JP2015008551A - Non-contact power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power transmission device capable of determining a failure of foreign matter detection means and reliably detecting foreign matters entered between a primary coil of a power supply unit and a secondary coil of a power reception unit.SOLUTION: A power supply unit 2 supplies the power to a power reception unit 4 in a non contact manner. The power supply unit 2 includes: a substrate 42; a primary coil 44 which is disposed on the substrate 42 to generate an AC current; a cover 40 attached to the substrate 42 to cover the primary coil 44; a foreign matter detection means 14 that detects an object existing on the cover 40; and monitor means 17 that monitors the foreign matter detection means 14. Since the power supply unit 2 includes a foreign matter detection means 14 which is capable of detecting an object existing on cover 40 and monitors the operation of the foreign matter detection means 14, a foreign matter entering between the primary coil 44 and the secondary coil of the power reception unit 4 can be safely and reliably detected.

Description

  The present invention relates to a non-contact power transmission device used for charging an electric propulsion vehicle such as an electric vehicle or a plug-in hybrid vehicle.

  FIG. 8 is a schematic diagram illustrating a configuration of a conventional non-contact power transmission apparatus 101. In FIG. 8, the non-contact power feeding device (primary side) F connected to the power panel of the ground side power source 104 is supplied with power to the power receiving device (secondary side) G mounted on the electric propulsion vehicle. It arrange | positions so that it may oppose through the air gap which is a space | gap space without a physical connection. In this arrangement state, when an alternating current is applied to the primary coil 102 provided in the power feeding device F to form a magnetic flux, an induced electromotive force is generated in the secondary coil 103 provided in the power receiving device G, and thereby the primary coil 102 is provided. Is transmitted to the secondary coil 103 in a non-contact manner.

  The power receiving device G is connected to, for example, the in-vehicle battery 105, and the in-vehicle battery 105 is charged with the electric power transmitted as described above. The in-vehicle motor 106 is driven by the electric power stored in the in-vehicle battery 105. During the non-contact power supply process, necessary information exchange is performed between the power supply apparatus F and the power reception apparatus G, for example, by the wireless communication apparatus 107.

  FIG. 9 is a schematic diagram illustrating the internal structure of the power feeding device F and the power receiving device G. In particular, FIG. 9A is a schematic diagram illustrating an internal structure when the power feeding device F is viewed from above and the power receiving device G is viewed from below. FIG. 9B is a schematic diagram illustrating an internal structure when the power feeding device F and the power receiving device G are viewed from the side.

  In FIG. 9, the power feeding device F includes a primary coil 102, a primary magnetic core 108, a back plate 110, a cover 111, and the like. Briefly described, the power receiving device G has a symmetric structure with the power feeding device F, and includes a secondary coil 103, a secondary magnetic core 109, a back plate 110, a cover 111, and the like. The surface of the secondary core 108 and the surfaces of the secondary coil 103 and the secondary core 109 are covered and fixed with a mold resin 112 mixed with a foam material 113, respectively.

  That is, in both the power feeding device F and the power receiving device G, the mold resin 112 is filled between the back plate 110 and the cover 111, and the primary coil 102, the secondary coil 103, the primary magnetic core 108, and the secondary magnetic core 109 inside. The surface of is covered and fixed. The mold resin 112 is made of, for example, silicon resin, and by fixing the interior in this way, the primary coil 102 and the secondary coil 103 are positioned and fixed, and the mechanical strength is ensured and the heat dissipation function is also exhibited. That is, the primary coil 102 and the secondary coil 103 generate heat due to Joule heat through an exciting current, but are radiated and cooled by heat conduction of the mold resin 112.

JP 2008-87733 A

  Since the power feeding device F and the power receiving device G are basically installed outdoors, it is conceivable that foreign matter may be placed on the cover 111. In particular, if a metal object, which is an example of a foreign object, is placed on the cover 111 during power transmission and left as it is, the metal object will be overheated. In particular, when a loop-shaped conductor capable of interlinking magnetic flux is inserted between the primary coil 102 and the secondary coil 103, an electromotive force is generated at both ends of the conductor. If the invading foreign matter is excessively heated, there is a possibility that the power feeding device F and the power receiving device G may be damaged. From the above, when a foreign object enters between the primary coil 102 and the secondary coil 103 during power transmission, it is required to reliably detect the entry of the foreign object. Furthermore, it is necessary to monitor whether or not the means for detecting the foreign matter is operating normally. If the means for detecting is out of order, overheating of the foreign matter that has entered cannot be detected.

  Therefore, an object of the present invention is to provide a non-contact power transmission device that can reliably monitor the intrusion of foreign matter between a primary coil and a secondary coil.

  In order to solve the above-described problem, according to one aspect of the present invention, a power feeding device that supplies power to a power receiving device in a non-contact manner, the power feeding device being disposed on the substrate and the AC, A primary coil that generates magnetic flux by an electric current, a cover that is attached to the substrate and covers the primary coil, a capacitance sensor that detects an object present on the cover, and a monitor that monitors the capacitance sensor A contactless power transmission device comprising means is provided.

  According to another aspect of the present invention, there is provided a power receiving device that receives power supply from a power feeding device in a non-contact manner, the power receiving device being disposed on the substrate, and a primary coil of the power feeding device is generated. A secondary coil that generates an electromotive force by magnetic flux, a cover that is attached to the substrate and covers the secondary coil, a capacitance sensor that detects an object present on the cover, and monitoring of the capacitance sensor There is provided a non-contact power transmission device including monitoring means for performing the above.

  According to the present invention, the power feeding device and the power receiving device of the non-contact power transmission device include a capacitance sensor that can detect an object present on the cover, and further includes a monitoring unit that monitors the capacitance sensor. Therefore, it is possible to always detect the entry of foreign matter between the primary coil and the secondary coil safely and reliably.

Block diagram of a non-contact power transmission apparatus according to the present invention Front view of the non-contact power transmission device shown in FIG. Block diagram of foreign matter detection means which is a capacitance sensor (A) Partial sectional view of the power feeding device (B) Partial sectional view of another type of power feeding device Flow chart showing foreign object detection and transmission power control Flow chart showing foreign object detection means abnormality process Flow chart showing foreign object intrusion processing Schematic diagram showing the configuration of a conventional non-contact power transmission device The schematic diagram which shows the internal structure of the receiving device G arrange | positioned facing the electric power feeder F of FIG.

  One embodiment of the present invention is a power feeding device that supplies power to a power receiving device in a contactless manner, the power feeding device being disposed on the substrate, a primary coil that generates magnetic flux by alternating current, A cover that is attached to the substrate and covers the primary coil, a capacitance sensor that detects an object present on the cover, and a monitoring unit that monitors normal operation of the capacitance sensor.

  According to another aspect of the present invention, there is provided a power receiving device that receives power from the power feeding device in a non-contact manner, the power receiving device being disposed on the substrate and a magnetic flux generated by a primary coil of the power feeding device. A secondary coil that generates an electromotive force, a cover that is attached to the substrate and covers the secondary coil, a capacitance sensor that detects an object present on the cover, and a normal operation of the capacitance sensor. Monitoring means for monitoring is provided.

  As described above, the power feeding device and the power receiving device of the non-contact power transmission device include a capacitance sensor that can detect an object present on the cover and a monitoring unit that monitors normal operation of the capacitance sensor. It becomes possible to always detect the entry of foreign matter between the primary coil and the secondary coil safely and reliably.

  In this specification, “on the cover” means above the outer surface of the cover or above the outer surface of the cover.

  The electrostatic capacitance sensor is preferably installed between the cover and the coil in order to be protected from the outside.

  The monitoring means for monitoring the capacitance sensor is preferably subjected to sensor signal processing by a control unit such as a microcomputer, and the monitoring timing is monitored at predetermined intervals, and the vehicle approaches the power feeding device. The present invention is not limited by this embodiment, such as when a control signal is received from a vehicle.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a block diagram of a non-contact power transmission apparatus according to the present invention. FIG. 2 is an external view of the vehicle installed in the parking space. As shown in FIGS. 1 and 2, the non-contact power transmission device includes a power feeding device 2 installed in, for example, a parking space, and a power receiving device 4 mounted on, for example, an electric propulsion vehicle.

  The power feeding device 2 receives signals from the power supply box 8 connected to the commercial power source 6, the inverter unit 10, the coil unit 12, the foreign matter detection unit 14, the control unit (for example, a microcomputer) 16, and the foreign matter detection unit 14. Monitoring means 17 for monitoring is provided. On the other hand, the power receiving device 4 includes a coil unit 18, a rectifying unit 20, a load (battery) 22, and a control unit (for example, a microcomputer) 24.

  In the power supply device 2, the commercial power source 6 is a 200 V commercial power source that is a low-frequency AC power source, and is connected to the input end of the power source box 8, and the output end of the power source box 8 is connected to the input end of the inverter unit 10. The output end of the unit 10 is connected to the coil unit 12. On the other hand, in the power receiving device 4, the output end of the coil unit 18 is connected to the input end of the rectifying unit 20, and the output end of the rectifying unit 20 is connected to the load 22.

  The coil unit 12 is laid on the ground, and the power supply box 8 is erected at a position separated from the coil unit 12 by a predetermined distance, for example. On the other hand, the coil unit 18 is attached to, for example, the bottom of the vehicle body (for example, a chassis).

  The control unit 16 performs wireless communication with the control unit 24, and the control unit 24 determines a power command value according to the detected residual voltage of the load 22 and transmits the determined power command value to the control unit 16. The control unit 16 compares the supplied power detected by the coil unit 12 with the received power command value, and drives the inverter unit 10 to obtain the power command value.

  During power feeding, the control unit 24 detects the received power and changes the power command value to the control unit 16 so that the load 22 is not overcurrent or overvoltage.

  As shown in FIG. 2, when power is supplied from the power feeding device 2 to the power receiving device 4, the coil unit 18 is disposed so as to face the coil unit 12 by appropriately moving the vehicle, and the control unit 16 causes the inverter unit 10 to operate. By controlling the driving, a high-frequency electromagnetic field is formed between the coil unit 12 and the coil unit 18. The power receiving device 4 takes out electric power from the high frequency electromagnetic field and charges the load 22 with the taken out electric power.

  The foreign matter detection means 14 is for detecting whether or not there is a foreign matter in the electromagnetic field region and the vicinity thereof, and is provided, for example, in the coil unit 12 of the power feeding device 2 as shown in FIG.

  Note that the “foreign matter” in the present invention is an object that may enter a high-frequency electromagnetic field region, and in particular, a non-contact charging device (in the present embodiment, a power feeding device 2) by raising the temperature by an electromagnetic field. ) Is a piece of metal that may cause damage.

  FIG. 3 is a block diagram of the foreign matter detection means 14. The foreign matter detection means 14 is a capacitance sensor that measures the capacitance between the foreign matter and is configured to detect the foreign matter based on a change in the measured capacitance. For this purpose, the foreign matter detection means 14 includes an electrode 30, a voltage supply unit 32, a C / V conversion unit 34, and a signal processing unit 36. The signal processed by the signal processing unit 36 is monitored by the monitoring unit 17 of the control unit 16 in FIG. 1 to monitor whether there is a signal change and to determine whether the capacitance sensor is operating normally. Deciding.

  Specifically, the foreign matter detection means 14 (its electrode 30) is installed on the back side of the cover 40 of the coil unit 12, as shown in FIG. The cover 40 of the coil unit 12 is attached to the substrate 42 so as to cover the primary coil 44 from above in order to protect the primary coil 44 disposed on the substrate 42. The electrode 30 of the foreign matter detection means 14 is the back side of the cover 40, that is, the primary side of the cover 40 so as to be protected from the outside so that the capacitance between the foreign matter 38 existing on the cover 40 can be measured. It is installed between the coil 44.

  In addition, as shown in FIG. 4B, the electrode 30 of the foreign matter detection means 14 may be incorporated in the cover 40 so as not to be exposed to the outside.

  As shown in FIG. 3, the voltage supply unit 32 of the foreign matter detection unit 14 applies a predetermined potential with respect to the ground (GND) potential to the electrode 30. As a result, a capacitance C1 is generated between the electrode 30 and the foreign substance 38, and the capacitance C1 is expressed by Equation 1.

  In Equation 1, ε0 is the dielectric constant of vacuum, εr is the relative dielectric constant, S is the minimum area opposite to the electrode 30 and the foreign material 38, and d is the distance between the electrode 30 and the foreign material 38.

  The C / V conversion unit 34 of the foreign matter detection means 14 converts the capacitance C1 into a voltage value. Here, when the electrostatic capacitance between the foreign substance 38 and the GND potential is C2, the C / V conversion unit 34 converts the electrostatic capacitance C1 + C2 into a corresponding voltage value.

  As shown in FIG. 1, the signal processing unit 36 of the foreign matter detection unit 14 generates a signal corresponding to the voltage value generated by the conversion of the C / V conversion unit 34, that is, a signal corresponding to the measured capacitance. It transmits to the control part 16 of the electric power feeder 2.

  According to such foreign matter detection means 14, when the measured value fluctuates during the measurement of the capacitance, it indicates that the foreign matter 38 has approached the electrode 30 as shown in FIG. 3. Accordingly, the foreign matter detection unit 14 is appropriately provided, and the monitoring unit 17 monitors the change in signal to determine the normal operation of the capacitance sensor. Therefore, the foreign matter present on the cover 40 of the power feeding device 2 can be reliably detected. Can be detected.

  Next, the determination of normal operation of the foreign object detection unit 14 by the foreign object detection unit 14 and the monitoring unit 17 and transmission power control based on the foreign object detection will be described with reference to the flowchart of FIG.

  In step S1 of the flowchart in FIG. 5, the vehicle on which the power receiving device 4 is mounted gives a command from the vehicle to the control unit 16 of the power feeding device until the vehicle coil unit 18 approaches the coil unit 12 and stops opposite. Send. When the control unit 16 receives a control command from the control unit 24, the control unit 16 starts the measurement operation of the electrostatic capacity signal of the foreign matter detection means 14 in step S2, and the monitoring means 17 monitors the signal change. Start. The capacitance measured by the foreign matter detection means 14 of the coil unit 12 is determined based on the proximity of the vehicle, the vehicle body opposed to the power receiving device 4, and the vehicle coil unit 18, and the capacitance of the capacitance due to changes in the surrounding environment as shown in FIG. A ring change occurs.

  Accordingly, since a change in capacitance occurs in step S3, a signal change occurs in the monitoring means 17, which is input to the control unit 16 in step S4 and stored as an initial value. For example, the capacitance when the vehicle is stopped and the foreign object 38 is not present on the cover 40 of the power feeding device 2 is stored as the initial value.

  However, if there is no change in the capacitance, the process proceeds to step S5, and abnormality processing is performed. The flowchart of FIG. 6 shows the flow of the abnormality processing of the foreign matter detection means 14. First, in step S21, the abnormality of the foreign matter detection means 14 is notified by a notification means such as a display or sound. For example, the notification is made by the speaker 46 shown in FIG. If it is determined that the foreign matter detection unit is abnormal, the function of the power supply device 2 is stopped in step 32 and the power supply operation is not performed. By this initial check, the normal operation of the foreign matter detection means 14 can be confirmed, and thereafter the reliable operation of foreign matter detection is executed.

  In step S4, after storing the initial value, the control unit 16 instructs the inverter unit 10 to start power transmission, and starts power supply from the coil unit 12 to the coil unit 18.

  In step S6, the control unit 16 compares the capacitance measured by the foreign object detection means 14 during power supply with the stored initial value, and determines whether or not a foreign object has entered during power supply. It is determined whether or not the capacitance measured by the foreign matter detection means 14 has changed from the initial value and exceeded due to the intrusion. Note that, for example, when the absolute value of the difference between the measured capacitance and the initial value exceeds a predetermined value, it may be determined that a foreign object has entered.

  If it is determined in step S6 that a foreign object has entered during power supply, the process moves to step S7 to prevent the power supply device 2 from being expanded due to overheating of the foreign object, and a foreign object intrusion process for controlling transmission power. I do. If it is determined in step S7 that no foreign matter has entered, the control unit 16 causes the inverter unit 10 to continue power transmission in step S8.

  The flowchart in FIG. 7 shows the flow of foreign object intrusion processing. First, in step S31, the foreign object intrusion is notified by a display means such as a display or sound. For example, the notification is made by the speaker 46 shown in FIG.

  Next, in step S32, it is determined whether or not the capacitance measured by the foreign object detection unit 14 during power supply exceeds a preset value. The set value is set to a capacitance value that can be taken when the foreign object is a metal object, for example.

  If it is determined in step S32 that the capacitance exceeds the set value, the process proceeds to step S33, and the control unit 16 transmits the transmission power from the coil unit 12 to the coil unit 18 by a predetermined amount (for example, 1/2) Control to decrease or stop power transmission. Furthermore, in step S34, the notification means 46 such as a display or sound notifies that the transmission power is controlled by the entry of the foreign object, and the foreign object intrusion process is terminated.

  If it is determined in step S32 that the capacitance does not exceed the set value, the foreign substance intrusion process is terminated bypassing steps S33 and S34.

  Returning to FIG. 5, in step S9, when there is an instruction to interrupt power transmission for reasons such as the removal of a foreign object by a person or the use of a car, the process proceeds to step S10, and the control unit 16 causes the inverter unit 10 to end power transmission. The power supply from the coil unit 12 to the coil unit 18 is stopped, and the foreign matter detection means 14 ends the capacitance measurement operation.

  In step S9, when there is no instruction to interrupt power transmission, the process proceeds to step S10, where it is determined whether charging is completed. If charging is not completed, the process returns to step S6, and charging is completed. In step S10, the power supply is terminated and the foreign object detection operation is terminated.

  According to the present embodiment, since the power feeding device 2 includes the foreign matter detection means (capacitance sensor) 14 that can detect an object present on the cover 40, the power supply device 2 is provided between the coil unit 12 and the coil unit 18. It is possible to securely and reliably detect the entry of foreign matter into the body.

  Although the present invention has been described with reference to the above-described embodiment, the present invention is not limited to the above-described embodiment.

  For example, in place of or in addition to the provision of the foreign matter detection means (capacitance sensor) 14 in the power supply device 2, the foreign matter detection means (capacitance sensor) and the monitoring means 17 are provided in the power receiving device 4 and monitored. Similarly, the start trigger may be performed by approaching the relative positional relationship of the power feeding device 2. In this case, since the operation of the detecting means for the foreign matter attached to or approaching the cover of the power receiving device 4 facing the power feeding device 2 is monitored, the foreign matter can always be reliably detected.

  As described above, the contactless power transmission device of the present invention can reliably detect foreign matter that has entered near the electromagnetic field region during power feeding from the power feeding device to the power receiving device. Or it is useful for safety systems, such as the electric power feeding to the receiving device of the electric propulsion vehicle which may approach accidentally.

2 Power feeding device 4 Power receiving device 6 Commercial power supply 8 Power supply box 10 Inverter unit 12 Coil unit 14 Foreign matter detection means (capacitance sensor)
16 Control Unit 17 Monitoring Unit 18 Coil Unit 20 Rectification Unit 22 Load (Battery)
24 Control Unit 30 Electrode 32 Voltage Supply Unit 34 C / V Conversion Unit 36 Signal Processing Unit 40 Cover 42 Substrate 44 Primary Coil

Claims (5)

A power supply device that supplies power to a power receiving device in a contactless manner,
The power supply device
A substrate,
A primary coil disposed on the substrate and generating a magnetic flux by an alternating current;
A cover attached to the substrate and covering the primary coil;
A non-contact power transmission apparatus comprising: a capacitance sensor that detects an object present on the cover; and a monitoring unit that monitors a signal of the capacitance sensor.   The non-contact power transmission device according to claim 1, wherein the capacitance sensor is installed between the cover and the primary coil. A power receiving device that receives power from a power feeding device in a contactless manner,
The power receiving device is:
A substrate,
A secondary coil disposed on the substrate and generating an electromotive force by a magnetic flux generated by a primary coil of the power feeding device;
A cover attached to the substrate and covering the secondary coil;
A non-contact power transmission apparatus comprising: a capacitance sensor that detects an object present on the cover; and a monitoring unit that monitors a signal of the capacitance sensor.   The non-contact power transmission apparatus according to claim 1, wherein the monitoring unit monitors a change in signal of the capacitance sensor triggered by a relative positional relationship of the power receiving apparatus approaching.   The non-contact power transmission device according to claim 3, wherein the monitoring unit monitors a change in signal of the capacitance sensor triggered by the relative positional relationship of the power feeding device approaching.

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