JP2017127159A - Power transmission apparatus, power transmission system and control method for power transmission apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid excessive power supply to a power reception apparatus without need for addition of a protective circuit even when the power reception apparatus is moved suddenly during charging.SOLUTION: The power transmission apparatus, having power transmission means for transmitting electric power to a power reception apparatus in a non-contact manner and communication means for communicating with the power reception apparatus, includes: position detection means for detecting a position of the power reception apparatus; movement detection means for detecting movement of the power reception apparatus; transmission power calculation means for calculating at least two transmission power setting values to be transmitted to the power reception apparatus; and transmission power setting means for selecting the transmission power setting value calculated by the transmission power calculation means according to a detection result of the movement detection means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power transmission device, a power transmission system, and a method for controlling the power transmission device, and more particularly to transmission power control of the power transmission device.

  In recent years, non-contact charging using electromagnetic induction has attracted attention. As an application example of this non-contact charging system, many proposals have been made regarding small electronic devices such as mobile phones. In the non-contact power transmission system, a single power transmission device can charge a battery to a plurality of power reception devices of the same standard. Thereby, it becomes unnecessary to own a plurality of chargers corresponding to the battery. In addition, it is expected to expand to applications that improve user convenience, such as simultaneous charging to a plurality of power receiving devices and charging in public facilities.

  However, unlike contact-type power transmission, in non-contact-type power transmission, the power received by the power receiving apparatus is not always constant. For example, the above-described received power varies depending on the distance between the power transmission device and the power reception device, the positional relationship between the antennas, and obstacles. Therefore, various problems may occur in the power receiving device, such as the power receiving device receiving excessive power depending on the power receiving conditions, and such a problem may occur in a system that transmits larger power to a long distance. Increases nature.

  As a means for solving the above-described problems, for example, Patent Document 1 discloses a communication power control method that includes a communication unit that performs communication between a power transmission device and a power reception device, and that corresponds to a communication result of the communication unit. In Patent Document 1, first, as the power value at the start of power transmission from the power transmission device to the power reception device, the transmission power is increased stepwise from a small power value, and the minimum power value at which the power reception device can communicate is A first transmitted power value is determined. Next, after the communication is confirmed, a coupling coefficient between the power transmission device and the power reception device is obtained, a second transmission power value optimum for operating the power reception device is calculated, and the second transmission power value is calculated from the first transmission power value. The transmission power is switched to Thereby, the possibility that excessive power is supplied to the power receiving apparatus is reduced, and the transmission power is set to an optimum power value required by the power receiving apparatus.

JP 2009-268310 A JP 2012-5308 A

However, in the conventional technique disclosed in Patent Document 1 described above, when the power receiving apparatus is suddenly moved in a direction in which the coupling coefficient increases after the second transmitted power is determined, the power receiving apparatus is excessively supplied with power. May end up. Further, when a protection circuit is used as a countermeasure against overpower application, the scale of the protection circuit increases as the assumed transmission power increases, making it difficult to mount in a small portable device.
An object of the present invention is to make it possible to avoid excessive power supply to a power receiving device without adding a protection circuit even when the power receiving device is suddenly moved during charging in view of the above-described problems. To do.

  The power transmission device of the present invention is a power transmission device including a power transmission unit that transmits power to the power reception device in a contactless manner and a communication unit that communicates with the power reception device, and a position detection unit that detects a position of the power reception device; , According to the detection result of the motion detection unit, a motion detection unit that detects movement of the power reception device, a transmission power calculation unit that calculates at least two transmission power setting values to be transmitted to the power reception device, Transmission power setting means for selecting a transmission power setting value calculated by the transmission power calculation means.

  According to the present invention, it is possible to avoid excessive power supply to the power receiving device without adding a protection circuit even when the power receiving device is suddenly moved during charging.

It is a block diagram which shows an example of a structure of the electric power transmission system which concerns on embodiment of this invention. It is explanatory drawing which shows an example of the hardware constitutions of the power transmission apparatus which concerns on embodiment of this invention. It is explanatory drawing of the transmission means of the electric power which concerns on embodiment of this invention. It is explanatory drawing which shows an example of a structure of the motion detection part which concerns on embodiment of this invention. It is explanatory drawing which shows an example of the hardware constitutions of the power receiving apparatus which concerns on embodiment of this invention. It is a flowchart explaining operation | movement of the power transmission apparatus which concerns on embodiment of this invention. It is a flowchart showing the determination flow of the transmission power W0 which concerns on embodiment of this invention. It is explanatory drawing which shows the relationship between the battery voltage of a secondary battery, and charging current. It is explanatory drawing of the positional relationship of a power transmission apparatus and a power receiving apparatus.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
(Power transmission system configuration)
FIG. 1 is a block diagram showing a configuration of a power transmission system 10 according to an embodiment of the present invention.
The power transmission system 10 includes a power transmission device 100 that transmits power without contact, and a power reception device 200 that receives the power transmitted by the power transmission device 100.
The power transmission device 100 includes a control unit 101, a power transmission unit 102, a communication unit 103, a storage unit 104, a motion detection unit 105, and a display unit 107. From the power supply unit 121 via an external power connection terminal 120 including a connector, a jack, and the like. Electric power is supplied to the power transmission device 100.

The control unit 101 controls the entire power transmission apparatus 100 and includes a communication control unit 111, a transmitted power calculation unit 112, a power transmission control unit 113, and a position information calculation unit 114.
The communication control unit 111 controls the communication unit 103. The transmission power calculation unit 112 calculates a transmission power value transmitted from the power transmission unit 102. The power transmission control unit 113 controls the power transmission unit 102. For example, the transmission power of the power transmission unit 102 is controlled to be the power value calculated by the transmission power calculation unit 112. The position information calculation unit 114 calculates the positional relationship between the power transmission device 100 and the power reception device 200. The calculation method of the positional relationship between the power transmitting device 100 and the power receiving device 200 is disclosed in Patent Document 2 and the like, and is a well-known technique, and therefore the details are omitted.

The power transmission unit 102 is a power transmission unit included in the power transmission device 100 and wirelessly transmits power to an external device such as the power reception device 200 in a non-contact manner.
The communication unit 103 is a communication unit included in the power transmission device 100 and performs wired / wireless communication with an external device such as the power reception device 200.

The storage unit 104 is a storage unit included in the power transmission device 100. For example, when there are a plurality of power reception devices, each transmission power information, positional relationship, and the like are stored.
The motion detection unit 105 is a motion detection unit included in the power transmission device 100 and detects in advance whether the power reception device 200 moves.
The display unit 107 is a display unit included in the power transmission device 100 and displays various information such as a warning.
The power transmission apparatus 100 includes a ROM (Read Only Memory) in which control data such as programs used by the control unit 101 and control parameters are recorded, and a RAM (Random Access memory) that temporarily stores programs executed by the control unit 101. ) Or the like.

  In FIG. 1, the power reception device 200 includes a control unit 201, a power reception unit 202, a communication unit 203, a transformer / regulator 204, a power supply unit 205, and a received power detection unit 206.

The control unit 201 is configured by an MPU or the like, and plays a role of controlling the entire power receiving apparatus 200 and performing various processes.
The power receiving unit 202 is a power receiving unit included in the power receiving device 200 and receives the power transmitted from the power transmitting device 100 wirelessly.

The communication unit 203 is a communication unit included in the power receiving device 200 and performs wired / wireless communication with an external device such as the power transmission device 100.
The transformer / regulator 204 performs voltage transformation based on the power received by the power receiving unit 202, smoothing the voltage after transformation, and making the voltage constant.

The power supply unit 205 is an internal power supply included in the power receiving device 200 and accumulates received power. In addition, the power supply unit 205 supplies a driving voltage that drives each unit of the power receiving device 200.
The received power detection unit 206 outputs a detection result corresponding to the received power level of the received power.

(Power transmission device configuration)
FIG. 2 is a block diagram illustrating an example of a hardware configuration of the power transmission device 100 according to the embodiment of the present invention.
The antenna circuit 150 and the carrier wave transmission circuit 151 function as the power transmission unit 102 in the power transmission device 100. The power transmission unit 102 can have a configuration corresponding to a transmission method such as electromagnetic induction of electric power, radio waves, magnetic field resonance, and electric field coupling.

As an example, FIG. 3 illustrates a configuration example of an electromagnetic induction power transmission unit 102 and a power reception unit 202.
In FIG. 3, the power transmission unit 102 includes an AC power supply, a capacitor, and an inductor. The power receiving unit 202 includes a rectifier circuit including an inductor, a capacitor, and a diode.
The power transmission unit 102 causes the AC power to flow through the inductor with the AC power and generates magnetic flux around the inductor. And the power receiving part 202 rectifies | straightens the alternating current which flows into an inductor with the above-mentioned magnetic flux, and obtains direct current. When electromagnetic induction is used as the power transmission method, the power receiving device 200 can obtain power from the power transmitting device 100 in this manner.

  The MPU 152 functions as the control unit 101 that controls the entire power transmission apparatus 100. Further, the MPU 152 can also serve as a communication control unit 111, a transmission power calculation unit 112, a power transmission control unit 113, and a position information calculation unit 114, which will be described later, in the power transmission device 100.

The ROM 153 stores programs used by the MPU 152 and control data such as calculation parameters, and temporarily records programs executed by the RAM 154.
The recording medium 155 functions as the storage unit 104 and stores, for example, power information to be transmitted to each power receiving apparatus, an application, and the like. Here, examples of the recording medium 155 include a magnetic recording medium such as a hard disk, and a nonvolatile memory such as an EEPROM, a flash memory, an MRAM, an FeRAM, and a PRAM, but are not limited thereto.

The display device 156 functions as the display unit 107. The display device includes a display device, a TFT LCD, an organic EL display, and the like, and displays display image data written in the RAM 154 or the recording medium 155.
The communication interface 159 is a communication unit included in the power transmission device 100 and functions as the communication unit 103 for performing wireless / wired communication with an external device such as the power reception device 200. Examples of the communication interface 159 include, but are not limited to, a communication antenna and an RF circuit, an IEEE 802.15.1 port and a wireless transmission / reception circuit, or a LAN terminal and a wireless transmission / reception circuit.

  The proximity sensor 160 functions as the motion detection unit 105. Examples of the proximity sensor 160 include, but are not limited to, an inductive proximity sensor, an ultrasonic proximity sensor, a photoelectric proximity sensor, or image processing. Here, a case where image processing is used for the proximity sensor will be described as an example.

FIG. 4 shows a configuration example of a block that performs image processing.
The photographing lens 1 includes a plurality of lenses such as a zoom lens and a focus lens. The shutter 2 has an aperture function. The solid-state imaging device 3 converts an analog signal obtained by converting an optical image into an electric signal, and outputs the digital signal. The image processing circuit 4 performs predetermined pixel interpolation processing and color conversion processing on the data from the solid-state imaging device 3. The exposure control unit 5 controls the shutter 2 having a diaphragm function. The lens control unit 6 performs lens control such as focus control for controlling the focus of the photographing lens 1 and zoom control for controlling zooming.

  The image processing circuit 4 performs predetermined arithmetic processing using the captured image data. Then, the image processing circuit 4 has an AE (automatic exposure) process, a TTL (through-the-lens) system, in which the MPU 152 controls the exposure control unit 5 and the lens control unit 6 based on the obtained calculation result. AF (autofocus) processing is performed. Furthermore, the image processing circuit 4 performs predetermined arithmetic processing using the captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained arithmetic result.

  The captured image is stored in the RAM 154 or the recording medium 155, and a subject is detected from the captured image and used as a proximity sensor. Since the subject detection method is a well-known technique, a detailed description thereof will be omitted. However, a moving object around the power receiving apparatus 200 may be recognized as a detection target by using pattern matching or a block matching method.

  It is determined whether or not there is a possibility that the power receiving apparatus 200 is moved by the output signal from the motion detection unit 105 corresponding to the distance and the moving speed with respect to the detected subject. For example, a detection signal may be output from the motion detection unit 105 when the proximity of the distance and the speed of speed exceed a predetermined threshold. Further, the proximity sensor 160 may be provided outside the power receiving device 200 or the power transmitting device 100 and the power receiving device 200. In the following description, the proximity sensor 160 is advanced on the assumption that the power transmission device 100 is provided.

The external power supply 161 functions as the power supply unit 121. The external power supply 161 is a power supply unit including a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, an AC adapter, or the like.
The power transmission apparatus 100 configures a power transmission system capable of realizing the power transmission method according to the present embodiment with the hardware configuration illustrated in FIG. 2.

(Power receiving device configuration)
FIG. 5 is an explanatory diagram illustrating an example of a hardware configuration of the power receiving device 200 according to the embodiment of the present invention.
The power receiving apparatus 200 includes an antenna circuit 250, an MPU 251, a ROM 252, a RAM 253, a communication interface 258, an internal power supply 259, and a received power detection circuit 260. In addition, the power receiving apparatus 200 connects each component via a bus 270 as a transmission path for data and the like.

The antenna circuit 250 functions as the power receiving unit 202 in the power receiving device 200. The antenna circuit 250 can take a configuration corresponding to the power transmission method in the power transmission unit 102 included in the power transmission device 100.
The MPU 251 functions as a control unit 201 that controls the entire power receiving apparatus 200. The ROM 252 stores control data such as programs and calculation parameters used by the MPU 251 and allowable power information of the power receiving apparatus 200, and the RAM 253 temporarily stores programs executed by the MPU 251.

  The communication interface 258 is a communication unit included in the power receiving device 200 and functions as the communication unit 203 for performing wireless / wired communication with an external device such as the power transmission device 100. Examples of the communication interface 258 include, but are not limited to, a communication antenna and an RF circuit, an IEEE 802.15.1 port and a wireless transmission / reception circuit, or a LAN terminal and a wireless transmission / reception circuit.

  The internal power source 259 is a power source included in the power receiving device 200 that can store received power and supply a driving voltage that drives each unit of the power receiving device 200. Here, examples of the internal power supply 259 include a secondary battery such as a lithium ion secondary battery, but are not limited thereto.

The received power detection circuit 260 functions as the received power detection unit 206 and outputs the power value received by the power receiving apparatus 200. For example, a sense resistor for reading the charging current value may be provided, the current value and the voltage value output from the transformer / regulator 204 may be read, and a value obtained by integrating these values may be output.
The power receiving apparatus 200 configures a power transmission system capable of realizing the power transmission method according to the present embodiment with the hardware configuration illustrated in FIG. 5.

[First Embodiment]
The operation flow according to the first embodiment of the present invention will be described below with reference to FIG.
First, in S601, communication between the power transmission device 100 and the power reception device 200 is started.
After starting communication, in step S602, the control unit 101 determines whether communication has been confirmed. The determination of communication confirmation is made based on whether or not the power transmission device 100 has received a response from the power reception device 200. When communication is not fixed, it progresses to S603 and the control part 101 of the power transmission apparatus 100 determines whether predetermined time passed (whether it timed out).

If the control unit 101 does not determine that the predetermined time has elapsed in S603, the power transmission device 100 repeats the processing from S602. When the control unit 101 determines in S603 that the predetermined time has elapsed, the power transmission device 100 ends the power transmission process.
If the control unit 101 determines in S <b> 602 that the communication has been confirmed, the process proceeds to S <b> 604 and information on the power receiving apparatus is received from the power receiving apparatus 200. At this time, the information received by the power transmission device 100 is information required in the following processing flow, and receives the allowable power of the power reception device 200, the battery voltage value before charging, the battery temperature, and the like.

In S605, based on the information sent from the power receiving device 200 in S604, the control unit 101 sets the transmitted power value of the power transmitting device 100 to W0 [W]. A method for calculating W0 will be described later. After the transmission power is set, in S606, power transmission from the power transmission device 100 to the power reception device 200 is started under the control of the control unit 101.
In S607, the position of the power receiving apparatus 200 is detected from the power information transmitted in S606. In the position detection of the power receiving apparatus 200, the position information calculation unit 114 detects the position of the power receiving apparatus 200 with respect to the power transmitting apparatus 100.

  In S608, the transmission power calculation unit 112 calculates two transmission powers W1 [W] and W2 [W]. Details of the procedure for calculating the transmission power W1 and W2 will be described later. After calculating the transmitted power W1 and W2, in S609, it is detected whether or not there is a possibility that the power receiving apparatus 200 is moved. Whether the power receiving apparatus 200 is moved is determined by the control unit 101 based on an output signal corresponding to the detection result of the motion detection unit 105.

If the control unit 101 determines in step S609 that the power receiving apparatus 200 may be moved, the process proceeds to step S611, and the control unit 101 sets the transmission power W2. After the transmission power W2 is set, the processing from S607 is repeated. Here, when the power receiving device 200 is moved and the power transmission efficiency is changed, the control unit 101 may display a warning display or the like on the display unit 107 to warn the user.
If the control unit 101 determines in step S609 that there is no possibility that the power receiving apparatus 200 is moved, the process proceeds to step S610, and the control unit 101 sets the transmission power W1.

  After the transmission power W1 is set, the process proceeds to S612, and the control unit 101 determines whether the battery of the power receiving device 200 is fully charged. If it is determined in S612 that the battery is not fully charged, the process proceeds to S613, and the control unit 101 determines whether or not the battery voltage when the transmission power W1 and W2 is set is charged to a predetermined threshold value Vth or more. Do.

If it is determined in S613 that the battery voltage is greater than the predetermined threshold Vth, the transmission power W0 is reset in the same procedure as in S605, and the process proceeds to S608 to reset the transmission power W1 and W2. The relationship between Vth and charging power will be described later. If the control unit 101 determines in step S613 that the battery voltage is equal to or lower than the predetermined threshold value Vth, the processing from step S609 is repeated.
In S612, when the control unit 101 determines that the battery is fully charged, the power transmission device 100 ends the power transmission process.

  Since communication is periodically performed between the power transmission device 100 and the power reception device 200, the power transmission processing of the power transmission device 100 is terminated at the timing when the battery voltage transmitted from the power reception device 200 reaches the full charge voltage. Good. When a plurality of power receiving devices 200 are simultaneously charged, and charging of one power receiving device 200 is completed and the power transmission processing of the power transmission device 100 is completed, a warning that informs the user that the power transmission processing is completed is displayed on the display unit 107. You may go.

Next, a method for setting the transmission power W0 in S605 will be described with reference to the flowchart of FIG.
First, the information regarding the power receiving apparatus 200 described above in S701 is transmitted from the power receiving apparatus 200 to the power transmitting apparatus 100.
In step S702, the control unit 101 compares predetermined power values Wmax1 and Wmax2. Wmax1 is the allowable power of the power receiving apparatus 200 transmitted in S701, and Wmax2 is a power value determined by the battery voltage of the power receiving apparatus 200.

FIG. 8 is a diagram illustrating a relationship between a battery voltage and a charging current of a general secondary battery.
First, trickle charging (small current charging) is performed with the charging current I1 until the battery voltage reaches a predetermined voltage Vth2. When the battery voltage reaches the voltage Vth2, the charging current is changed to I2, and constant current charging is performed. Thereafter, when the battery voltage reaches a predetermined voltage Vth1, constant voltage charging is performed, and the charging current gradually decreases.

Wmax2 is determined to be a power value that is equal to or lower than the charging current defined according to the voltage value, based on the relationship between the battery voltage and the charging current shown in FIG. For example, Wmax2 is set to transmission power at which the battery charging current is I1 when the battery voltage is equal to or lower than voltage Vth2.
In S702, when it is determined by the control unit 101 that Wmax2 is larger than Wmax1, the process proceeds to S703, and the control unit 101 sets the value of the transmitted power W0 to Wmax1. If it is determined in S702 that Wmax2 is equal to or less than Wmax1, the process proceeds to S704, and the control unit 101 sets the value of the transmitted power W0 to Wmax2.

Next, an example of a method for calculating the transmission power W1 and W2 will be described.
FIG. 9 shows the positional relationship between the power transmission device 100 and the power reception device 200. The power transmission efficiency changes according to the distance r between the antenna centers of the power transmission device 100 and the power reception device 200, which is obtained by the position information calculation unit 114. Here, a coefficient that changes according to the inter-antenna distance r is defined as k. k is recorded in the storage unit 104 of the power transmission apparatus 100 as table data of power transmission efficiency corresponding to the distance. k is a numerical value from 0 to 1, and approaches 1 as the inter-antenna distance r decreases. Assuming that the value of the coefficient k at the distance r is kr and the value of the coefficient k at the distance r at which the distance between the antennas is minimum is kmin, the values of W1 and W2 are expressed by the following equations.
W1 = W0 / kr (Formula 1)
W2 = W0 / kmin (Formula 2)

W1 is the maximum power that can be received by the power receiving apparatus 200 at the inter-antenna distance r, and W2 is the maximum power that can be received by the power receiving apparatus 200 when the distance between the power transmitting apparatus 100 and the power receiving apparatus 200 is minimized. Since the strength of the magnetic field or electric field varies depending on the distance, W1 and W2 may be calculated from the distance between the antennas. For example, since the strength of the magnetic field changes in inverse proportion to the square of the distance, the distance between the antennas may be calculated from this relationship.
In the present embodiment, with reference to the table data, the distance between the power transmission device 100 and the power reception device 200 is transmitted at at least two positions, the distance at the start of charging the power reception device 200 and the minimum distance. The power calculation unit 112 calculates the transmission power set value. With such a setting, the power transmission power can be determined so as to be the maximum power that can be received by the power receiving device 200 based on the current inter-antenna distance r, if the user is not moving. In addition, when the movement of the power receiving apparatus 200 is detected in S609, safe power supply is realized by temporarily setting W2. This is because, regardless of how the power receiving apparatus moves, the maximum power that can be allowed is set when the power can be supplied most efficiently (that is, at the minimum distance). That is, the output is set so as not to exceed the power allowable by the power receiving apparatus.
In the present embodiment, when power is transmitted to a plurality of power receiving apparatuses 200, the control unit 101 selects the minimum value among the transmission power setting values calculated for each power receiving apparatus.

Next, the relationship between Vth and charging power in S613 will be described.
The voltage value of Vth is determined according to the relationship between the battery voltage and the charging current shown in FIG. For example, similarly to the calculation of W0 described above, when the Vth voltage value has two voltage values of Vth1 and Vth2, and the battery voltage value exceeds the threshold voltage, the value of W0 is changed to Wmax1 or Wmax2. Switching is performed, and transmission power W1, W2 is calculated again. Thus, the transmission power set value is changed according to the battery voltage value in the power receiving device.
Through the above processing, the transmission power is temporarily changed to the maximum received power at the position where the power can be received most efficiently according to the movement of the power receiving apparatus. Thereby, it can be set as the transmission power which does not exceed the electric power which can be accept | permitted no matter what position a power receiving apparatus moves. That is, safe power feeding can be realized.
As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

(Other embodiments)
The present invention is also realized by executing the following processing. That is, software (computer program) that implements the functions of the above-described embodiments is supplied to a system or apparatus via a network or various computer-readable storage media. Then, the computer (or CPU, MPU, etc.) of the system or apparatus reads out and executes the program.

DESCRIPTION OF SYMBOLS 100 Power transmission apparatus 101 Control part 102 Power transmission part 103 Communication part 104 Storage part 105 Motion detection part 107 Display part 111 Communication control part 112 Transmission power calculation part 113 Power transmission control part 114 Position information calculation part 120 Connector part 121 Power supply part 200 Power receiving apparatus 201 Control Unit 202 Power Receiving Unit 203 Communication Unit 204 Transformer / Regulator 205 Power Supply Unit 206 Received Power Detection Unit

Claims (12)

A power transmission device having power transmission means for transmitting power to the power reception device in a non-contact manner and communication means for communicating with the power reception device,
Position detecting means for detecting the position of the power receiving device;
Motion detection means for detecting movement of the power receiving device;
Transmission power calculation means for calculating at least two transmission power setting values to be transmitted to the power receiving device;
Transmission power setting means for selecting a transmission power setting value calculated by the transmission power calculation means according to the detection result of the motion detection means,
A power transmission device comprising:   The power transmission device according to claim 1, wherein the transmission power calculation unit calculates the transmission power setting value from information on the power reception device obtained from the communication unit and a detection result of the position detection unit. Storage means for storing table data of power transmission efficiency according to the distance between the power transmission device and the power reception device;
The transmission power set value is calculated by referring to the table data by the transmission power calculation means, and the distance between the power transmission device and the power receiving device is calculated at at least two positions when charging the power receiving device is at a minimum and when the charging is started. The power transmission device according to claim 1, wherein the power transmission device is provided.   The power transmission device according to any one of claims 1 to 3, wherein the transmission power set value is changed according to a battery voltage value in the power receiving device. It further has a display means,
5. The power transmission device according to claim 1, wherein when the transmission power setting value is changed according to a detection result of the motion detection unit, the display unit displays a warning.   When the power transmission efficiency at the start of charging to the power receiving device obtained by referring to the table data is maximized, the transmission power setting means determines the transmission power according to the detection result of the motion detection means. The power transmission device according to any one of claims 3 to 5, wherein the set value is not changed.   The power transmission setting unit selects a minimum value among transmission power setting values calculated by each power receiving device when transmitting power to the plurality of power receiving devices. The power transmission device according to item 1.   The information of the power receiving device includes at least one of an allowable power of the power receiving device, a battery voltage value before charging, and a battery temperature, according to any one of claims 1 to 7. Power transmission device. A power transmission device according to any one of claims 1 to 8,
A power receiving device that receives power from the power transmitting device;
A power transmission system comprising:   The power transmission system according to claim 9, wherein the power receiving apparatus includes a detecting unit that detects a received power value and a transmitting unit that transmits information on the power receiving apparatus to the power transmitting apparatus. A power transmission device control method comprising: a power transmission unit that transmits power to a power reception device in a contactless manner; and a communication unit that communicates with the power reception device,
A position detecting step for detecting a position of the power receiving device;
A motion detection step of detecting movement of the power receiving device;
A transmission power calculation step of calculating at least two transmission power setting values to be transmitted to the power receiving device;
In accordance with the detection result in the motion detection step, a transmission power setting step for selecting the transmission power setting value calculated in the transmission power calculation step,
A method for controlling a power transmission device, comprising:   The computer-readable program for functioning a computer as each means of the power transmission apparatus of any one of Claims 1 thru | or 8.

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