JP6857534B2 - Contactless power transfer system - Google Patents

Description

The present invention relates to a non-contact power transfer system that performs alignment of a vehicle with a capacitor to a charging station.

In this type of non-contact power transmission system, after the vehicle is aligned with respect to the charging station, the constant power (normal power) transmitted from the charging station is used to fully charge the capacitor of the vehicle.

The alignment is performed before the main charging, and when performing the alignment, weak power for alignment is transmitted from the charging station from the viewpoint of power saving and suppression of EMI (Electro Magnetic Interference). Will be done.

The vehicle that has received the weak electric power travels for alignment based on the weak electric power so as to match the position of the charging station.

The aligned vehicle performs the main charging to the capacitor of the vehicle in a non-contact manner at the position of the charging station by the steady power of the large power switched from the weak power.

For example, in Patent Document 1, when a weak electric power is transmitted from a power transmission unit of a charging station that has received a power transmission request signal from a vehicle and the weak electric power starts to be detected by the power receiving unit of the vehicle, the strength of the weak electric power (power receiving voltage). A non-contact power transmission system that performs alignment to a charging station (power transmission unit) based on the above is disclosed (Patent Document 1 [0029]).

Japanese Patent No. 5937631

By the way, when aligning the vehicle with respect to the power transmission unit of the charging station, the position of the power receiving unit of the vehicle is optimally positioned with respect to the position of the power transmission unit of the charging station (the power transmission / reception efficiency at the time of main charging is maximized). It is desirable to align the position with respect to the power transmission coil of the power transmission unit (the position where the power reception coil of the power reception unit is concentrically arranged) in a plan view.

However, Patent Document 1 does not disclose the point of aligning the position of the power receiving portion of the vehicle to the optimum position, and there is room for improvement.

The present invention has been made in consideration of such a problem, and is non-contact that enables the position of the power receiving portion of the vehicle with respect to the power transmitting portion of the charging station to be accurately adjusted to the optimum position or the vicinity of the optimum position. The purpose is to provide a power transmission system.

The non-contact power transmission system according to the present invention is
A non-contact power transmission system including a charging station having a power transmission unit for transmitting weak power and a vehicle having a power receiving unit for receiving the weak power in a non-contact manner.
The control unit of the vehicle
A voltage value detecting unit that detects a weak voltage value of the weak power received by the power receiving unit, and a voltage value detecting unit.
A voltage value characteristic storage unit that stores in advance the weak voltage value characteristics that represent the correspondence between the weak voltage value and the distance from the power transmission unit to the power reception unit.
It is provided with a relative position calculation unit that calculates a relative position that is a distance from the power transmission unit to the power reception unit by referring to the weak voltage value characteristic with the detected weak voltage value as an argument .
The control unit further has a weak voltage integrated value characteristic that represents a correspondence relationship between the weak voltage integrated value obtained by position-integrating the weak voltage value characteristic and the distance from the power transmitting unit to the power receiving unit.
The relative position calculation unit calculates the distance from the power transmission unit to the power reception unit by referring to the weak voltage integrated value characteristic with the integrated value of the weak voltage value detected by the voltage value detection unit as an argument. To.

According to the present invention, the relative position calculation unit refers to the weak voltage value characteristic with the weak voltage value detected by the voltage value detection unit as an argument, and accurately calculates the distance from the power transmission unit to the power reception unit, that is, the relative position. be able to.

The weak voltage value becomes the maximum value (maximum peak value) when the power receiving unit matches the power transmission unit. Therefore, by ending the alignment execution when the maximum value is reached, the charging station can be used. The position of the power receiving unit of the vehicle with respect to the power transmitting unit can be accurately adjusted to the optimum position.

Further, the weak voltage value characteristic is likely to have a peculiar portion in which the weak voltage value does not increase or decreases even if the distance from the power transmission unit to the power receiving unit is shortened. Even if there is a part peculiar to the weak voltage value characteristic, the integrated value of the weak voltage value in the direction toward the power transmission section increases. Therefore, by referring to the weak voltage integrated value characteristic with the integrated value of the detected weak voltage value as an argument, the distance from the power transmission unit to the power receiving unit, that is, the relative position of the power receiving unit with respect to the power transmitting unit can be accurately specified. ..

That is, there is a part where the weak voltage value does not increase even if the distance to the power transmission part becomes short, and a part (distance) where the weak voltage value becomes the same even if the distance is different due to the decrease of the weak voltage value. Even so, since the weak voltage value is generated, the weak voltage integrated value increases with the distance. Thus, in the above both portions can be uniquely calculated distance (position) by referring to the weak electric圧積minute value.

In addition, the relative position calculation unit
When the detected weak voltage value is equal to or higher than the predetermined voltage value, the distance from the power transmission unit to the power reception unit is calculated based on the weak voltage value characteristic.

If it is equal to or higher than the predetermined voltage value, the position is uniquely specified based on the weak voltage value characteristic, and the weak voltage value characteristic at the position near the power transmission unit is the characteristic value per unit distance as compared with the weak voltage integrated value characteristic. Since the amount of increase, that is, the sensitivity {(voltage value rise / unit distance)> (integrated voltage value rise / unit distance) is large, the alignment of the predetermined voltage value or more, in other words, in the vicinity of the power transmission unit, is a weak voltage value characteristic. It is possible to perform more accurate alignment by performing the alignment based on.

In this case, if the weak voltage value is less than the predetermined voltage value, the distance from the power transmission unit is calculated based on the weak voltage integrated value characteristic and the detected voltage value.
When the voltage value is equal to or higher than the predetermined voltage value, the distance from the power transmission unit is calculated based on the weak voltage value characteristic.

According to the present invention, in the region near the power transmission unit where the weak voltage value is equal to or higher than a predetermined voltage value, the position is calculated with reference to the weak voltage value characteristic with high sensitivity of the voltage change with respect to the position, and the position outside the vicinity region is calculated. Then, since the position is calculated by referring to the weak voltage integrated value characteristic, the position of the power receiving unit with respect to the power transmission unit is calculated reliably by the weak voltage integrated value, and the position of the power receiving unit with respect to the power transmission unit is calculated. It can be aligned to the optimum position by the weak voltage value.

Further, a vehicle speed sensor that detects the vehicle speed of the vehicle and a vehicle speed sensor
An induced voltage storage unit that stores the correspondence between the vehicle speed and the induced voltage is provided.
When the weak voltage value is equal to or higher than the predetermined voltage value, the weak voltage value characteristic is corrected based on the correspondence between the vehicle speed and the induced voltage, and the weak voltage integrated value characteristic of the corrected weak voltage value characteristic is corrected. The distance from the power transmission unit to the power reception unit is calculated with reference to.

In a peculiar region where the weak voltage value changes with the generation of the induced voltage due to the vehicle speed of the vehicle, the weak voltage value characteristic is set to vehicle speed = 0 with reference to the correspondence relationship between the vehicle speed and the induced voltage. The distance from the power transmission unit to the power receiving unit is determined by referring to the weak voltage integrated value characteristic of the corrected weak voltage value characteristic, in other words, the weak voltage integrated value characteristic of vehicle speed = 0. Since the calculation is performed, the accurate relative position can be calculated even if there is a region where the induced voltage is generated at the vehicle speed.

According to the present invention, the position of the power receiving unit of the vehicle with respect to the power transmitting unit of the charging station can be accurately adjusted to the optimum position or the vicinity of the optimum position.

It is a side view schematic diagram of the non-contact power transmission system which concerns on this embodiment. It is a perspective schematic diagram of the non-contact power transmission system shown in FIG. FIG. 3A is a schematic plan view showing a state in which the power receiving pad is accurately aligned with the power transmission pad. FIG. 3B is a schematic plan view showing a state in which the power receiving pad is displaced in the y-axis direction. FIG. 3C is a schematic plan view showing a state in which the power receiving pad is in the close range region. It is a functional block diagram of a vehicle. It is a schematic plan view provided for the explanation of alignment. It is a characteristic explanatory diagram of a weak voltage value characteristic and a weak voltage integral value characteristic. It is explanatory drawing which shows the example image of the parking support. It is explanatory drawing which shows the other example image of a parking support. It is a characteristic explanatory diagram which drew the weak voltage value characteristic to both positive and negative sides of the origin. FIG. 10A is a schematic plan view showing the vehicle in the initial position. FIG. 10B is a schematic plan view showing a vehicle in the process of alignment. It is a schematic plan view which is subjected to the estimation process of the y-axis movement amount from the vehicle movement amount. It is a characteristic explanatory diagram which is subjected to the estimation process of the y-axis movement amount from the vehicle movement amount. It is explanatory drawing for obtaining the position coordinate of a vehicle by a mathematical formula. It is an overall flowchart of a relative position detection process. It is a detailed flowchart provided for the calculation of the vehicle movement amount as a parameter, the reset process / initialization process of the vehicle movement amount and the weak voltage integral value, and the like. It is a detailed flowchart provided for the explanation of the calculation process of the weak voltage integral value. It is a detailed flowchart (1/2) provided for the explanation of the detection process (calculation process) of the relative position of a power receiving pad with respect to a power transmission pad. It is a detailed flowchart (2/2) provided for the explanation of the detection process (calculation process) of the relative position of a power receiving pad with respect to a power transmission pad.

[Constitution]
FIG. 1 is a side-view schematic diagram of the non-contact power transmission system 10 according to this embodiment, and FIG. 2 is a perspective schematic diagram of the non-contact power transmission system 10 shown in FIG.

As shown in FIGS. 1 and 2, the non-contact power transmission system 10 basically includes a charging station 30 and a vehicle 20 including a capacitor (BAT) 50 which is a battery.

The capacitor 50 of the vehicle 20 is charged non-contactly (wirelessly) from the charging station 30.

The charging station 30 connects a power transmission pad (primary pad) 21 as a power transmission unit provided on the ground 23 and a power transmission coil 11 in the power transmission pad 21 to a low frequency, for example, 50 Hz to 60 Hz via a cable 62. It has a power supply unit 31 that supplies an AC power source having a reference frequency fr of several hundred [kHz] or less, which is higher than a commercial frequency such as.

In this embodiment, as schematically shown in FIG. 1, the power transmission pad 21 is provided on the ground 23 of a parking lot or the like.

The vehicle 20 is an EV vehicle (electric vehicle), a PHV vehicle (plug-in hybrid vehicle), or a PFCV (plug-in fuel cell vehicle), and a power receiving coil 12 as a secondary coil provided at the bottom of the vehicle 20 is used. It has a power receiving pad (secondary pad) 22 as a power receiving unit.

FIG. 3A is a schematic plan view showing a state in which the power receiving pad 22 symmetrically arranged with respect to the vehicle body center line 25 of the vehicle 20 is aligned with the power transmission pad 21 of the charging station 30. In FIG. 3A, the directions of the arrows indicate the front direction, the rear direction, the left direction, and the right direction of the vehicle 20, respectively.

1 and 2 show a state in which the power receiving pad 22 is aligned with the power transmitting pad 21. In FIG. 1, the directions of the arrows indicate the front direction, the rear direction, the downward direction, and the upward direction of the vehicle 20, respectively.

In the aligned state, the main surface of the power transmission coil 11 (generally the upper surface of the power transmission pad 21) and the main surface of the power reception coil 12 (generally the lower surface of the power reception pad 22) face each other in a parallel state.

In FIGS. 2 and 3A, the shape of the power receiving coil 12 on the vehicle 20 side is circular as shown by a thick broken line in the square power receiving pad 22. On the other hand, the shape of the power transmission coil 11 on the charging station 30 side is generally a horizontally long ellipse as shown by a thick broken line in the rectangular power transmission pad 21.

The shape of the power transmission coil 11 and the power reception coil 12 may be a square (square or rectangular) coil or a circular coil.

As shown in FIG. 1, the power supply unit 31 of the charging station 30 has a power supply ECU (Electronic Control Unit) 61 and a communication device 81 including a transmission / reception antenna, and is connected to a commercial AC power supply of 50 Hz to 60 Hz (not shown). Will be done.

The power supply unit 31 generates, for example, a low-frequency transmission power P1 of about several tens of kHz from the AC power supply, and supplies power to the power transmission coil 11 of the power transmission pad 21 via the cable 62. The transmission power P1 is switched by the power supply ECU 61 between a weak power Plpe (lpe: low power excitation) due to a weak current for alignment and a main power Pn due to a normal current for main charging. The weak power corresponding to the weak power Plpe (this weak power is also referred to as Plpe) or the main power corresponding to the main power Pn (this main power is also referred to as Pn) is transmitted from the transmission pad 21.

In FIG. 2, the vehicle 20 so that the xyz axes drawn on the power transmission pad 21 (power transmission coil 11) coincide with the XYZ axes drawn on the power reception pad 22 (power reception coil 12) of the vehicle 20 in a plan view. The alignment process is executed by running. The origin position (coordinate origin) o of the xyz axis (xyz coordinate) of the power transmission pad 21 (transmission coil 11) is taken at the center of the power transmission coil 11, and the XYZ axis (XYZ coordinates) of the power reception pad 22 (power reception coil 12) is taken. The origin position (coordinate origin) O of is taken at the center of the power receiving coil 12.

Therefore, in the alignment process, when viewed in a plan view, the center of the power receiving coil 12 of the power receiving pad 22 of the vehicle 20 (coordinate origin o) is relative to the center of the power transmission coil 11 of the power transmission pad 21 of the charging station 30 (coordinate origin o). It is a process of matching O).

When the centers of the power are aligned (the z-axis and the Z-axis are aligned), the power is supplied even if the XY axis of the power transmission pad 11 (power transmission coil 11) is rotated with respect to the xy axis of the power reception pad 22 (power reception coil 12). The transmission efficiency (power receiving efficiency = Prn / Pn = power received by the power receiving pad 22 / power transmitted by the power transmitting pad 11) does not change.

As shown in FIG. 1, the power receiving pad 22 of the vehicle 20 is connected to the capacitor 50 through the wiring 42, the rectifier 44, the wiring 48 with the contactor 46, and the voltage sensor 52.

The rectifier 44, the contactor 46, and the capacitor 50 are controlled by an ECU (Electronic Control Unit) 60.

Further, the ECU 60 is connected to the in-vehicle communication line 66 in order to control the entire vehicle 20.

The in-vehicle communication line 66 includes a rear camera (imaging device) 71 for viewing the rear of the vehicle 20, a display (display device) 72 that also serves as an input device (touch sensor) operated by an occupant such as a driver, and the like. The speaker buzzer 73, vehicle speed sensor 74, accelerator pedal sensor 76, steering angle sensor 78, shift position sensor (shift position sensor) 79, etc. are connected, and vehicle information detected by each sensor 74, 76, 78, 79 {vehicle speed Vv, accelerator pedal opening (accelerator opening) θa, steering angle (corresponding to the direction angle of the front wheels) θs, shift position Sp (parking position P, backward position R, neutral position N, forward position D)} are in the ECU 60. Used for use.

As the display 72, for example, a display such as a navigation device installed on the dashboard is used, and on the display 72, the ECU 60 is used as support information for the driver's alignment running, such as information in the process of alignment. Is displayed.

Further, the ECU 60 communicates with the power supply ECU 61 through the communication device 82 having a transmission / reception antenna connected to the ECU 60 via the communication device 81 of the power supply unit 31 such as pairing.

In this embodiment, the driver drives and steers the vehicle 20 while observing the alignment support information (positioning status) on the display 72 to align the power receiving pad 22 with respect to the power transmission pad 21 of the charging station 30. However, the alignment process may be performed by so-called automatic parking.

FIG. 4 is a functional block diagram of the vehicle 20.

In the vehicle 20, the drive wheels 84 are mechanically rotationally driven by the motor 80 via the transmission 86. The motor 80 is electrically rotationally driven through an inverter 88, which is a drive device.

DC power is supplied from the power storage device 50 to the power input end of the inverter 88, and the DC power of the power storage device 50 is supplied to the control input end of the inverter 88 to the accelerator pedal opening θa or the like output from the accelerator pedal sensor 76. The on / off control signal of the switching element for converting into the corresponding three-phase power (three-phase AC power) is supplied.

The motor 80 for driving the vehicle is power-driven by the three-phase AC electric power, and the torque of the motor 80 is transmitted to the drive wheels 84 of the vehicle 20 via the transmission 86. In addition to the drive mechanism including the motor 80, the vehicle 20 includes a steering mechanism including a steering wheel and an electric power steering device (not shown), and a braking mechanism such as an electric brake and a disc brake.

The power supply ECU 61, which is the control unit of the charging station 30, and the ECU 60, which is the control unit of the vehicle 20, are computers including a microcomputer, a CPU (central processing unit), a memory ROM (including EEPROM), and a RAM. (Random access memory), in addition, it has an input / output device such as an A / D converter and a D / A converter, a timer as a timing unit, etc., and the CPU reads and executes a program recorded in the ROM. As a result, it functions as various function realization units (function realization means), for example, a control unit, a calculation unit, a processing unit, and the like. These functions can also be realized by hardware. The ECU 60 may be divided into a plurality of ECUs such as a vehicle ECU, a charging ECU, and a capacitor ECU instead of one.

In this embodiment, the ECU 60 includes a voltage value detection unit 102 that captures a weak voltage value (received voltage) vrpe detected by the voltage sensor 52, a significance determination unit 104 of the weak voltage vulpe, a position differentiation unit 106p, and a time differentiation unit. The differential unit 106 including the 106t, the weak power detection range inside / outside determination unit 108, the movement amount detection unit (movement displacement amount detection unit) 110, the movement direction detection unit 111, the initial position / parameter setting unit 112, and the operation. The amount calculation / setting / notification unit 114, the weak voltage integrated value calculation unit 115, the relative position calculation unit 116 that calculates the position (relative position) of the power receiving coil 12 with respect to the power transmission coil 11, and the power reception coil 12 are the power transmission coil 11. It includes a positive / negative determination unit 118 that determines whether the user is on the positive side (see FIG. 2) or the negative side on the x-axis, and an image generation unit 119 that generates a support image or the like for alignment.

Further, the ECU 60 stores the voltage value characteristic (also referred to as weak voltage value characteristic) 202 of the weak voltage value vlp in the weak voltage value characteristic storage unit (voltage value characteristic storage unit) 200v in its own storage unit 200. The weak voltage integrated value characteristic storage unit (voltage integrated value characteristic storage unit) 200i stores the weak voltage integrated value vilp characteristic (referred to as weak voltage integrated value characteristic) 204, which is the position integrated value of the weak voltage value characteristic 202. There is.

The weak voltage integrated value vilp obtained from the weak voltage integrated value characteristic 204 is generated from the weak voltage value characteristic 202 corresponding to the z-axis height zh each time the alignment parking is executed without being stored in advance. You may.

Here, the weak voltage value characteristic 202 and the weak voltage integrated value characteristic 204 are three-dimensional maps of the weak voltage value vrpe and the weak voltage integrated value vilpe with the position xy and the z-axis height zh as parameters.

Further, the induced voltage characteristic storage unit 200e of the storage unit 200 is a map showing the correspondence between the distance (radial distance) from the power transmission coil 11, the vehicle speed Vv, and the induced voltage of the power receiving coil 12, and the vehicle speed induced voltage characteristic 206. Is remembered.

[motion]
Next, each operation of the [overall operation] and the [first to sixth embodiments] of the above-described embodiment will be described.

[Overall operation]
At the charging station 30 of the parking lot, the driver of the vehicle 20 trying to charge the capacitor 50 first puts the own vehicle 20 on the x-axis of the power transmission pad 21 of the charging station 30 before the pairing at the time of alignment. The vehicle 20 is moved backward along the side wall of the parking lot, along the side line of the parking frame, and / or while watching the image of the rear camera 71 on the display 72 so that the vehicle body center lines 25 of the above are aligned. Run (backward running).

White lines may be drawn on the x-axis and y-axis on the power transmission pad 21.

When the driver drives the vehicle 20 close to the power transmission pad 21, for example, to a position where the power transmission pad 21 touches the bottom surface of the vehicle 20 and the power transmission pad 21 cannot be confirmed in the image of the rear camera 71, the vehicle 20 is once driven. Stop the car.

At this stop position, the driver presses the start button of the "alignment process" of the non-contact charging on the touch panel type display 72.

The ECU 60 that has detected the pressing of the start button of the "alignment process" performs pairing for a weak power transmission request through the communication device 82 via the communication device 81 of the power supply ECU 61 and the power supply ECU 61 via a wireless LAN such as WiFi. I do.

When mutual authentication is established by pairing, the power supply ECU 61 of the charging station 30 causes a weak current of constant alternating current to flow through the power transmission coil 11 of the power transmission pad 21, and the weak current causes the weak power from the power transmission pad 21 (power transmission coil 11). Wirelessly transmit.

On the other hand, when the authentication is established, the contactor 46 is closed by the ECU 60 of the vehicle 20, and the voltage value detection unit 102 starts the detection of capturing the weak voltage value vrpe through the voltage sensor 52. The value vlpe is out of the detection range, and the weak voltage value vlpe is a zero value and is not detected. The voltage sensor 52 may be provided with a noise removal filter.

When the accelerator pedal 77 is lightly stepped on, the motor 80 rotates, and the vehicle 20 starts to run slowly, the reception of weak electric power is started at a known position (initial position), and the voltage value detection unit 102 starts receiving weak power that is not a zero value. The detection (acquisition) of the voltage value vrpe is started.

Next, the ECU 60 analyzes the weak voltage value vlp, which is the received voltage, using the weak voltage value characteristic 202 and the like, and from the analysis result, the position of the power transmission coil 11 on the charging station 30 side and the power reception on the vehicle 20 side with respect to the position. By displaying the position (relative position) of the coil 12 and the like on the display 72 and notifying the driver, it contributes to the alignment running.

Then, when the alignment running is continued and it is detected that the weak voltage value vlpe has reached the known maximum peak value vlppemax, the alignment process is terminated and the driving of the motor 80 of the vehicle 20 is stopped.

At the end position of the alignment process, the ECU 60 of the vehicle 20 notifies the power supply ECU 61 of the charging station 30 that the alignment has been completed.

After that, the power supply ECU 61 switches the transmission power P1 of the power supply unit 31 from the weak power Plpe to the main power Pn, and supplies power to the power transmission coil 11 of the power transmission pad 21. As a result, non-contact charging based on the main power Pn is performed on the capacitor 50 through the power receiving coil 12 of the power receiving pad 22.

[First Example]
<Method 1 for detecting the relative position of the power receiving coil 12 with respect to the power transmitting coil 11>
The position of the vehicle 20 shown on the upper side in the schematic plan view of FIG. 5 is the power transmission pad 21 from above (positive side) of the x-axis in the figure during transmission of weak electric power from the power transmission coil 11 after pairing. The vehicle 20 traveling backward toward the center o of the (power transmission coil 11) detects weak power for the first time through the voltage sensor 52 by the voltage value detection unit 102 of the vehicle 20, and the weak voltage value vlpe (vlpe = 0+). Indicates the position where

When the weak voltage value vrpe is detected for the first time, the ECU 60 refers to the weak voltage value characteristic 202, sets the position to the initial position xint {xint = (x, y) = (xint, 0)} at a known distance, and sets the position to the initial position xint {xint = (x, y) = (xint, 0)}. After that, the alignment process is started while referring to the weak voltage value characteristic 202. At the same time, the calculation of the weak voltage integrated value vilpe, in which the detected weak voltage value vulpe is position-integrated by the weak voltage integrated value calculation unit 115, is started.

Here, at the initial position xint, the vehicle body center line 25 of the vehicle 20 coincides with the x-axis of the power transmission coil 11.

In practice, the distance x from the origin o of the power transmission coil 11 at the initial position xint is a distance equal to or less than the vehicle width of the vehicle 20, and the driver cannot directly see it through the rear camera 71 of the vehicle 20.

In FIG. 5, the x-axis distance is set to take a positive value in the quadrant (position) above the y-axis, and the x-axis distance x is set to take a negative value in the quadrant (position) below the y-axis. ing. Also, in the quadrant (position) to the right of the x-axis, the y-axis distance y takes a positive value, and in the quadrant (position) to the left of the x-axis, the y-axis distance y takes a negative value. There is.

After pairing, the vehicle 20 is set back from the front of the initial position xint at a constant target vehicle speed Vvtar, which is slower than the slow-moving speed specified by the ECU 60 or the like so that the vehicle 20 can be stopped immediately. I'm driving together.

In FIG. 5, the vehicle 20 shown on the right side is the current position (current coordinate position, relative radius) ra {(ra = (x)) of the vehicle 20 drawn by exaggerating the amount of misalignment of the vehicle 20 during alignment and backward traveling. , Y)}. The current position ra (x, y) of the vehicle 20 is the center position (origin O) of the power receiving pad 22 (power receiving coil 12).

In FIG. 5, the vehicle displacement from the initial position xint to the current position ra is defined as the vehicle movement amount (also referred to as movement amount or movement displacement amount) cvp. The vehicle movement amount cvp can be obtained from the vehicle speed Vv and the minute time dt by the integrated value ∫Vv · dt = cvp in the movement amount detection unit (also referred to as the movement displacement amount detection unit) 110, and the vehicle speed. If Vv is constant, it can be calculated by multiplying the vehicle speed Vv by the required time.

Here, when the vehicle 20 retracts straight along the x-axis, the relative movement amount (movement amount, vehicle movement) of the power receiving coil 12 on the x-axis from the initial position xint to the current position ra (x, y). Amount, x-axis movement amount) xvp can be obtained by the following equation (1).
xvp = xint-x ... (1)

The x-axis position is calculated by the following equation (2), which is a modification of equation (1).
x = xint-xbp ... (2)

For example, when the vehicle 20 travels straight backward along the x-axis and the distance x becomes x = 0, the alignment is completed.

In this first embodiment, the voltage characteristic (referred to as weak voltage value characteristic 202) by electromagnetic induction of the power receiving coil 12 and the power transmission coil 11 and the weak voltage value characteristic 202 are set to the center of the power transmission coil 11 from the initial position xint (the above). The voltage characteristic (weak voltage integrated value characteristic 204) whose position is integrated up to the coordinate origin o), the relative movement amount xvp on the x-axis, and the x-axis position (distance x) are acquired.

The upper view of FIG. 6 shows the weak voltage value characteristic 202 previously stored as a map in the weak voltage value characteristic storage unit 200v, and the lower figure of FIG. 6 is previously mapped to the weak voltage integrated value storage unit 200i. The weak voltage integral value characteristic 204 stored as is shown.

The weak voltage value characteristic 202 and the weak voltage integrated value characteristic 204 are the difference in height between the power transmission coil 11 and the power reception coil 12 from the ground 23 (horizontal plane) on the z-axis (hereinafter, also referred to as z-axis height) zh (hereinafter, also referred to as z-axis height). (See FIG. 2) is one characteristic when the height (distance) is known.

When the z-axis height zh is different from the known height, the height-corrected weak voltage value characteristic 202 and the weak voltage integrated value characteristic 204 can be used.

In the weak voltage value characteristic 202, the vertical axis represents the weak voltage value blpe, and the horizontal axis represents the distance x from the origin o on the x-axis.

In the weak voltage value characteristic 202, the weak voltage value characteristic 2020s shown by the solid line is the characteristic on the x-axis when the value on the y-axis is y = 0 [mm] and the vehicle speed Vv is Vv = 0 [mm / s]. is there.

The weak voltage value characteristic 2021s shown by the broken line has a y-axis value of y = ya [mm]. In this embodiment, ya has a value of about ya <xint / 2 and a vehicle speed Vv of Vv = 0 [mm / s]. ] Is the characteristic on the x-axis.

The weak voltage value vlp when the vehicle speed is Vv = 0 is a static electromotive voltage which is a voltage generated by a magnetic field vibrating at the reference frequency fr, and the value is both coils (transmission coil 11 and power receiving coil 12). In this embodiment, the distance x is in the range of x = 0 to xint, as can be understood from the weak voltage value characteristic 2020s at y = 0 and the weak voltage value characteristic 2021s at y = ya. Then, even if the values on the y-axis are different (in the range of y = 0 to ya), the voltage values are substantially the same.

The reason for this is that, as shown in FIG. 3B, since the power transmission coil 11 has a shape close to a horizontally long elliptical shape, the interlinkage magnetic flux of the power transmission coil 11 with respect to the deviation of the circular power receiving coil 12 having a small area in the y-axis direction. The effect of the number decrease on the weak voltage value vrpe is extremely small, and if the deviation in the y-axis direction is a certain distance ya or less (y ≦ ya), the difference in the weak voltage value vrpe on the y-axis of x = 0 is almost the same. Due to not having.

On the other hand, as shown in FIG. 3C, since the power transmission coil 11 has a shape close to a horizontally long elliptical shape, if the power transmission coil 11 is separated by x> ya minutes or more in the x direction, the number of interlinkage magnetic fluxes of the power transmission coil 11 The decrease has a large effect on the weak voltage value vlp.

Therefore, in the close-range region Dc where the distance x is close to the coordinate origin o up to the close-range threshold position xc, a weak voltage value vlpe equal to or higher than the weak voltage value (threshold) vlpec can be detected. With reference to the weak voltage value characteristic 202 as an argument, the relative movement amount xvp (see FIG. 5) on the x-axis can be obtained with high sensitivity and accuracy.

As described above, in the weak voltage value characteristic 202, the weak voltage value characteristic 2020s shown by the solid line is a characteristic when the y-axis value is y = 0 [mm] and the vehicle speed Vv is Vv = 0 [mm / s]. Is.

On the other hand, the weak voltage value characteristic 2020d shown by the alternate long and short dash line is when the y-axis value is y = 0 [mm] and the vehicle speed Vv is the target vehicle speed Vvtar (Vv = Vvtar [mm / s]). It is a characteristic.

Comparing the weak voltage value characteristic 2020s when the vehicle speed Vv is Vv = 0 (stopped) and the weak voltage value characteristic 2020d when the vehicle speed Vv is the target vehicle speed Vvtar, the close distance threshold position where the distance x from the origin o is short. The close-range region Dc to xc and the long-distance region Df from the short-distance threshold position xn to the initial position xint, where the distance x from the origin o is long, both have substantially monotonous decreasing characteristics, but the distance from the origin o. In the short-distance region Dn from the close-range threshold position xc where x is in the middle to the short-distance threshold position xn, the portion where the voltage changes due to the vehicle speed Vv (Vv = 0, Vv = Vvtar) (the portion where both characteristics 2020s and 2020d deviate from each other). ).

The reason is that the dynamic electromotive voltage (induced voltage), which is the voltage generated by the law of electromagnetic induction when the power receiving coil 12 itself moves at the vehicle speed Vv = Vvtar, is the voltage generated by the magnetic field vibrating at the reference frequency fr. This is due to being added to the static electromotive voltage (vehicle speed Vv = 0).

It is known that the portion (distance) at which this voltage change occurs depends on the coil shapes of the power receiving coil 12 and the power transmitting coil 11.

Therefore, in this embodiment, the correspondence between the vehicle speed Vv and the dynamic electromotive voltage (induced voltage) is stored in advance in the induced voltage characteristic storage unit 200e.

As shown in FIG. 6, in the weak voltage value characteristic 2020s or the like, the weak voltage value vlppe is vlpe = 0 and a zero value between the close-range threshold position xc and the short-distance threshold position xn (in FIG. 6, the offset portion is There is a position (point) at which the added bottom peak value is voltage), and this position is referred to as a bottom position (bottom distance) xb.

In this way, the weak voltage value characteristic 202 (particularly, the static weak voltage value characteristic 2020s, etc.) is transmitted from the center of the transmission coil 11 to the entire circumference in the radial direction because the distribution of the magnetic field is not constant due to the coil shape or the like. The value along the vertical cross section of the weak voltage value vrpe corresponding to the magnitude of the weak power becomes smaller from the maximum peak value (maximum value) vrpemax of the transmission coil 11 (center of the transmission unit) toward the outer side in the radial direction. The bottom peak value (minimum value) is voltage (vlpeth ≈ 0), and the value increases from the bottom peak value voltage to the outward side in the radial direction to become the side peak value (maximum value) voltage, and further from the side peak value voltagen. It has a characteristic that it descends toward the outside in the radial direction and becomes a zero value at which weak power cannot be detected.

As described above, due to the characteristic that the weak voltage value vlpe has irregularities toward the outer side in the radial direction, the same weak voltage value vlppe is obtained in the separation distance region Ds in which the short distance region Dn and the long distance region Df are combined. However, the distance x exists at three places (three positions), and the distance x and the relative movement amount xvp cannot be uniquely determined from the weak voltage value vlppe.

On the other hand, as can be seen from the weak voltage value characteristic 202, the weak voltage value vlpec exceeds the side peak value (maximum value) Vlpen in the separation distance region Ds with a margin. In the close range region Dc set as described above, the gradient of the weak voltage value characteristic 202 is steep, and the distance x is uniquely determined with respect to the weak voltage value vlpe. Therefore, the weak voltage value characteristic 202 having a steep gradient Can be used to measure the distance x (relative movement amount xvp) with good sensitivity (accuracy).

At the origin o at the distance x = 0, the weak voltage value blpe becomes the maximum peak value (maximum value) blpemax, and when the vehicle 20 goes too far beyond the origin o, the value of the distance x becomes a negative value and the weak voltage. The value characteristic 202 has a characteristic that is line-symmetrical with respect to the y-axis.

The weak voltage value (side peak value) vulpen and the weak voltage value (maximum peak value) vulpemax, which are the maximum values at x> 0 during alignment, are so-called inflection points, respectively. The position differential value (weak voltage position differential value) vdplpe of the weak voltage value vlppe shown in Eq. (3) becomes a zero value (vdplpe = 0).
vdplpe = d (vlppe) / dx ... (3)

In order to uniquely determine the distance x and the relative movement amount xvp in the separation distance region Ds, the weak voltage integral value characteristic 204 shown at the lower side of FIG. 6 is used.

The vertical axis of the weak voltage integrated value characteristic 204 is the integrated value of the weak voltage value vulpe calculated in advance from the weak voltage value characteristic 202 by the following equation (4) (hereinafter, referred to as the weak voltage integrated value vilpe), and the horizontal axis. Is the distance x from the origin o on the x-axis.
vilp = ∫vlp ・ dx… (4)

The weak voltage integral value characteristic 2040s shown by the solid line in the weak voltage integral value characteristic 204 is a characteristic when the y-axis value is y = 0 [mm] and the vehicle speed Vv is Vv = 0 [mm / s].

The weak voltage integral value characteristic 2041s shown by the broken line is a characteristic when the value on the y-axis is y = ya [mm] and the vehicle speed Vv is Vv = 0 [mm / s].

The weak voltage integral value characteristic 2040d shown by the alternate long and short dash line is a characteristic when the value on the y-axis is y = 0 [mm] and the vehicle speed Vv is Vv = Vvtar [mm / s].

The weak voltage integral value characteristic 2041d shown by the alternate long and short dash line is a characteristic when the value on the y-axis is y = ya [mm] and the vehicle speed Vv is Vv = Vvr [mm / s] (referred to as the reference vehicle speed).

In the weak voltage integrated value characteristic 204, in the separated distance region Ds in which the short distance region Dn and the long distance region Df are combined, the weak voltage integrated value vilp increases monotonically as the relative movement amount xvp increases, and the weak voltage integrated value It can be seen that the distance x by the voltage is uniquely determined.

At the position on the x-axis of the weak voltage integrated value characteristic 204, the value of the weak voltage integrated value vilp is zero at the initial position xint, and the value at the short-range threshold position xn is the weak voltage value. Weak voltage integral value vilp (vilpen = ∫vlpe · dx: integration interval is xint-xn from 0 value of xint, which is the position integral value from the initial position xint of the characteristic 202 to the short-distance threshold position xn (side peak value vlpen). The value at the close-range threshold position xc is the weak voltage integral value vilpec (vilpen = ∫vrpe · dx), which is the position integral value from the initial position xint to the close-range threshold position xc (weak voltage value vlpec). : The integration interval is from 0 value of xint to xint-xc value), and at the position of the origin o (distance x is zero value), the weak voltage integration value vilpeh (vilpen = ∫vrpe · dx: the integration interval is xint From 0 value to xint value).

Further, when the origin o is exceeded, the weak voltage integrated value characteristic 204 becomes a point-symmetrical increasing characteristic centered on the weak voltage integrated value vilpeh. Therefore, within the separation distance region Ds, it can be determined that the distance x is “positive” when the weak voltage integral value vilp is less than the weak voltage integral value vilpec, and the distance x is “negative” when it is greater than or equal to the weak voltage integral value vilpec.

That is, whether the weak voltage integral value vilp is less than the weak voltage integral value (weak voltage threshold integral value) vilpec determines whether the position from the front side to the excess side is positive (vilpe <vilpec) or negative (vilpe> vilpec). be able to.

Therefore, as described in the balloon of FIG. 6, in this first embodiment, the distance x on the x-axis from the origin o is referred to with reference to the weak voltage integrated value characteristic 204 and the weak voltage value characteristic 202. That is, when the relative movement amount xvp on the x-axis is obtained from the position of the power receiving coil 12, in other words, the initial position xint, the detected weak voltage value vlpe and its position integral value are used for each minute movement amount dx. Find a certain weak voltage integral value coil.

Then, in the range from the initial position xint where the relative movement amount xvp on the x-axis is not uniquely determined from the obtained weak voltage value blpe to the close-distance threshold position xc (short-distance region Dn and long-distance Df), the obtained weak voltage With the integrated value vilp as an argument, the weak voltage integrated value characteristic 204 in which the relative movement amount xvp is uniquely determined is referred to, and the distance x from the origin o, that is, the relative movement amount xvp on the x-axis is obtained from the initial position xint.

On the other hand, in the range from the close distance threshold position xc where the relative movement amount xvp on the x-axis is uniquely determined from the weak voltage value blpe to the origin o (distance x = 0) (close distance region Dc), the weak voltage value blpe is set. As an argument, the weak voltage value characteristic 202 is referred to, and the relative movement amount xvp on the x-axis is obtained from the distance x from the origin o, that is, the initial position xint.

[Display of parking assistance]
Here, the image display on the display 72 for the alignment parking support for the driver of the vehicle 20 will be described.

In order to align the position of the power receiving coil 12 of the vehicle 20 with the position of the power transmission coil 11 of the charging station 30, the target accelerator pedal opening (target accelerator pedal opening degree), which is the strength with which the accelerator pedal 77 is depressed to obtain the target vehicle speed Vvtar. It is preferable to notify the driver of the target accelerator opening) θatar and the time Tp required for positioning, which is the time when the driver is stepping on.

As shown in FIG. 7, a schematic alignment support image 73a generated by the image generation unit 119 is displayed on the display 72.

On the support image 73a, the accelerator pedal image 77a, the accelerator opening (accelerator pedal opening) θap at the current vehicle speed Vvp, and the accelerator pedal opening (target accelerator opening) required to obtain the target vehicle speed Vvtar. The θatar and the operation direction 77b of the accelerator pedal 77 are displayed as images. By displaying these images, the driver assists the smooth positioning operation of the accelerator pedal 77.

The accelerator pedal image 77a drawn with a broken line shows the original position of the accelerator pedal 77, and the accelerator pedal image 77a drawn with a solid line shows the current position of the accelerator pedal 77.

Further, on the support image 73a, the gauge image 90i shows the time Tp required for alignment in order to notify how many seconds the target position, the origin o, is reached when the current accelerator opening θap is continuously depressed. It is displayed with.

In this way, the optimum target vehicle speed Vvtar [km / m] for smooth parking is defined, and this is set as the target accelerator opening θatar. It is possible to visually notify the driver of the current accelerator opening θap and the target accelerator opening θatar in an easy-to-understand manner.

FIG. 8 shows an image display of another support image 73b for schematic alignment generated by the image generation unit 119.

On the support image 73b, the current position of the power receiving pad image 22i based on the position of the power transmission pad image 21i, the left / right adjustment amount of the steering wheel, and the remaining distance xp from the current position to the origin o which is the target position are notified. The gauge image 91i is displayed as an image.

By displaying the support images 73a and 73b for alignment in this way, the driver does not have to be proficient in the accurate (accurate) alignment position (the position where the origin o and the origin O match in a plan view). ) Can park the vehicle 20.

As described above, in this first embodiment, the weak voltage value vulpe due to electromagnetic induction of the power receiving coil 12 and the power transmission coil 11 and the weak voltage integrated value vilpe corresponding to the moving displacement of the power receiving coil 12 are connected to the x-axis of the power transmission coil 11. The distance x, which is the relative position of the power receiving coil 12 from the coordinate origin o, can be estimated (acquired).

In this case, in the close-range region Dc where the distance x is uniquely determined, the distance x is calculated from the weak voltage value vlpe with reference to the weak voltage value characteristic 202 set corresponding to the known z-axis height zh.

In this case, the positive / negative determination of the x-axis in the close-range region Dc is determined from the slope of the weak voltage position differential value vdlpe and the shift position Sp shown in Eq. (3).

Further, in the determination of whether or not the weak voltage value vlp has exceeded the weak voltage value vlpec, or whether or not the weak voltage integrated value vilp has entered the close range region Dc from the short-distance region Dn is at the same position as the weak voltage value vlpec. It is determined by whether or not it exceeds the weak voltage integral value vilpc in.

The positive / negative determination of the x-axis in the separation distance region Ds is determined from the slope of the weak voltage integrated value vilp (weak voltage integrated value position differential value) vdpilpe slope and the shift position Sp calculated by the following equation (5).
vdpilpe = d (vilpe) / dx ... (5)

In the separation distance region Ds in which the distance x is not uniquely determined from the weak voltage value characteristic 202, the distance x is calculated from the weak voltage integrated value characteristic 204 in which the distance x is uniquely determined.

The current position (radial distance) ra (x, y) of the vehicle 20 is simply a weak voltage from the weak voltage detection range (outside the weak voltage detection range) Dout without using the weak voltage integrated value characteristic 204. Vehicle movement amount cvp calculated based on the initial position xint when entering the long-distance region Df of the detection range region Din, the vehicle speed Vv by the vehicle speed sensor 74, and the steering angle θs by the steering angle sensor 78 (see FIG. 5). You may ask from.

Further, in the short-range region Dn, an induced voltage is generated according to the relative moving speed of the power receiving coil 12 and the power transmitting coil 11, so that the vehicle speed induced voltage is a map of the corresponding characteristics of the induced voltage obtained in advance from the vehicle speed Vv. With reference to the characteristic 206, the weak voltage value vlppe obtained by offset-correcting the weak voltage value vlppe is obtained. Further, as the weak voltage integrated value vilpe, the value obtained by integrating the corrected weak voltage value vulpe is used.

Further, since the weak voltage value characteristic 202 changes depending on the z-axis height zh, which is the gap between the power receiving coil 12 and the power transmission coil 11, the weak voltage value characteristic 202 is selected in consideration of the z-axis height zh. Or correct.

Furthermore, since the weak voltage integral value reset also integrates the error, when the vehicle speed Vv = 0 where the induced voltage is not generated, the weak voltage integral value is obtained from the current weak voltage value reset and the weak voltage integrated value reset. The vilp is reset to a value on the weak voltage integral value characteristic 204 with respect to the weak voltage value vlpe at which the vehicle speed Vv is Vv = 0, that is, a reference value.

In this case, each region of the close-range region Dc, the short-distance region Dn, and the long-distance region Df is determined from the current weak voltage integral value vile, and the weak voltage is used as the reset weak voltage integral value vile for each region. The value on the weak voltage integral value characteristic 204 corresponding to the value of the value vlp, that is, the reference value may be substituted and reset.

[Second Example]
[Identification judgment between Dout in the weak voltage detection range and Din in the weak voltage detection range]
As described above, in this embodiment, basically, the movement amount xvp of the x-axis of the power receiving coil 12 from the initial position xint that first received the weak voltage value vlp, in other words, the x-axis from the origin o. The position (distance) x of is calculated.

Therefore, in the weak voltage detection range out-of-range Dout, the weak voltage integral value vilp and the x-axis movement amount xvp are reset, and the vehicle 20 enters the weak voltage detection range out-of-range Din (when entering from outside the detection range into the detection range). Then, the parameters such as the weak voltage integral value vilp are reset to set the initial position xint, and the calculation of the weak voltage integral value vilp and the x-axis movement amount xvp is started.

In the weak voltage detection range out-of-range Dout, the weak voltage value vrpe sticks to the lower limit (some random noise and offset are mixed), but even in the weak voltage detection range out-of-range Din, the bottom position xb Then, the weak voltage value vrpe becomes the lower limit value, and the weak voltage detection range inside / outside region cannot be accurately determined only by the weak voltage value vrpe.

The weak voltage value vulpe always exceeds the zero value in the weak voltage detection range region Din except for the bottom position xb, so that the voltage slightly exceeds the zero value, that is, the voltage corresponding to the bottom peak value vulpe described above. Weak voltage threshold {Since they are substantially the same value, they are referred to as weak voltage threshold blpet with the same reference numerals. (See Fig. 6)}.

Therefore, if the weak voltage value vrpe is equal to or greater than the weak voltage threshold blpet, it is determined that the region is in the weak voltage detection range Din. Since the noise is removed and the offset portion is removed by filtering, the weak voltage threshold value blpes is set to a value of 0+ (a value that is positive but close to zero).

Further, when the weak voltage value lvpe is equal to or less than the weak voltage threshold blpeth and the vehicle is stopped (Vv = 0), it is not possible to determine whether the position is the weak voltage detection range Dout position or the bottom position xb. The parameter value (weak voltage integral value vilp, etc.) detected in is retained without being reset.

Further, the period during which the weak voltage value vrpe is equal to or less than the weak voltage threshold vrpeth and the time differential value vdtlppe of the weak voltage value vrpe shown in the following equation (6) is zero while traveling (Vv ≠ 0). If Tth continues for the threshold time, it is determined that the region is out of the weak voltage detection range Dout, and the parameter value is reset.
vdtlpe = d (vlpe) / dt ... (6)

Furthermore, if the weak voltage value vlppe is equal to or less than the weak voltage threshold value vlpeth and the weak voltage time differential value vdtlpe changes to Vdtlppe ≠ 0 during traveling (Vv ≠ 0), it is determined that the weak voltage detection range region Din. To do.

Further, the x-axis position x is calculated from the initial position xint when entering the weak voltage detection range region Dout from the weak voltage detection range region Dout and the vehicle movement amount cvp calculated from the vehicle speed sensor 74 and the steering angle sensor 78. , The positive or negative of the x position may be determined from the calculated x-axis position.

[Third Example]
[Calculation method of x-axis movement amount xvp]
FIG. 9 shows the weak voltage value characteristic 2020s (z-axis height zh is zh1) and the weak voltage value characteristic 2020s' (z-axis height zh = zh2, zh2> drawn up to both the positive and negative sides of the origin o of the x-axis. zh1) is shown.

The weak voltage value characteristic 2020s'is a characteristic when the z-axis height is zh = zh2 and higher than the z-axis height zh = zh1, and the weak voltage value vulpe is the entire region of the weak voltage detection range region Din. It becomes a low value.

For example, when the vehicle 20 enters the weak voltage detection range region Dout (+) from the weak voltage detection range region Dout (+), the weak voltage position differential value vdplpe shown in equation (3) becomes a zero value (vdplpe = 0). ) To a non-zero value (vdplpe ≠ 0).

As shown in FIG. 10A, the position where the weak voltage position differential value vdplpe transitions from the zero value to the non-zero value is set as the initial position xint.

As shown in FIG. 10B, the x-axis position (distance x) can be obtained by subtracting the movement amount xvp from the initial position xint (xint, 0). The amount of movement on the y-axis is approximated to be so small that it can be ignored.

In this third embodiment, the close-range threshold position xc (xc) with a little margin in the close-range threshold position + xbcb at which the weak voltage value vlpe becomes the side peak value (vlpen) for the second time from the initial position xint (xint, 0). , 0) or close distance threshold position + xbc, the x-axis movement amount xvp is calculated by vehicle speed Vv × required time, for example, Vvtar × required time, or ∫Vv · dx, and the side peak value (vlpen) is the second time. From the position (close-range threshold position + xbc) or the close-range threshold position xc (xc, 0) to the origin o (0,0), refer to the weak voltage value characteristic 2020 (2020s or 2020s') of the close-range region Dc. Then, the x-axis movement amount xvp is calculated.

As a result, the power receiving coil 11 of the vehicle 20 can be reliably and simply aligned from the initial position (initial detection position) + xint of the weak power to the position of the maximum peak value vrpemax (maximum peak value detection position).

In FIG. 9, the other side peak value vlpen'indicates the side peak value of the weak voltage value characteristic 2020s'.

[Fourth Example]
[X-axis positive / negative judgment]
The relative front-rear position (positive / negative position) of the power receiving coil 12 with respect to the power transmission coil 11 is estimated from the shift position Sp, the weak voltage value vlppe, the weak voltage integrated value vilpe with respect to the vehicle displacement, and the weak voltage position differential value vdplpe with respect to the vehicle displacement.

Further, the positive / negative at the initial position xint is determined from the shift position Sp when the vehicle 20 enters the weak voltage detection range region Dout from the weak voltage detection range region Dout.

In the short-distance region Dn and the long-distance region Df, the positive / negative of the x-axis is determined from the weak voltage integral value vilp.

In the close range region Dc, it is estimated whether the power receiving coil 12 is close to or separated from the power transmission coil 11 from the differential value of the weak voltage value vlpe with respect to the vehicle displacement, that is, the positive or negative of the weak voltage position differential value vdplpe. By determining the forward or backward movement of the vehicle 20 from the shift position Sp, the positive or negative of the x-axis position is determined.

[Fifth Example]
[Estimation of y-axis movement amount]
When it is estimated that the vehicle 20 is located within the close range region Dc from the vehicle movement amount xvp shown in FIG. 11 and the weak voltage value vlpe shown in FIG. 12, the y-axis direction distance (y-axis movement amount) is estimated.

In FIG. 12, in the weak voltage value characteristic 202, the weak voltage value characteristic 2020s shown by the solid line is the x-axis when the y-axis value is y = 0 [mm] and the vehicle speed Vv is Vv = 0 [mm / s]. The above characteristics.

The weak voltage value characteristic 2022s shown by the broken line is a characteristic on the x-axis when the value on the y-axis is y = yb (yb> ya) [mm] and the vehicle speed Vv is Vv = 0 [mm / s].

The weak voltage value characteristic 2020d shown by the alternate long and short dash line is a characteristic when the value on the y-axis is y = 0 [mm] and the vehicle speed Vv is a constant minute speed target vehicle speed Vvtar (Vv = Vvtar [mm / s]).

The weak voltage value characteristic 2020d shown by the alternate long and short dash line is a characteristic on the x-axis when the value on the y-axis is y = yb [mm] and the vehicle speed Vv is a constant minute speed target vehicle speed Vvtar [mm / s].

The characteristics 2040s, 2040d, 2042s, and 2042d are weak voltage integral value characteristics corresponding to the characteristics 2020s, 2020d, 2022s, and 2022d, respectively.

When the vehicle 20 is estimated to be located in the close range Dc, if the displacement of the y-axis direction distance is within ya, the weak voltage value vlpe increases as the x-axis movement amount xvp increases. However, when the deviation in the y-axis direction is large, for example, y = yb> ya, the weak voltage value vlpe decreases as the x-axis movement amount xvp increases.

Therefore, the y-axis movement amount is obtained from the x-axis movement amount xvp shown in FIG. 11, for example, xvp = vehicle speed Vv × required time, and the characteristics 202 and 204 shown in FIG. The positive or negative of the y-axis movement amount can be determined from the steering angle θs of the vehicle 20.

[Sixth Example]
[Method for obtaining x-axis position x and y-axis position y]
As shown in FIG. 13, when the current coordinate position ra (x, y) is obtained on the assumption that the power transmission coil in the power transmission pad 21'is a circular power transmission coil 11', the following equation (7) is used. As shown in, the vehicle movement amount cvp is calculated from the vehicle speed Vv.
cvp = ∫Vv ・ dt… (7)

The following equations (8) and (9) can be obtained from the three-square theorem.
y ² + x ² = ra ² … (8)
y ² + (cb−x) ² = cbp ² … (9)

Here, ra is the magnitude of the vector obtained from the weak voltage value vlppe when y is y <ya with reference to the weak voltage value characteristic 202. cb is equal to the initial position (initial distance) xint.

Solving the equations (8) and (9) for x and y gives the following equations (10) and (11), and the current coordinate position (radius) ra (y, x) can be obtained by the equations. it can.
^{x = ra 2 -cvp 2 + cb} 2/2 · cb ... (10)
y = {(ra + cb + cbp) (ra-cb + cbp) (ra + cb + cbp) (-ra + cb + cbp)} ^1/2 / 2cb ... (11)

[Explanation of operation by flowchart]
Next, the alignment process of the power receiving pad (power receiving coil 12) of the vehicle 20 with respect to the power transmission pad 21 (transmission coil 11) of the charging station 30, in other words, the detection process (calculation) of the relative position of the power receiving coil 12 with respect to the power transmission coil 11. Processing) will be described with reference to the flowchart.

FIG. 14 is an overall flowchart of the relative position detection process. The execution body of the program related to the flowchart is the ECU 60, but a part of the description will be omitted in order to avoid complication. Also, the overall flow chart is repeatedly executed in a small amount of time.

In step S1, the ECU 60 performs parameter calculation, reset processing and initialization processing of the calculated parameters.

The parameters are basically the movement amount cvp of the vehicle 20 and the weak voltage integral value vilp. When the y-axis movement amount is so small that it can be ignored, the movement amount cvp may be the x-axis relative movement amount (x-axis movement amount) xvp. In the initialization process, the initialization process of the current position ra (x, y), that is, the process of setting cvp (x, y) = xint (xint, 0) is performed.

In step S2 after the reset / initialization process, the ECU 60 performs a process of calculating the weak voltage integrated value file from the detected weak voltage value file.

Next, in step S3, the positive / negative of the x-axis is determined.

Further, in step S4, the power receiving pad (power receiving coil 12) as the power receiving unit of the vehicle 20 with respect to the power transmission pad 21 (transmission coil 11) as the power transmission unit of the charging station 30 based on the weak voltage value vlp and the weak voltage integrated value vilpi. Performs the detection process (calculation process) of the relative position of.

FIG. 15 is a detailed flowchart of the process of step S1 provided for the calculation of the vehicle movement amount cvp as a parameter and the reset process / initialization process of the vehicle movement amount cvp and the weak voltage integrated value vilp.

In step S1a, the weak voltage value vrpe is detected. When detecting the weak voltage value blpe, filter processing for noise removal, offset detection, removal, etc. is performed.

Next, in step S1b, the position differential value vdplpe and the time differential value vdtlppe of the weak voltage value vlppe are calculated.

Next, in step S1c, it is determined whether or not the detected weak voltage value blpe is a value equal to or higher than the weak voltage threshold blpeth.

In the first determination, since the vehicle 20 is in the weak voltage detection range out-of-range region Dout, the weak voltage value vlpe is less than the weak voltage threshold value vlpeth, and this determination is negative (step S1c: NO).

Next, in step S1d, the vehicle speed Vv is detected, it is determined whether or not the vehicle 20 is moving (displaced), and if it is moving, the position differential value vdplpe and / or the time derivative is obtained in step S1e. As shown in the following equations (12) and (13), it is determined whether or not the value vdtlp is equal to or less than the threshold (position differential threshold dpt, time differential threshold dth).
vdplpe ≤ dpt… (12)
vdtlpe ≤ dth… (13)

If at least one of the determinations is positive (step S1e: Yes) in step S1e, it is determined in step s1f whether or not the threshold time Tth of the minute time has elapsed, and the determination has elapsed. If (step S1f: YES), it is determined in step S1g that the power receiving coil 12 of the vehicle 20 is in the weak voltage detection range out-of-range region Dout.

On the other hand, when the weak voltage value vlpe is equal to or higher than the weak voltage threshold value vlpeth in the determination in step S1c described above (step S1c: YES), and in the determination in step S1e, at least one of the differential values exceeds the threshold value (step S1c: YES). In the case of step S1e: NO), it is determined in step S1h that the power receiving coil 12 of the vehicle 20 is in the weak voltage detection range region Din.

Next, in step S1i, it is determined whether or not the weak voltage detection range out-of-range Dout has entered (transitioned) into the weak voltage detection range in-range Din.

If it has not entered (transitioned) (step S1i: NO), in other words, if it continues to the area outside the detection range Dout, or if it continues to the area within the detection range Din, in step S1j. It is assumed that there is no parameter reset request.

On the other hand, in the case of entering (transition) (step S1i: YES), it is assumed that there is a parameter reset request and an initialization request in step S1k.

Next, in step S1l, when there is a parameter reset request and an initialization request (step S1l: YES), in step S1m, the weak voltage integral value vilp is reset to a zero value, and the movement amount cvp is initially set. Initialization processing is performed to set the position to xint (xint, 0).

If there is no parameter reset request and initialization request in step S1l (step S1l: NO), the X-axis movement amount component of the movement amount cvp of the vehicle 20 is assumed to be ultra-low speed running in step S1n. And the Y-axis movement amount component is obtained based on the vehicle specifications such as the vehicle speed Vv and the wheelbase length and the steering angle θs.

The movement amount cvp can be obtained by using a positioning device such as a GPS device, or can be obtained by using inertial navigation.

FIG. 16 is a detailed flowchart of the process of step S2 provided for the explanation of the process of calculating the weak voltage integrated value vilp.

In step S2a, when the power receiving coil 12 is in the short-distance region Dn, the weak voltage value vlp is corrected (LPE-induced voltage correction) in consideration of the influence of the induced voltage caused by the vehicle speed Vv.

Next, in step S2b, it is determined whether or not there is a parameter reset / initialization request, and if there is (step S2b: YES), further, in step S2c, referring to the shift position Sp, forward parking is performed. Determine whether to park backwards.

In the case of forward parking, in step S2d, the x-axis is set as a negative value and the weak voltage integrated value vilp is substituted as the integrated value initial value.

In the case of backward parking, in step S2e, the x-axis is set as a positive value and the weak voltage integrated value vilp is substituted as the integrated value initial value.

If there is no parameter reset / initialization request in the determination in step S2b, after confirming that the region is within the weak voltage detection range Din in step S2f, the vehicle speed Vv is 0 [km / h] in step S2g. If the vehicle is stopped (step S2g: YES), the static voltage characteristic correction process of the weak voltage integrated value reset is performed in step S2h.

In this static voltage characteristic correction process, in order to eliminate and reset the error integrated in the weak voltage integrated value vilp, the short-distance region Dc, the short-distance region Dn, and the long-distance region from the current weak voltage integrated value vile. Each region of Df is determined, and the value on the weak voltage integrated value characteristic 204 corresponding to the current weak voltage integrated value vrpe, that is, the reference value is substituted for each region as the weak voltage integrated value vilpe after reset. ..

If the vehicle speed Vv is not a zero value but is running (step S2g: NO) in the determination of step S2g, the weak voltage integral value vilpe is calculated in step S2i.

In consideration of the case where the vehicle 20 starts traveling from a stopped state in the weak voltage detection range Din, the weak voltage integral value vilp is a backup held when the vehicle speed Vv becomes zero last time. Use the value.

17 and 18 are for explanation of the x-axis positive / negative determination process of step S3 of the power receiving pad (power receiving coil 12) and the relative position detection process (calculation process) of step S4 with respect to the power transmission pad 21 (power transmission coil 11), respectively. It is a detailed flowchart (1/2 and 2/2) provided.

In step S3a of FIG. 17, for example, information on the z-axis height zh between the charging station 30 and the power receiving coil 12 is acquired, and a weak voltage value characteristic 202 suitable for the z-axis height zh is set (selected). To do.

In step S3b, the detection range inside / outside determination result (flag in the program) of the above steps S1g and S1h is viewed.

When the power receiving coil 12 is in the detection range region Din (step S3b: NO), the determination result of the shift position Sp in step S2c is seen in step S3c, and if it is the backward position R, power is received in step S3d. The x-axis position of the coil 12 is "positive". If it is the forward position D, the x-axis position of the power receiving coil 12 is set to “negative” in step S3e.

On the other hand, if it is determined in step S3b that the power receiving coil 12 is in the weak voltage detection range region Din (step S3b: YES), in step S3f, whether it is in the close distance region Dc or the separation distance region Ds. Determine if you are inside.

In the determination in step S3f, for example, if the detected weak voltage value vrpe is equal to or greater than the weak voltage value (threshold value) vrpec (see FIG. 6), it is determined that the user is within the close range region Dc, and the weak voltage value (? If it is less than the threshold value) Vlpec, it is determined that the user is within the separation distance region Ds.

When it is within the separation distance region Ds, in step S3g, it is determined whether the weak voltage integral value vilp is less than or more than the weak voltage integral value (threshold value) vilpec (see FIG. 6).

If it is less than the weak voltage integral value (threshold value) vilpec, the x-axis position is determined to be "positive" in step S3h, and if it is more than the weak voltage integral value (threshold value) vilpec, the x-axis position is determined in step S3i. Is determined to be "negative".

If it is determined in step S3f that the vehicle is within the close-range region Dc, in step S3j, the shift position Sp is in the backward position R or the forward position in order to determine whether the shift position is in the close-range region Dc. Determine if it is in D.

If it is in the backward position R, in step S3k, it is determined whether or not at least one of the weak voltage position differential value vdplpe and the weak voltage time differential value vdtlppe is a positive value, and if it is a positive value, the transmission pad 21 Since the power receiving pad 22 (power receiving coil 12) is close to (transmission coil 11), the x-axis position is determined to be "positive" in step S3l, and if it is a negative value, the step At S3m, the power receiving pad 22 (power receiving coil 12) is too far away from the position of the power transmitting pad 21 (transmission coil 11), so that the x-axis position is determined to be “negative”.

In the determination of step S3j, if the shift position Sp is in the forward position D, it is determined in step S3n whether at least one of the weak voltage position differential value vdplpe and the weak voltage time differential value vdtlppe is a positive value. If the value is positive, the power receiving pad 22 (power receiving coil 12) is close to the power transmission pad 21 (power transmission coil 11), so that the x-axis position is set to "negative" in step S3o. If it is determined and the value is negative, in step S3p, the power receiving pad 22 (power receiving coil 12) has exceeded the position of the power transmission pad 21 (power transmission coil 11) and is in a position separated from the position. The axis position is determined to be "positive".

Next, in step S4a of the flowchart of FIG. 18, it is determined whether the user is in the close distance region Dc or the separated distance region Ds.

When it is determined that the device is within the separation distance region Ds, the relative radius ra is referred to in step S4b with reference to the weak voltage value characteristic 202 and the weak voltage integrated value characteristic 204, respectively, with the weak voltage value vrpe and the weak voltage integrated value vilpe as arguments. Is calculated.

When it is determined in step S4a that the vehicle is within the close-range region Dc, further, in step S4c, it is determined whether or not the vehicle movement amount cvp shown in FIG. 11 is within the close-range region Dc, and the close-range distance is determined. If it is within the region Dc, the x-axis movement amount xvp is calculated from the weak voltage value vlpe in step S4d, and if it is outside the close distance region Dc, the relative radius ra is calculated from the weak voltage value vlppe in step S4e. ..

Next, in step S4f, it is determined whether or not the y-axis movement amount yvp is below the threshold value, and if it is not below the threshold value (step S4f: NO), in step S4g, the initial position xint and the relative radius ra , The xy axis position ra (x, y) is calculated from the movement amount cbp of the vehicle 20.

In step S4f, it is determined whether or not the vehicle Y-axis movement amount yvp is equal to or less than the threshold value, and if it is equal to or less than the threshold value (step S4f: YES), the x-axis position x is calculated in step S4h (x). The axis position x is approximated to the relative radius ra), and further, the y-axis position is calculated as the vehicle y-axis movement amount ybp in step S4i.

[Summary and modification examples]
As described above, the above-mentioned non-contact power transmission system 10 has a charging station 30 having a power transmission coil 11 as a power transmission unit for transmitting weak power for alignment, and a power receiving unit that receives the weak power in a non-contact manner. 20 and the vehicle 20 having the power receiving coil 12 as the above.

The ECU 60 as a control unit of the vehicle 20 receives power from the voltage value detection unit 102 that detects the weak voltage value vulpe corresponding to the magnitude of the weak power received by the power receiving coil 12, the weak voltage value vulpe, and the transmission coil 11. Refer to the voltage value characteristic storage unit 200v in which the weak voltage value characteristic 202 indicating the correspondence with the distance to the coil 12 is stored in advance and the weak voltage value characteristic 202 with the detected weak voltage value vlp as an argument, and from the transmission coil 11 A relative position calculation unit 116 for calculating a relative position, which is a distance to the power receiving coil 12, is provided.

As described above, the relative position calculation unit 116 refers to the weak voltage value characteristic 202 with the weak voltage value vlpe detected by the voltage value detection unit 102 as an argument, and determines the distance (radial distance) from the power transmission coil 11 to the power reception coil 12. That is, the relative position can be calculated accurately.

The weak voltage value vlp is the maximum value (maximum peak value) vlpmax when the center of the power receiving coil 12 is aligned with the center of the power transmission coil 11 in a plan view. By ending the execution of the alignment when the voltage reaches vlpmax, the position of the power receiving coil 12 of the vehicle 20 with respect to the power transmission coil 11 of the charging station 30 can be accurately aligned with the optimum position.

In this case, ECU 60 further has a weak voltage integral value characteristics 204 representing the correspondence between the distance to the power receiving coil 12 from weak electrostatic圧積integral value vilpe the power transmission coil 11 which is positioned integral weak voltage characteristic 202.

The relative position calculation unit 116 takes the integrated value ∫vlppe · dx of the weak voltage value vlpe detected by the voltage value detecting unit 102 as an argument, and refers to the weak voltage integrated value characteristic 204, from the power transmission coil 11 to the power receiving coil 12. The distance may be calculated.

The weak voltage value characteristic 202 is likely to have a peculiar portion in which the weak voltage value vlppe does not increase or decreases even if the distance from the power transmitting coil 11 to the power receiving coil 12 is shortened. Even if there is a peculiar part in the weak voltage value characteristic 202, the integrated value ∫vlpe · dx of the weak voltage value vlpe in the direction toward the power transmission coil 11 increases. Therefore, by referring to the weak voltage integrated value characteristic 204 with the detected weak voltage value vlpe integrated value ∫vlpe · dx as an argument, the distance from the power transmitting coil 11 to the power receiving coil 12, that is, the power receiving coil 12 with respect to the power transmitting coil 11 The relative position can be specified accurately.

That is, a portion where the weak voltage value vlpe does not increase even if the distance to the power transmission coil 11 is shortened, and a position (distance) where the weak voltage value vlpe becomes the same value even if the distance is different due to the decrease of the weak voltage value vlpe. (For example, in the weak voltage value characteristic 2020s of FIG. 6, the values are the same at three positions of both sides of the side peak and the part between the bottom position xb and the close-range threshold position xc). However, since the weak voltage value coil is generated, the weak voltage integrated value coil increases with the distance. Thus, in the above equivalent portion, it is possible to uniquely calculate the distance (position) by referring to the weak electric圧積partial value characteristic 204.

The relative position calculation unit 116 has a weak voltage value characteristic 202 in the region from the position near the power transmission coil 11 where the weak voltage value vrpe is equal to or higher than the weak voltage value (threshold) vrpec, which is a predetermined voltage value, to the position of the power transmission coil 11. The distance from the power transmission coil 11 to the power reception coil 12 is calculated based on the above.

If it is equal to or higher than the weak voltage value (threshold) vlpec, which is a predetermined voltage value, the position is uniquely specified based on the weak voltage value characteristic 202, and the weak voltage value characteristic at the position near the transmission coil 11 (within the close range region Dc). 202 is the amount of increase in the characteristic value per unit distance, that is, the sensitivity {(voltage value increase / unit distance)> (integrated voltage value increase / unit) as compared with the weak voltage integrated value characteristic 204 at the position near the transmission coil 11. Since the distance) is large, the alignment is more accurate than the predetermined voltage value {weak voltage value (threshold) vlpec}, in other words, the alignment in the vicinity of the transmission coil 11 is performed based on the weak voltage value characteristic 202. It can be carried out.

Here, in the weak voltage value characteristic 202, the value along the vertical cross section of the weak voltage value vlpe corresponding to the magnitude of the weak power transmitted from the power transmission coil 11 in the entire radial direction is the center of the power transmission coil 11. From the maximum peak value voltagemax of the above, it becomes smaller toward the outside in the radial direction to become the bottom peak value voltage, and from the bottom peak value voltage further toward the outside in the radial direction, the value increases to become the side peak value voltagen. It has the characteristic that it descends further toward the outside in the radial direction and becomes a zero value.

In this case, the relative position calculation unit 116 starts from the bottom peak value vlpeth and the bottom peak value vlpeth from the zero value to the side peak value vlpen from the weak voltage value vlpe from the outside to the inside in the radial direction of the power transmission coil 11. Further, the distance from the power transmission coil 11 to the power receiving coil 12 is calculated with reference to the weak voltage integrated value characteristic 204 until the position becomes the same value as the side peak value vulpen toward the inner side in the radial direction, and becomes the same value as the side peak value vulpen. At a position inside the position, the distance from the power transmission coil 11 to the power reception coil 12 is calculated with reference to the weak voltage value characteristic 202.

In this way, the position from the position (initial position) xint where the weak voltage value vrpe is first detected to the predetermined voltage value {in the example of FIG. 6, the weak voltage value (threshold) vrpec} is weak. The distance from the power transmission coil 11 is calculated with reference to the voltage integrated value characteristic 204, and from the position (close distance threshold position xc) equal to or higher than the predetermined voltage value {weak voltage value (threshold) vrpec} to the position where the maximum peak value vrpemax is obtained. Is a region near the transmission coil 11 in which the weak voltage value vrpe is equal to or higher than a predetermined voltage value {weak voltage value (threshold) vrpec} by calculating the distance from the transmission coil 12 with reference to the weak voltage value characteristic 202. In the close range region Dc, the position is calculated with reference to the weak voltage value characteristic 202, which is highly sensitive to the voltage change with respect to the position. Since the position is calculated with reference to the weak voltage integrated value characteristic 204 that increases monotonically, the position of the power receiving coil 12 with respect to the power transmitting coil 11 is calculated reliably, and the power receiving coil 12 with respect to the power transmitting coil 11 is calculated. The position can be aligned to the optimum position.

Further, the vehicle speed sensor 74 for detecting the vehicle speed Vv of the vehicle 20 and the induced voltage storage unit 200e for preliminarily storing the vehicle speed induced voltage characteristic 206 which is the correspondence between the vehicle speed Vv and the induced voltage are provided, and the vehicle from the outside to the inside. From the position where the side peak value is vulpen (predetermined voltage value) (short distance threshold position xn), the position where the side peak value is equal to the side peak value vrpen (predetermined voltage value) toward the inside in the radial direction (approximately close distance). Up to the threshold position xc) is a peculiar region in which the weak voltage value vlpe changes with the generation of the induced voltage due to the vehicle speed Vv of the vehicle 20.

In the peculiar region, the relative position calculation unit 116 corrects the weak voltage value characteristic 202 with reference to the correspondence between the vehicle speed Vv and the induced voltage, and the weak voltage integral value of the corrected weak voltage value characteristic 202. The distance from the power transmitting coil 11 to the power receiving coil 12 is calculated with reference to the characteristic 204.

As described above, in the peculiar region where the weak voltage value vlpe changes with the generation of the induced voltage by the vehicle speed Vv of the vehicle 20, the weak voltage value characteristic 202 is referred to with reference to the correspondence between the vehicle speed Vv and the induced voltage. To the characteristic of vehicle speed = 0, and refer to the weak voltage integrated value characteristic 204 of the corrected weak voltage value characteristic 202, in other words, the weak voltage integrated value characteristic 204 of vehicle speed = 0, from the transmission coil 11. Since the distance to the power receiving coil 12 is calculated, the accurate relative position can be calculated even if there is a region where the induced voltage is generated at the vehicle speed Vv.

[Modification example]
In the non-contact power transmission system 10 according to the above-described embodiment, the vehicle 20 or the driver of the vehicle 20 that has received the weak power for alignment transmitted from the charging station 30 causes the vehicle 20 to receive the weak power based on the weak power. The alignment with the charging station 30 is executed, but the present invention is not limited to this, and the charging station 30 that has received the weak power for alignment transmitted from the vehicle 20 communicates with the vehicle 20 to perform the weakness. The vehicle 20 or the driver of the vehicle 20 may be made to perform the alignment of the vehicle 20 with the charging station 30 based on the electric power.

In this case, the vehicle 20 may share the coil for weak power transmission and the coil for main charging, or may be configured separately. Further, the charging station 30 may share the coil for receiving weak power with the power transmission coil 11, or may be configured separately. The ECU 60 of the vehicle 20 and the power supply ECU 61 of the charging station 30 communicate with each other to transmit information from the charging station 30 to the vehicle 20 side during the alignment, and coordinately execute the alignment process.

That is, in this modification, a vehicle having a power transmission unit (power transmission coil) for transmitting weak power for alignment and a charging station having a power reception unit (power reception coil) for receiving the weak power in a non-contact manner are provided. It is a non-contact power transmission system.

The control unit of the charging station according to this modification includes a voltage value detection unit that detects a weak voltage value corresponding to the magnitude of the weak power received by the power receiving unit, and the weak voltage value and the power transmission unit. The voltage value characteristic storage unit that stores the weak voltage value characteristic that represents the correspondence with the distance to the power receiving unit in advance and the weak voltage value characteristic with the detected weak voltage value as an argument are referred to, and the power receiving unit receives the power. It is provided with a relative position calculation unit for calculating a relative position which is a distance to the unit.

According to this modification, the relative position calculation unit refers to the weak voltage value characteristic with the weak voltage value detected by the voltage value detection unit as an argument, and accurately calculates the distance from the power transmission unit to the power reception unit, that is, the relative position. can do.

The weak voltage value becomes the maximum value (maximum peak value) when the power receiving unit is aligned with the power transmission unit, so charging is performed by ending the alignment execution when the maximum value is reached. The position of the power transmission unit of the vehicle with respect to the power reception unit of the station can be accurately adjusted to the optimum position.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various configurations can be adopted based on the contents described in this specification.

10 ... Non-contact power transmission system 11 ... Transmission coil 12 ... Power receiving coil 20 ... Vehicle 21 ... Transmission pad 22 ... Power receiving pad 202 ... Weak voltage value characteristic 204 ... Weak voltage integrated value characteristic

Claims (4)

A non-contact power transmission system including a charging station having a power transmission unit for transmitting weak power and a vehicle having a power receiving unit for receiving the weak power in a non-contact manner.
The control unit of the vehicle
A voltage value detecting unit that detects a weak voltage value of the weak power received by the power receiving unit, and a voltage value detecting unit.
A voltage value characteristic storage unit that stores in advance the weak voltage value characteristics that represent the correspondence between the weak voltage value and the distance from the power transmission unit to the power reception unit.
A relative position calculation unit that calculates a relative position that is a distance from the power transmission unit to the power reception unit by referring to the weak voltage value characteristic with the detected weak voltage value as an argument.
Equipped with a,
The control unit further has a weak voltage integrated value characteristic that represents a correspondence relationship between the weak voltage integrated value obtained by position-integrating the weak voltage value characteristic and the distance from the power transmitting unit to the power receiving unit.
The relative position calculation unit calculates the distance from the power transmission unit to the power reception unit by referring to the weak voltage integrated value characteristic with the integrated value of the weak voltage value detected by the voltage value detection unit as an argument. A non-contact power transmission system characterized by the fact that. In the non-contact power transmission system according to claim 1,
The relative position calculation unit
A non-contact power transmission system characterized in that when the detected weak voltage value is equal to or higher than a predetermined voltage value, the distance from the power transmission unit to the power reception unit is calculated based on the weak voltage value characteristic. In the non-contact power transmission system according to claim 2.
When the weak voltage value is less than the predetermined voltage value, the distance from the power transmission unit is calculated based on the weak voltage integrated value characteristic and the detected voltage value.
A non-contact power transmission system characterized in that the distance from the power transmission unit is calculated based on the weak voltage value characteristic when the voltage value is equal to or higher than the predetermined voltage value. In the non-contact power transmission system according to claim 3.
Further, a vehicle speed sensor that detects the vehicle speed of the vehicle and a vehicle speed sensor
An induced voltage storage unit that stores the correspondence between the vehicle speed and the induced voltage is provided.
When the weak voltage value is equal to or higher than the predetermined voltage value, the weak voltage value characteristic is corrected based on the correspondence between the vehicle speed and the induced voltage, and the weak voltage integrated value characteristic of the corrected weak voltage value characteristic is corrected. A non-contact power transmission system, characterized in that the distance from the power transmission unit to the power reception unit is calculated with reference to.

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