 controls the power transmission by the power transmission/communication unit 20 based on the continuous power transmission time derived based on the power supply efficiency derived according to the power supply efficiency.

In addition, the wireless power transmitting device 12 of the wireless power feeding system 10 of each of the above embodiments wirelessly receives power from the wireless power receiving device 14, and also receives power transmission information indicating power transmitted by the wireless power receiving device 14, or transmits power. a power reception/communication unit 30 that transmits desired transmission power information representing the desired power to the wireless power reception device 14; and a microcomputer 34 that derives power feeding efficiency, which is the ratio of the received power received by the power transmission/communication unit 20 to the transmitted power. and.

As described above, according to the wireless power supply system 10 of each of the above embodiments, each of the wireless power transmission device 12 and the wireless power reception device 14 uses the obtained information to determine the continuous power transmission time (as an example of power supply control information) based on the power supply efficiency. Continuous power transmission time on the power transmitting side and continuous power transmission time on the power receiving side) can be derived.

For example, as in each of the above embodiments, when the continuous power transmission time on the power transmitting side and the continuous power transmission time on the power receiving side are different, if the longer time is used as the continuous power transmission time, there is a concern that the amount of heat generated will increase. On the other hand, according to the wireless power supply system 10 of each of the embodiments described above, when the continuous power transmission time on the power transmitting side and the continuous power transmission time on the power receiving side are different, the shorter time can be used as the continuous power transmission time, so that heat generation is prevented. In addition, it is possible to suppress the continuous power transmission time and set the continuous power transmission time to an appropriate time.

Therefore, according to the wireless power transmission device 12 of each of the embodiments described above, the processing efficiency of wireless power supply can be improved.

Note that in each of the above embodiments, the wireless power supply system 10 that performs wireless power supply using an electromagnetic induction method has been described, but the wireless power supply system is not limited to this. For example, a magnetic resonance method, an electric field coupling method, a microwave method, etc. may be used.

Furthermore, in the wireless power supply system 10 of each of the embodiments described above, the antenna used for wireless communication and the antenna used for wireless power supply are shared antennas (the coil antenna 22 and the coil antenna 32), but the present invention is limited to this embodiment. First, an antenna used for wireless communication and an antenna used for wireless power supply may be provided separately.

Further, in each of the embodiments described above, the wireless power receiving device 14 includes the ADC 36 and the ADC 38, but the present invention is not limited to this embodiment. For example, if information indicating the correspondence between the current and voltage of the received power is obtained in advance, only one of the ADC 36 and the ADC 38 may be provided. For example, as shown in FIG. 9, a comparator 37 may be provided in place of the ADC 36, and a comparator 39 may be provided in place of the ADC 38, but in this case, the measurement accuracy of the received power will be lower than in the case where the ADC 36 and the ADC 38 are provided. do.

Further, in each of the embodiments described above, the continuous power transmission time is used as an example of the power supply control information, but the present invention is not limited to this embodiment. For example, it may be the transmission power value per unit time that the wireless power transmission device 12 transmits, or both the transmission power value per unit time and the continuous power transmission time. When using the transmitted power value per unit time and continuous power transmission time as power supply control information, information 25 and information 35 include power supply efficiency, continuous power transmission time, and power transmission per unit time, as in the example shown in FIG. Information indicating the correspondence with the power value (transmitted power) may be used.

In addition, although the wireless power supply system 10 of each of the embodiments described above includes one wireless power transmission device 12 and one wireless power reception device 14, the present invention is not limited to this configuration. For example, the wireless power feeding system 10 includes one wireless power transmitting device 12 and a plurality of wireless power receiving devices 14, and may transmit power (power feeding) to the plurality of wireless power receiving devices 14 at the same time. In this case, the wireless power transmitting device 12 receives the power receiving side continuous power transmission time from each of the plurality of wireless power receiving devices 14 in the power transmission control process. The microcomputer 24 may set the shortest time as the continuous power transmission time from among the plurality of continuous power transmission times on the power receiving side and continuous power transmission times on the power transmitting side.

Furthermore, in each of the embodiments described above, the wireless power transmitting device 12 includes the microcomputer 24 and the wireless power receiving device 14 includes the microcomputer 34, but the present invention is not limited to this configuration. For example, instead of the microcomputer 24 and the microcomputer 34 in which hardware and software operate together, a processing circuit or the like which operates only by hardware may be used.

Furthermore, the configurations and operations of the wireless power supply system 10, the wireless power transmission device 12, and the wireless power receiving device 14 described in the other embodiments described above are merely examples, and may be modified according to the situation without departing from the gist of the present invention. Needless to say, it can be changed.

10 Wireless power supply system 12 Wireless power transmission device 14 Wireless power reception device 20 Power transmission/communication section 24 Microcomputer 30 Power reception/communication section 34 Microcomputer

Claims (4)

a power transmission unit that wirelessly transmits power to the wireless power receiving device;
a power transmitting side communication unit that receives desired transmitted power information indicating power that the wireless power receiving device desires to transmit;
The power transmission is performed using time information predetermined for the power supply efficiency, which is the ratio of the power received by the wireless power receiving device to the power transmitted according to the desired power transmission information received by the power transmission side communication unit. a control unit that controls the transmission time of electric power by the unit;
Equipped with
The power transmission side communication unit further receives continuous power transmission time information representing a first continuous power transmission time during which power is continuously transmitted from the wireless power receiving device, and power feeding efficiency information representing the power feeding efficiency,
The control unit derives a second continuous power transmission time based on the power feeding efficiency, and uses the shorter of the first continuous power transmission time and the second continuous power transmission time as the time information.
Wireless power transmission device. a power transmission unit that wirelessly transmits power to the wireless power receiving device;
a power transmitting side communication unit that receives desired transmitted power information indicating power that the wireless power receiving device desires to transmit;
The power transmission is performed using time information predetermined for the power supply efficiency, which is the ratio of the power received by the wireless power receiving device to the power transmitted according to the desired power transmission information received by the power transmission side communication unit. a control unit that controls the transmission time of electric power by the unit;
Equipped with
The power transmitting side communication unit further receives continuous power transmission time information representing a first continuous power transmission time during which power is continuously transmitted from the wireless power receiving device, and received power information representing the received power,
The control unit derives the power feeding efficiency using the received power represented by the received power information received by the power transmission side communication unit, derives the second continuous power transmission time based on the power feeding efficiency, and calculates the second continuous power transmission time based on the power feeding efficiency. using the shorter of the first continuous power transmission time and the second continuous power transmission time as the time information;
Wireless power transmission device. A wireless power supply system comprising a wireless power transmission device and a wireless power reception device,
The wireless power transmission device includes a power transmission unit that wirelessly transmits power to the wireless power reception device, a power transmission side communication unit that receives desired transmission power information representing power that the wireless power reception device desires to transmit, and the desired transmission power. A control unit that controls the power transmission time by the power transmission unit using time information predetermined for power supply efficiency, which is a ratio of received power received by the wireless power receiving device to transmitted power according to the information. including,
The power transmission side communication unit further receives continuous power transmission time information representing a first continuous power transmission time during which power is continuously transmitted from the wireless power receiving device, and power feeding efficiency information representing the power feeding efficiency,
The control unit derives a second continuous power transmission time based on the power feeding efficiency, and uses the shorter of the first continuous power transmission time and the second continuous power transmission time as the time information,
The wireless power receiving device includes a power receiving unit that wirelessly receives power from the wireless power transmitting device, a power receiving side communication unit that transmits desired transmission power information indicating power desired to be transmitted, and a power receiving unit that receives power from the wireless power transmitting device. including a derivation unit that derives power supply efficiency as a proportion of received power;
Wireless power supply system. Transmits power wirelessly to the wireless power receiving device,
The wireless power receiving device receives desired transmission power information indicating power desired to be transmitted;
When controlling power transmission time using time information predetermined for power supply efficiency, which is a ratio of received power received by the wireless power receiving device to transmitted power according to the desired transmitted power information,
Further, receiving continuous power transmission time information representing a first continuous power transmission time during which power is continuously transmitted from the wireless power receiving device, and power feeding efficiency information representing the power feeding efficiency,
A second continuous power transmission time is derived based on the power supply efficiency, and the shorter of the first continuous power transmission time and the second continuous power transmission time is used as the time information.
Wireless power transfer method including processing.