JP2013172497A - Non-contact power reception device, non-contact power transmission system, and non-contact power reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power reception device which can control decline in the charging efficiency of a battery.SOLUTION: A non-contact power reception device 20 according to an embodiment of the invention obtains power without contact from a non-contact power supply device 10. The non-contact power reception device 20 comprises: a radio communication unit 29 for searching for the non-contact power supply device 10 by use of radio communication; a power reception coil 21 for obtaining power by use of electromagnetic coupling from the non-contact power supply device 10 searched for by the radio communication unit 29; and a rectifier unit 22 for rectifying alternating-current power from the power reception coil 21 and generating direct-current voltage to charge a power storage device 23. It searches for the non-contact power supply device 10 by use of the radio communication unit 29 in the case where a charging rate to the full charging of the power storage device 23 is at or below a first prescribed rate.

Description

  The present invention relates to a non-contact power receiving apparatus, a non-contact power transmission system, and a non-contact power receiving method for performing non-contact power transmission.

  As environmentally friendly vehicles, electric vehicles such as electric vehicles and hybrid vehicles have been put into practical use. In an electric vehicle, an in-vehicle power storage device (for example, a battery) can be charged from a power source (for example, a power outlet) outside the vehicle. For example, charging is performed by connecting a power outlet provided at home or a common facility to a charging port provided in the vehicle with a charging cable. On the other hand, plug-in hybrid vehicles that enable charging of an in-vehicle power storage device from a power source outside the vehicle have also been put to practical use.

  Incidentally, in recent years, non-contact power feeding without using a cable has attracted attention as a power feeding method from the outside of the vehicle to the vehicle. As a non-contact power feeding method, for example, a method using electromagnetic coupling (a method using electromagnetic induction, a method using electromagnetic waves, a resonance method, etc.) has been studied. Patent Document 1 discloses a contactless power feeding system using a resonance method.

  In the resonance method, the positional deviation (distance) between the power transmitting side resonator (self-resonant coil) and the power receiving side resonator (self-resonant coil) affects the transmission efficiency. In order to improve the transmission efficiency, communication between the power transmission side (infrastructure side) and the power reception side (vehicle side) is performed by the driver's parking operation, so that the resonator on the power transmission side and the resonator on the power reception side are connected. Need to align.

International Publication No. 2011/001524 Pamphlet

  By the way, in the non-contact power feeding system disclosed in Patent Document 1, when the vehicle is parked, a power feeding flow is automatically started. However, the battery of the parked vehicle may be in a fully charged state or nearly in a fully charged state. If power is automatically supplied even in such a battery state, power is supplied with low power, and the battery There was a problem of poor charging efficiency.

  Therefore, an object of the present invention is to provide a non-contact power receiving apparatus, a non-contact power transmission system, and a non-contact power receiving method that can suppress a decrease in battery charging efficiency.

  The non-contact power receiving device of the present invention acquires power in a non-contact manner from a non-contact power feeding device. This non-contact power receiving device uses a wireless communication unit that searches for a non-contact power supply device using wireless communication and a non-contact power supply device searched by the wireless communication unit to acquire power using electromagnetic coupling. And a rectifier unit that rectifies AC power from the power receiving coil and generates a DC voltage for charging the power storage device, and a charging rate with respect to a full charge of the power storage device is equal to or less than a first predetermined rate. In some cases, the wireless communication unit searches for the non-contact power feeding device.

  The non-contact power receiving method of the present invention acquires power in a non-contact manner from a non-contact power feeding device. In the non-contact power receiving method, when the charging rate with respect to the full charge of the power storage device is equal to or less than the first predetermined rate, the wireless communication unit searches for the non-contact power feeding device using wireless communication, and the wireless communication unit The power is acquired from the contactless power supply device searched for by using the electromagnetic coupling by the power receiving coil, the AC power from the power receiving coil is rectified by the rectifier unit, and the power storage device is charged.

  According to the non-contact power receiving device and the non-contact power receiving method, the wireless communication unit searches for the non-contact power feeding device when the charging rate with respect to the full charge of the power storage device is equal to or less than the first predetermined rate. That is, when the power storage device is in a fully charged state or nearly in a fully charged state, the search for the non-contact power supply device is not performed, that is, the battery is not charged, thereby suppressing the decrease in the charging efficiency of the battery. it can.

  In the non-contact power receiving device described above, when the voltage of the power storage device that correlates with the charging rate with respect to the full charge of the power storage device is equal to or lower than the first predetermined value that correlates with the first predetermined rate, the non-contact by the wireless communication unit It is preferable to search for a power feeding device. Further, the non-contact power receiving device described above is further provided with a rectifier relay that is disposed between the rectifier unit and the power storage device, and forms a charging path from the rectifier unit to the power storage device, and the rectifier relay is turned on. Thus, it is preferable to obtain the voltage of the power storage device.

  According to this, it is possible to easily determine whether or not the power storage device is in a fully charged state or a state close to full charge using the charging path from the rectifier unit to the power storage device.

  In the non-contact power receiving apparatus described above, when power is acquired from the non-contact power supply apparatus, when the charging ratio with respect to the full charge of the power storage apparatus reaches the second predetermined ratio, the charging of the power storage apparatus is stopped. It is preferable that the second predetermined ratio is greater than or equal to the first predetermined ratio.

  In addition, the non-contact power transmission system of the present invention performs power transmission in a non-contact manner from a non-contact power feeding device to a non-contact power receiving device. The non-contact power supply device supplies power to the non-contact power receiving device using electromagnetic coupling according to the wireless communication by the power supply wireless communication unit that performs wireless communication with the non-contact power receiving device and the wireless communication by the power supply wireless communication unit. And a feeding coil. On the other hand, a non-contact power receiving device uses electromagnetic coupling from a power receiving wireless communication unit that searches for a non-contact power feeding device using wireless communication and a non-contact power feeding device searched by the power receiving wireless communication unit. A power receiving coil for performing power acquisition and a rectifier unit that rectifies AC power from the power receiving coil and generates a DC voltage for charging the power storage device. In this non-contact power receiving device, when the charging rate with respect to the full charge of the power storage device is equal to or less than the first predetermined rate, the wireless communication unit for power reception searches for the non-contact power feeding device.

  According to this non-contact power transmission system, since the same non-contact power receiving apparatus as described above is provided, it is possible to suppress a decrease in charging efficiency of the battery.

  According to the present invention, it is possible to suppress a decrease in charging efficiency of a battery.

It is a schematic diagram which shows the structure of the electric power system of the non-contact electric power transmission system which concerns on one Embodiment of this invention. It is a circuit block diagram which shows the electric power and control system of the non-contact electric power transmission system which concern on one Embodiment of this invention. It is a flowchart which shows operation | movement of the non-contact electric power supply apparatus of this embodiment shown in FIG. It is a flowchart which shows operation | movement of the vehicle (non-contact power receiving apparatus) of this embodiment shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a schematic diagram illustrating a configuration of a power system of a contactless power transmission system according to an embodiment of the present invention, and FIG. 2 illustrates power and control of the contactless power transmission system according to an embodiment of the present invention. It is a circuit block diagram which shows a system | strain. A non-contact power transmission system 100 shown in FIGS. 1 and 2 includes a non-contact power feeding apparatus 10 provided in a charging parking space at home or a common facility (for example, a gas station), and an electric vehicle such as an electric vehicle or a hybrid vehicle ( A non-contact power receiving device) 20 for power transmission from the non-contact power feeding device 10 to the vehicle 20 in a non-contact manner.

  The non-contact power feeding device 10 includes an inverter unit 11, a power feeding coil unit 12, a wireless communication unit 13, and a parking detection sensor 14. On the other hand, the vehicle 20 includes a power receiving coil unit 21, a rectifier unit 22, a driving battery (power storage device) 23, a rectifier relay 24, a battery monitoring unit 25, a power management ECU (Electronic Control Unit) 26, and power feeding. A control ECU (Electronic Control Unit) 27, a power supply start switch 28, and a wireless communication unit 29 are provided.

  First, in the non-contact power supply apparatus 10, the inverter unit 11 has an inverter, and converts a system power supply (commercial power supply) from an electric power company into high-frequency power. The inverter unit 11 supplies this high frequency power (high frequency current) to the feeding coil unit 12.

  The power feeding coil unit 12 has a power feeding coil, and uses the electromagnetic induction action between the power feeding coil and the power receiving coil in the power receiving coil unit 21 to supply power supplied from the inverter unit 11 to the power receiving coil unit 21 in a non-contact manner. Supply. For example, the feeding coil unit 12 is provided on the floor surface of the charging parking space.

  The wireless communication unit 13 communicates wirelessly with the wireless communication unit 29 in the vehicle 20, and transmits and receives various types of information between the contactless power supply device 10 and the vehicle 20. Information transmitted from the non-contact power supply apparatus 10 to the vehicle 20 includes a connection response, precharge OK / NG, a power supply stop request, which will be described later, and information transmitted from the vehicle 20 to the non-contact power supply apparatus 10 will be described later. The connection request, the precharge request, the output power (current) of the rectifier unit 22, the state of charge of the battery, the power supply stop request, and the like. In the present embodiment, the wireless communication unit 13 is mounted on the inverter unit 11.

  The parking detection sensor 14 detects whether or not the vehicle 20 is parked in the charging parking space, and activates the wireless communication unit 13 when the vehicle 20 is parked (set to an on state). On the other hand, the parking detection sensor 14 stops the wireless communication unit 13 when the vehicle 20 leaves the charging parking space (sets to an off state). Various sensors such as a load sensor, an ultrasonic sensor, and an infrared sensor can be applied as the parking detection sensor 14.

  Next, in the vehicle 20, the power receiving coil unit 21 has a power receiving coil, and acquires AC power from the power feeding coil unit 12 in a non-contact manner using the electromagnetic induction action as described above. For example, the power receiving coil unit 21 is provided on the bottom surface of the vehicle body.

  The rectifier unit 22 rectifies the AC power acquired by the power receiving coil unit 21 and converts it into DC power. Moreover, the rectifier unit 22 has a DC / DC converter, and raises / lowers the rectified DC power to the battery voltage equivalent. Further, the rectifier unit 22 has a voltage sensor, and by monitoring the voltage of the drive battery 23 via the rectifier relay 24, the drive battery 23 is in a fully charged state or a state close to full charge. Whether or not there is can be monitored. The rectifier unit 22 is connected to the drive battery 23 via the rectifier relay 24.

  The driving battery 23 is a DC power source that can be recharged by a DC voltage from the rectifier unit 22. For example, as the driving battery 23, a secondary battery such as lithium ion or nickel metal hydride can be applied.

  The rectifier relay 24 connects the rectifier unit 22 to the drive battery 23 when charging. When charging is not performed, the rectifier relay 24 releases the connection between the rectifier unit 22 and the drive battery 23.

  The battery monitoring unit 25 monitors the state of the driving battery 23 for each cell, and transmits a battery state in which the state of each cell is integrated to the power management ECU 26. For example, the battery monitoring unit 25 monitors the balance of the charging state of each cell, or performs abnormality detection for each cell (fail safe). In the present embodiment, the battery monitoring unit 25 is mounted on the driving battery 23.

  The power management ECU 26 manages the state of the drive battery 23 during power feeding and during travel. The state of the driving battery 23 includes SOC (State Of Charge), voltage, current, temperature, and the like.

  The power supply control ECU 27 performs overall control when power is supplied from the non-contact power supply apparatus 10 to the vehicle 20. For example, when the power supply control ECU 27 supplies power to the vehicle 20 from the non-contact power supply device 10, the rectifier relay 24 is turned on so that the drive battery 23 can be charged by the rectifier unit 22, and the output adjustment of the rectifier unit 22 is adjusted. Do. On the other hand, when power is not supplied from the non-contact power supply apparatus 10 to the vehicle 20, the power supply control ECU 27 turns off the rectifier relay 24 and disconnects the drive battery 23 from the rectifier unit 22. The power supply control ECU 27 performs activation control of the power management ECU 26 and the wireless communication unit 29 when the vehicle 20 is parked in the parking space, and the power management ECU 26 and the wireless communication unit when the vehicle 20 is parked from the parking space. 29 stop control is performed. Note that the rectifier unit 22, the power management ECU 26, and the wireless communication unit 29 and the power supply control ECU 27 are connected by, for example, a CAN (Controller Area Network).

  Further, the power supply control ECU 27 turns on the rectifier relay 24 in accordance with the operation of the power supply start switch 28 by the user, and enables the drive battery 23 to be charged by the rectifier unit 22 described above.

  The wireless communication unit 29 wirelessly communicates with the wireless communication unit 13 in the contactless power supply device 10 and transmits and receives the various types of information described above between the vehicle 20 and the contactless power supply device 10. In the present embodiment, the wireless communication unit 29 is mounted on the rectifier unit 22.

  Next, a non-contact power receiving method from the non-contact power feeding device 10 to the vehicle (non-contact power receiving device) 20 will be described. FIG. 3 is a flowchart showing the operation of the non-contact power feeding apparatus 10, and FIG. 4 is a flowchart showing the operation of the vehicle 20.

  First, as shown in FIG. 3, on the non-contact power feeding apparatus 10 side, the presence or absence of a parked vehicle is detected by the parking detection sensor 14 continuously or intermittently (S101). At this time, the wireless communication unit 13 that requires power for operation is in a stopped state.

  On the other hand, as shown in FIG. 4, on the vehicle 20 side, the power supply control ECU 27 continuously or intermittently monitors whether or not the vehicle is parked in the parking space (S201). At this time, the power management ECU 26 and the wireless communication unit 29 that require power for operation are in a stopped state. For example, the power supply control ECU 27 determines the completion of parking by a gear parking operation.

  When parking is completed, the charging ratio with respect to the full charge of the battery is monitored, and it is determined whether or not charging is performed according to the charging ratio. For example, when the charging rate is equal to or less than a predetermined value (for example, 80% of the fully charged state: the first predetermined rate), a search on the power feeding side is started for charging, and the charging rate is greater than the predetermined value. Determines that it is in a fully charged state or a state close to full charging, and does not search for the power supply side.

  Specifically, the power supply control ECU 27 turns on the rectifier relay (S202), and the rectifier unit 22 monitors the battery voltage correlated with the charging ratio with respect to the full charge (S203). When the battery voltage is equal to or lower than a predetermined value (for example, a voltage value of 80% of the voltage in the fully charged state: a first predetermined value correlated with the first predetermined ratio), the power supply control ECU 27 performs the wireless communication unit 29. And the wireless communication unit 29 starts searching for a communication device on the non-contact power feeding apparatus 10 side (S204). The power supply control ECU 27 also activates the power management ECU 26. If the battery voltage is greater than the predetermined value, it is determined that the battery is in a fully charged state or a state close to full charging, and the process proceeds to step S212 described later.

  On the other hand, as shown in FIG. 3, on the non-contact power feeding apparatus 10 side, the parking detection sensor 14 detects the vehicle 20 parked in the charging parking space, activates the wireless communication unit 13, and enables the wireless function. (S102).

  Then, as shown in FIG. 4, on the vehicle 20 side, the wireless communication unit 29 recognizes the wireless communication unit 13 of the non-contact power feeding apparatus 10 (S205) and transmits a connection request (S206). If no wireless device is found, the process proceeds to step S212 described later.

  When the connection request is transmitted from the vehicle 20 side, as shown in FIG. 3, the wireless communication unit 13 recognizes the connection request on the non-contact power supply apparatus 10 side (S103) and transmits a connection response (S104). . If there is no connection request, the connection request is waited until a predetermined time has elapsed since the detection of the parked vehicle. When the predetermined time has elapsed, it is determined that the parked vehicle has no intention to charge, and the process proceeds to step S115 described later. (S105).

  When a connection response is transmitted from the non-contact power supply apparatus 10 side, as shown in FIG. 4, the vehicle 20 side recognizes the connection response by the wireless communication unit 29 (S207), and transmits a precharge request (S208). ). When there is no connection response, the process proceeds to step S212 described later.

  When the precharge request is transmitted from the vehicle 20 side, as shown in FIG. 3, the wireless communication unit 13 recognizes the precharge request on the non-contact power supply device 10 side (S106), and the inverter unit 11 and the power supply coil unit. 12 starts precharge output (S107). If there is no precharge request, it waits for a precharge request until a predetermined time elapses from the detection of the connection request, and when a predetermined time elapses from the detection of the connection request, it is determined that the parked vehicle has no intention of charging, The process proceeds to step S115 described later (S108).

  Here, precharging is a test of the power supply environment (for example, whether or not the positions of the feeding coil and the receiving coil are appropriate) prior to full-scale power supply. To do.

  During precharging, on the non-contact power feeding device 10 side, the wireless communication unit 13 acquires the output power (current) information of the rectifier unit 22 from the vehicle 20 side, and the output power (current) of the rectifier unit 22 is greater than or equal to a predetermined value. It is determined whether or not there is (S109). When the output power (current) of the rectifier unit 22 is greater than or equal to a predetermined value, the wireless communication unit 13 notifies the vehicle 20 side of precharge OK (S110). On the other hand, when the output power (current) of the rectifier unit 22 is less than the predetermined value, the wireless communication unit 13 notifies the vehicle 20 side of precharge NG (S112), and the process proceeds to step S114 described later.

  In the case of precharge NG, the parking position adjustment is notified to the user, the position of the power receiving coil on the vehicle 20 side with respect to the power feeding coil on the non-contact power feeding device 10 side is adjusted, and the above operation is performed again.

  When the precharge OK is notified from the non-contact power supply apparatus 10 side, as shown in FIG. 4, the vehicle 20 side recognizes the precharge OK by the wireless communication unit 29 (S209) and waits for the main charge. On the other hand, when the precharge NG is recognized by the wireless communication unit 29, the process proceeds to step S211 described later.

  Returning to FIG. 3, after notification of precharge OK, the non-contact power supply apparatus 10 starts full-scale power supply (S111). During power feeding, on the non-contact power feeding apparatus 10 side, the wireless communication unit 13 acquires information on the battery charge state from the vehicle 20 side, and continuously or intermittently monitors the battery charge state. On the non-contact power supply apparatus 10 side, the wireless communication unit 13 monitors the power supply stop request from the vehicle 20 side continuously or intermittently (S113). When the battery reaches a fully charged state or a state close to full charging, for example, the charging rate with respect to the full charging of the battery is a predetermined value (for example, the same as the first predetermined rate described above, or the first More specifically, the battery voltage correlated with the charging ratio with respect to the full charge is equal to or lower than the predetermined value (the same as the first predetermined value described above or the first predetermined value). The second predetermined value larger than the predetermined value, which is equal to or less than the second predetermined value correlated with the second predetermined ratio), it is determined that charging is complete, and the power supply output is stopped (S114). The connection is released (S115). If a request for stopping power supply is received, it is determined that the vehicle 20 has no intention to charge due to some problem, power supply output is stopped (S114), and connection is released (S115).

  On the other hand, referring to FIG. 4, during power feeding, on the vehicle 20 side, the wireless communication unit 13 continuously or intermittently monitors a request to stop power feeding from the non-contact power feeding device 10 side (S210). When a request for stopping power supply is received, it is determined that the non-contact power supply apparatus 10 cannot supply power due to some problem, and the connection is released (S211).

  Thereafter, on the vehicle 20 side, the rectifier relay 24 is turned off by the power supply control ECU 27 (S212). Thereafter, on the vehicle 20 side, the operation of the power supply start switch 28 by the user, that is, the presence or absence of the user's power supply request is continuously or intermittently monitored. If there is a power supply request, the process returns to step S201 and the above operation is performed. Again. On the vehicle 20 side, parking cancellation is monitored continuously or intermittently, and when the vehicle leaves the parking space, the process returns to step S201 (S213).

  On the other hand, returning to FIG. 3, the wireless communication unit 13 is stopped and the wireless function is disabled on the non-contact power supply apparatus 10 side after the end of power supply (S116). Thereafter, the parking detection sensor 14 monitors the departure of the parked vehicle continuously or intermittently (S117), and when the parked vehicle leaves the vehicle, the process returns to step S101.

  Here, in the charging of the driving battery 23, two types of modes, that is, a constant current (CC) mode and a constant voltage (CV) mode are used, and are in a fully charged state or close to a full charge. In the state, the constant voltage mode is used. As a result, in a fully charged state or a state close to full charging, the current is limited and charging is performed with low power. At this time, since the output current of the inverter unit 11 on the power supply side is limited, the efficiency of the inverter unit 11 is lowered, and as a result, the charging efficiency of the driving battery 23 is deteriorated.

  However, according to the vehicle (non-contact power reception device) 20 and the non-contact power reception method of the present embodiment, the voltage of the drive battery 23 (correlation with the charge ratio with respect to full charge) correlates with the predetermined value (first predetermined ratio). If it is equal to or less than the first predetermined value), the wireless communication unit 29 searches for the non-contact power feeding device 10. That is, when the driving battery 23 is in a fully charged state or a state close to full charging, the contactless power supply device 10 is not searched, that is, the driving battery 23 is not charged. Can be suppressed.

  Further, according to the non-contact power receiving device 20 and the non-contact power receiving method of the present embodiment, when the driving battery 23 is in a fully charged state or a state close to full charging, that is, power supply from the non-contact power supply device 10. Is not transmitted or received by the wireless communication unit 29 and the wireless communication unit 13 for supplying power from the contactless power supply device 10 to the vehicle 20, so the contactless power supply device 10 and the vehicle 20 are not transmitted. Power consumption can be reduced.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in this embodiment, the battery voltage is exemplified as a parameter that correlates with the charging rate with respect to the full charge of the battery, but other parameters that correlate with the charging rate with respect to the full charge of the battery can be used instead of the battery voltage. It is. In this case, instead of the voltage sensor, the rectifier unit 22 has a sensor that monitors another parameter that correlates with the charging rate with respect to the full charge of the battery.

  Further, in the present embodiment, the fully correlated state or the state close to the fully charged state is determined by using the parameter correlated with the charging rate with respect to the fully charged state as it is, but the charging rate is calculated from this parameter, and the calculated charging rate is calculated. It may be used to determine a full charge state or a state close to full charge.

  In the present embodiment, the first predetermined value may be set by the user. Some users feel annoying that charging is performed automatically every time they park, but this annoyance can be alleviated.

  Further, in the present embodiment, during the precharge, the output power (current) information of the rectifier unit 22 is transmitted from the vehicle 20 side to the contactless power supply device 10 side, and the precharge OK or the Although the NG determination is made, the precharge OK or NG determination may be made on the vehicle 20 side. In this case, precharge output power (current) information is transmitted from the non-contact power feeding apparatus 10 side to the vehicle 20 side.

  In the present embodiment, the battery charge state information is transmitted from the vehicle 20 side to the non-contact power supply device 10 side, and the full charge state of the battery is determined on the non-contact power supply device 10 side. The battery may be fully charged.

  Moreover, in this embodiment, although the form which carries out pressure | voltage rise / fall to battery voltage equivalent was illustrated in the rectifier unit 22 by the side of the vehicle 20, it is not limited to this. For example, you may raise / lower pressure in the inverter unit 11 by the side of the non-contact electric power feeder 10. FIG.

  In the present embodiment, the power feeding coil unit 12 and the power receiving coil unit 21 each have a coil, and the power transmission is performed in a non-contact manner using electromagnetic induction, but the feature of the present invention is that The coil unit 12 and the power receiving coil unit 21 each have a resonance circuit composed of a coil and a capacitor, and can be applied to a form in which electric power is transmitted in a contactless manner using a resonance method.

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power feeder, 11 ... Inverter unit, 12 ... Power feeding coil unit (power feeding coil), 13 ... Wireless communication part (wireless communication part for electric power feeding), 14 ... Parking detection sensor, 20 ... Vehicle, 21 ... Power receiving coil unit (Power receiving coil), 22 ... rectifier unit, 23 ... drive battery (power storage device), 24 ... rectifier relay, 25 ... battery monitoring unit, 26 ... power management ECU, 27 ... feed control ECU, 28 ... feed start switch, 29 ... wireless communication part (power receiving wireless communication part), 100 ... non-contact power transmission system.

Claims (6)

A non-contact power receiving device that performs non-contact power acquisition from a non-contact power feeding device,
A wireless communication unit that searches for the non-contact power supply device using wireless communication;
From the non-contact power feeding device searched by the wireless communication unit, a power receiving coil for obtaining power using electromagnetic coupling,
A rectifier unit that rectifies AC power from the power receiving coil and generates a DC voltage for charging the power storage device;
With
When the charging rate with respect to the full charge of the power storage device is equal to or less than a first predetermined rate, the wireless communication unit searches for the non-contact power feeding device.
Non-contact power receiving device. When the voltage of the power storage device that correlates with the charging ratio with respect to the full charge of the power storage device is equal to or lower than a first predetermined value that correlates with the first predetermined ratio, Search,
The non-contact power receiving device according to claim 1. Further comprising a rectifier relay disposed between the rectifier unit and the power storage device to form a charging path from the rectifier unit to the power storage device;
By turning on the rectifier relay, the voltage of the power storage device is obtained.
The non-contact power receiving device according to claim 2. When acquiring power from the non-contact power supply device, if the charging rate with respect to the full charge of the power storage device reaches a second predetermined rate, the charging of the power storage device is stopped,
The second predetermined ratio is greater than or equal to the first predetermined ratio;
The non-contact power receiving device according to claim 1. A non-contact power transmission system that performs non-contact power transmission from a non-contact power feeding device to a non-contact power receiving device,
The non-contact power feeding device is:
A wireless communication unit for feeding that performs wireless communication with the non-contact power receiving device;
In accordance with wireless communication by the wireless communication unit for power supply, a power supply coil for supplying power to the non-contact power receiving device using electromagnetic coupling,
With
The non-contact power receiving device is:
A power receiving wireless communication unit that searches for the non-contact power supply device using wireless communication;
From the non-contact power feeding device searched by the power receiving wireless communication unit, a power receiving coil for acquiring power using electromagnetic coupling,
A rectifier unit that rectifies AC power from the power receiving coil and generates a DC voltage for charging the power storage device;
With
In the non-contact power receiving device, when the charging ratio with respect to the full charge of the power storage device is equal to or less than a first predetermined ratio, the wireless communication unit for power reception searches for the non-contact power feeding device.
Non-contact power transmission system. A non-contact power receiving method for acquiring power in a non-contact manner from a non-contact power supply device,
When the charging rate with respect to the full charge of the power storage device is equal to or less than the first predetermined rate, the wireless communication unit searches for the non-contact power supply device using wireless communication,
From the non-contact power feeding device searched by the wireless communication unit, by using a power receiving coil, obtain power using electromagnetic coupling,
The rectifier unit rectifies AC power from the power receiving coil and charges the power storage device.
Non-contact power receiving method.

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