Non-contact charging device for vehicle

Abstract

To suppress an increase in size and the number of components of a non-contact charging device for vehicle.SOLUTION: A non-contact charging device for vehicle 11 includes a control unit 15 that supplies and stops electric power to a power supply coil 13. When a device to be charged 12 is brought close to a chargeable position of the power supply coil 13, a voltage is induced in a power receiving coil 14 of the device to be charged 12 through power supply to the power supply coil 13 by the control unit 15. As a result, the device to be charged 12 is charged by receiving power supply from the power receiving coil 14. When the device to be charged 12 approaches the chargeable position, the control unit 15 supplies electric power to the power supply coil 13 to be in a charging state. On the other hand, when the device to be charged 12 moves away from the chargeable position, the control unit stops power supply to the power supply coil 13 to be in a standby state. When the power supply coil 13 is switched from the standby state to the charging state after being switched from the charging state to the standby state, the control unit 15 changes a frequency of electric power supplied to the power supply coil 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wireless charging device for a vehicle. [Background technology]

[0002] In the wireless charging device for vehicles disclosed in Patent Document 1, when a device to be charged is brought close to a power feeding coil to a position where it can be charged, a voltage is induced in the power receiving coil of the device to be charged through the supply of power to the power feeding coil. As a result, the device to be charged receives power from the power receiving coil and is charged.

[0003] However, if the harmonics of the frequency of the power supplied to the power supply coil of the wireless charging device for vehicles are close to the frequency tuned to by the radio installed in the vehicle, noise may be introduced into the radio broadcast. For this reason, the wireless charging device for vehicles in Patent Document 1 is designed to be able to change the frequency of the power supplied to the power supply coil, and when such noise is introduced into the radio broadcast, the user can change the frequency by operating an operating unit such as a switch. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-124003 Summary of the Invention [Problem to be solved by the invention]

[0005] The wireless charging device for a vehicle of Patent Document 1 must be provided with an operating unit such as a switch, which increases the size of the device and the number of parts. [Means for solving the problem]

[0006] Next, various aspects of a wireless charging device for a vehicle that solves the above problems will be described. (Aspect 1) 1. A wireless charging device for a vehicle including a control unit that starts and stops supplying power to a power feeding coil, and when a device to be charged approaches the power feeding coil to a position where it can be charged, a voltage is induced in a power receiving coil of the device to be charged through power supply to the power feeding coil by the control unit, whereby the device to be charged receives power supply from the power receiving coil and is charged. The control unit places the power feeding coil in a charging state by supplying power to the power feeding coil when the device to be charged approaches the power feeding coil to a position where it can be charged, and places the power feeding coil in a standby state by stopping the supply of power to the power feeding coil when the device to be charged moves away from the position where it can be charged. The wireless charging device for a vehicle includes a control unit that starts and stops supplying power to the power feeding coil when the state of the power feeding coil is switched from charging to standby and then from standby to charging.

[0007] According to the above configuration, when the target device being charged is moved away from the power supply coil and then brought closer to the power supply coil, the control unit switches the power supply coil from charging to standby, and then from standby to charging. When such a change in the state of the power supply coil occurs, in other words, when the user moves the target device to cause the change, the frequency of the power supplied to the power supply coil is changed. Therefore, there is no need to provide the wireless vehicle charging device with an operating unit such as a switch for changing the frequency. This prevents the wireless vehicle charging device from becoming larger or having more components, as would be the case if an operating unit such as a switch were provided in the wireless vehicle charging device.

[0008] (Aspect 2) The control unit is capable of switching the frequency of the power supplied to the power supply coil between a first frequency and a second frequency, and when the power supply coil is switched from the charging state to the standby state and then from the standby state to the charging state, if the frequency of the power supplied to the power supply coil is the first frequency, the control unit switches the frequency of the power supplied to the power supply coil to the second frequency, and if the frequency of the power supplied to the power supply coil is the second frequency, the control unit switches the frequency of the power supplied to the power supply coil to the first frequency (the wireless charging device for a vehicle according to aspect 1).

[0009] According to the above configuration, the frequency of the power supplied to the power feeding coil is changed as follows. That is, if the frequency of the power supplied to the power feeding coil is the first frequency f1, it is switched to the second frequency f2. Also, if the frequency of the power supplied to the power feeding coil is the second frequency f2, it is switched to the first frequency f1. In this way, the frequency of the power supplied to the power feeding coil is changed between the first frequency f1 and the second frequency f2, making the change easy.

[0010] (Aspect 3) The wireless charging device for a vehicle according to (Aspect 1) or (Aspect 2), wherein the control unit measures an elapsed time from when the power supply coil is switched from the charging state to the standby state until when the power supply coil is switched back to the charging state, and changes the frequency of the power supplied to the power supply coil only when the elapsed time is within a predetermined time range.

[0011] According to the above configuration, the user can instruct a change in the frequency of power supplied to the power feeding coil by moving the target device closer or farther away from the power feeding coil so that the elapsed time falls within the time range. On the other hand, if the user's operation of moving the target device closer or farther away from the power feeding coil is not intended to instruct a change in the frequency, the elapsed time falls outside the time range, and the frequency is not changed. Therefore, unnecessary changes in the frequency can be prevented.

[0012] (Aspect 4) The wireless charging device for a vehicle according to (Aspect 3), wherein the time range is 0.5 seconds or more and 5 seconds or less.

[0013] According to the above configuration, the time range is set to 0.5 seconds or more and 5 seconds or less. Therefore, if the target device being charged moves out of the chargeable position due to vehicle vibration and then returns to the chargeable position, the elapsed time t does not fall within the time range. This prevents the frequency of the power supplied to the power feeding coil from being erroneously changed under the above-mentioned circumstances. Furthermore, a user may move the target device away from the power feeding coil to end charging midway, use the target device, and then bring it close to the power feeding coil again to charge it. In this case, too, the time range is set to 0.5 seconds or more and 5 seconds or less. This prevents the frequency of the power supplied to the power feeding coil from being erroneously changed.

[0014] (Aspect 5) The wireless charging device for a vehicle according to any one of (Aspect 1) to (Aspect 4), further comprising an alarm unit that notifies a user when the control unit switches the power supply coil from charging to standby.

[0015] According to the above configuration, when the control unit switches the power supply coil from charging to standby, the notification unit notifies the user of this, thereby urging the user to bring the device to be charged closer to the power supply coil again in order to change the frequency of power supplied to the device to be charged. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing the configuration of a wireless charging device for a vehicle. [Figure 2] 4 is a flowchart showing a procedure for changing a frequency by the wireless charging device for a vehicle of FIG. [Figure 3]4 is a flowchart showing a procedure for changing a frequency by the wireless charging device for a vehicle of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of a contactless charging device for a vehicle will be described with reference to FIGS. 1 is used to charge a device 12 to be charged, such as a smartphone, inside a vehicle. The device 11 includes a power feeding coil 13 used to charge the device 12, and a control unit 15 that controls the supply and stop of power to the power feeding coil 13. When the device 12 to be charged approaches the power feeding coil 13 to a position where it can be charged, a voltage is induced in a power receiving coil 14 of the device 12 to be charged through the power supply from the control unit 15 to the power feeding coil 13. As a result, the device 12 to be charged receives power from the power receiving coil 14 and is charged.

[0018] The wireless charging device for a vehicle 11 includes a power supply circuit 16, a DC-DC converter 17, a coil driver 18, a detection unit 19, and an indicator 20. The control unit 15 is configured by, for example, a microcomputer. The control unit 15 controls various devices in the wireless charging device for a vehicle 11, such as the DC-DC converter 17, the coil driver 18, and the indicator 20. The power supply circuit 16 receives power from a battery mounted on the vehicle and supplies power to various devices in the wireless charging device for a vehicle 11, such as the control unit 15.

[0019] The DC-DC converter 17 and the coil driver 18 are used to supply power from the power supply circuit 16 to the power feeding coil 13. The DC-DC converter 17 is used to increase or decrease the voltage when power is supplied to the power feeding coil 13. The coil driver 18 is used to supply power to the power feeding coil 13. The control unit 15 is able to start and stop the supply of power to the power feeding coil 13 through control of the coil driver 18. The control unit 15 is also able to change the frequency of the power supplied to the power feeding coil 13 through control of the coil driver 18.

[0020] When the target device 12 approaches the power feeding coil 13 to a position where charging is possible, the detection unit 19 detects a change in the characteristics of the power feeding coil 13 and outputs a signal corresponding to the approach to the control unit 15. The control unit 15 supplies power to the power feeding coil 13 by controlling the coil driver 18 based on the signal from the detection unit 19. This causes the control unit 15 to determine that the power feeding coil 13 is being charged. By supplying power to the power feeding coil 13 in this manner, a voltage is induced in the power receiving coil 14 of the target device 12. As a result, the target device 12 receives power from the power receiving coil 14 and enters a charging state.

[0021] Furthermore, based on a change in the characteristics of the power feeding coil 13 when the target device 12 moves away from the chargeable position, the detection unit 19 outputs a signal corresponding to the movement to the control unit 15. While the target device 12 is moving away from the chargeable position, the detection unit 19 outputs the signal corresponding to the movement to the control unit 15. Based on the signal from the detection unit 19, the control unit 15 controls the coil driver 18 to stop the supply of power to the power feeding coil 13. As a result, the control unit 15 puts the power feeding coil 13 into standby mode. When the supply of power to the power feeding coil 13 is stopped in this way, charging of the target device 12 is stopped.

[0022] The indicator 20 can notify the user whether the charging state of the target device 12 by the vehicular wireless charging device 11 is charging or on standby by lighting up in a color corresponding to the charging state. Specifically, the control unit 15 of the vehicular wireless charging device 11 lights up the indicator 20 in a color corresponding to charging or on standby, depending on whether the power supply coil 13 is charging or on standby.

[0023] <Regarding changing the frequency of power supplied to the power supply coil 13> In the wireless charging device 11 for vehicles, harmonics of the frequency of the power supplied to the power feeding coil 13 may be close to the frequency tuned to by the radio installed in the vehicle, causing noise in the radio broadcast. To address this issue, in the wireless charging device 11 for vehicles, when the user instructs a change in the frequency of the power supplied to the power feeding coil 13, the control unit 15 changes the frequency.

[0024] Specifically, when noise is present in the radio broadcast, the user moves the charge target device 12, which is being charged, away from the power feeding coil 13 and then moves it closer to the power feeding coil 13 again. In this case, the control unit 15 switches the power feeding coil 13 from charging to standby, and then from standby to charging. As described above, when the power feeding coil 13 is switched from charging to standby, and then from standby to charging, the control unit 15 determines that the user has instructed to change the frequency. Based on this determination, the control unit 15 changes the frequency of the power supplied to the power feeding coil 13.

[0025] The frequency change is performed, for example, as follows: The control unit 15 can switch the frequency of the power supplied to the power feeding coil 13 between a first frequency f1 and a second frequency f2. The first frequency f1 is set to, for example, 127.7 kHz, and the second frequency f2 is set to, for example, 120.5 kHz.

[0026] When the power feeding coil 13 is switched from charging to standby and then from standby to charging, the control unit 15 changes the frequency as follows: If the frequency of the power supplied to the power feeding coil 13 is the first frequency f1, the control unit 15 switches it to the second frequency f2. Also, if the frequency of the power supplied to the power feeding coil 13 is the second frequency f2, the control unit 15 switches it to the first frequency f1.

[0027] <Operation of the vehicle wireless charging device 11> 2 and 3 are flowcharts showing the procedure for changing the frequency of power supplied to the power supply coil 13. The process shown in this flowchart is started when the wireless vehicle charging device 11 is powered on and started up.

[0028] After starting up the in-vehicle wireless charging device 11, the control unit 15 initializes the flag F, which is used to determine whether the device to be charged 12 has approached the power feeding coil 13 to a position where it can be charged, to "0" as the process of step 101 (S101) in Fig. 2. Furthermore, as the process of S101, the control unit 15 stops the supply of power to the power feeding coil 13, thereby putting the power feeding coil 13 into standby. Furthermore, as the process of S101, the control unit 15 lights up the indicator 20 in a color corresponding to the fact that the power feeding coil 13 is in standby, for example, green, to notify the user that the power feeding coil 13 is in standby.

[0029] After being set to "0" in S101 as described above, the flag F is set as follows depending on whether the target device 12 has approached the chargeable position relative to the power feeding coil 13. That is, the flag F is set to "1" when the target device 12 has approached the chargeable position relative to the power feeding coil 13, and is set to "0" when the target device 12 has moved away from the chargeable position relative to the power feeding coil 13. After executing step S101, the process proceeds to step S102.

[0030] In the process of S102, the control unit 15 determines whether the flag F is "1". If the target device 12 has not been brought close enough to the power feeding coil 13 to be charged, the flag F is set to "0", and therefore it is determined in S102 that the flag is "0". In this case, the process of S102 is repeatedly executed. On the other hand, if the target device 12 has been brought close enough to the power feeding coil 13 to be charged, the flag F is set to "1", and therefore it is determined in S102 that the flag F is "1". In this case, the process proceeds to S103.

[0031] In the process of S103, the control unit 15 supplies power to the power feeding coil 13, thereby charging the power feeding coil 13. In addition, in the process of S103, the control unit 15 lights up the indicator 20 in a color corresponding to the fact that the power feeding coil 13 is being charged, for example, orange, to notify the user that the power feeding coil 13 is being charged. Then, the process proceeds to S104.

[0032] In the process of S104, the control unit 15 determines whether the flag F is "0". If the target device 12 remains close to the power feeding coil 13 up to the chargeable position, the flag F is set to "1", and therefore it is determined in S102 that the flag is "1". In this case, the process of S104 is repeatedly executed. On the other hand, if the target device 12 is moved away from the chargeable position with respect to the power feeding coil 13, the flag F is set to "0", and therefore it is determined in S104 that the flag F is "0". In this case, the process proceeds to S105.

[0033] In the process of S105, the control unit 15 stops the supply of power to the power feeding coil 13, thereby putting the power feeding coil 13 into standby. In addition, in the process of S105, the control unit 15 causes the indicator 20 to flash in green, for example, to notify the user that the power feeding coil 13 has been switched from charging to standby. Then, the process proceeds to S106.

[0034] The control unit 15 executes a counting process of the counter C as the process of S106. In this counting process, the value of the counter C is counted up by "0.1" every time a predetermined time elapses. The counter C is used to measure the time from when the control unit 15 switches the power feeding coil 13 from charging to standby. Next, in the process of S107 of FIG. 3, the control unit 15 determines whether the flag F is "1" or not, in other words, whether the control unit 15 has switched the power feeding coil 13 from charging to standby and then switched from standby to charging. If it is determined in S107 that the flag F is "1," that is, if it is determined that the control unit 15 has switched the power feeding coil 13 from charging to standby and then switched from standby to charging, the process proceeds to S108.

[0035] In the process of S108, the control unit 15 determines whether the value of the counter C is within a predetermined range, i.e., the range of "X1 to X2." The determination in S108 that the value of the counter C is within the predetermined range, i.e., the range of "X1 to X2," means that the elapsed time t from when the power supply coil 13 was switched from charging to standby to when it was switched back to charging was within a predetermined time range. In other words, the range of "X1 to X2" is defined to reflect this meaning. It should be noted that the time range can be, for example, 0.5 to 5 seconds. If it is determined in S108 that the value of the counter C is within the range of "X1 to X2," the process proceeds to S109.

[0036] When the process proceeds to S109 in this way, the control unit 15 determines that the user has issued an instruction to change the frequency of the power supplied to the power feeding coil 13. In the process of S109, the control unit 15 supplies power to the power feeding coil 13, thereby setting the power feeding coil 13 to be charging. In addition, in the process of S109, the control unit 15 lights up the indicator 20 in orange to notify the user that the power feeding coil 13 is being charged. Thereafter, the process proceeds to S110. In the process of S110, the control unit 15 changes the frequency of the power supplied to the power feeding coil 13. In addition, in the process of S110, the control unit 15 flashes the indicator 20 in orange a predetermined number of times, for example, twice, to notify the user that the frequency of the power supplied to the power feeding coil 13 has been changed. Thereafter, the process proceeds to S111.

[0037] In the process of S111, the control unit 15 lights up the indicator 20 in orange to notify the user that the power feeding coil 13 is being charged. In the process of S111, the control unit 15 resets the value of the counter C to the initial value "0". Then, the process returns to S104 in FIG. 2.

[0038] 3, if it is determined that the flag F is "0," that is, if it is determined that the power feeding coil 13 remains in standby after the control unit 15 has switched from charging to standby, the process proceeds to S113. In the process of S113, the control unit 15 determines whether the value of the counter C is greater than the value X2 of the predetermined range "X1 to X2." If it is determined in S113 that the value of the counter C is less than the value X2, the process returns to S106 in FIG.

[0039] 3, if it is determined that the value of counter C is greater than value X2, in other words, if it is determined that the time since the control unit 15 switched the power feeding coil 13 from charging to standby is outside the above-mentioned time range, the process proceeds to S114. Proceeding to S114 in this way means that the target device 12 that has moved away from the power feeding coil 13 has not approached the power feeding coil 13.

[0040] In the process of S114, the control unit 15 turns on the indicator 20 in green to notify the user that the power supply coil 13 is on standby. Furthermore, in the process of S114, the control unit 15 resets the value of the counter C to the initial value "0". Thereafter, the process returns to S102 in FIG. 2. In S108 of FIG. 3, it is determined that the value of the counter C is not within the predetermined range "X1 to X2" when the value of the counter C is less than the value X1 in the predetermined range "X1 to X2." In this case, the process proceeds to S112. Proceeding to S112 in this way means that the elapsed time t from when the power feeding coil 13 is switched from charging to standby to when it is switched back to charging is not within the above-mentioned time range. In the process of S112, the control unit 15 supplies power to the power feeding coil 13, thereby setting the power feeding coil 13 to charging. In addition, in the process of S112, the control unit 15 lights up the indicator 20 in orange to notify the user that the power feeding coil 13 is being charged. Furthermore, in the process of S112, the control unit 15 resets the value of the counter C to the initial value "0." Thereafter, the process returns to S104. According to the present embodiment described above in detail, the following effects can be obtained.

[0041] (1) In the above-described wireless charging device for vehicles 11, if noise is detected in the radio broadcast while the target device 12 is being charged, the user instructs the wireless charging device for vehicles 11 to change the frequency of the power supplied to the power feeding coil 13 as follows: Specifically, the user moves the target device 12, which is being charged, away from the power feeding coil 13 and then moves it closer to the power feeding coil 13 again. This causes the control unit 15 to switch the power feeding coil 13 from charging to standby, and then from standby to charging. When this state change occurs in the power feeding coil 13, in other words, when the user moves the target device 12 to cause the state change, the frequency of the power supplied to the power feeding coil 13 is changed. Therefore, there is no need to provide the wireless charging device for vehicles 11 with an operating unit such as a switch for changing the frequency. This prevents the wireless charging device for vehicles 11 from becoming larger and the number of parts from increasing, which would be caused by providing an operating unit such as a switch in the wireless charging device for vehicles 11.

[0042] (2) The change in the frequency of the power supplied to the power feeding coil 13 is performed as follows. That is, if the frequency of the power supplied to the power feeding coil 13 is the first frequency f1, it is switched to the second frequency f2. Also, if the frequency of the power supplied to the power feeding coil 13 is the second frequency f2, it is switched to the first frequency f1. In this way, the frequency of the power supplied to the power feeding coil 13 is changed between the first frequency f1 and the second frequency f2, making the change easy.

[0043] (3) The user can instruct a change in the frequency of power supplied to the power feeding coil 13 by moving the target device 12 closer or farther away from the power feeding coil 13 so that the elapsed time t falls within the above-mentioned time range. On the other hand, if the user's operation of moving the target device 12 closer or farther away from the power feeding coil 13 is not intended to instruct a change in the frequency, the elapsed time t falls outside the above-mentioned time range, and therefore the frequency is not changed. This prevents the frequency from being changed unnecessarily.

[0044] (4) Because the time range is set to 0.5 seconds or more and 5 seconds or less, if the target device 12 being charged moves out of the chargeable position due to vehicle vibration and then returns to the chargeable position, the elapsed time t does not fall within the time range. This prevents the frequency of the power supplied to the power feeding coil 13 from being erroneously changed under the above-mentioned circumstances. It is also possible that a user may move the target device 12 away from the power feeding coil 13 to end charging midway, use the target device 12, and then move it back close to the power feeding coil 13 for charging. In this case, too, because the time range is set to 0.5 seconds or more and 5 seconds or less, it prevents the frequency of the power supplied to the power feeding coil 13 from being erroneously changed.

[0045] (5) When the control unit 15 switches the power feeding coil 13 from charging to standby, the indicator 20 notifies the user of this. Specifically, the indicator 20 flashes green to notify the user that the power feeding coil 13 has switched from charging to standby. This prompts the user to move the target device 12 closer to the power feeding coil 13 again in order to change the frequency of the power supplied to the target device 12.

[0046] The above embodiment can be modified as follows, for example: The above embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. Although the indicator 20 that provides a visual notification is provided as the notification unit, it is also possible to provide a buzzer or speaker that provides an auditory notification instead of or in addition to the indicator 20.

[0047] The detection unit 19 may be omitted by providing the control unit 15 with the function of the detection unit 19. The above time range can be changed as needed. For example, the time range may be changed to 0.5 to 3 seconds.

[0048] The first frequency f1 may be a frequency other than 127.7 kHz. The second frequency f2 may be a frequency other than 120.5 kHz. The frequency of the power supplied to the power feeding coil 13 is changed between two frequencies, the first frequency f1 and the second frequency f2, but may be changed between three or more frequencies.

[0049] The device to be charged 12 is not limited to a smartphone, and may be other devices. [Explanation of symbols]

[0050] 11... Wireless charging device for vehicles 12. Devices to be charged 13...Power supply coil 14...Receiving coil 15...Control unit 16…Power circuit 17...DC-DC converter 18...Coil driver 19...Detection unit 20...Indicator

Claims

1. a control unit that starts and stops supplying power to a power feeding coil, and when a device to be charged approaches the power feeding coil to a position where the device can be charged, a voltage is induced in the power receiving coil of the device to be charged through the power supply from the power receiving coil by the control unit; the control unit supplies power to the power feeding coil when the device to be charged approaches the power feeding coil to a position where the device can be charged, and stops supplying power to the power feeding coil when the device to be charged moves away from the position where the device can be charged, thereby putting the power feeding coil into a standby state; the control unit changes the frequency of the power supplied to the power supply coil when the power supply coil is switched from the charging state to the standby state and then switched from the standby state to the charging state.

2. 2. The wireless charging device for a vehicle according to claim 1, wherein the control unit is capable of switching the frequency of the power supplied to the power supply coil between a first frequency and a second frequency; and when the power supply coil is switched from the charging state to the standby state and then from the standby state to the charging state, if the frequency of the power supplied to the power supply coil is the first frequency, the control unit switches the frequency of the power supplied to the power supply coil to the second frequency, and if the frequency of the power supplied to the power supply coil is the second frequency, the control unit switches the frequency of the power supplied to the power supply coil to the first frequency.

3. 3. The wireless charging device for a vehicle according to claim 1, wherein the control unit measures an elapsed time from when the power supply coil is switched from the charging state to the standby state until when the power supply coil is switched back to the charging state, and changes the frequency of the power supplied to the power supply coil only when the elapsed time is within a predetermined time range.

4. The wireless charging device for a vehicle according to claim 3 , wherein the time range is from 0.5 seconds to 5 seconds.

5. 3. The wireless charging device for a vehicle according to claim 1, further comprising a notification unit that notifies a user when the control unit has switched the power supply coil from charging to standby.

Images