JP6464994B2 - Non-contact power transmission device - Google Patents

Description

  The present invention relates to a non-contact power transmission device for performing non-contact power transmission between a vehicle and a power supply stand.

  In recent years, electric vehicles (EV) and hybrid vehicles (HV / EHV) are becoming widespread. Charging methods for charging batteries mounted on these vehicles with an external power source include non-contact power transmission using electromagnetic induction, electromagnetic resonance, or radio waves in addition to wired contact power transmission. In particular, non-contact power transmission attracts attention because it is expected to be more convenient than contact power transmission, such as being able to start charging the battery just by parking in a predetermined space, or charging while running the vehicle. Yes.

  By the way, in order to improve transmission efficiency in non-contact power transmission using an electromagnetic field, it is necessary to accurately match the relative positions of the coils on the power feeding side and the power receiving side. For this purpose, for example, when the vehicle is parked in a space for power supply, accurate alignment is required.

  In order to adjust the position of the vehicle to the space for power feeding, it is conceivable to use an optical sensor or a position sensor provided on the vehicle or outside, but due to poor visibility due to weather or detection failure due to obstacles There is a possibility that the vehicle cannot be parked accurately in a predetermined space.

  Further, as a conventional technique, a method has been proposed in which the vehicle acquires the transmission efficiency at the current position to notify the driver of whether charging is possible or impossible, or notifies the transmission efficiency value itself. However, even though this method can know whether charging is possible or impossible at the current position, it is not easy for the driver to know whether the parking position of the vehicle is optimal.

  In order to solve these problems, Patent Document 1 discloses a technique for notifying the driver whether the transmission efficiency is increasing or decreasing with respect to the movement of the vehicle. According to this, the driver can know the direction in which the vehicle heads to the optimum position. Specifically, if the transmission efficiency is increased with respect to the traveling direction, it is only necessary to proceed in the same direction, and if the transmission efficiency is decreased, it may be retracted with respect to the traveling direction.

JP2013-116004A

  However, in the invention disclosed in Patent Document 1, even if the direction in which the vehicle should be moved is known, the distance to be moved cannot be recognized. For this reason, the driver needs to proceed as it is while the transmission efficiency is increasing, and once confirming that the transmission efficiency decreases, the driver needs to move backward to find the optimum position. That is, when the invention disclosed in Patent Document 1 is adopted, the driver goes forward and backward at least twice while paying attention to the increase or decrease in transmission efficiency in order to find the optimal parking position of the vehicle. There is a need. This is not efficient in terms of time and route, and may cause discomfort such as annoyance to the driver.

  The present invention has been made in view of the above problems, and aims to provide a non-contact power transmission device capable of shortening the time until parking and allowing the vehicle to be parked more accurately in the power supply space. To do.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and limit the technical scope of the invention. Not what you want.

In order to achieve the above object, the present invention provides a power supply unit (11) that is installed in a space (10) where a vehicle (20) is parked and transmits power, and power that is mounted on the vehicle and transmitted from the power supply unit. A power reception unit (21) that receives power, a position acquisition unit (22) that acquires the current position of the vehicle, a transmission efficiency calculation unit (23) that calculates transmission efficiency of power between the power supply unit and the power reception unit, A control unit (24) for controlling power transmission between the unit and the power receiving unit, the control unit including a vehicle position acquired by the position acquisition unit, and a transmission efficiency calculated by the transmission efficiency calculation unit. The position differential value of the transmission efficiency is calculated based on the above, and the vehicle is determined to be in the optimum position in the space on the condition that the position differential value becomes zero , and the driver is further notified. An image that informs the relative position of the vehicle and space A display unit (27) for displaying is provided, and the control unit continuously generates images such that the distance between the vehicle and the space on the image becomes shorter as the absolute value of the position differential value approaches zero. And it is characterized by displaying on a display part .

  In the vicinity of the position where the transmission efficiency is maximum, the transmission efficiency is substantially parabolic with the maximum position as the apex. That is, if the vehicle moves linearly, the transmission efficiency changes to a substantially parabolic shape that is convex upward depending on the position of the vehicle. The position where the transmission efficiency is maximum is the apex of the parabola, and the differential value of the transmission efficiency with respect to the position is zero.

  This non-contact power transmission device determines that the vehicle is at an optimal position in the space on the condition that the position differential value becomes zero, and notifies the driver. Since the driver only has to stop the vehicle based on this notification, it is possible to find an optimum position for power reception by one forward or backward movement. That is, the vehicle position can be easily aligned. Therefore, it is possible to shorten the time until parking and to park the vehicle more accurately in the power feeding space.

  In particular, it is preferable to inform the driver of the relative position between the vehicle and the optimum position in the parking space. According to this, the driver can park in the power feeding space more accurately without passing through the optimum position.

It is a block diagram which shows schematic structure of the non-contact electric power transmission apparatus concerning 1st Embodiment. It is a figure which shows the position dependence of transmission efficiency and its position differential value. It is a flowchart which shows the operation | movement flow of a non-contact electric power transmission apparatus. It is a figure which shows an example of the image displayed on a display part. It is a figure which shows an example of the image displayed on a display part. It is a figure which shows an example of the image displayed on a display part. It is a figure which shows an example of the image displayed on a display part. It is a figure which shows the relationship between the position differential value of transmission efficiency, and the display mode of an image. In the modification 1, it is a figure which shows the relationship between the relative distance L on the screen of the display which shows a vehicle, and the display which shows the optimal position of parking, and the position differential value of transmission efficiency. It is a flowchart which shows the operation | movement flow of the non-contact electric power transmission apparatus concerning 2nd Embodiment. It is a figure which shows the relationship between the target vehicle speed and the position differential value of transmission efficiency. It is a figure which shows the relationship between the target vehicle speed in the modification 2, and the position differential value of transmission efficiency. It is a flowchart which shows the operation | movement flow of the non-contact electric power transmission apparatus concerning 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals are given to the same or equivalent parts.

(First embodiment)
Initially, with reference to FIG. 1 and FIG. 2, schematic structure of the non-contact electric power transmission apparatus which concerns on this embodiment is demonstrated.

  The non-contact power transmission device in the present embodiment is a device for charging a battery mounted on a vehicle wirelessly. Charging is performed when the vehicle is parked in a predetermined parking space. It does not matter whether the non-contact power feeding and power receiving are electromagnetic induction, electromagnetic resonance, or radio wave.

  As illustrated in FIG. 1, the non-contact power transmission apparatus 100 includes a power feeding unit 11, a power receiving unit 21, a position acquisition unit 22, a transmission efficiency calculation unit 23, and a control unit 24. In addition, the non-contact power transmission apparatus 100 according to the present embodiment includes a power supply side communication unit 12, a power reception side communication unit 25, a vehicle speed sensor 26, and a display unit 27.

  The power feeding unit 11 and the power feeding side communication unit 12 are included in the parking space 10. For example, the power supply unit 11 is embedded so as to be disposed below the vehicle 20 when parked, and the power supply side communication unit 12 is disposed near the vehicle 20 when parked. It has become. The power feeding unit 11 transmits power to the power receiving unit 21 that is approaching. On the other hand, the power reception unit 21, the position acquisition unit 22, the transmission efficiency calculation unit 23, the control unit 24, the power reception side communication unit 25, the vehicle speed sensor 26, and the display unit 27 are mounted on the vehicle 20. When the vehicle 20 parks in the parking space 10, the power reception unit 21 receives power from the power supply unit 11. Thereby, a battery (not shown) is charged.

  The power feeding unit 11 outputs electric power supplied from a power source (not shown) to the outside in the form of an electromagnetic field or a radio wave. For example, when power transmission is performed using an electromagnetic field, the power supply unit 11 includes a coil, and generates an electromagnetic field based on a current flowing through the coil.

  The power feeding side communication unit 12 communicates with a power receiving side communication unit 25 described later, and controls the power feeding unit 11 according to the situation on the vehicle 20 side. For example, the power supply side communication unit 12 receives the charge status of the battery mounted on the vehicle 20 from the power reception side communication unit 25, and stops the power output of the power supply unit 11 when the battery is fully charged. I have control.

  The power receiving unit 21 receives the energy output from the power feeding unit 11 and converts it into electrical energy. For example, the power receiving unit 21 includes a coil as in the case of the power supply unit 11, and converts an electromagnetic field generated in the vicinity of the power supply unit 11 into electric energy.

  The power received by the power receiving unit 21 with respect to the power output from the power feeding unit 11 is referred to as transmission efficiency. The transmission efficiency varies depending on the relative position of the coil of the power feeding unit 11 and the coil of the power receiving unit 21 and the surrounding environment. In the vicinity of the position where the transmission efficiency is maximized, the relative position between the power feeding unit 11 and the power receiving unit 21 is substantially dominant. In the vicinity of the position where the transmission efficiency is maximized, the transmission efficiency becomes a substantially parabolic shape which is convex upward with the position where the transmission efficiency is maximized. Assuming that the vehicle 20 to be parked moves substantially linearly to go to the parking position, the transmission efficiency E changes to a substantially parabolic shape with respect to the vehicle position x as shown by a solid line in FIG. In FIG. 2, the position of the vehicle 20 at which the transmission efficiency E is maximized is x = 0. It is preferable that the vehicle 20 stops at the position of x = 0 and receives power supply from the power supply unit 11.

The position acquisition unit 22 acquires the current position of the power reception unit 21, and thus the current position of the vehicle 20. The position acquisition unit 22 in the present embodiment is connected to a vehicle speed sensor 26 described later that detects the speed of the vehicle 20 (that is, the vehicle speed). The position acquisition unit 22 calculates the travel distance of the vehicle 20 by integrating the vehicle speed information detected by the vehicle speed sensor 26 with the elapsed time. Specifically, the vehicle speed S _i at the current time is integrated at a predetermined sampling interval Δt to calculate the movement distance Δx of the vehicle 20. Note that the travel distance of the vehicle 20 can be calculated using, for example, a change in the rotation angle of the electric motor in addition to the method using the vehicle speed as in the present embodiment. The method for calculating the distance is not limited to the above example.

  The transmission efficiency calculation unit 23 calculates the transmission efficiency E when the power reception unit 21 receives power from the power supply unit 11. As described above, the transmission efficiency E is the power received by the power receiving unit 21 with respect to the power output from the power feeding unit 11. The transmission efficiency calculation unit 23 acquires the power P output from the power supply unit 11 via the power supply side communication unit 12 and the power reception side communication unit 25. Further, the power p received by the power receiving unit 21 is acquired. The transmission efficiency calculation unit 23 calculates p / P to obtain the transmission efficiency E.

  The control unit 24 is a part that controls rectification in the power reception unit 21, integrates information received by the power reception side communication unit 25, and outputs necessary information to the power supply side communication unit 12. In addition, the control unit 24 acquires the travel distance of the vehicle 20 from the position acquisition unit 22. Further, the control unit 24 acquires the transmission efficiency E from the transmission efficiency calculation unit.

The control unit 24 acquires the movement distance Δx of the vehicle 20 at a predetermined sampling interval and acquires the transmission efficiency E. Control unit 24 calculates the transmission efficiency E _i at the current time, the difference ΔE between the transmission efficiency E _i-1 of the previously acquired. Then, the control unit 24 calculates the average change rate ΔE / Δx of the position with respect to the transmission efficiency. If the transmission efficiency E changes around x = 0 as shown by the solid line in FIG. 2, the average rate of change ΔE / Δx becomes as shown by the broken line in FIG. That is, ΔE / Δx = 0 at x = 0.

  Ideally, it is preferable to calculate the limit of Δx → 0. In FIG. 2, the average rate of change ΔE / Δx is expressed as a position differential value dE / dx of transmission efficiency. Since the sampling interval for obtaining the vehicle speed and transmission efficiency cannot be strictly zero, ΔE / Δx is not a pure position differential, but the sampling interval is preferably as short as possible. This average rate of change ΔE / Δx corresponds to the position differential value of the transmission efficiency described in the claims.

  Furthermore, the control part 24 is outputting the information which should be alert | reported to a driver | operator on the display part 27 mentioned later. The operation of the control unit 24 will be described in detail later.

  The power receiving side communication unit 25 communicates with the power feeding side communication unit 12 and controls the power feeding unit 11 according to the situation on the vehicle 20 side. For example, the power receiving side communication unit 25 transmits the charging status of the battery mounted on the vehicle 20 to the power feeding side communication unit 15 and instructs the power feeding unit 11 to start power feeding. Alternatively, when the battery is fully charged, control is performed such as stopping output of power from the power supply unit 11. In addition, information on the power output from the power supply unit 11 is received from the power supply side communication unit 12 and transmitted to the control unit 24.

The vehicle speed sensor 26 is a sensor that detects the speed of the vehicle 20. The vehicle speed sensor 26 is connected to the position acquisition unit 22. Then, the position acquisition unit 22 calculates the movement distance Δx of the vehicle 20 based on the vehicle speed _Si and the sampling interval Δt.

  The display unit 27 is an output device for notifying the driver of the state of the vehicle 20. The display unit 27 may be, for example, a display attached to a car navigation system, or a head-up display that projects an image on a windshield or the like. The display unit 27 displays an image generated by the control unit 24 or a separately prepared GPU to the driver. The display unit 27 in the present embodiment notifies the driver of visual information such as how far the vehicle 20 is away from the optimal position for charging. Moreover, you may make it display the value of the transmission efficiency which concerns on charge of a battery, and its average change rate (position differential value). In addition to the visual information, a function for notifying the relative relationship between the optimum charging position and the position of the vehicle 20 by voice may be added.

  Next, the operation of the non-contact power transmission apparatus 100, particularly the processing flow of the control unit 24, will be described with reference to FIGS.

  As shown in FIG. 3, step S1 is first executed. Step S1 is a step in which the control unit 24 determines whether or not the vehicle 20 is in a parking operation. The parking operation is in a state where, for example, the power receiving side communication unit 25 in the vehicle 20 and the power feeding side communication unit 12 in the parking space 10 exist within a communicable area. This operation flow is executed while the vehicle 20 is parked. Therefore, when the power receiving side communication unit 25 and the power feeding side communication unit 12 are not within the communicable range, a NO determination is made, and step S1 is repeated until the vehicle 20 enters the parking operation. On the other hand, when the power receiving side communication unit 25 and the power feeding side communication unit 12 are within the communicable range, the control unit 24 determines that the vehicle 20 is in the parking operation, and step S1 is YES.

If YES is determined in step S1, the process proceeds to step S2. Step S2 is a step in which the control unit 24 acquires the transmission efficiency E _i at the current time. The control unit 24 acquires the transmission efficiency E _i calculated by the transmission efficiency calculation unit 23.

After step S2, the process proceeds to step S3. Step S3 is a step position acquisition unit 22 calculates the moving distance Δx of the vehicle 20 based on the vehicle speed S _i and the sampling interval Delta] t. The vehicle speed S _i is detected by the vehicle speed sensor 26, and Δx = Δx + S _i Δt is calculated by the position acquisition unit 22. Δx on the right side in the above equation is 0 when Δx is reset in step S7 described later. In other words, if Δx is not reset, S _i Δt is integrated for each sampling, and Δx is calculated.

After step S3, the process proceeds to step S4. Step S4 is a step in which the control unit 24 compares the transmission efficiency E _i with a predetermined threshold value T1. The threshold value T1 is a criterion for determining whether or not the vehicle 20 exists at a position where the transmission efficiency at that time can be approximated to a parabolic shape. As will be described later, the non-contact power transmission apparatus 100 according to the present embodiment performs charging at a position where the transmission efficiency E _i is maximized by stopping the vehicle 20 in the vicinity where the position differential value of the transmission efficiency is zero. To do. On the other hand, if the vehicle 20 is far from the optimal charging position, the transmission efficiency E _i gradually approaches zero, so that the position differential value also becomes substantially zero. Therefore, if the transmission efficiency E _i is less than the threshold value T1, even if the position is far from the true optimum position, it may be erroneously determined that it is the optimum position. Step S4 is a step for preventing this erroneous determination. That is, if the transmission efficiency E _i is equal to or greater than the threshold value T1, the control unit 24 determines that the optimum position where the vehicle 20 should be stopped can be determined based on the position differential value of the transmission efficiency. Conversely, if the transmission efficiency E _i is smaller than the threshold value T1, it is determined that the above determination is impossible.

In step S4, for example, when the vehicle 20 is far away from the optimal charging position (x = 0), E _i <T1 and NO is determined. In this case, the process proceeds to step S8. Step S8 is a step in which the control unit 24 or the GPU generates an image to be notified to the driver. Since step S4 is NO determination, as shown in FIG. 4, the control part 24 produces | generates the image for alert | reporting to a driver | operator that the parking position has shifted | deviated largely. In step S9, the display unit 27 displays the generated image.

In step S4, if the transmission efficiency E _i is equal to or greater than the threshold value T1, a YES determination is made. In this case, the process proceeds to step S5 as shown in FIG. Step S5 is a step in which the position acquiring unit 22 calculates the moving distance Δx of the vehicle 20 based on the vehicle speed S _i and the sampling interval Delta] t, is compared with a threshold value T2.

  By the way, Δx is used to calculate the average rate of change ΔE / Δx of transmission efficiency. Δx is calculated at a predetermined sampling interval. If the vehicle 20 does not move during the sampling interval (Δx = 0), the average rate of change ΔE / Δx cannot be defined. Even if Δx ≠ 0, if Δx is extremely small, the influence on the average change rate ΔE / Δx of the circuit noise superimposed on the change ΔE in transmission efficiency may be large. In other words, it is preferable to secure Δx such that ΔE changes sufficiently with respect to noise.

  For this reason, in step S5, Δx is compared with the threshold value T2, and it is determined whether Δx is secured to T2 or more. If Δx <T2 in step S5, the determination is NO and the process proceeds to step S8. In this case, the control unit 24 continues to generate an image immediately before step S5 is NO. In step S9, the display unit 27 displays the generated image. Specifically, when the vehicle 20 is temporarily stopped during the parking operation, Δx = 0 and Δx <T2 is satisfied. In this case, the display of FIGS. maintain.

In step S5, if the moving distance Δx is equal to or greater than the threshold value T2, a YES determination is made. In this case, the process proceeds to step S6 as shown in FIG. Step S6 is a step in which the control unit 24 calculates the average rate of change ΔE / Δx for the position of the transmission efficiency E. ΔE is the difference between the transmission efficiency E _i obtained at the current time, the transmission efficiency E _i-1 of the previously acquired. Alternatively, when the previous acquisition is NO in step S4 or step S5 and step S6 is not passed, ΔE is the amount of change in transmission efficiency in the same time interval as the accumulated time of the movement distance Δx. The control unit 24 calculates the average rate of change ΔE / Δx for the position from the values of ΔE and Δx. The calculated average change rate ΔE / Δx may be subjected to low-pass processing to remove noise. As shown by the broken line in FIG. 2, the average rate of change ΔE / Δx becomes positive when approaching x = 0 that gives the maximum value of the transmission efficiency E, and becomes negative when moving away. At x = 0 giving the maximum value, ΔE / Δx = 0.

It progresses to step S7 after step S6. Step S7 is a step in which the control unit 24 replaces the transmission efficiency E _i acquired at the current time with the previous acquired value E _i−1 in order to use it in the future calculation of ΔE. At the same time, the control unit 24 also resets the value of Δx so that Δx = 0.

  It progresses to step S8 after step S7. Step S8 is a step in which the control unit 24 or the GPU generates an image to be notified to the driver. The generated image is displayed by the display unit 27 toward the driver in step S9.

  For example, it is assumed that the vehicle 20 moves toward the parking space 10 while moving forward. In a region where the average rate of change ΔE / Δx is positive, the vehicle 20 moves forward and approaches the optimum parking position x = 0. At this time, the control unit 24 generates an image as shown in FIG. On the screen, for example, a broken line A indicating the optimum position and a solid line B in which the current position of the vehicle 20 is expressed in a pseudo manner are displayed. The solid line B is displayed below the broken line A on the screen. The average rate of change ΔE / Δx decreases as the vehicle 20 approaches the optimal parking position. Accordingly, the control unit 24 continuously generates images so that the solid line B approaches the dashed line A that is fixedly displayed. At this time, as shown in FIG. 5, the image generated by the control unit 24 may be displayed to instruct the driver to move forward. The driver can recognize that the vehicle indicated by the solid line B is moving toward the optimum position to be parked indicated by the broken line A.

  When the average change rate ΔE / Δx becomes zero, the control unit 24 generates an image as shown in FIG. That the average rate of change ΔE / Δx is zero is synonymous with the vehicle 20 being in a position optimal for charging. Therefore, the control unit 24 generates an image for notifying the driver that the vehicle 20 is at the optimum position in the parking space 10.

  Even when the average rate of change ΔE / Δx is a positive region, an image different from that shown in FIG. 5 is generated when the vehicle 20 moves backward toward the parking space 10. Specifically, as shown in FIG. 7, the solid line B is displayed on the broken line A on the screen. The average rate of change ΔE / Δx decreases as the vehicle 20 approaches the optimal parking position. Accordingly, the control unit 24 continuously generates images so that the solid line B approaches the dashed line A that is fixedly displayed. At this time, as shown in FIG. 7, the image generated by the control unit 24 may be displayed to instruct the driver to move backward.

  Whether the vehicle 20 moves forward or backward, if the average rate of change ΔE / Δx is positive, the control unit 24 generates an image so that the solid line B approaches the broken line A, and the average rate of change ΔE / Δx is negative. If so, the control unit 24 generates an image so that the solid line B moves away from the broken line A. FIG. 8 shows an example of a change in the relative relationship between the broken line A and the solid line B with respect to the average rate of change ΔE / Δx (synonymous with the position differential value dE / dx).

  Next, the effect by employ | adopting the non-contact electric power transmission apparatus 100 is demonstrated.

  In the non-contact power transmission device 100, the vehicle 20 is in an optimal position in the parking space 10 on condition that the average rate of change ΔE / Δx (synonymous with the position differential value dE / dx) of the transmission efficiency E becomes zero. The driver is informed and notified. Since the driver only has to stop the vehicle 20 based on this notification, it is possible to find an optimum position for power reception by one forward or backward movement.

  Further, since the non-contact power transmission device 100 includes the display unit 27, as shown in FIG. 8, the current position of the vehicle 20 according to the position differential value dE / dx of the transmission efficiency E, and the optimal position for parking The relative position can be notified to the driver. For this reason, the driver can visually recognize the direction and distance in which the vehicle 20 should be directed. Therefore, the driver can stop the vehicle 20 by performing a brake operation while grasping the position where the vehicle should be parked visually.

  That is, the vehicle position can be easily aligned. Therefore, it is possible to shorten the time until parking and to park the vehicle more accurately in the power feeding space.

(Modification 1)
When the distance between the broken line A and the solid line B displayed on the display unit 27 is L, as described in the first embodiment, the distance L changes according to the position differential value dE / dx. In the first embodiment, an example is shown in which L = 0 at a single point where dE / dx = 0. That is, an example is shown in which an image as shown in FIG. 6 is displayed at a single point where dE / dx = 0. On the other hand, it is preferable to give robustness to the position differential value dE / dx that should be L = 0.

  As shown in FIG. 9, let L be the distance between the broken line A indicating the optimum position and the solid line B indicating the current position of the vehicle 20 on the screen displayed on the display unit 27. Note that L when the solid line B approaches the broken line A is positive, and L when the solid line B moves away from the broken line A is defined as negative. When the vertical axis is L and the horizontal axis is the average rate of change ΔE / Δx (synonymous with the position differential value dE / dx), L increases as ΔE / Δx increases.

  In the first embodiment, L = 0 is unique only at one point of ΔE / Δx = 0 as shown by a broken line graph in FIG. In this case, even when the position of the vehicle 20 slightly deviates from L = 0, it is displayed that the stop position of the vehicle 20 is not the optimum position for charging as shown in FIGS. For this reason, there is a possibility that the driver may feel uneasy or uncomfortable.

  On the other hand, in this modification, L = 0 is set in a predetermined range X including ΔE / Δx = 0 as shown by a solid line graph in FIG. This means that a parking instruction is displayed on the display unit 27 with a certain range in the vicinity of the optimum position for charging.

  According to this, even when L = 0, when the vehicle 20 stops at a parking position where the transmission efficiency is a maximum or a value in the vicinity thereof, an image of L = 0 shown in FIG. 6 is displayed. . For this reason, the driver can stop the vehicle 20 without feeling unnecessary anxiety or discomfort.

  Note that if the range X that should be L = 0 is set too wide, the vehicle 20 may stop at a location that is out of the optimal position or a position where transmission efficiency close to the optimal is obtained. Need to be done.

(Second Embodiment)
By adding the flow of vehicle speed control to the operation flow of the control unit 24 described in the first embodiment, the vehicle 20 can be parked more accurately at the optimal position for charging. Note that the configuration on the power feeding side and the configuration on the power receiving side are the same as those described in the first embodiment, and a description thereof will be omitted.

  As shown in FIG. 10, the control unit 24 in the present embodiment performs the operation illustrated in FIG. 3 during the parking operation in which the power supply side communication unit 12 and the power reception side communication unit 25 can communicate with each other, as illustrated in FIG. 10. After executing step S9 in the flow, step S10 is executed.

Step S <b> 10 is a step in which the control unit 24 controls the vehicle speed to limit the movement amount of the vehicle 20. The control unit 24 sets a target vehicle speed S _{i + 1} according to the average change rate ΔE / Δx (synonymous with the position differential value dE / dx) of the transmission efficiency E. The target vehicle speed S _{i + 1} is a vehicle speed that the vehicle 20 should realize after a predetermined time has elapsed with respect to the vehicle speed S _{i at the} current time. The controller 24 controls the torque of the electric motor, the regenerative brake, and the brake operation by the braking device so that the vehicle 20 approaches the target vehicle speed S _{i + 1} . Specifically, for example, the torque output of the electric motor is adjusted according to the difference between the target vehicle speed S _{i + 1} and the vehicle speed S _{i at} the current time, and the vehicle speed of the vehicle 20 is controlled. When sudden deceleration is required or when the target vehicle speed S _{i + 1} is zero, a regenerative brake by an electric motor or a brake by a braking device is used in combination.

For example, the target vehicle speed S _{i + 1} is set as shown in FIG. The target vehicle speed S _{i + 1} is S _{i + 1} = 0 when dE / dx ≦ 0. That is, the target vehicle speed S _{i + 1} becomes zero when the vehicle 20 is present at the optimal parking position x = 0 for charging or moves away from x = 0.

Further, when dE / dx> 0, the target vehicle speed S _{i + 1} increases linearly as dE / dx increases, and the target vehicle speed S _{i + 1} becomes an arbitrary predetermined value when reaching a predetermined dE / dx. That is, when the vehicle 20 is moving so as to approach the optimum position x = 0, the target vehicle speed S _{i + 1} is set smaller as x = 0. That is, the vehicle speed is limited.

According to this, the vehicle 20 decelerates as x = 0 is approached, and the target vehicle speed S _{i + 1} becomes zero when the optimum position x = 0. Therefore, the vehicle 20 can be parked without greatly passing the position of x = 0.

(Modification 2)
In the second embodiment, when the vehicle 20 approaches the optimal parking position x = 0, the example in which S _{i + 1} = 0 is set for the first time when the position differential value dE / dx = 0 has been described. However, the position differential value dE / dx It is preferable to provide robustness.

By the way, in 2nd Embodiment, as shown in FIG. 11, when dE / dx was zero or less, it was set to S _{i + 1} = 0. In this case, since the target vehicle speed S _{i + 1} becomes zero at the time when the vehicle 20 reaches the optimal parking position, the vehicle 20 may slightly exceed the optimal parking position due to inertial motion.

On the other hand, the target vehicle speed S _{i + 1} in this modification is set as shown in FIG. That is, the target vehicle speed S _{i + 1} = 0 is set when dE / dx is equal to or less than the positive predetermined value Y. According to this, when the vehicle 20 approaches the optimum position x = 0 and dE / dx decreases, the target vehicle speed S _{i + 1} becomes zero before dE / dx = 0, so that the vehicle 20 is driven by inertial motion. Can be stopped at a position closer to the optimum position.

  Note that if the positive predetermined value Y is excessively large, the vehicle 20 may stop before the optimal position, so the predetermined value Y needs to be set appropriately.

(Modification 3)
In the second embodiment and the second modification, the example in which the vehicle speed is limited according to the average change rate dE / dx of the transmission efficiency E has been described. In this modified example, in addition to that, an example will be described in which the vehicle speed limit can be canceled by interruption of the accelerator operation by the driver. Although this modification is demonstrated with reference to FIG. 13, since the operation | movement flow to step S9 is the same as the flow to step S9 of 1st and 2nd embodiment, description is abbreviate | omitted.

  As shown in FIG. 13, step S11 is executed after step S10 of the vehicle speed limiting process. Step S11 is a step in which the control unit 24 determines whether or not there has been an accelerator operation by the driver. If there is no accelerator operation, the determination is NO and the vehicle speed restriction is continued. On the other hand, if the accelerator operation is performed by the driver, the determination is YES, and the process proceeds to step S12.

  Step S12 is a step in which the control unit 24 releases the restriction on the vehicle speed. Specifically, the control unit 24 returns the torque output of the electric motor, the regenerative brake, and the brake control by the braking device to normal control.

  This makes it possible to quickly reflect the driver's intention without being subjected to vehicle speed restrictions when it is necessary to start suddenly during the parking operation.

(Other embodiments)
The preferred embodiments of the present invention have been described above. However, 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 each embodiment described above, the configuration in which the non-contact power transmission apparatus 100 includes the display unit 27 has been described, but the display unit 27 is not necessarily a necessary element. In the description of each embodiment, the display unit 27 is effective for visually indicating the relative relationship between the position of the own vehicle and the optimum position to be parked, but can also notify the driver only by voice, for example. Specifically, when the vehicle 20 shifts to the parking operation, a notification sound is intermittently emitted at a predetermined interval. As the position differential value of the transmission efficiency E becomes smaller, the interval between the notification sounds is shortened, and when the position differential value becomes zero, the continuous sound is eliminated. Accordingly, the driver can grasp the optimum parking position where the transmission efficiency E is maximized.

  Further, in each of the above-described embodiments, the example in which the position acquisition unit 22 calculates the movement distance Δx of the vehicle 20 based on the vehicle speed detected by the vehicle speed sensor 26 has been shown, but the movement distance Δx of the vehicle 20 is, for example, an electric motor It can also be calculated from the change in the rotor rotation angle.

  Further, in each of the above-described embodiments, as an example of the condition for determining that the vehicle 20 is in the parking operation, the power-feeding-side communication unit 12 and the power-receiving-side communication unit 25 are present in an area where they can communicate with each other. It is not limited to this example. For example, it may be a condition for determining that the transmission efficiency E is greater than a predetermined value as a parking operation, or a condition that the vehicle speed is smaller than a predetermined value.

  Also, the layouts and designs in the images shown in FIGS. 4 to 7 are merely examples, and the images generated by the control unit 24 and the GPU are arbitrary as long as they do not differ from the purpose to be notified to the driver. Needless to say.

DESCRIPTION OF SYMBOLS 10 ... Parking space, 11 ... Power feeding part, 12 Power feeding side communication part, 20 ... Vehicle, 21 ... Power receiving part, 22 ... Position acquisition part, 23 ... Transmission efficiency calculation part, 24 ... Control part, 25 ... Power receiving side communication part, 26 ... Vehicle speed sensor, 27 ... Display section

Claims (6)

A power feeding unit (11) installed in a space (10) in which the vehicle (20) is parked to transmit power;
A power receiving unit (21) that is mounted on the vehicle and receives power transmitted from the power feeding unit;
A position acquisition unit (22) for acquiring a current position of the vehicle;
A transmission efficiency calculation unit (23) for calculating a transmission efficiency of power between the power supply unit and the power reception unit;
A control unit (24) for controlling power transmission between the power feeding unit and the power receiving unit,
The control unit calculates a position differential value of the transmission efficiency based on the position of the vehicle acquired by the position acquisition unit and the transmission efficiency calculated by the transmission efficiency calculation unit,
Under the condition that the position differential value becomes zero, it is determined that the vehicle is in an optimal position in the space, and the driver is notified ,
And a display unit (27) for displaying an image for notifying a driver of a relative position between the vehicle and the space,
The control unit continuously generates an image in which the distance between the vehicle and the space on the image is shortened as the absolute value of the position differential value approaches zero, and is displayed on the display unit. Non-contact power transmission device to be displayed . Wherein, on condition that the position differential value is within a predetermined range including zero, the vehicle according to claim to be displayed on the display unit and generates an image indicating that there the optimum position 1 The non-contact power transmission device described in 1. The non-contact power transmission device according to claim 1 , wherein when the vehicle is parked, the control unit limits a vehicle speed as the position differential value approaches zero. A power feeding unit (11) installed in a space (10) in which the vehicle (20) is parked to transmit power;
A power receiving unit (21) that is mounted on the vehicle and receives power transmitted from the power feeding unit;
A position acquisition unit (22) for acquiring a current position of the vehicle;
A transmission efficiency calculation unit (23) for calculating a transmission efficiency of power between the power supply unit and the power reception unit;
A control unit (24) for controlling power transmission between the power feeding unit and the power receiving unit,
The control unit calculates a position differential value of the transmission efficiency based on the position of the vehicle acquired by the position acquisition unit and the transmission efficiency calculated by the transmission efficiency calculation unit,
Under the condition that the position differential value becomes zero, it is determined that the vehicle is in an optimal position in the space, and the driver is notified ,
When the vehicle is in a parking operation, the control unit limits the vehicle speed as the position differential value approaches zero . Wherein, if the position differential value is a positive predetermined value, according to claim 3 or claim 4 wherein the position differential value for controlling the vehicle speed such that the vehicle at the timing that led to zero to stop Non-contact power transmission device. The non-contact according to any one of claims 3 to 5 , wherein, when an accelerator operation by a driver intervenes, the control unit releases the restriction on the vehicle speed based on the position differential value and gives priority to the accelerator operation. Power transmission device.

Images