JP2015061425A - Power reception equipment and non-contact power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide power reception equipment and a non-contact power transmission device, including an impedance converter unit having an inductor, capable of suppressing an excessive temperature rise of the inductor.SOLUTION: Power reception equipment 21 includes: a second impedance converter 32 having second inductors 32a, 32b; a temperature sensor 40 for measuring the temperatures of the second inductors 32a, 32b; and a DC/DC converter 25, disposed between the second impedance converter 32 and a vehicle battery 22, for performing, when each temperature of the second inductors 32a, 32b becomes higher than a threshold temperature, impedance adjustment in a manner to reduce each current value flowing through the second inductors 32a, 32b.

Description

  The present invention relates to a power receiving device and a non-contact power transmission apparatus.

  As a non-contact power transmission device that does not use a power cord or a power transmission cable, for example, a power transmission device having a primary coil to which AC power is input and a secondary side that can receive AC power in a non-contact manner from the primary coil What is provided with the power receiving apparatus which has a coil is known (for example, refer patent document 1). In such a non-contact power transmission device, AC power is transmitted from a power transmitting device to a power receiving device in a non-contact manner, for example, by magnetic resonance between the primary side coil and the secondary side coil.

JP 2009-106136 A

  The power receiving device and the non-contact power transmission apparatus as described above may include an impedance conversion unit that converts to a desired impedance from the viewpoint of improving transmission efficiency. For example, an LC circuit having an inductor and a capacitor may be used as the impedance converter. In this case, the present inventors find that the temperature of the inductor of the impedance conversion unit tends to be high depending on the use environment and the like, and an excessive current flows due to the temperature of the inductor becoming high. I found out.

  An object of the present invention has been made in view of the above-described circumstances, and provides a power receiving device and a non-contact power transmission device that can suppress an excessive temperature rise of the inductor in the case of including an impedance conversion unit having an inductor. It is to be.

  A power receiving device that achieves the above object is capable of receiving the AC power in a non-contact manner from a power transmission device having a primary coil to which AC power is input, and the AC power in a non-contact manner from the primary coil. A secondary coil capable of receiving power; a load; and an impedance converter provided between the secondary coil and the load, wherein the impedance converter includes at least an inductor; A measurement unit that measures a physical quantity related to temperature, and is provided between the impedance conversion unit and the load. When the physical quantity becomes larger than a predetermined threshold value, a current value flowing through the inductor is reduced. And an adjustment unit for adjusting impedance.

  According to this configuration, when the physical quantity related to temperature becomes larger than the threshold value, the adjustment unit adjusts the impedance so that the value of the current flowing through the inductor becomes small. Thereby, the heat generation of the inductor can be suppressed. Therefore, an excessive temperature rise of the inductor can be suppressed.

  The power receiving device includes a rectifying unit that rectifies AC power received by the secondary coil, and the impedance conversion unit is provided between the secondary coil and the rectifying unit, and the adjustment The unit is a DC / DC converter that is provided between the rectifying unit and the load and has a switching element that is periodically turned on and off, and the power receiving device has the physical quantity larger than the threshold value. In this case, it is preferable to provide a duty ratio control unit that controls the on / off duty ratio of the switching element so as to increase the impedance from the input terminal of the DC / DC converter to the load. According to such a configuration, when the physical quantity becomes larger than the threshold value, the on / off duty ratio of the switching element is controlled so that the impedance from the input end of the DC / DC converter to the load is increased. As a result, the value of the current flowing through the inductor is reduced, so that the heat generation of the inductor can be suppressed. Therefore, an excessive temperature rise of the inductor can be suppressed.

  A non-contact power transmission device that achieves the above object is capable of receiving AC power in a non-contact manner from an AC power source capable of outputting AC power, a primary coil to which the AC power is input, and the primary coil. A secondary coil, a load, and an impedance converter provided between the output terminal of the AC power source and the load, and an impedance converter having at least an inductor, and a physical quantity related to the temperature of the inductor Impedance adjustment is performed between the impedance measuring unit and the load, and the current value flowing through the inductor is reduced when the physical quantity exceeds a predetermined threshold. And an adjustment unit that performs the above.

  According to this configuration, when the physical quantity related to temperature becomes larger than the threshold value, the adjustment unit adjusts the impedance so that the value of the current flowing through the inductor becomes small. Thereby, the heat generation of the inductor can be suppressed. Therefore, an excessive temperature rise of the inductor can be suppressed.

  The non-contact power transmission device includes a rectifier that rectifies AC power received by the secondary coil, and the impedance converter is provided between the secondary coil and the rectifier. The adjustment unit is a DC / DC converter that is provided between the rectification unit and the load and has a switching element that is periodically turned on and off. A duty ratio control unit that controls the on / off duty ratio of the switching element so as to increase the impedance from the input terminal of the DC / DC converter to the load when the threshold value is greater than a threshold value may be provided. According to such a configuration, when the physical quantity becomes larger than the threshold value, the on / off duty ratio of the switching element is controlled so that the impedance from the input end of the DC / DC converter to the load is increased. As a result, the value of the current flowing through the inductor is reduced, so that the heat generation of the inductor can be suppressed. Therefore, an excessive temperature rise of the inductor can be suppressed.

  About the said non-contact electric power transmission apparatus, after the impedance adjustment by the said adjustment part is performed, the power supply control part which stops the said alternating current power output from the said alternating current power supply or makes the electric power value of the said alternating current power small is provided. It is good to be. According to this configuration, after the impedance is adjusted by the adjustment unit, the AC power output from the AC power supply is stopped or the power value of the AC power is reduced. Thereby, the value of the current flowing through the inductor can be further reduced. Further, even when the reflected wave power or the like is generated due to the impedance adjustment performed by the adjustment unit, the power value of the reflected wave power is reduced. Therefore, it is possible to suppress inconvenience that may occur due to the adjustment of the impedance by the adjustment unit, that is, the burden on the AC power source and the like.

  A non-contact power transmission device that achieves the above object is capable of receiving AC power in a non-contact manner from an AC power source capable of outputting AC power, a primary coil to which the AC power is input, and the primary coil. A secondary coil, a load, and an impedance converter provided between the output terminal of the AC power supply and the load, and an impedance converter having at least an inductor, and measuring the temperature of the inductor And a power source for stopping the AC power output from the AC power source or reducing the power value of the AC power when the temperature of the inductor is higher than a predetermined threshold by the measuring unit. And a control unit.

  According to such a configuration, when the temperature of the inductor is higher than the threshold value, the AC power output from the AC power supply stops or the power value of the AC power decreases. As a result, the value of the current flowing through the inductor is reduced. Therefore, heat generation of the inductor can be suppressed, and an excessive temperature rise of the inductor can be suppressed.

  According to this invention, an excessive temperature rise of the inductor can be suppressed.

The block circuit diagram which shows the outline | summary of a receiving device and a non-contact electric power transmission apparatus. The flowchart which shows the temperature response process performed with a vehicle side controller.

Hereinafter, an embodiment in which a non-contact power transmission device (non-contact power transmission system), a power transmission device (power transmission device), and a power reception device (power reception device) are applied to a vehicle will be described.
As shown in FIG. 1, the non-contact power transmission device 10 includes a power transmission device 11 (ground side device, primary side device) and a power receiving device 21 (vehicle side device, secondary side device) capable of non-contact power transmission. It has. The power transmission device 11 is provided on the ground, and the power receiving device 21 is mounted on the vehicle.

  The power transmission device 11 includes an AC power supply 12 that can output AC power having a predetermined frequency. The AC power supply 12 is configured to be able to convert the system power into AC power and output the converted AC power when the system power is input from the system power supply as the infrastructure.

  Although the specific configuration of the AC power supply 12 is arbitrary, for example, an AC / DC conversion unit that converts system power into predetermined DC power, and DC power converted by the AC / DC conversion unit into the AC power described above. A DC / AC conversion unit for conversion may be provided. In this case, the DC / AC converter may be a class D amplifier, for example. In the present embodiment, the AC power source 12 is, for example, a voltage source.

  The AC power output from the AC power supply 12 is transmitted to the power receiving device 21 in a non-contact manner, and used for charging the vehicle battery 22 provided in the power receiving device 21. Specifically, the non-contact power transmission apparatus 10 performs power transmission between the power transmission device 11 and the power reception device 21, and includes a power transmitter 13 provided in the power transmission device 11 and a power receiver provided in the power reception device 21. 23.

  The power transmitter 13 and the power receiver 23 have the same configuration, and both are configured to be capable of magnetic field resonance. Specifically, the power transmitter 13 includes a resonance circuit including a primary coil 13a and a primary capacitor 13b connected in parallel. The power receiver 23 has a resonance circuit including a secondary coil 23a and a secondary capacitor 23b connected in parallel. Both resonance frequencies are set to be the same.

  According to such a configuration, when AC power is input to the power transmitter 13 (primary coil 13a) in a situation where the relative position between the power transmitter 13 and the power receiver 23 is in a position where magnetic resonance can occur, The power receiver 23 (secondary coil 23a) performs magnetic field resonance. As a result, the power receiver 23 receives a part of the energy of the power transmitter 13. That is, the power receiver 23 receives AC power from the power transmitter 13.

  Incidentally, the frequency of the AC power output from the AC power supply 12 is set corresponding to the resonance frequency of the power transmitter 13 and the power receiver 23 so that power transmission is possible between the power transmitter 13 and the power receiver 23. Yes. For example, the frequency of AC power is set to be the same as the resonance frequency of the power transmitter 13 and the power receiver 23. In addition, it is not restricted to this, The frequency of alternating current power and the resonant frequency of the power transmission device 13 and the power receiving device 23 may have shifted | deviated within the range which can be transmitted.

  The power receiving device 21 includes a rectifier 24 (rectifying unit) that rectifies AC power received by the power receiver 23, and a DC / DC converter 25 provided between the rectifier 24 and the vehicle battery 22. The DC / DC converter 25 receives DC power rectified by the rectifier 24, and performs voltage value conversion of the DC power. When the DC power whose voltage value has been converted by the DC / DC converter 25 is input to the vehicle battery 22, the vehicle battery 22 is charged. In the present embodiment, the vehicle battery 22 corresponds to a load, and the DC / DC converter 25 corresponds to an adjustment unit.

  The power transmission device 11 includes a power supply side controller 14 that controls the AC power supply 12 and the like. In addition, the power receiving device 21 includes a vehicle-side controller 26 configured to be capable of wireless communication with the power-side controller 14. The controllers 14 and 26 start or end power transmission through the exchange of information with each other.

  As shown in FIG. 1, the non-contact power transmission device 10 includes a plurality of impedance converters 31 and 32 (impedance conversion units) provided between the AC power supply 12 and the vehicle battery 22. Specifically, the non-contact power transmission apparatus 10 includes a first impedance converter 31 (first impedance converter) provided in the power transmission device 11 and a second impedance converter 32 (second second) provided in the power receiving device 21. Impedance conversion unit). The first impedance converter 31 is provided between the AC power supply 12 and the power transmitter 13, and the second impedance converter 32 is provided between the power receiver 23 and the rectifier 24.

  Each of the impedance converters 31 and 32 includes at least an inductor, and includes, for example, an LC circuit having an inductor and a capacitor. Specifically, the first impedance converter 31 is provided for the first inductors 31a and 31b provided on the two power lines EL11 and EL12 from the AC power supply 12 to the power transmitter 13, and the first inductors 31a and 31b. This is an LC circuit having a first capacitor 31c provided in a subsequent stage and connected in parallel to the first inductors 31a and 31b.

  The second impedance converter 32 is provided in the preceding stage with respect to the second inductors 32a and 32b provided on the two power lines EL21 and EL22 from the power receiver 23 to the vehicle battery 22, and the second inductors 32a and 32b. And an LC circuit having a second capacitor 32c connected in parallel to the second inductors 32a and 32b.

  Here, the present inventors have contributed to the transmission efficiency between the power transmitter 13 and the power receiver 23 by the real part of the impedance from the output end of the power receiver 23 (secondary coil 23a) to the vehicle battery 22. I found out. Specifically, it has been found that a specific resistance value Rout having relatively higher transmission efficiency than other resistance values exists in the real part of the impedance from the output terminal of the power receiver 23 to the vehicle battery 22. .

  Specifically, if a virtual load X is provided at the input end of the power transmitter 13, the resistance value of the virtual load X is Ra, and from the power receiver 23 (specifically, the output end of the power receiver 23) to the virtual load X. When the resistance value of Rb is Rb, the specific resistance value Rout is √ (Ra × Rb).

  Based on the above knowledge, the impedance of the second impedance converter 32 from the output end of the power receiver 23 to the vehicle battery 22 (impedance at the input end of the second impedance converter 32) approaches the specific resistance value Rout (preferably The impedance from the input terminal of the rectifier 24 to the vehicle battery 22 is converted.

  Here, the power value of the AC power output from the AC power supply 12 depends on the impedance from the output terminal of the AC power supply 12 to the vehicle battery 22 (impedance at the input terminal of the first impedance converter 31).

  In this configuration, in the first impedance converter 31, the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 approaches the specific resistance value Rout so that AC power having a desired power value is output from the AC power supply 12. The impedance Zin from the input end of the power transmitter 13 to the vehicle battery 22 in the situation is converted.

  For example, the power value of the output power of the AC power source 12 required for the power value of DC power input to the vehicle battery 22 to be a power value suitable for charging is defined as AC power having a power value suitable for charging. To do. The impedance from the output terminal of the AC power supply 12 for the output of AC power having a power value suitable for charging from the AC power supply 12 to the vehicle battery 22 is defined as an input impedance Zt suitable for charging. In this case, the first impedance converter 31 is connected to the input of the power transmitter 13 so that the impedance from the output terminal of the AC power supply 12 to the vehicle battery 22 approaches (preferably matches) the input impedance Zt suitable for the charging. Impedance conversion is performed on the impedance Zin from the end to the vehicle battery 22.

  In other words, the AC power supply 12 is configured to output AC power having a desired power value under the condition that the impedance from the output terminal of the AC power supply 12 to the vehicle battery 22 is the input impedance Zt suitable for the charging. It can be said that it is done. The specific resistance value Rout, the input impedance Zt suitable for charging, and the like correspond to the desired impedance.

  In the non-contact power transmission apparatus 10 configured as described above, the present inventors, in a situation where AC power is output from the AC power supply 12, depending on the usage environment, positional deviation of the coils 13a and 23a, and the like. It has been found that the temperatures of the inductors 31a, 31b, 32a and 32b of the impedance converters 31 and 32 tend to be high. In addition, when the temperature of the inductors 31a, 31b, 32a, and 32b becomes excessively high, the inventors greatly deviate from the design value, and as a result, the power lines EL11, EL12, EL21, and EL22 are excessively large. I found that the current flows.

  In particular, the present inventors have found that the temperature of the second inductors 32a and 32b of the second impedance converter 32 mounted on the vehicle tends to increase due to the mounting space. Specifically, the installation space of the second impedance converter 32 is likely to be smaller than the installation space of the first impedance converter 31 because of being mounted on the vehicle. For this reason, the second impedance converter 32 is more likely to accumulate heat than the first impedance converter 31, and as a result, the temperature of the second inductors 32a and 32b is likely to increase.

  On the other hand, the non-contact power transmission apparatus 10 of the present embodiment has a configuration for dealing with the heat generation of the inductors 31a, 31b, 32a, and 32b. The configuration will be described together with the detailed configuration of the DC / DC converter 25.

  As shown in FIG. 1, the power receiving device 21 includes a temperature sensor 40 that measures the temperature of each of the second inductors 32 a and 32 b of the second impedance converter 32 and transmits the measurement result to the vehicle-side controller 26. . Thereby, the vehicle side controller 26 can grasp | ascertain the temperature of each 2nd inductor 32a, 32b. The temperature sensor 40 corresponds to the measurement unit.

  Next, a detailed configuration of the DC / DC converter 25 will be described. As shown in FIG. 1, the DC / DC converter 25 includes, for example, a switching element 41 provided on one power line EL21 and a diode provided in a subsequent stage of the switching element 41 and connected in parallel to the switching element 41. 42. Further, the DC / DC converter 25 is a subsequent stage of the diode 42 and is provided with a coil 43 provided on one power line EL 21 and a subsequent stage of the coil 43 and a capacitor 44 connected in parallel to the coil 43. And. The switching element 41 is composed of, for example, an n-type power MOSFET.

  The drain of the switching element 41 is connected to the input end of the DC / DC converter 25, that is, the output end of the rectifier 24. The source of the switching element 41 is connected to one end of the coil 43. The cathode of the diode 42 is connected to one power line EL21, and the anode of the diode 42 is connected to the other power line EL22. The other end of the coil 43 is connected to the vehicle battery 22 via the output end of the DC / DC converter 25. One end of the capacitor 44 is connected to one power line EL21, and the other end of the capacitor 44 is connected to the other power line EL22.

  According to this configuration, when the switching element 41 is periodically turned on / off (switching or chopping) in a situation where DC power is input, the DC power rectified by the rectifier 24 is the same as the battery voltage of the vehicle battery 22. Converted to voltage DC power. In this case, the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22 depends on the on / off duty ratio of the switching element 41. Specifically, when the duty ratio is small (that is, the ON time of the switching element 41 per cycle is short), the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22 is high. That is, the DC / DC converter 25 adjusts the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22.

  Here, the impedance from the output end of the power receiver 23 to the vehicle battery 22 depends on the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22. In this case, since the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 becomes the specific resistance value Rout, the impedance ZL from the input terminal of the DC / DC converter 25 to the vehicle battery 22 is defined as the first impedance ZL1. To do. The on / off duty ratio of the switching element 41 in which the impedance ZL from the input terminal of the DC / DC converter 25 to the vehicle battery 22 becomes the first impedance ZL1 is defined as the first duty ratio.

  The non-contact power transmission device 10 was understood to be in a state in which power could be transmitted between the power transmitter 13 and the power receiver 23 by exchanging information between the controllers 14 and 26. In this case, the vehicle battery 22 is charged. Specifically, the power supply side controller 14 controls the AC power supply 12 such that charging AC power is output from the AC power supply 12. Then, the vehicle-side controller 26 controls the switching element 41 so that the switching element 41 is turned on / off at the first duty ratio. Thereby, electric power transmission is performed from the power transmitter 13 toward the power receiver 23, and the vehicle battery 22 is charged.

  In a situation where the vehicle battery 22 is being charged, the vehicle-side controller 26 cooperates with the power supply-side controller 14 to control the power value and duty ratio of the AC power supply 12 based on the measurement result of the temperature sensor 40. Perform the temperature handling process. The temperature handling process will be described in detail with reference to FIG. The temperature handling process is periodically executed while the vehicle battery 22 is being charged.

First, as shown in FIG. 2, in step S101, the vehicle-side controller 26 grasps the temperatures of the second inductors 32a and 32b.
In step S102, the vehicle-side controller 26 determines whether or not the heat generation is suppressed. The heat generation suppression state is a state in which the power value control and duty ratio control of the AC power supply 12 for suppressing the temperature rise of the second inductors 32a and 32b have already been performed. In step S102, the vehicle controller 26 determines whether or not the heat generation suppression state flag is set in a predetermined storage area of the vehicle controller. As will be described later, the heat generation suppression state flag is set when the temperature of the second inductors 32a and 32b is higher than the threshold temperature, and is erased when the temperature of the second inductors 32a and 32b is equal to or lower than the threshold temperature. .

  If the vehicle-side controller 26 is not in the heat generation suppression state (when the heat generation suppression state flag is not set), the vehicle-side controller 26 proceeds to step S103 and determines whether the temperatures of the second inductors 32a and 32b are higher than a predetermined threshold temperature. Determine whether or not. In this determination process, for example, it may be determined whether or not the temperature of each of the second inductors 32a and 32b is higher than the threshold temperature, and the temperature of either one of the second inductors 32a and 32b is a threshold value. You may determine whether it is higher than temperature.

  When the temperature of the second inductors 32a and 32b is equal to or lower than the threshold temperature, the vehicle-side controller 26 ends this process as it is. On the other hand, when the temperature of the second inductors 32a and 32b is higher than the threshold temperature, the vehicle-side controller 26 suppresses the heat generation of the second inductors 32a and 32b from the normal charging state in steps S104 to S106. The process for shifting to the heat generation suppression state is executed.

  Specifically, first, in step S104, the vehicle-side controller 26 adjusts the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22 so that the value of the current flowing through the second inductors 32a and 32b becomes small. . Specifically, the vehicle-side controller 26 determines the duty of the switching element 41 so that the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22 becomes the second impedance ZL2 higher than the first impedance ZL1. The ratio is changed from the first duty ratio to the second duty ratio. The second duty ratio is a value smaller than the first duty ratio.

  Thereafter, in step S <b> 105, the vehicle-side controller 26 transmits a small AC power output command to the power supply-side controller 14. The power supply side controller 14 controls the alternating current power supply 12 so that small alternating current power whose power value is smaller than the alternating current power for charging is output from the alternating current power supply 12 when the output command of the small alternating current power is received. And the vehicle side controller 26 sets a heat_generation | fever suppression state flag in step S106, and complete | finishes this process. That is, the heat generation suppression state is a state in which the on / off duty ratio of the switching element 41 is smaller and the power value of the AC power output from the AC power source 12 is smaller than that in the normal charge state. .

  On the other hand, if the current state is the heat generation suppression state, the vehicle-side controller 26 proceeds to step S107. In step S107, the vehicle-side controller 26 determines whether or not the temperatures of the second inductors 32a and 32b are equal to or lower than the threshold temperature.

  If the temperature of the second inductors 32a and 32b is higher than the threshold temperature, the vehicle-side controller 26 ends this process as it is and continues the heat generation suppression state. On the other hand, when the temperature of the second inductors 32a and 32b is equal to or lower than the threshold temperature, the vehicle-side controller 26 executes a process of returning from the heat generation suppression state to the normal charge state in Step S108 to Step S110.

Specifically, first, in step S108, the vehicle-side controller 26 changes the on / off duty ratio of the switching element 41 from the second duty ratio to the first duty ratio.
Thereafter, the vehicle-side controller 26 transmits an output command for charging AC power to the power-side controller 14 in step S109. The power supply controller 14 controls the AC power supply 12 so that the AC power for charging is output from the AC power supply 12 based on the reception of the output command for the AC power for charging.

  And the vehicle side controller 26 erase | eliminates the heat_generation | fever suppression state flag in step S110, and complete | finishes this process. In the present embodiment, the vehicle-side controller 26 corresponds to a duty ratio control unit and a power supply control unit.

Next, the operation of this embodiment will be described.
When the temperature of the second inductors 32a and 32b becomes higher than the threshold temperature, the on / off duty ratio of the switching element 41 is controlled. Specifically, the on / off duty ratio of the switching element 41 is changed from the first duty ratio to a second duty ratio that is smaller than the first duty. Thereby, the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22 is adjusted to the second impedance ZL2 higher than the first impedance ZL1. Then, the current value that flows after the input terminal of the DC / DC converter 25 decreases, and the current value that flows in each of the second inductors 32a and 32b of the second impedance converter 32 decreases. Thereby, the calorific value of each second inductor 32a, 32b becomes small.

  In addition, the power value of the AC power output from the AC power supply 12 becomes smaller after the duty ratio for turning on and off the switching element 41 is changed. Thereby, the value of the current flowing through the second inductors 32a and 32b is further reduced.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) The power receiving device 21 includes a second impedance converter 32 having second inductors 32a and 32b, and a temperature sensor 40 that measures the temperature of the second inductors 32a and 32b. And the power receiving apparatus 21 is provided between the 2nd impedance converter 32 and the vehicle battery 22, and when the temperature of 2nd inductor 32a, 32b becomes higher than threshold temperature, it is 2nd inductor 32a, 32b. Is provided with a DC / DC converter 25 in which the impedance is adjusted so that the value of the current flowing through the capacitor becomes small. As a result, when the temperature becomes higher than the threshold temperature, the value of the current flowing through each of the second inductors 32a and 32b becomes small, so that the heat generation of the second inductors 32a and 32b can be suppressed accordingly. Thereby, the excessive temperature rise of 2nd inductor 32a, 32b can be suppressed.

  (2) The DC / DC converter 25 has a switching element 41 that periodically turns on and off, and the on / off duty ratio of the switching element 41 is such that the temperature of the second inductors 32a and 32b is higher than the threshold temperature. In this case, the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22 is adjusted to be high. Specifically, when the temperature of the second inductors 32a and 32b becomes higher than the threshold temperature, the vehicle-side controller 26 changes the on / off duty ratio of the switching element 41 from the first duty ratio to the first duty ratio. Change to a small second duty ratio. Thereby, since the value of the current flowing through the second inductors 32a and 32b becomes small, the heat generation of the second inductors 32a and 32b can be suppressed, and the excessive temperature rise of the second inductors 32a and 32b can be suppressed.

  (3) In particular, as already described, due to space limitations, the temperatures of the second inductors 32a and 32b of the second impedance converter 32 mounted on the vehicle are the first inductors 31a and 32a provided in the power transmission device 11. It is likely to be higher than 31b. In this regard, in the present embodiment, the vehicle-side controller 26 measures the temperature of the second inductors 32a and 32b whose temperature tends to be high, and based on the measurement result, the vehicle battery from the input end of the DC / DC converter 25 is measured. The impedance ZL up to 22 is adjusted. Thereby, it can respond to the temperature rise of each inductor 31a, 31b, 32a, 32b more suitably.

  (4) Furthermore, the second inductors 32a and 32b that are the objects of temperature measurement and the DC / DC converter 25 (the switching element 41) that is the object of adjustment are mounted on the same device (that is, the power receiving device 21). Accordingly, the vehicle controller 26 can reduce the value of the current flowing through the second inductors 32a and 32b without exchanging information with the power supply controller 14. Therefore, it is possible to suppress an increase in the time required for shifting from the normal charging state to the heat generation suppression state due to the time lag related to the information transmission from the vehicle side controller 26 to the power source side controller 14. That is, it is possible to improve the followability of the impedance adjustment of the DC / DC converter 25 with respect to the temperature change of the second inductors 32a and 32b. Furthermore, even if information cannot be exchanged between the controllers 14 and 26 due to a communication failure or the like, an excessive temperature rise of the second inductors 32a and 32b can be suppressed.

  (5) The power supply side controller 14 adjusts the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22 by the vehicle side controller 26, and then the AC power output from the AC power supply 12. The AC power supply 12 is controlled so that the value becomes smaller. Thereby, the value of the current flowing through the second inductors 32a and 32b can be further reduced. Further, in the configuration in which reflected wave power is generated by adjusting the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22, the power value of the AC power output from the AC power supply 12 is set. By reducing the power value, the power value of the reflected wave power is reduced, so that the burden on the AC power supply 12 can be reduced.

  (6) When the temperature of the second inductors 32a and 32b is equal to or lower than the threshold temperature, the vehicle-side controller 26 shifts from the heat generation suppression state to the normal charge state. Thereby, the battery 22 for vehicles can be charged efficiently, suppressing the excessive temperature rise of the 2nd inductors 32a and 32b.

In addition, you may change the said embodiment as follows.
The temperature measurement target is not limited to the second inductors 32a and 32b of the second impedance converter 32, but may be the first inductors 31a and 31b of the first impedance converter 31. Specifically, the power transmission device 11 includes a measurement unit that measures the temperature of the first inductors 31 a and 31 b, and the power supply side controller 14 transmits information regarding the temperature of the first inductors 31 a and 31 b to the vehicle side controller 26. The vehicle-side controller 26 may control the on / off duty ratio of the switching element 41 based on the information regarding the temperature.

  The non-contact power transmission apparatus 10 measures the temperature of each inductor 31a, 31b, 32a, 32b, and when the temperature of at least one inductor of each inductor 31a, 31b, 32a, 32b is a threshold temperature, You may transfer to a heat generation suppression state from a charge state.

  The measurement parameters of the second inductors 32a and 32b are not limited to temperature, and are arbitrary as long as they are physical quantities related to temperature. For example, the measurement unit may measure the value of current flowing through the second inductors 32a and 32b as a physical quantity related to temperature. In this case, the non-contact power transmission apparatus 10 may shift from the normal charging state to the heat generation suppressing state when the value of the current flowing through the second inductors 32a and 32b becomes larger than a predetermined threshold current value. The vehicle-side controller 26 may control the on / off duty ratio of the switching element 41 based on both the temperature of the second inductors 32a and 32b and the value of the current flowing through the second inductors 32a and 32b.

  The power supply controller 14 may control the AC power supply 12 such that the AC power output from the AC power supply 12 stops when the temperature of the second inductors 32a and 32b is higher than the threshold temperature.

  ○ When the temperature of the second inductors 32a and 32b is higher than the threshold temperature, either the ON / OFF duty ratio control of the switching element 41 or the power value control of the AC power supply 12 may be performed. . For example, when the temperature of the second inductors 32 a and 32 b is higher than the threshold temperature, the power supply side controller 14 stops the AC power output from the AC power supply 12 or the power of the AC power output from the AC power supply 12. Decrease the value. On the other hand, the vehicle-side controller 26 may be configured to maintain the ON / OFF duty ratio of the switching element 41 at the first duty ratio even when the temperature of the second inductors 32a and 32b is higher than the threshold temperature. .

  That is, in the heat generation suppression state, (A) the duty ratio of on / off of the switching element 41 is smaller than in the normal charge state, and (B) the power value of the AC power output from the AC power source 12 is smaller. As long as at least one of the conditions is satisfied, it is sufficient.

  The threshold temperature used in the determination process in step S103 (hereinafter referred to as the first threshold temperature) and the threshold temperature used in the determination process in step S107 (hereinafter referred to as the second threshold temperature) may be the same. And may be different. For example, the second threshold temperature may be set lower than the first threshold temperature. In this case, it is possible to avoid a situation in which the normal charging state is shifted again to the heat generation suppressing state immediately after the heat generation suppressing state is shifted to the normal charging state.

  In the embodiment, the DC / DC converter 25 is used to adjust the impedance. However, the present invention is not limited to this. For example, an LC circuit having a variable constant (impedance) may be provided between the second impedance converter 32 and the rectifier 24. In this case, when the temperature of the second inductors 32a and 32b becomes higher than the threshold temperature, the constant of the LC circuit can be changed so that the impedance from the output terminal of the second impedance converter 32 to the vehicle battery 22 is increased. Control should be performed.

  In the other example, the control of the duty ratio of on / off of the switching element 41 may not be performed, or may be performed together with the variable control of the constant of the LC circuit. . Further, the constant can be said to be a conversion ratio, or an inductance or a capacitance.

  ○ The execution subject of the temperature handling process is arbitrary. For example, the power supply controller 14 may execute the temperature handling process. In this case, the power supply side controller 14 requests the temperature of the second inductors 32a and 32b from the vehicle side controller 26, and grasps the temperature of the second inductors 32a and 32b by receiving the request result. Then, the power supply side controller 14 determines the on / off duty ratio of the switching element 41 according to the temperature of the second inductors 32 a and 32 b, and transmits the determination result to the vehicle side controller 26. The vehicle-side controller 26 controls the switching element 41 based on the determination result. In this example, the power supply side controller 14 corresponds to a duty ratio control unit and a power supply control unit.

  Further, a controller other than the controllers 14 and 26 may execute the temperature handling process. That is, the duty ratio control unit and the power supply control unit may be either the power supply side controller 14 or the vehicle side controller 26, and may be a controller different from these controllers 14 and 26. However, in view of the fact that the on / off duty ratio of the switching element 41 can be controlled without performing communication, it is preferable that the vehicle-side controller 26 executes the temperature handling process.

  The second duty ratio is arbitrary as long as it is smaller than the first duty ratio. For example, the second duty ratio may be a predetermined constant value regardless of the temperature of the second inductors 32a and 32b, or may vary according to the temperature of the second inductors 32a and 32b. Further, the second duty ratio may be set so that the burden on the AC power supply 12 and the transmission efficiency do not fall outside a predetermined allowable range.

The constant (impedance) of each impedance converter 31 and 32 may be a variable value or a fixed value.
O The number of impedance converters provided in the power transmission device 11 and the number of impedance converters provided in the power receiving device 21 are arbitrary, and may be two or more, for example. Further, the first impedance converter 31 or the second impedance converter 32 may be omitted.

The AC power supply 12 is a voltage source, but may be a power source or a current source.
In the configuration in which the AC power supply 12 is a power source, the impedance converters 31 and 32 may perform impedance matching. The second impedance converter 32 performs impedance conversion so that the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 matches the impedance from the output terminal of the power receiver 23 to the AC power supply 12. Also good. The first impedance converter 31 also connects the input terminal of the power transmitter 13 to the vehicle battery 22 so that the impedance from the output terminal of the AC power supply 12 to the vehicle battery 22 matches the output impedance of the AC power supply 12. Impedance conversion may be performed on the impedance Zin.

  The first impedance converter 31 converts the impedance Zin from the input end of the power transmitter 13 to the vehicle battery 22 so that the power factor is improved (reactance approaches 0). Also good.

  In the normal charging state, the power supply side controller 14 may change the power value of the AC power output from the AC power supply 12 according to the charging state (SOC) of the vehicle battery 22. In this case, the vehicle-side controller 26 allows the AC power supply so that the impedance ZL from the input end of the DC / DC converter 25 to the vehicle battery 22 is constant regardless of the power value of the AC power output from the AC power supply 12. The on / off duty ratio of the switching element 41 may be controlled according to the power value of the AC power output from the power source 12. That is, the first duty ratio may be variable according to the power value of AC power that can be output in a normal charging state. In such a configuration, the second duty ratio may be smaller than the first duty ratio that is currently set (that is, at the time of transition from the normal charge state to the heat generation suppression state).

  The specific circuit configuration of each impedance converter 31 and 32 is arbitrary. For example, the first impedance converter 31 may be an inverted L-type LC circuit in which the first inductor 31b is omitted, and the second impedance converter 32 is an L-type LC in which the second inductor 32b is omitted. It may be a circuit or the like.

  As long as the DC / DC converter 25 has at least a switching element, its specific circuit configuration is arbitrary, and may be either step-up or step-down. The DC / DC converter 25 may have a plurality of switching elements.

In the embodiment, the resonance frequency of the power transmitter 13 and the resonance frequency of the power receiver 23 are set to be the same. However, the present invention is not limited to this, and may be different within a range in which power transmission is possible.
In embodiment, although the power transmission device 13 and the power receiving device 23 were the same structures, it is not restricted to this, A different structure may be sufficient.

In the embodiment, the capacitors 13b and 23b are provided, but these may be omitted. In this case, magnetic field resonance is performed using the parasitic capacitances of the coils 13a and 23a.
In embodiment, although the primary side coil 13a and the primary side capacitor | condenser 13b were connected in parallel, it is not restricted to this, Both may be connected in series. Similarly, the secondary coil 23a and the secondary capacitor 23b may be connected in series.

In the embodiment, magnetic field resonance is used in order to realize non-contact power transmission. However, the present invention is not limited to this, and electromagnetic induction may be used.
In the embodiment, the AC power received by the power receiver 23 is used for charging the vehicle battery 22, but is not limited thereto, and may be used for other purposes, for example.

The AC power supply 12 may be omitted, and the system power supply and the first impedance converter 31 may be directly connected.
The power transmitter 13 may include a resonance circuit including a primary side coil 13a and a primary side capacitor 13b, and a primary side coupling coil that is coupled to the resonance circuit by electromagnetic induction. Similarly, the power receiver 23 may include a resonance circuit including a secondary coil 23a and a secondary capacitor 23b, and a secondary coupling coil coupled to the resonance circuit by electromagnetic induction.

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power transmission apparatus, 11 ... Power transmission apparatus, 12 ... AC power supply, 13a ... Primary side coil, 21 ... Power receiving apparatus, 22 ... Vehicle battery (load), 23a ... Secondary side coil, 24 ... Rectifier 25 ... DC / DC converter (adjustment unit) 31, 32 ... impedance converter, 31a, 31b, 32a, 32b ... inductor, 40 ... temperature sensor (measurement unit), 41 ... switching element.

Claims (6)

In a power receiving device capable of receiving the AC power in a contactless manner from a power transmitting device having a primary side coil to which AC power is input,
A secondary coil capable of receiving the AC power in a non-contact manner from the primary coil;
Load,
An impedance converter provided between the secondary coil and the load and performing impedance conversion, and having at least an inductor;
A measurement unit for measuring a physical quantity related to the temperature of the inductor;
An adjustment unit that is provided between the impedance conversion unit and the load, and that adjusts an impedance so that a current value flowing through the inductor is reduced when the physical quantity is greater than a predetermined threshold;
A power receiving device comprising: A rectifier that rectifies the AC power received by the secondary coil;
The impedance converter is provided between the secondary coil and the rectifier,
The adjustment unit is a DC / DC converter that is provided between the rectification unit and the load and has a switching element that is periodically turned on and off,
The power receiving device controls a duty ratio control for controlling an on / off duty ratio of the switching element so that an impedance from an input terminal of the DC / DC converter to the load is increased when the physical quantity is larger than the threshold. The power receiving device according to claim 1, further comprising a unit. AC power supply capable of outputting AC power,
A primary coil to which the AC power is input;
A secondary coil capable of receiving the AC power in a non-contact manner from the primary coil;
Load,
Provided between the output end of the AC power supply and the load and performs impedance conversion, and at least an impedance conversion unit having an inductor,
A measurement unit for measuring a physical quantity related to the temperature of the inductor;
An adjustment unit that is provided between the impedance conversion unit and the load, and that adjusts an impedance so that a current value flowing through the inductor is reduced when the physical quantity is greater than a predetermined threshold;
A non-contact power transmission device comprising: A rectifier that rectifies the AC power received by the secondary coil;
The impedance converter is provided between the secondary coil and the rectifier,
The adjustment unit is a DC / DC converter that is provided between the rectification unit and the load and has a switching element that is periodically turned on and off,
The non-contact power transmission device controls an on / off duty ratio of the switching element so that an impedance from an input terminal of the DC / DC converter to the load is increased when the physical quantity is larger than the threshold value. The contactless power transmission device according to claim 3, further comprising a duty ratio control unit.   The power supply control part which stops the said alternating current power output from the said alternating current power supply or makes the electric power value of the said alternating current power small after the impedance adjustment by the said adjustment part is performed. The non-contact power transmission device described in 1. AC power supply capable of outputting AC power,
A primary coil to which the AC power is input;
A secondary coil capable of receiving the AC power in a non-contact manner from the primary coil;
Load,
Provided between the output end of the AC power supply and the load and performs impedance conversion, and at least an impedance conversion unit having an inductor,
A measuring unit for measuring the temperature of the inductor;
When the temperature of the inductor is higher than a predetermined threshold by the measurement unit, the AC power output from the AC power supply is stopped, or a power supply control unit that reduces the power value of the AC power;
A non-contact power transmission device comprising: