WO2013118368A1

WO2013118368A1 - Charging station and relative position control method

Info

Publication number: WO2013118368A1
Application number: PCT/JP2012/080022
Authority: WO
Inventors: 順治井上; 孝治比嘉; 加藤　伊三美; 近藤　直; 博樹戸叶
Original assignee: 株式会社豊田自動織機
Priority date: 2012-02-08
Filing date: 2012-11-20
Publication date: 2013-08-15
Also published as: JP2013162707A

Abstract

When performing wireless charging between a charging station having a primary coil and a vehicle having a secondary coil, a test power is transmitted from the primary coil to the secondary coil and the inter-coil distance is estimated from the power received by the secondary coil. When transmitting the test power, the transmission intervals thereof are made longer, as the power received decreases.

Description

Charging stand and relative position control method

The present invention relates to a charging stand for charging a battery included in a vehicle in a contactless manner.

In order to charge a battery mounted on a vehicle such as a hybrid vehicle or an electric vehicle, non-contact charging using electromagnetic induction has been proposed. In this non-contact charging, a high frequency current is passed through the primary coil of the charging stand, and the magnetic field generated in the primary coil is periodically changed. Thus, an induction current is generated in the secondary coil of the vehicle by electromagnetic induction from the primary coil, and electric power is transmitted to the secondary coil via the primary coil. The battery is charged using the power received by the vehicle.

In such non-contact charging, the ratio between the power transmitted from the primary coil and the power received by the secondary coil (hereinafter referred to as power reception efficiency) depends on the relative position between the primary coil and the secondary coil. Change. And power receiving efficiency will fall, so that the relative position of a primary coil and a secondary coil leaves | separates.

Therefore, in non-contact charging, the relative position of the primary coil and the secondary coil between the vehicle and the charging stand is conventionally positioned at a relative position (hereinafter referred to as an optimal position) at which optimal power reception efficiency is obtained. Control for alignment (hereinafter referred to as alignment control) is performed.

Further, the technology relating to the alignment between the primary coil of the charging stand and the secondary coil of the vehicle is disclosed in the following Patent Documents 1 to 4 and the like.

In Patent Document 1, before power is supplied to a moving body, a test signal having a lower intensity than a radio wave for charging is output from the antenna of the power feeding device in order to align the antenna. Then, according to the strength of the test signal received by the antenna of the moving body, it is described that the positional relationship between the antenna of the power feeding device and the antenna of the moving body is grasped and the positional relationship is adjusted to the optimum position. Yes.

In Patent Document 2, when the vehicle starts parking, a magnetic field is generated from the power feeding device. Then, the vehicle detects the magnetic field strength in the power receiving unit. Further, the detected magnetic field strength is compared with the magnetic field strength generated by the power feeding device. Thereby, the power receiving efficiency of the power receiving unit at the current position of the vehicle is specified, and it is determined whether or not the positional relationship between the power feeding device and the vehicle is optimal. Further, it is described that the power reception guidance process for guiding the vehicle to the optimal position is repeatedly performed at a predetermined cycle based on the power reception efficiency.

In Patent Document 3, a positioning marker is installed behind the parking space. Then, when the vehicle is parked in the parking space, the positioning marker is imaged with a camera mounted on the vehicle, and the image is displayed on the display unit. This describes that the vehicle is guided to the optimum position.

In Patent Document 4, a minute electric power is supplied to the power supply coil to generate a magnetic field. In addition, it is described that when a minute electric power is transmitted from the power supply side coil to the power reception side coil, it is determined that the power supply side coil and the power reception side coil are in a positional relationship where power can be supplied.

JP2011-182633 JP 2010-172184 A JP 2010-226945 JP2011-182624

Conventionally, it has been disclosed that the positional relationship between a primary coil and a secondary coil is grasped based on a test signal or magnetic field strength from a power feeding device side power feeding unit (primary coil) received by a vehicle side power receiving unit (secondary coil). ing.

However, since the output intensity from the primary coil is constant even if the reception intensity of the secondary coil increases, there is a problem that the transmission power on the power feeding device side is wasted.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a charging stand that suppresses power consumption in alignment control between a primary coil and a secondary coil.

In order to solve the above-described problems and achieve the object, the test power is periodically transmitted from the primary coil of the charging stand to the secondary coil of the vehicle, and the received power of the secondary coil is measured. In the charging stand that determines that the distance between the primary coil and the secondary coil is shorter as the received power is larger, the transmission interval of the test power is changed according to the received power of the secondary coil. A control unit is provided.

According to the present invention, it is possible to suppress the power consumption of the alignment control between the primary coil and the secondary coil.

It is a block diagram of the non-contact charge system of Embodiment 1. 3 is a flowchart of charge start control according to the first embodiment. 3 is a flowchart of alignment control according to the first embodiment. 3 is a flowchart of alignment control according to the first embodiment. 6 is an explanatory diagram of a transmission interval according to Embodiment 1. FIG. It is a block diagram of the non-contact charge system of Embodiment 2.

Hereinafter, the non-contact charging system of the embodiment will be described.
[Embodiment 1]
The non-contact charging system of Embodiment 1 will be described.

FIG. 1 is a configuration diagram of the contactless charging system according to the first embodiment.

The contactless charging system according to Embodiment 1 includes a vehicle 100 and a charging stand 200. The vehicle 100 also includes a secondary coil 101, a wireless communication unit A102, a charging control unit 103, a converter 104, a battery 105, a load 106, a wattmeter 107, and a storage unit A108. . The charging stand 200 includes a primary coil 201, a wireless communication unit B202, a power supply control unit 203, a high frequency power supply 204, and a storage unit B205.

As the secondary coil 101, for example, a known coil configured by winding an electric wire such as a copper wire can be employed. Secondary coil 101 is disposed on the bottom surface of vehicle 100.

A known wireless terminal can be adopted as the wireless communication unit A102. And a signal is transmitted / received between radio | wireless communication parts B202 by the side of the charging stand 200. FIG. The wireless communication unit A102 can be used not only for the wireless communication unit B202 but also for transmission and reception of signals with other wireless terminals.

The charging control unit 103 may employ a computer equipped with a memory as a work space such as an ECU (Electronic Control Unit). When the alignment control is performed, the secondary coil 101 is monitored, and the power value measured by the wattmeter 107 when the secondary coil 101 receives the test power transmitted from the primary coil 201. Get the received power value. Further, control is performed to transmit the acquired received power value from the vehicle 100 to the charging station 200 by the wireless communication unit A102. Further, during the charging of the battery of the vehicle 100, various controls relating to charging are performed.

The converter 104 includes, for example, an AC-DC converter and a DC-DC converter. When power is supplied from the secondary coil 101, the AC-DC converter converts AC current into DC current, and the DC-DC converter transforms the voltage to supply charging current to the battery 105. .

The battery 105 may be a storage battery such as a lithium ion battery, a lead battery, a nickel cadmium battery, or a nickel metal hydride battery. More specifically, it is used as a high voltage power source for driving the load 106 by connecting a plurality of battery cells in series to form an assembled battery.

The load 106 is, for example, an inverter circuit for driving a motor, and is a component of the vehicle 100 that is driven by power supplied from the battery 105.

The wattmeter 107 has, for example, a configuration including a voltmeter and an ammeter. The wattmeter 107 connects a voltmeter in parallel with the secondary coil 101 to measure the electromotive force of the secondary coil, and connects an ammeter in series with the secondary coil 101 to the secondary coil 101. Measure the induced current that flows. Further, the wattmeter 107 calculates the received power value of the secondary coil 101 from the voltage value and current value measured using this voltmeter and ammeter. Further, the wattmeter 107 outputs the received power value to the charging control unit 103 in response to a request from the charging control unit 103. The calculation of the received power value is performed by the charging control unit 103 by transmitting the voltage value and the current value measured by the wattmeter 107 to the charging control unit 103 in response to a request from the charging control unit 103. You may do it.

As the storage unit A108, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive) or the like can be employed. The storage unit A 108 stores various data necessary for the processing of the charging control unit 103.

As the primary coil 201, for example, a known coil configured by winding an electric wire such as a copper wire can be employed. The primary coil 201 is embedded in the ground of the parking position where the vehicle 100 is parked when charging using the charging stand 200.

For example, a known wireless terminal can be used as the wireless communication unit B202. And a signal is transmitted / received between radio | wireless communication parts A102 by the side of the vehicle 100. FIG. The wireless communication unit B202 can be used not only for the wireless communication unit A102 but also for transmission / reception of signals with other wireless terminals.

The power supply control unit 203 can employ, for example, a computer equipped with a memory as a work space such as an ECU (Electronic Control Unit).

And the electric power feeding control part 203 controls the electric current supplied to the primary coil 201 from the high frequency power supply 204. FIG.

Specifically, when performing the alignment control, the power feeding control unit 203 intermittently generates a first current that is an alternating current necessary for transmitting test power from the primary coil 201 to the secondary coil 101. The high frequency power supply 204 is controlled so as to be supplied to the primary coil 201. Note that an electromagnetic wave transmitted from the primary coil 201 when a first current is supplied to the primary coil 201 is referred to as a first electromagnetic wave. That is, the first electromagnetic wave is an electromagnetic wave transmitted from the primary coil 201 to the secondary coil 101 when test power is transmitted from the primary coil 201 to the secondary coil 101.

In addition, when charging the battery 105, the power supply control unit 203 supplies a second current, which is an alternating current necessary for transmitting charging power, which is charging power required from the vehicle 100, to the primary coil 201. The high frequency power supply 204 is controlled so as to be supplied to Note that the electromagnetic wave transmitted from the primary coil 201 when the second current is supplied to the primary coil 201 is referred to as a second electromagnetic wave. That is, the second electromagnetic wave is an electromagnetic wave transmitted from the primary coil 201 to the secondary coil 101 when charging power is transmitted from the primary coil 201 to the secondary coil 101.

In the following explanation, unless otherwise noted, the explanation will be made assuming that the charging power is always constant for simplicity. Moreover, the magnitude | size of test electric power should just be a magnitude | size which can grasp | ascertain the positional relationship of the primary coil 201 and the secondary coil 101. FIG. Therefore, it can be made sufficiently smaller than the magnitude of the charging power. The magnitude of the test power may be constant or may be changed according to the distance between the coils. The output time of the test power is to measure the power value (hereinafter referred to as test power value) of the test power transmitted from the primary coil 201 to the secondary coil 101 with the accuracy desired by the user using the power meter 107. It should be set so that it can.

In addition, when the test power is transmitted from the primary coil 201, the power supply control unit 203 stores the power value in the work space. And the electric power feeding control part 203 will calculate electric power reception efficiency using following formula (1), if the received electric power value which the secondary coil 101 received from the vehicle 100 is received.
Received power value / Test power value = Power reception efficiency (1)
Further, the power feeding control unit 203 extracts the obtained power receiving efficiency and the inter-coil distance corresponding to the power receiving efficiency-coil distance table 503 shown in FIG. Then, the power feeding control unit 203 transmits the extracted inter-coil distance to the vehicle 100 via the wireless communication unit B202.

Furthermore, the power supply control unit 203 changes the cycle (transmission interval) at which the test power is transmitted from the high-frequency power source 204 to the vehicle 100 according to the extracted inter-coil distance. Specifically, the power supply control unit 203 increases the transmission interval when the inter-coil distance is long, and shortens the transmission interval as the inter-coil distance approaches. Further, depending on the application, the power supply control unit 203 may perform control to shorten the transmission interval when the inter-coil distance is long and to increase the transmission interval as the inter-coil distance approaches.

The high frequency power supply 204 is connected to the system power supply 300 and converts AC power taken from the system power supply 300 into a sine wave signal having a predetermined cycle. The high-frequency power supply 204 supplies an alternating current having a required magnitude to the primary coil 201 by being controlled by the power supply control unit 203. Further, the high frequency power supply 204 may be configured to convert AC power taken from the system power supply 300 into a pulse signal as long as the signal has a predetermined cycle.

The storage unit B205 can employ, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like. In the storage unit B205, various types of data necessary for the processing of the power supply control unit 203 are stored. The various data includes at least a test power value, a charging power value, a power reception efficiency-coil distance table 503, a test power output time, and an optimum power reception efficiency. The optimum power receiving efficiency is a power receiving efficiency suitable for charging. When this power receiving efficiency is obtained, the power feeding control unit 203 positions the primary coil 201 and the secondary coil 101 at the optimum positions. Judge that there is. This optimum power receiving efficiency is a value determined by the user through experiments based on the shapes and materials of the primary coil 201 and the secondary coil 101. Further, when a constant value is used for the alignment control, one value may be stored as the test power value. On the other hand, when changing the test power value in the alignment control, it is preferable to provide a test power value table. As an example of the test power value table, although not particularly shown, it is preferable to store an inter-coil distance-test power value table in which a test power value is set according to the inter-coil distance.

Further, the storage unit B205 is a feature of the present invention. The inter-coil distance-transmission interval table 504 shown in FIG. 5 is used to change the transmission interval of the first electromagnetic wave (test power) according to the inter-coil distance. Is remembered. The inter-coil distance-transmission interval table 504 is a table showing the correspondence between the inter-coil distance and the transmission interval of the first electromagnetic wave. The fact that the transmission interval at the inter-coil distance c is not defined indicates that the primary coil and the secondary coil are aligned at the optimum position at the inter-coil distance c. That is, since it is not necessary to transmit the test power, the transmission interval is not determined.

Next, the operation of the contactless charging system according to the first embodiment will be described with reference to FIGS.

Hereinafter, the operation of the contactless charging system according to the first embodiment will be described in detail. However, the present invention is not limited to this, and the operation can be appropriately changed as long as the characteristics of the present invention can be applied.

FIG. 2 is a flowchart of charge start control according to the first embodiment.

In the following description, unless otherwise specified, it is assumed that each piece of information is transmitted and received by a signal representing that information. A signal transmitted from the vehicle 100 is generated by the charging control unit 103, and a signal transmitted from the charging station 200 is generated by the power supply control unit 203. In addition, transmission / reception of signals between the vehicle 100 and the charging station 200 is performed between the wireless communication unit A102 and the wireless communication unit B202. The charging stand 200 will be described on the assumption that the charging of the vehicle 100 is acceptable.

First, when the driver of the vehicle 100 decides to stop at the charging station and start charging, a vehicle authentication signal is sent from the vehicle 100 to the charging station 200 by pressing a vehicle authentication signal output switch (not shown). Output (S201). This vehicle authentication signal is a connection request signal for the charging station 200 of the vehicle 100.

Then, when the charging station 200 receives the vehicle authentication signal (S202), the charging station 200 transmits the stand authentication signal and the vehicle authentication signal to the vehicle 100 (S203). This stand authentication signal is a signal for confirming the response of the vehicle 100. If the stand that has received the vehicle authentication signal at the time of S202 has already charged the other vehicle 100 or cannot accept the charge of the vehicle 100 for other reasons, it cannot be accepted from the charging stand 200. May be transmitted to the vehicle 100. When there are a plurality of charging stations 200 that can receive the vehicle 100, the station authentication signal is transmitted to the vehicle 100 only from the charging station 200 having the highest vehicle authentication signal reception level among the charging stations 200. You may do it. In this case, the comparison of the reception level of the vehicle authentication signal of each charging station 200 may be performed by a stand control unit (not shown) to which each charging station 200 is connected.

When the vehicle 100 receives the stand authentication signal and the vehicle authentication signal (S204), the vehicle 100 authenticates the connection of communication with the charging stand 200 and recognizes that the charging stand 200 can be charged. It is determined to charge at 200 (S205). Then, the vehicle 100 transmits a stand authentication signal to the charging stand 200 (S206).

In addition, when the charging station 200 receives the station authentication signal (S207), the charging station 200 authenticates the communication connection with the vehicle 100 and recognizes the vehicle 100 as a vehicle to be charged (S208).

Next, the charging station 200 starts alignment control for guiding the vehicle 100 to the optimum position (S209). Details of the alignment control will be described with reference to FIGS.

When the alignment control is completed, charging of the battery 105 of the vehicle 100 is started by transmitting charging power for charging from the charging stand 200 (S210). The charging power is obtained by controlling the high-frequency power supply 204 so that the power feeding control unit 203 acquires the charging power value stored in the storage unit B 205 and supplies the power of the charging power value to the primary coil 201. Is transmitted.

Note that the authentication of the vehicle 100 and the charging station 200 in S201 to S208 uses almost the same method as a general three-way handshake, but is not limited to this, and any method that allows mutual authentication is used as appropriate. A known technique can be applied. In the above description, since the charging power is constant, the charging power value stored in the storage unit B205 is used. However, the charging power may be appropriately changed based on the charging power value requested from the vehicle 100. good.

Next, the alignment control operation of the first embodiment will be described.

3 and 4 are flowcharts of the alignment control according to the first embodiment.

In the following description, vehicle 100 is capable of identifying the first electromagnetic wave from authenticated charging station 200 and measuring the received power value even when there are a plurality of charging stations 200. . For example, the charging station 200 includes a modulation circuit, and the identification signal of the charging station 200 is superimposed on the first electromagnetic wave. Furthermore, the vehicle 100 includes a demodulation circuit, and the vehicle 100 recognizes the identification signal superimposed on the first electromagnetic wave. Thereby, it is preferable to recognize the first electromagnetic wave from the authenticated charging stand 200.

First, in FIG. 3, the power supply control unit 203 acquires a test power value used for alignment control from the storage unit B 205, and based on the acquired test power value, a first current is supplied from the high-frequency power source 204 to the primary coil 201. (S301). Furthermore, the power supply control unit 203 stores the test power value acquired from the storage unit B205 in the workspace.

The power supply control unit 203 acquires the output time of the test power stored in the storage unit B205, and supplies the first current from the high frequency power supply 204 to the primary coil 201 during the acquired output time of the test power. Control is performed (S302).

Further, when the first current is input from the high frequency power supply 204, the primary coil 201 transmits the first electromagnetic wave (S303).

Then, the secondary coil 101 receives the first electromagnetic wave (S304).

Further, when the charging control unit 103 detects that the secondary coil 101 has received the first electromagnetic wave, the charging control unit 103 causes the wattmeter 107 to measure the received power (S305). Furthermore, the charging control unit 103 acquires a received power value from the wattmeter 107 and transmits the received power value to the charging station 200 (S306).

When the charging station 200 receives the received power value (S307), the power supply control unit 203 uses the test power value and the received power value stored in the workspace to obtain the power receiving efficiency according to the equation (1). Is calculated (S308).

Furthermore, the power supply control unit 203 compares the power reception efficiency (calculated value) calculated in S308 with the optimum power reception efficiency stored in the storage unit B205, and the calculated power reception efficiency is equal to or greater than the optimum power reception efficiency. It is determined whether or not (S309).

As a result, when the power receiving efficiency calculated is lower than the optimum power receiving efficiency (No in S309), the process proceeds to S310 in FIG. Then, the power supply control unit 203 refers to the power reception efficiency-coil distance table 503 shown in FIG. 5 stored in the storage unit B205 (S310), and extracts the inter-coil distance corresponding to the calculated power reception efficiency (S310). S311).

Then, the power supply control unit 203 transmits the extracted distance between the coils to the vehicle 100 (S312). The vehicle 100 also informs the driver of the distance between the coils by using notifying means such as a display and a speaker (not shown). Thereby, in the vehicle 100, a driver | operator can be induced | guided | derived so that the primary coil 201 and the secondary coil 101 may be made into an optimal position.

Further, the power supply control unit 203 refers to the inter-coil distance-transmission interval table 504 and extracts a transmission interval corresponding to the inter-coil distance extracted in S310 (S313).

The power supply control unit 203 waits for the transmission interval extracted in S313, and then proceeds to S302 (S314). Thereafter, S302 to S309 are executed.

In S309 of FIG. 3, when the calculated reception efficiency is equal to or higher than the optimal power reception efficiency (Yes in S309), it is determined that the primary coil 201 and the secondary coil 101 are in the optimal positions, and is shown in FIG. The process proceeds to S315. At this time, since the primary coil 201 and the secondary coil 101 are aligned at the optimum positions, the transmission of the test power is finished.

Then, the power feeding control unit 203 acquires the charging power value from the storage unit B 205 and supplies the second current supplied to the primary coil 201 to transmit the charging power value from the high-frequency power source 204 to the primary coil 201. Set to supply. Then, the process proceeds to S210 in FIG.

In the above processing, when a constant test power is always used, an optimal received power value corresponding to the constant test power is stored in the storage unit B205 instead of the optimal power receiving efficiency. In S309, the optimum received power value is compared with the received power value received from the vehicle 100. If the received received power value is equal to or greater than the optimum received power value, the primary coil 201 and the secondary coil 101 are compared. May be determined to be in the optimum position. Further, as shown in the received power-transmission interval table 505 shown in FIG. 5, the correspondence relationship between the received power value and the inter-coil distance corresponding to the constant test power is stored in the storage unit B205, and in S311, The corresponding inter-coil distance may be extracted directly from the received power value. Further, as shown in the received power-transmission interval table 505 shown in FIG. 5, the correspondence relationship between the received power value and the transmission interval corresponding to a constant test power is stored in the storage unit B205, and in S313, the received power is received. The corresponding transmission interval may be extracted directly from the power value. By setting in this way, when a constant test power is used, the calculation of the power reception efficiency in S308 can be omitted, and the processing can be simplified.

FIG. 5 is an explanatory diagram of a transmission interval according to the first embodiment.

The power reception efficiency-coil distance graph A501 indicates the transmission interval of the first electromagnetic wave (test power) of the first embodiment. The horizontal axis is the distance between the coils. The distance between the primary coil 201 and the secondary coil 101 in the order of the inter-coil distance a, the inter-coil distance d, the inter-coil distance b, the inter-coil distance e, and the inter-coil distance c. Is approaching. The vertical axis represents the power reception efficiency, and the curve shown in the power reception efficiency-inter-coil distance graph A501 indicates the power reception efficiency according to the inter-coil distance. The up arrow is the transmission timing of the first electromagnetic wave transmitted intermittently from the primary coil 201 during the alignment control.

In the first embodiment, as shown in the power receiving efficiency-inter-coil distance graph A501, the transmission interval is shortened as the inter-coil distance approaches. As a result, when the detailed alignment between the primary coil 201 and the secondary coil 101 is not required, that is, when the inter-coil distance is long, the transmission interval can be increased to reduce power consumption. . In addition, when a section where detailed alignment between the primary coil 201 and the secondary coil 101 is required, that is, when the distance between the coils is short, the transmission interval is shortened and the distance between the coils is transmitted to the driver in detail. Can do.

In this case, the times ta to td indicating the transmission intervals in the inter-coil distance-transmission interval table 504 are set to be shorter in the order of time ta, time td, time tb, time te, and time tc.

The power reception efficiency-coil distance graph B502 shows the setting of the transmission interval of another first electromagnetic wave (test power) of the first embodiment. The horizontal axis represents the distance between the coils, and the distance between the coils approaches in order of the distance between the coils a, the distance d between the coils, the distance b between the coils, the distance e between the coils, and the distance c between the coils. The vertical axis represents the power reception efficiency, and the curve shown in the power reception efficiency-coil distance graph B502 represents the power reception efficiency according to the distance between the coils. The up arrow is the transmission timing of the first electromagnetic wave transmitted intermittently from the primary coil 201 during the alignment control.

In another control of the first embodiment, as shown in the power receiving efficiency-inter-coil distance graph B502, the transmission interval is increased as the inter-coil distance approaches. Thereby, when the position of the primary coil 201 and the secondary coil 101 is near, power consumption can be suppressed. Further, when the distance between the primary coil 201 and the secondary coil 101 is long and the power reception efficiency is poor, the received power measured by acquiring a plurality of measurement values by shortening the transmission interval. The value can be appropriately corrected by a known technique to improve the measurement accuracy.

In this case, the times ta to td indicating the transmission intervals in the inter-coil distance-transmission interval table 504 are set to increase in the order of time ta, time td, time tb, time te, and time tc. Yes.

In the first embodiment, the test power value, the charging power value, the power reception efficiency-coil distance graph A501 (power reception efficiency-coil distance graph B502), the test power output time, and the optimum power reception efficiency are obtained. Although stored in the storage unit B205, these pieces of information may be stored in the storage unit A108.

In addition, although the power reception efficiency is calculated by the power supply control unit 203, the charge control unit 103 may acquire and calculate necessary information.

The output of the test power (first electromagnetic wave) may be set to increase as the distance between the coils increases and decrease as the distance between the coils approaches. As a result, when the distance between the coils is long and the first electromagnetic wave is susceptible to noise due to external factors, the noise can be made relatively small compared to the first electromagnetic wave. Therefore, the measurement accuracy of the received power can be improved. On the other hand, when the distance between the coils is short, noise due to external factors received by the first electromagnetic wave is reduced, so that the first electromagnetic wave is reduced within an output range where desired measurement accuracy can be obtained. Therefore, power consumption can be suppressed when the distance between the coils is short.
[Embodiment 2]
FIG. 6 is a configuration diagram of the contactless charging system according to the second embodiment.

Embodiment 2 has a configuration including a modulation / demodulation circuit A 602 and a modulation / demodulation circuit B 612 in place of the wireless communication unit A 102 and the wireless communication unit B 202 of the first embodiment. Other configurations and controls are the same as those in the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the modulation / demodulation circuit A 602 and the modulation / demodulation circuit B 612 will be described.

The modulation / demodulation circuit A 602 includes a known modulator and demodulator. The modulation / demodulation circuit A 602 is controlled by the charging control unit 103 and transmits a signal to the charging stand 610 by applying a voltage to the secondary coil 101. Further, the modulation / demodulation circuit A 602 detects a signal received from the charging stand 610 by demodulating a signal superimposed on the electromagnetic wave received by the secondary coil 101, and inputs it to the charging control unit 103.

The modulation / demodulation circuit B 612 includes a known modulator and demodulator. Modulation / demodulation circuit B 612 is controlled by power supply control unit 203 and applies a voltage to primary coil 201 to transmit a signal to vehicle 600. Further, the modulation / demodulation circuit B 612 detects a signal received from the vehicle 600 by demodulating a signal superimposed on the electromagnetic wave received by the primary coil 201 and inputs the detected signal to the power feeding control unit 203.

With the above configuration, in the second embodiment, communication can be performed between the vehicle 600 and the charging stand 610 without using the wireless communication unit A102 and the wireless communication unit B202. The same control can be realized with different configurations.

Claims

The test power is periodically transmitted from the primary coil included in the charging stand to the secondary coil included in the vehicle, and the received power of the secondary coil is measured. As the received power increases, the primary coil and the 2 In the charging stand that determines that the distance to the next coil is short,
A charging station comprising: a control unit that changes a transmission interval of the test power according to the received power of the secondary coil.
The charging station according to claim 1, wherein the control unit increases the transmission interval of the test power as the received power decreases.
The charging station according to claim 2, wherein the control unit shortens a transmission interval of the test power as the received power increases.
The charging station according to claim 1, wherein the control unit increases the transmission interval of the test power as the received power increases.
The charging station according to claim 4, wherein the control unit shortens the transmission interval of the test power as the received power decreases.
The test power is periodically transmitted from the primary coil included in the charging stand to the secondary coil included in the vehicle, and the received power of the secondary coil is measured. As the received power increases, the primary coil and the 2 In the relative position estimation method performed by the charging stand that determines that the distance between the secondary coil and the next coil is short,
A relative position estimation method, wherein a transmission interval of the test power is changed in accordance with received power of the secondary coil.