JP2013150430A - Contactless feed apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contactless feed apparatus that can detect foreign matter and control a feed state in accordance with whether there is foreign matter.SOLUTION: In the contactless feed apparatus, a transmission side control device 41 controls a transmission control circuit 42 to stop power transmission if transmission efficiency detected during the power transmission is less than a reference value. The transmission efficiency varies according to a relative position, and the transmission efficiency is best when, for example, a vehicle side pad 30 and a ground side pad 50 are positioned closest (in reference position). The transmission efficiency lowers as the two are separated. If actual transmission efficiency is less than the reference value of transmission efficiency based on the relative position, a determination can be made that it is for some reason, for example, due to intervening foreign matter.

Description

  The present invention relates to a non-contact power feeding device that feeds power from an external power source to a battery of a vehicle in a non-contact manner.

  An electric vehicle such as an electric vehicle and a hybrid vehicle is equipped with a battery that can charge electric power for traveling from an external power source. Known methods for supplying power for charging include a plug-in type power supply device that connects a power supply port on the power supply side and a vehicle charging port with a cable, and a non-contact type power supply device that does not use a cable. .

  A non-contact type power supply device includes a method using electromagnetic induction. In the method using electromagnetic induction, the metallic foreign object generates heat due to the high-frequency magnetic field and becomes high temperature. A device for stopping is provided. Further, the transmission efficiency is detected during power supply, and it is detected that a foreign object such as an object or a person is approaching during power supply based on the transmission efficiency (see, for example, Patent Document 1).

  Further, when non-contact power feeding is used for charging while the car is parked, there are variations in the parking position, so that the positional deviation between the power transmitting unit and the power receiving unit is different each time. Therefore, in the conventional technique described in Patent Document 2, a technique for adjusting the relative position so as to improve the transmission efficiency by using the transmission efficiency between power transmission and reception is disclosed.

JP 2010-119246 A JP 2006-345588 A

  In the prior art described in Patent Document 1, it is impossible to determine whether the efficiency is deteriorated due to foreign matter or the efficiency is deteriorated due to misalignment. Therefore, there is a problem that the efficiency deterioration due to the position shift may be erroneously determined as the efficiency deterioration due to the foreign matter, and the power supply may be stopped.

  In response to such problems, power is transmitted while changing the frequency with a small amount of power, and the frequency characteristics of the efficiency are detected, and it is determined whether the efficiency is deteriorated due to foreign matter or the coil is displaced depending on the detection result. A technique for adjusting the coil position using a coil position adjustment unit is conceivable. In the prior art described in Patent Document 2, a means for moving the primary coil so as to maximize the efficiency of the power supply coil and minimizing deterioration in efficiency due to misalignment is shown. However, these means require a circuit that changes the frequency of the power supply and a mechanism that physically moves the coil. Therefore, there is a problem that not only the manufacturing cost becomes high, but also if foreign matter enters between the coils during power feeding, the presence or absence of the foreign matter cannot be detected.

  Therefore, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a non-contact power feeding device that can detect foreign matter and control a power feeding state according to the presence or absence of the foreign matter.

  The present invention employs the following technical means in order to achieve the aforementioned object.

In invention of Claim 1, it is a non-contact electric power feeder (10) which performs non-contact electric power transmission from a power transmission part (50) to a power receiving part (30),
Efficiency detection means (41) for detecting the transmission efficiency of power transmitted from the power transmission unit to the power reception unit;
Position detecting means (46) for detecting a relative position between the power transmitting unit and the power receiving unit;
A reference value calculating means (41) for calculating a reference value of transmission efficiency at the relative position using the relative position detected by the position detecting means;
Control means (41) for controlling power transmission from the power transmission unit to the power reception unit,
The control means controls the power transmission unit to stop power transmission when the transmission efficiency detected by the efficiency detection means during power transmission is less than the reference value obtained by the reference value calculation means. This is a non-contact power feeding device.

  According to the first aspect of the present invention, when the transmission efficiency detected by the efficiency detecting means is less than the reference value obtained by the reference value calculating means, the control means stops the power transmission by the control means. Is controlled. The transmission efficiency varies depending on the relative position. For example, when the power transmission unit and the power reception unit are closest to each other (reference position), the transmission efficiency is the highest. In addition, the transmission efficiency decreases as the distance between the two increases. Therefore, when the actual transmission efficiency is less than the reference value of the transmission efficiency at the relative position, it can be determined that it is caused by some cause, for example, the entry of foreign matter. Therefore, as described above, when the control means is less than the reference value, the power supply state can be controlled according to the presence or absence of foreign matter by stopping power transmission.

The invention according to claim 2 further includes power amount calculation means (41) for calculating the amount of power necessary for power transmission from the power transmission unit to the power reception unit,
The reference value calculating means calculates a reference value of transmission efficiency at the relative position using the relative position and the calculated electric energy.

  According to the second aspect of the invention, it further includes power amount calculation means for calculating the amount of power necessary for power transmission from the power transmission unit to the power reception unit. This is because the resistance loss of the wiring differs depending on the required amount of power, and these effects are taken into consideration. The reference value calculation means calculates a reference value of transmission efficiency at the relative position using the relative position and the calculated electric energy. Therefore, the control of the power transmission stop by the control unit can be more reliably performed in consideration of the influence of the required power amount.

  Furthermore, the invention described in claim 3 further includes a determination means (41) for determining whether or not the position detection means can be used.

  According to the third aspect of the present invention, since it further includes determination means for determining whether or not the position detection means can be used, the control means can change the control according to whether or not the position detection means can be used. For example, the control means can perform control using the strictest reference value when the position detection means is not mounted or when the position detection means cannot be used due to some malfunction.

  Further, the invention according to claim 4 is characterized in that the control means controls the power transmission section so as to stop power transmission when the position detection means is determined to be unusable by the determination means.

  According to the fourth aspect of the present invention, when the determination unit determines that the position detection unit is unusable, the control unit controls the power transmission unit so as to stop the power transmission. Therefore, when the position detection unit is not usable, for example, when the position cannot be detected, power transmission is stopped. As a result, power can be transmitted only when power can be reliably transmitted.

  Furthermore, in the invention according to claim 5, the control means controls the power transmission using the highest reference value when the position detection means is determined to be unusable by the judgment means and when power transmission is possible. Features.

  According to the fifth aspect of the present invention, when the position detection unit is determined to be unusable by the determination unit, and when power transmission is possible, control is performed to transmit power using the highest reference value. The highest reference value is a reference value at a position where the transmission efficiency is highest. By using such strict conditions, power transmission can be reliably stopped if there is a foreign object even if the position detection means is unusable.

  Furthermore, the invention described in claim 6 further includes a determination notification means (45) for notifying the determination result of the determination means.

  According to the sixth aspect of the present invention, the information processing apparatus further includes a determination notification unit that notifies the determination result of the determination unit. Accordingly, the user can recognize the determination result and can recognize the presence or absence of a foreign object.

  Furthermore, the invention described in claim 7 further includes power transmission notifying means (45) for notifying power transmission stop when power transmission is stopped.

  According to the seventh aspect of the invention, it further includes power transmission notifying means for notifying power transmission stop when power transmission is stopped. As a result, the user can recognize that power transmission has stopped for some reason.

Furthermore, in the invention according to claim 8, the relative position includes the rotation angle of the power receiving unit with respect to the power transmitting unit,
The position detecting means further detects the rotation angle.

  According to the invention described in claim 8, the position detecting means further detects the rotation angle. The transmission efficiency varies depending on the rotation angle. By using such a rotation angle, a more accurate reference value can be calculated.

Furthermore, in the invention according to claim 9, the relative position includes an inclination angle of the power receiving unit with respect to the power transmitting unit,
The position detecting means further detects the tilt angle.

  According to the invention described in claim 9, the position detecting means further detects the tilt angle. The transmission efficiency also changes depending on the inclination angle. By using such an inclination angle, a more accurate reference value can be calculated.

  Further, the invention according to claim 10 is characterized in that the position detecting means detects a relative position using an arrival time until an ultrasonic wave transmitted from the predetermined position is received at the predetermined position. .

  According to the tenth aspect of the present invention, the position detecting means detects the relative position using the arrival time until the ultrasonic wave transmitted from the predetermined position is received at the predetermined position. Accordingly, the relative position can be detected accurately.

  Further, the invention according to claim 11 is characterized in that the position detecting means images the mark (33) given at a predetermined position and detects a relative position using the position of the imaged mark. To do.

  According to the eleventh aspect of the present invention, the position detecting means images the mark given to the predetermined position, and detects the relative position using the position of the imaged mark. Accordingly, the relative position can be detected accurately.

  Furthermore, in the invention described in claim 12, the position detection means detects the relative position by irradiating the reflection portion provided at the predetermined position with infrared rays and detecting the reflected wave from the reflection portion. Features.

  According to the twelfth aspect of the present invention, the position detection means detects the relative position by irradiating the reflection portion provided at the predetermined position with infrared rays and detecting the reflected wave from the reflection portion. Accordingly, the relative position can be detected accurately.

  In addition, the code | symbol in the bracket | parenthesis of each above-mentioned means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is a block diagram illustrating a non-contact power feeding system 10 according to a first embodiment. 4 is a flowchart illustrating a charging process of a power transmission side control device 41. 3 is a plan view showing a ground side pad 50. FIG. 3 is a plan view showing a vehicle-side pad 30. FIG. It is a graph which shows a reference | standard efficiency map. It is a graph which shows an electric current correction coefficient map. It is a top view showing vehicle side pad 30A. It is a graph which shows the reference | standard efficiency map in case rotation angle (alpha) is 0 degree | times. It is a graph which shows the reference | standard efficiency map in case rotation angle (alpha) is 5 degree | times. It is a top view which shows the vehicle side pad 30B. It is a graph which shows the reference | standard efficiency map in case angle (alpha) = (beta) = (gamma) is 0 degree | times. It is a graph which shows the standard efficiency map of other examples. It is a top view which shows 50C of ground side pads. It is a top view which shows 30C of vehicle side pads.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. In some embodiments, portions corresponding to the matters described in the preceding embodiments may be given the same reference numerals, or one letter may be added to the preceding reference numerals, and overlapping descriptions may be omitted. In addition, when a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those of the embodiment described in advance. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination does not hinder the combination.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram illustrating an electrical configuration of a contactless power feeding system 10 according to the first embodiment. The non-contact power supply system 10 can be applied when charging a main battery such as an electric vehicle and a plug-in hybrid vehicle. The non-contact power supply system 10 is a system that transmits power by a non-contact electromagnetic induction method between a main battery 11 that is a secondary battery and an external power source (not shown) installed outside the vehicle 12. . The electromagnetic induction method is a method of sending electric power using an induced magnetic flux generated between the power transmission side and the power reception side. The non-contact power supply system 10 includes a power receiving device 20 and a vehicle side pad 30 mounted on the vehicle 12, and a power transmission device 40 and a ground side pad 50 installed outside the vehicle 12. The ground side pad 50 and the vehicle side pad 30 are collectively referred to as a non-contact power feeding device.

  First, the power transmission device 40 will be described. The power transmission device 40 is provided in, for example, homes, apartment houses, parking facilities such as coin parking, commercial facilities, and public facilities. The power transmission device 40 is connected to an external power source (not shown) that is external to the vehicle 12 and a ground pad 50. The external power source is, for example, a system power source. The power transmission device 40 operates when power is supplied to the vehicle-side pad 30 of the vehicle 12. Therefore, the power transmission device 40 transmits power from the external power source to the vehicle 12. The power transmission device 40 includes a power transmission side control device 41, a power transmission control circuit 42, a power transmission circuit 43, a power transmission side wireless communication circuit 44, a notification unit 45, and a position detection unit 46. The power transmission device 40 is controlled by the power transmission side control device 41.

  The power transmission side wireless communication circuit 44 wirelessly communicates with the power receiving device 20 and transmits / receives various information of the power transmitting device 40 and various information of the power receiving device 20. The power transmission side wireless communication circuit 44 provides the received information to the power transmission side control device 41. Further, the power transmission side wireless communication circuit 44 transmits information from the power transmission side control device 41 to the power receiving device 20.

  The notification unit 45 is a notification unit that notifies the user of the status of the power transmission device 40 and the power reception device 20. The notification unit 45 notifies information given from the power transmission side control device 41, for example, a charge completion time and a charge amount.

  The position detection unit 46 is position detection means, and detects a relative position between the ground side pad 50 and the vehicle side pad 30. The position detection unit 46 gives the detected relative position to the power transmission side control device 41.

  The power transmission control circuit 42 controls the power transmission circuit 43 to control the start and stop of power transmission. The power transmission control circuit 42 is controlled by the power transmission side control device 41. Although not shown, the power transmission circuit 43 includes a high frequency conversion circuit and a resonance circuit.

  The high-frequency conversion circuit converts power supplied from an external power source into high-frequency power and supplies it to the resonance circuit. In order to transmit power efficiently, the resonance circuit converts the voltage and current of the power applied from the high-frequency conversion circuit so as to coincide with each other, and applies the same to the ground pad 50.

  The power transmission side control device 41 controls the power transmission control circuit 42 based on the information from the power transmission side wireless communication circuit 44, the information from the position detection unit 46, and the voltage and current transmitted to the ground side pad 50.

  Next, the ground side pad 50 will be described. The ground side pad 50 has a power transmission coil (primary side coil) that transmits electric power in a non-contact manner, and is provided so as to be exposed to the ground. A portion of the outer surface of the ground pad 50 covers a power transmission coil (not shown) and a part thereof is exposed to the ground.

  The power transmission coil is built in the ground side pad 50. The power transmission coils are each installed or embedded in a parking space defined in the parking facility together with the ground side pad 50, and are configured to generate an electromagnetic field by predetermined energization. The power transmission coil performs non-contact power transfer between the power reception coil provided on the vehicle 12 side. The power transmission coil is connected to the power transmission circuit 43 and transmits high-frequency power supplied from the power transmission circuit 43 to the vehicle 12 on which the power reception coil is mounted by electromagnetic induction.

  Next, the vehicle side pad 30 will be described. The vehicle-side pad 30 has a power receiving coil (secondary side coil) that receives power in a non-contact manner, and is provided on the vehicle 12 so as to be exposed outside the vehicle.

  A power receiving coil (not shown) is built in the vehicle-side pad 30. The power receiving coil performs non-contact power transfer with the power transmitting coil. In the power receiving coil, an electromagnetic field is also generated in the power receiving coil due to the influence of the electromagnetic field generated by the power transmitting coil, a current flows through the power receiving coil, and a voltage is generated. The power receiving coil is connected to the power receiving circuit 23 and supplies the generated high frequency power to the power receiving circuit 23.

  First, the power receiving device 20 will be described. The power receiving device 20 is connected to the vehicle-side pad 30. The power receiving device 20 operates when charging the main battery 11 using an external power source. The power receiving device 20 includes a power receiving side control device 21, a power receiving control circuit 22, a power receiving circuit 23, a power receiving side wireless communication circuit 24, and the main battery 11. The power receiving device 20 is controlled by the power receiving side control device 21.

  The power receiving side wireless communication circuit 24 wirelessly communicates with the power transmission device 40 and transmits / receives various information of the power receiving device 20 and various information of the power transmission device 40. The power receiving side wireless communication circuit 24 gives the received information to the power receiving side control device 21. The power receiving side wireless communication circuit 24 transmits information from the power receiving side control device 21 to the power receiving device 20.

  The power reception control circuit 22 controls the power reception circuit 23 to control start and stop of power reception. The power receiving circuit 23 outputs the power supplied from the power receiving coil built in the vehicle side pad 30 as a DC voltage, and charges the main battery 11. The power reception circuit 23 is controlled by the power reception control circuit 22. Although not shown, the power receiving circuit 23 includes a resonance circuit, a rectifier circuit, and a booster circuit.

  In order to transmit power efficiently, the resonant circuit converts the voltage and current of the power supplied from the power receiving coil so as to coincide with each other, and supplies the rectifier circuit with the converted voltage. The rectifier circuit is composed of a diode and a capacitor. The rectifier circuit rectifies the high-frequency power supplied from the resonance circuit with a diode, smoothes it with a capacitor, and then supplies it to the booster circuit. The booster circuit boosts the voltage of the power from the rectifier circuit to a voltage higher than that of the main battery 11 and supplies current to the main battery 11.

  A battery ECU 25 is mounted on the main battery 11. The battery ECU 25 monitors the charge amount, temperature, and the like of the main battery 11 and gives information on the main battery 11 to the power receiving side control device 21.

  The power receiving side control device 21 controls the power receiving control circuit 22 based on the information from the power receiving side wireless communication circuit 24, the information from the battery ECU 25, and the voltage and current transmitted to the main battery 11.

  Charging is started by the charging start button 26. When the user operates the charging start button 26, the power receiving side control device 21 operates, communicates with the power transmission device 40, and starts charging if charging can be started based on various information.

  Next, specific control of the power transmission side control device 41 will be described. FIG. 2 is a flowchart showing a charging process of the power transmission side control device 41. The charging process is a process executed when the power transmission device 40 is powered on.

  In step S1, it is determined whether or not the charge start button 26 is operated to make a charge start request (charge start ON). If the charge start ON is made, the process proceeds to step S2 and the charge start ON is made. Step S1 is repeated until

  In step S2, the presence or absence of the position detector 46 is confirmed, and the process proceeds to step S3. The case where there is no position detection unit 46 means that the power receiving device 20 (the vehicle 12) is not functioning due to a case where a configuration capable of detecting the position of the vehicle-side pad 30 is not mounted or some sort of malfunction. If there is no position detector 46, the position information detected by the position detector 46 cannot be used. Accordingly, the processing differs depending on the presence / absence of the position detection unit 46, and thus confirmation is made in step S2.

  In step S3, based on the result of step S2, it is determined whether or not there is a position detection unit 46. If there is a position detection unit 46, the process proceeds to step S4. If there is no position detection unit 46, step S3 is performed. Move on to S13.

  In step S4, the position information from the position detector 46 is acquired, and the process proceeds to step S5. In step S5, it is determined whether or not the position has been detected. If the position has been detected, the process proceeds to step S6. If the position cannot be detected (position information cannot be acquired), the process proceeds to step S14.

  In step S6, it is determined whether or not the relative position is within a predetermined range (within a predetermined distance). If the relative position is within the predetermined range, the process proceeds to step S7, and if the relative position is not within the predetermined range. The process proceeds to step S14.

  In step S7, a charge request current (hereinafter sometimes referred to as “request current”) is calculated, and the process proceeds to step S8. The required current is a current that can be charged efficiently, and is calculated using an SOC (State of Charge) detected by the battery ECU 25.

  In step S8, the reference efficiency is calculated, and the process proceeds to step S9. The reference efficiency is calculated using a relative position (relative position), and is a reference value of transmission efficiency at the relative position. The reference efficiency is obtained based on the correlation between the relative position and the transmission efficiency that the transmission efficiency is higher as the relative position is closer.

  In step S13, since there is no position detection unit 46, the reference efficiency when there is no position detection unit 46 is calculated, and the process proceeds to step S9. Since the relative position cannot be determined without the position detection unit 46, the reference efficiency under the strictest conditions (the position with the highest transmission efficiency) is calculated.

  In step S9, the power transmission control circuit 42 is controlled to start power transmission, and the process proceeds to step S10. In step S10, the charging current during power transmission is controlled, and the process proceeds to step S11. The control of the charging current instructs the power receiving device 20 to be the required current calculated in step S7. Accordingly, the power receiving device 20 controls the power reception control circuit 22 so that the charging current becomes the required current.

  In step S11, the current transmission efficiency is calculated, and the process proceeds to step S12. The transmission efficiency is calculated by dividing the output (effective value) of the power transmission circuit 43 by the output of the power reception circuit 23. In step S12, it is determined whether or not the transmission efficiency is higher than the reference efficiency. If the transmission efficiency is higher than the reference efficiency, the process proceeds to step S3. If the transmission efficiency is not higher than the reference efficiency, the process proceeds to step S14. Move. Therefore, when the transmission efficiency is equal to or higher than the reference efficiency, it is determined that there is no foreign matter between the ground pad 50 and the vehicle pad 30 and power can be transmitted smoothly, and the processing from step S3 is repeated again. .

  In step S14, since the transmission efficiency is not equal to or higher than the reference efficiency, there is a possibility that a foreign object has entered. Therefore, the notification unit 45 is controlled to output an alarm, power transmission is stopped, and the process returns to step S1. This is because the foreign matter may cause a loss in transmission efficiency, for example, a loss due to an eddy current in the metallic foreign matter. In step S14, if the position detection unit 46 is present in step S5 but the position cannot be detected, it is determined that there is some abnormality, an alarm is similarly output, and the process returns to step S1. In step S14, if the relative position is out of the predetermined range in step S6, it is determined that power transmission is difficult due to the position shift, an alarm is similarly output, and the process returns to step S1.

  Thus, the power transmission side control device 41 calculates the reference value of the transmission efficiency based on the relative positional relationship between the ground side pad 50 and the vehicle side pad 30, and when the transmission efficiency is less than the specified value, Pause power transmission. As a result, even when the ground pad 50 and the vehicle pad 30 are misaligned, foreign matter can be detected in real time during power feeding.

  Next, the configuration of the position detection unit 46 will be described. FIG. 3 is a plan view showing the ground side pad 50. FIG. 4 is a plan view showing the vehicle-side pad 30. The position detection method of the position detection unit 46 detects the relative position using the arrival time until the ultrasonic wave transmitted from the predetermined position is received at the predetermined position. Specifically, an ultrasonic oscillator 31 is provided at the center of the surface of the vehicle-side pad 30 located on the ground-side pad 50 side. Of the surface of the ground side pad 50, a plurality of ultrasonic receivers 51, three in this embodiment, are provided on the surface located on the vehicle side pad 30 side. The three ultrasonic receivers 51 are arranged away from each other. In the present embodiment, the three ultrasonic receivers 51 are respectively located at the vertices of an isosceles triangle that is centered on the center of the surface of the ground-side pad 50 and that forms a base line connecting two corners on the long side. Has been placed.

  In the position detection method, the ultrasonic waves transmitted from one ultrasonic oscillator 31 of the vehicle-side pad 30 are received by the three ultrasonic receivers 51, and the arrival times of the sound waves to the respective ultrasonic receivers 51 are received. Using the difference, the position of the ultrasonic oscillator 31 is specified by the principle of three-point surveying. Accordingly, the relative position can be detected accurately. As the position of the ultrasonic oscillator 31, a vehicle traveling direction X, a vehicle width direction Y, and a vehicle height direction Z are detected. Further, the displacement is calculated with the vehicle-side pad 30 and the ground-side pad 50 facing each other as viewed in the vehicle height direction Z and the center completely overlapping.

  Next, a method for calculating the reference efficiency will be described. FIG. 5 is a graph showing a reference efficiency map. FIG. 6 is a graph showing a current correction coefficient map. These maps are measured in advance and stored in the memory of the power transmission side control device 41 or the power reception side control device 21. The reference efficiency is calculated by the following equation (1).

Reference efficiency = reference efficiency (before correction) x current correction coefficient (1)
Here, the reference efficiency before correction is obtained using the map shown in FIG. 5 from the displacement (positional deviation) of X, Y, and Z described above. The map shown in FIG. 5 shows the relationship between the Y displacement and the reference efficiency (before correction) when Z is constant. The reference efficiency decreases as the Y displacement increases, and the reference efficiency decreases as the X displacement increases. The power transmission side control device 41 determines the reference efficiency (before correction) from the reference efficiency map.

  As a result, it is possible to consider a change in efficiency due to a positional shift between the vehicle side pad 30 and the ground side pad 50. Therefore, even if the pads 30 and 50 are displaced, foreign objects can be detected more accurately and power transmission can be stopped.

  The current correction coefficient is obtained using the current correction coefficient map of FIG. The current correction coefficient is smaller than 1 when the required current is small and large. This is affected by loss characteristics such as wiring. Since the required current is calculated by the above-described charging process, the power transmission side control device 41 determines the current correction coefficient from the current correction coefficient map.

  As a result, the influence of the loss of the power transmission circuit 43 / power receiving circuit 23 and the resistance loss of the wiring on the current change can be taken into consideration. Therefore, more accurate detection of foreign matter is possible, and power transmission can be stopped.

  As described above, the non-contact power feeding system 10 of the present embodiment is configured such that the transmission efficiency detected by the power transmission side control device 41 functioning as the efficiency detection unit during power transmission functions as the reference value calculation unit. If it is less than the reference value obtained by 41, the power transmission control circuit 42 functioning as a power transmission unit is controlled by the power transmission side control device 41 functioning as control means so as to stop power transmission. The transmission efficiency varies depending on the relative position. For example, when the vehicle side pad 30 and the ground side pad 50 are located closest to each other (reference position), the transmission efficiency is best. In addition, the transmission efficiency decreases as the distance between the two increases. Therefore, when the actual transmission efficiency is less than the reference value of the transmission efficiency at the relative position, it can be determined that it is caused by some cause, for example, the entry of foreign matter. Therefore, as described above, when the power transmission side control device 41 is less than the reference value, the power feeding state can be controlled according to the presence or absence of foreign matter by stopping power transmission.

  Moreover, in this embodiment, the power transmission side control apparatus 41 functions also as an electric energy calculation means which calculates the electric energy required for the power transmission from the ground side pad 50 which is a power transmission part to the vehicle side pad 30 which is a power receiving part. This is because the resistance loss and the like of the wiring differ depending on the required amount of power, and these effects are taken into consideration (see FIG. 6). The power transmission side control device 41 calculates the reference value of the transmission efficiency at the relative position using the relative position and the calculated electric energy. Therefore, the power transmission stop control by the power transmission side control device 41 can be more reliably performed in consideration of the influence of the necessary power amount.

  Furthermore, in the present embodiment, the power transmission side control device 41 also has a function of a determination unit that determines whether or not the position detection unit 46 that is a position detection unit can be used. The power transmission side control device 41 can change the control according to the availability of the position detection unit 46. For example, the power transmission side control device 41 can perform control using the strictest reference value when the position detection unit 46 is not mounted or cannot be used due to some trouble.

  Moreover, in this embodiment, when it is judged that the position detection part 46 cannot be used, it controls so that power transmission is stopped (refer step S5). Therefore, when the position detection unit 46 cannot be used, for example, when the position cannot be detected, power transmission is stopped. As a result, power can be transmitted only when power can be reliably transmitted.

  Furthermore, in this embodiment, when it is determined that the position detection unit 46 is unusable, and power transmission is possible, control is performed to transmit power using the highest reference value (see step S13). The highest reference value is a reference value at a position where the transmission efficiency is highest. By using such strict conditions, even if the position detection unit 46 is unusable, power transmission can be reliably stopped if there is a foreign object.

  Moreover, in this embodiment, the alerting | reporting part 45 has a function as a judgment alerting | reporting means which alert | reports the judgment result of the power transmission side control apparatus 41. FIG. As a result, the user can recognize the determination result and can recognize the presence or absence of a foreign object (see step S14).

  Furthermore, in this embodiment, the notification unit 45 has a function as power transmission notification means for notifying power transmission stop when power transmission is stopped. As a result, the user can recognize that the power transmission has stopped for some reason (see step S14).

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a plan view showing the vehicle-side pad 30A. The present embodiment is characterized in that, in the configuration of the position detection unit 46, two ultrasonic oscillators 31A are provided on the vehicle-side pad 30A. Two ultrasonic oscillators 31 </ b> A are provided on the surface of the vehicle-side pad 30 </ b> A located on the ground-side pad 50 side so as to be aligned in the vehicle width direction Y and spaced from each other.

  In the position detection method, the ultrasonic waves alternately transmitted from the two ultrasonic oscillators 31A of the vehicle-side pad 30A are received by the three ultrasonic receivers 51, and the sound waves to the respective ultrasonic receivers 51 are received. Using the difference in arrival time, the positions of the two ultrasonic oscillators 31A are specified by the principle of three-point surveying. Thereby, the rotation angle α around the vehicle height direction Z of the pad can also be detected. As described above, the position detection unit 46 of the present embodiment further includes a rotation angle detection unit that detects a rotation angle.

  Next, a method for calculating the reference efficiency will be described. FIG. 8 is a graph showing a reference efficiency map when the rotation angle α is 0 degree. FIG. 9 is a graph showing a reference efficiency map when the rotation angle α is 5 degrees.

  The reference efficiency before correction is obtained using the maps shown in FIGS. 8 and 9 from the aforementioned X, Y, Z displacement (positional deviation) and the rotation angle α. The map shown in FIG. 8 shows the relationship between the Y displacement and the reference efficiency (before correction) when the rotation angle α is 5 degrees and Z is constant. The map shown in FIG. 9 shows the relationship between the Y displacement and the reference efficiency (before correction) when the rotation angle α is 5 degrees and Z is constant. When the rotation angle α is different, the reference efficiency (before correction) is different. Accordingly, even when the vehicle 12 is bent with respect to the parking position and stopped, the reference efficiency can be accurately corrected. Therefore, it is possible to detect foreign matter more accurately.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a plan view showing the vehicle-side pad 30B. The present embodiment is characterized in that, in the configuration of the position detector 46, three ultrasonic oscillators 31B are provided on the vehicle-side pad 30B. Two ultrasonic oscillators 31 </ b> B are provided on the surface of the vehicle-side pad 30 </ b> B located on the ground-side pad 50 side so as to be aligned in the vehicle width direction Y and spaced apart from each other. The third ultrasonic oscillator 31B is provided at a position shifted from the center of the surface of the vehicle-side pad 30B toward the vehicle retreat direction.

  In the position detection method, ultrasonic waves alternately transmitted from the three ultrasonic oscillators 31B of the vehicle-side pad 30B are received by the three ultrasonic receivers 51, and the sound waves to the respective ultrasonic receivers 51 are received. Using the difference in arrival time, the positions of the three ultrasonic oscillators 31B are specified by the principle of three-point surveying. Thus, the three-dimensional rotation direction of the pad can be detected. Specifically, the pitch angle β around the vehicle width direction Y and the roll angle γ around the vehicle traveling direction X can be further detected. Therefore, the position detection unit 46 further includes an inclination angle detection unit that detects inclination angles (pitch angle β and roll angle γ).

  Next, a method for calculating the reference efficiency will be described. FIG. 11 is a graph showing a reference efficiency map when the angle α = β = γ is 0 degree. FIG. 12 is a graph showing a reference efficiency map when the rotation angle α is 10 degrees, the pitch angle β is 2 degrees, and the roll angle γ is 0 degrees.

  The reference efficiency before correction is obtained using the maps shown in FIGS. 11 and 12 from the displacements (positional deviations) of X, Y and Z and the angles α, β and γ. The map shown in FIG. 11 shows the relationship between the Y displacement and the reference efficiency (before correction) when the angle α = β = γ is 0 degree and Z is constant. The map shown in FIG. 12 shows the Y displacement and the reference efficiency (before correction) when the rotation angle α is 10 degrees, the pitch angle β is 2 degrees, the roll angle γ is 0 degrees, and Z is constant. Shows the relationship. When the angles α, β, and γ are different, the reference efficiency (before correction) is different. Accordingly, even when the vehicle 12 is bent with respect to the parking position and stopped, or even when the vehicle 12 is inclined with respect to the ground due to loading of luggage, the reference efficiency can be accurately corrected. Therefore, it is possible to detect foreign matter more accurately.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a plan view showing the ground pad 50C. FIG. 14 is a plan view showing the vehicle-side pad 30C. In the present embodiment, the position detection unit 46 is characterized in that the camera 32 is used instead of the ultrasonic oscillator 31B.

  Two cameras 32 (imaging means) are provided on the surface of the ground side pad 50C located on the vehicle side pad 30C side so as to be aligned in the vehicle width direction Y and spaced apart from each other.

  Three markers 33 are provided on the surface of the vehicle-side pad 30C located on the ground-side pad 50C side. The two markers 33 are arranged side by side in the vehicle width direction Y and spaced apart from each other. The third marker 33 is provided at a position shifted from the center of the surface of the vehicle-side pad 30C toward the vehicle reverse direction.

  The position detection unit 46 detects the position of the three markers 33 by the two cameras 32, identifies the three markers 33 by image recognition from the captured image data, and determines the three-dimensional position of each of the markers 33. Calculation is performed by a method using the parallax of the two cameras 32. If the positions of the three markers 33 can be specified in this way, the three-dimensional rotation direction of the vehicle-side pad 30C can be detected as in the third embodiment described above.

  By placing the high-cost camera 32 on the ground side pad 50C in this way, when the power transmission side and the power reception side become one-to-many, it is not necessary to increase the number of cameras 32 even if the power reception side is increased, thereby reducing the cost.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In the first embodiment described above, the control means is the power transmission side control device 41, but is not limited to the power transmission side control device 41, and any control means in the non-contact power feeding system 10 is shown in FIG. What is necessary is just to implement a charging process, for example, you may perform a charging process with the receiving side control apparatus 21. FIG. Further, since the power transmission side control device 41 and the power reception side control device 21 perform control while communicating with each other, the charging processing may be performed jointly by the two control devices with their roles determined.

  In the first embodiment described above, the position detection unit 46 has a configuration using ultrasonic waves. However, the position detection unit 46 is not limited to ultrasonic waves, and similarly uses light and radio waves to detect positions using a receiver and an oscillator. You may comprise. For example, using an infrared oscillator / receiver and an infrared reflection marker (reflecting part) as a mark (marker) given at a predetermined position, irradiating the reflection marker with infrared rays, and receiving the reflected wave again by the receiver Even if the arrival time is used, the position can be similarly detected.

  In the first embodiment described above, the non-contact power feeding device is used when charging the vehicle, but is not limited to the vehicle, and may be used for other moving bodies such as a ship and an aircraft. The supplied electric power is not limited to use for charging, and the supplied electric power may be supplied to an apparatus that consumes the electric power sequentially with a load.

10 ... Non-contact power feeding system (Non-contact power feeding device)
30 ... Vehicle side pad (power receiving part)
31 ... Ultrasonic oscillator 32 ... Camera 33 ... Marker
41... Power transmission side control device (efficiency detection means, reference value calculation means, control means, power amount calculation means, determination means)
45. Informing part (judgment informing means, power transmission informing means)
46: Position detection unit (position detection means)
50 ... Ground side pad (power transmission part)
51. Ultrasonic receiver

Claims (12)

A non-contact power feeding device (10) that performs non-contact power transmission from a power transmission unit (50) to a power reception unit (30),
Efficiency detection means (41) for detecting transmission efficiency of power transmitted from the power transmission unit to the power reception unit;
Position detection means (46) for detecting a relative position between the power transmission unit and the power reception unit;
A reference value calculating means (41) for calculating a reference value of the transmission efficiency at the relative position using the relative position detected by the position detecting means;
Control means (41) for controlling power transmission from the power transmission unit to the power reception unit,
When the transmission efficiency detected by the efficiency detection unit during power transmission is less than the reference value obtained by the reference value calculation unit, the control unit causes the power transmission unit to stop the power transmission. A non-contact power feeding device that is controlled. And further includes an electric energy calculating means (41) for calculating electric energy required for power transmission from the power transmitting unit to the power receiving unit,
The non-standard value calculating unit according to claim 1, wherein the reference value calculating unit calculates a reference value of the transmission efficiency at the relative position using the relative position and the calculated electric energy. Contact power supply device.   The non-contact power feeding apparatus according to claim 1, further comprising a determination unit (41) that determines whether or not the position detection unit can be used.   The contactless power feeding according to claim 3, wherein the control unit controls the power transmission unit to stop power transmission when the position detection unit is determined to be unusable by the determination unit. apparatus.   4. The control unit according to claim 3, wherein when the position detection unit is determined to be unusable by the determination unit and when power transmission is possible, the control unit controls power transmission using the highest reference value. The non-contact electric power feeder as described in.   The contactless power feeding device according to any one of claims 3 to 5, further comprising a determination notification unit (45) for notifying a determination result of the determination unit.   The non-contact power feeding device according to any one of claims 1 to 6, further comprising power transmission notification means (45) for notifying power transmission stop when the power transmission is stopped. The relative position includes a rotation angle of the power reception unit with respect to the power transmission unit,
The non-contact power feeding apparatus according to claim 1, wherein the position detection unit further detects the rotation angle. The relative position includes an inclination angle of the power reception unit with respect to the power transmission unit,
The non-contact power feeding apparatus according to claim 1, wherein the position detecting unit further detects the tilt angle.   The said position detection means detects the said relative position using the arrival time until the ultrasonic wave transmitted from the predetermined position is received at the predetermined position. The non-contact electric power feeder as described in one.   The said position detection means images the mark (33) provided in the predetermined position, and detects the said relative position using the position of the said imaged said mark. The non-contact electric power feeder as described in any one of these.   The said position detection means irradiates infrared rays to the reflection part provided to the predetermined position, detects the reflected wave from a reflection part, and detects the said relative position, The non-contact electric power feeder as described in any one of these.

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