JP6774379B2 - Contactless power transfer system - Google Patents

Description

The present invention relates to a non-contact power transmission system that transmits power between a primary coil and a secondary coil, and in particular, weak power from the power transmitting side to the power receiving side in order to align the primary coil and the secondary coil. The present invention relates to a device that detects an LPE (Low Power Activation) voltage generated across a resistor when a weak electric power is received.

Along with the development of electric vehicles such as electric vehicles and hybrid vehicles, technologies related to non-contact charging for non-contact charging of batteries of electric vehicles have also been developed. In order to efficiently perform non-contact charging, it is necessary to accurately align the primary coil provided in the charging station and the secondary coil provided in the electric vehicle.

Regarding the alignment of the primary coil and the secondary coil, for example, there is a technique as shown in Patent Document 1. Patent Document 1 discloses a device that detects the position of a wheel by a plurality of proximity sensors provided on the charging station side when aligning the primary coil and the secondary coil. In this device, the lighting state of the traffic light provided in the charging station is changed depending on whether the proximity sensor detects the wheel of the electric vehicle or not. The occupant operates the electric vehicle while observing the lighting state of the traffic light to align the primary coil and the secondary coil.

Japanese Unexamined Patent Publication No. 2014-099964 (paragraphs [0024]-[0031])

In the apparatus of Patent Document 1, the amount of misalignment of the secondary coil with respect to the primary coil is not taken into consideration when aligning the primary coil and the secondary coil. Therefore, it is difficult for the occupant to accurately align the primary coil and the secondary coil.

The present invention has been made in consideration of such a problem, and an object of the present invention is to provide a non-contact power transmission system capable of more accurately aligning a primary coil and a secondary coil.

The present invention
From the primary coil to the secondary coil in a state where the vertical direction of the charging station and the vehicle length direction of the electric vehicle are substantially parallel, and the horizontal direction of the charging station and the vehicle width direction of the electric vehicle are substantially parallel. On the other hand, it is a non-contact power transmission system that transmits power in a non-contact manner.
A voltage detector that detects the voltage generated by the weak power transmitted from the primary coil and received by the secondary coil.
Correspondence between the lateral misalignment amount when the vertical misalignment amount of the secondary coil with respect to the primary coil is 0 and the voltage value according to the lateral misalignment amount. A storage device that stores voltage value-positional deviation amount information indicating the relationship,
A maximum value determination unit that determines the maximum value of the voltage that fluctuates as the electric vehicle travels,
The lateral displacement amount corresponding to the maximum value is estimated based on the voltage value-positional deviation amount information stored in the storage device and the maximum value determined by the maximum value determination unit. It is characterized by including a deviation amount estimation unit.

According to the above configuration, the amount of lateral misalignment of the secondary coil with respect to the primary coil is determined based on the voltage value-misalignment amount information stored in the storage device and the maximum value of the voltage detected by the voltage detector. It can be easily estimated. Further, since the amount of lateral displacement of the secondary coil with respect to the primary coil can be estimated, the alignment of the primary coil and the secondary coil can be performed more accurately.

In the present invention
A notification control unit may be further provided to notify the lateral position deviation amount estimated by the deviation amount estimation unit by the notification device.

According to the above configuration, it is possible to notify the occupant of the amount of lateral displacement of the secondary coil with respect to the primary coil. Therefore, the occupant can easily align the primary coil and the secondary coil.

In the present invention
Further equipped with a distance sensor for detecting the mileage of the electric vehicle,
The maximum value determination unit determines the value of the voltage with respect to a minute mileage based on the value of the voltage detected by the voltage detector and the mileage of the electric vehicle detected by the distance sensor. The position differential value, which is the amount of change, may be calculated, and the value of the voltage when the position differential value becomes 0 may be determined as the maximum value.

According to the above configuration, the maximum value of the voltage can be calculated by a simple method such as calculating the position derivative value of the voltage value. Therefore, the alignment of the primary coil and the secondary coil can be easily performed.

According to the present invention, since the amount of lateral displacement of the secondary coil with respect to the primary coil can be estimated, the alignment of the primary coil and the secondary coil can be performed more accurately.

FIG. 1 is a system configuration diagram showing a non-contact power transmission system according to the present embodiment. FIG. 2 is an explanatory diagram provided for explaining the lateral displacement of the secondary coil with respect to the primary coil. FIG. 3 is a diagram showing the characteristics of the voltage value-horizontal distance. FIG. 4 is a flowchart showing the processing performed by the electric vehicle. 5A and 5B are explanatory views for explaining the parking operation of the electric vehicle with respect to the charging station.

Hereinafter, a preferred embodiment of the non-contact power transmission system according to the present invention will be described and described in detail with reference to the accompanying drawings.

[1 Configuration of non-contact power transmission system 10]
The configuration of the non-contact power transmission system 10 according to the first embodiment will be described with reference to FIG. The non-contact power transmission system 10 is composed of a charging station 20 on the primary side (power supply side) provided on the ground (installation surface) and an electric vehicle 40 on the secondary side (power receiving side). In FIG. 1, the component below the alternate long and short dash line indicates the charging station 20, and the component above the alternate long and short dash line indicates the electric vehicle 40. In the non-contact power transmission system 10, the battery 56 mounted on the electric vehicle 40 is non-contactly charged by the charging station 20.

The charging station 20 mainly includes a power transmission circuit 22, a primary side control device 34, and a primary side communication device 36. The power transmission circuit 22 includes an AC power supply 24, a power converter 26 that converts AC power supplied from the AC power supply 24 into power transmission power, a primary capacitor for resonance (not shown), and a primary coil 28. .. The primary coil 28 is covered with the primary pad 30 and arranged on the ground (installation surface).

The primary control device 34 functions as a predetermined operation unit when a processor (not shown) such as a CPU reads and executes a program stored in a storage device (not shown). In the first embodiment, the primary side control device 34 transmits a weak electric power for aligning the primary coil 28 and the secondary coil 44 and a charging electric power for charging the battery 56 to the primary coil 28. It functions as a power transmission control unit.

The primary side communication device 36 is connected to the primary side control device 34 by a communication line. The primary side communication device 36 performs wireless communication with the secondary side communication device 74 of the electric vehicle 40. For example, wireless communication such as Wi-Fi (registered trademark) and Bluetooth (registered trademark) can be used.

The electric vehicle 40 mainly includes a power receiving circuit 42, a battery 56, a secondary side control device 60, a secondary side communication device 74, a display device 76, an acoustic device 78, a distance sensor 80, and a traveling device 90. , Equipped with.

The power receiving circuit 42 includes a secondary capacitor (not shown) for resonance, a secondary coil 44, a rectifier 50 that rectifies the received power that is AC power received by the secondary coil 44, a power receiving circuit 42, and a battery 56. It includes a contactor 54 that switches between electrical connection and disconnection. The secondary coil 44 is covered with the secondary pad 46 and arranged on the lower surface of the electric vehicle 40.

Further, the power receiving circuit 42 includes a voltage detector 52 that can be freely connected between the rectifier 50 and the contactor 54. The voltage detector 52 has, for example, as shown in Japanese Patent No. 5937631, a parallel circuit (both not shown) of a predetermined resistor and a voltage sensor. The voltage sensor detects the voltage generated across the resistor when receiving weak power. This voltage is called the LPE voltage. When the switch device (not shown) receives a control instruction from the secondary control device 60 and performs a switching operation when receiving weak power, the voltage detector 52 is connected to the power receiving circuit 42. In the present embodiment, the LPE voltage is detected by using the power receiving circuit 42 used at the time of charging, but a circuit for detecting the LPE voltage is provided separately from the power receiving circuit 42, and a rectifier is provided therein. And the voltage detector 52 may be provided.

The battery 56 is made of a lithium ion battery or the like, and when the contactor 54 is connected and the primary coil 28 and the secondary coil 44 are magnetically coupled, the battery 56 is charged via the power receiving circuit 42.

The secondary side control device 60 is an ECU and manages the power receiving process. The secondary side control device 60 reads and executes a program stored in the storage device 70 by a processor (not shown) such as a CPU, so that the control unit 62, the maximum value determination unit 64, the deviation amount estimation unit 66, and the notification control It functions as a unit 68.

The control unit 62 controls and manages the power receiving process. The maximum value determination unit 64 is based on the LPE voltage value V_LPE (hereinafter referred to as voltage value V_LPE) detected by the voltage detector 52 and the mileage X of the electric vehicle 40 detected by the distance sensor 80. , The amount of change in the voltage value V_LPE with respect to a minute mileage X (mileage X per unit time), that is, the position differential value dV / dX with respect to the LPE voltage is calculated. Then, the voltage value V_LPE detected by the voltage detector 52 when the calculated value becomes 0 is determined to be the maximum value (peak value) V_LPEmax. The deviation amount estimation unit 66 corresponds to the maximum value V_LPEmax based on the voltage value-positional deviation amount information In stored in the storage device 70 and the maximum value V_LPEmax determined by the maximum value determination unit 64. The amount of misalignment A2 in the direction is estimated. The notification control unit 68 outputs a command signal corresponding to the lateral displacement amount A2 estimated by the displacement amount estimation unit 66, and notifies the lateral displacement amount A2 by the display device 76 and the sound device 78.

The storage device 70 stores voltage value-positional deviation amount information In in addition to predetermined values, default values, and the like used in various programs and various operations. The voltage value-positional displacement amount information In is the lateral displacement amount A2 when the vertical displacement amount A1 of the secondary coil 44 with respect to the primary coil 28 is 0, and the lateral displacement amount. It is information which shows the correspondence relationship with the voltage value V_LPE corresponding to A2. The voltage value-positional deviation amount information In will be further described in [2] below.

The secondary side communication device 74 is connected to the secondary side control device 60 by a communication line. As described above, the secondary side communication device 74 performs wireless communication with the primary side communication device 36 of the charging station 20.

The display device 76 displays information indicating the amount of misalignment A2 between the primary coil 28 and the secondary coil 44 in response to the command signal output from the secondary control device 60. For example, a bird's-eye view showing the positions of the primary coil 28 and the secondary coil 44 in a simulated manner and the misalignment amount A2 itself of the primary coil 28 and the secondary coil 44 are displayed on the screen. The sound device 78 outputs information indicating the misalignment amount A2 between the primary coil 28 and the secondary coil 44 from the speaker in response to the command signal output from the secondary control device 60.

The traveling device 90 includes a driving force device that generates a driving force according to the operation of the accelerator pedal performed by the occupant, a steering device that steers according to the operation of the steering wheel performed by the occupant, and an operation of the brake pedal performed by the occupant. Includes a braking device that generates braking force accordingly. The driving force device includes an electric motor to which power is supplied from the battery 56 as a driving source.

[2 Voltage value-Position deviation amount information In]
A scene in which the electric vehicle 40 moves straight and horizontally with the vertical direction of the charging station 20 and the vehicle length direction of the electric vehicle 40 substantially parallel to each other and the secondary coil 44 being vertically separated from the primary coil 28. Is assumed. At this time, as shown in FIG. 2, it is assumed that the lateral displacement amount A2 of the secondary coil 44 with respect to the primary coil 28 is 0. In this scene, the horizontal distance D between the primary coil 28 and the secondary coil 44 and the voltage value V_LPE detected by the voltage detector 52 have a relationship as shown in the curve B1 of FIG.

That is, the electric vehicle 40 approaches the primary coil 28 from a distance, and at a position {horizontal distance D = D1 (positional deviation amount A1 = D1)} where the secondary coil 44 can receive the weak electric power transmitted from the primary coil 28. When it reaches, the voltage value V_LPE starts to rise from the first predetermined value V_LPE1. As the electric vehicle 40 travels and the horizontal distance D decreases, the voltage value V_LPE gradually increases, and reaches the maximum value V_LPE2 at the position of the horizontal distance D = D2 (positional deviation amount A1 = D2). Further, as the electric vehicle 40 travels and the horizontal distance D becomes smaller, the voltage value V_LPE gradually becomes smaller, and becomes the minimum value V_LPE3 at the position of the horizontal distance D = D3 (positional deviation amount A1 = D3). Further, as the electric vehicle 40 travels and the horizontal distance D becomes smaller, the voltage value V_LPE gradually increases, and the position at the horizontal distance D = 0 (positional deviation amount A1 = 0), that is, the center 44c of the secondary coil 44 is primary. When the position above the center 28c of the coil 28 is reached, the maximum value V_LPEmax1 is reached.

Next, it is assumed that the electric vehicle 40 travels in a state of being displaced in the lateral direction. For example, when the lateral displacement amount A2 = a (> 0) of the secondary coil 44 with respect to the primary coil 28 as shown in FIG. 2, the voltage value V_LPE is as shown in the curve B2 of FIG. It is lower than the curve B1 when the misalignment amount A2 = 0. The maximum value V_LPEmax2 when the vertical misalignment amount A1 = 0 of the secondary coil 44 with respect to the primary coil 28 is lower than the maximum value V_LPEmax1. Further, as shown in FIG. 2, when the lateral displacement amount A2 = b (> a) of the secondary coil 44 with respect to the primary coil 28, the voltage value V_LPE is as shown in the curve B3 of FIG. It is lower than the curve B2 when the misalignment amount A2 = a. The maximum value V_LPEmax3 when the vertical displacement amount A1 = 0 of the secondary coil 44 with respect to the primary coil 28 is lower than the maximum value V_LPEmax1 and the maximum value V_LPEmax2. As described above, the maximum value V_LPEmax detected when the vertical displacement amount A1 = 0 becomes lower as the lateral displacement amount A2 of the secondary coil 44 with respect to the primary coil 28 becomes larger. The storage device 70 stores information such as the correspondence between the maximum value V_LPEmax and the lateral displacement amount A2, for example, A2 = 0 and V_LPE = V_LPEmax1, A2 = a and V_LPE = V_LPEmax2, A2 = b and V_LPE = V_LPEmax3. , Voltage value-Position deviation amount information In is stored.

[3 Alignment processing]
In the present embodiment, by detecting the maximum value V_LPEmax of the voltage value V_LPE, it is assumed that the vertical misalignment amount A1 of the secondary coil 44 with respect to the primary coil 28 is 0, and the primary coil 28 at that time. The lateral displacement amount A2 of the secondary coil 44 with respect to the relative coil 44 is estimated.

The alignment process performed on the electric vehicle 40 side according to the present embodiment will be described with reference to FIG. The process described below is performed when the occupant of the electric vehicle 40 turns on the parking start switch (not shown). As shown in FIGS. 2 and 5A, for example, the charging station 20 is partitioned by line 150. The occupant turns on the parking start switch at the position P1 away from the charging station 20 to drive the electric vehicle 40 toward the charging station 20. The operation signal of the parking start switch is transmitted to the secondary control device 60.

For the occupants, the vertical direction of the charging station 20 and the vehicle length direction of the electric vehicle 40 are substantially parallel, and the horizontal direction of the charging station 20 and the vehicle width direction of the electric vehicle 40 are substantially parallel. Operate the electric vehicle 40. Then, the electric vehicle 40 is run substantially straight to align the primary coil 28 and the secondary coil 44.

In step S1, the control unit 62 instructs the secondary communication device 74 to request transmission of weak power. The secondary side communication device 74 performs pairing such as authentication with the primary side communication device 36, and transmits a transmission request signal of weak power. The primary side control device 34 controls the power converter 26 in response to the transmission request signal received by the primary side communication device 36 to start power transmission. The power converter 26 converts the AC power supplied from the AC power supply 24 into a predetermined weak power and supplies it to the primary coil 28. Then, a weak electric power for alignment is transmitted from the primary coil 28 to the outside.

In step S2, the control unit 62 determines whether or not the voltage value V_LPE detected by the voltage detector 52 is equal to or higher than the first predetermined value V_LPE 1, that is, the secondary coil 44 receives weak power as shown in FIG. 5A. It is determined whether or not the range R (horizontal distance D = D1) is reached. When the value is equal to or greater than the first predetermined value V_LPE1, that is, when the secondary coil 44 enters the range R where weak power can be received (step S2: YES), the process proceeds to step S3. On the other hand, if it is less than the first predetermined value V_LPE1, that is, if the secondary coil 44 is not within the range R in which weak power can be received (step S2: NO), the process of step S2 is repeated.

When shifting from step S2 to step S3, the maximum value determination unit 64 determines the position differential value based on the voltage value V_LPE detected by the voltage detector 52 and the mileage X per unit time detected by the distance sensor 80. Calculate dV / dX.

In step S4, the maximum value determination unit 64 determines the voltage value V_LPE and the position differential value dV / dX. As shown in FIG. 3, for example, in the curve B1 showing the characteristic of the misalignment amount A2 = 0, the voltage value V_LPE becomes the maximum value V_LPE2 and the position differential value dV / dX becomes the maximum value V_LPE2 at the positions of the horizontal distances D = D2 and 0. It becomes 0. In the present embodiment, in order to correctly determine the maximum value V_LPEmax, in other words, in order not to determine the position of the horizontal distance D = D2 as the position of the vertical displacement amount A1 = 0, the voltage value V_LPE is set. The maximum value V_LPE2 detected at the position of the horizontal distance D = D2 on the largest curve B1 is set as the second predetermined value and stored in the storage device 70. When the voltage value V_LPE is larger than the second predetermined value V_LPE2 and the position differential value dV / dX is 0 (step S4: YES), the voltage value V_LPE is the maximum value V_LPEmax and the vertical misalignment amount A1. Estimating that the position is = 0, the process proceeds to step S5. On the other hand, when the voltage value V_LPE is equal to or less than the second predetermined value V_LPE2, or the position differential value dV / dX is not 0 (step S4: NO), the voltage value V_LPE is not the maximum value V_LPEmax and is displaced in the vertical direction. It is estimated that the position is not the position of the quantity A1 = 0, and the process returns to step S3.

In step S5, the deviation amount estimation unit 66 refers to the voltage value-positional deviation amount information In stored in the storage device 70, and the positional deviation corresponding to the voltage value V_LPE when the position differential value dV / dX becomes 0. Estimate the quantity A2.

In step S6, the notification control unit 68 outputs a command signal instructing the display device 76 and the sound device 78 to notify based on the position deviation amount A2 estimated by the deviation amount estimation unit 66. The display device 76 displays a bird's-eye view of the misalignment amount A2 or the primary coil 28 and the secondary coil 44 on the screen. The sound device 78 outputs a voice for notifying the misalignment amount A2 and a signal sound corresponding to the misalignment amount A2 from the speaker. For example, the interval between the output of the signal sound and the stop is changed according to the misalignment amount A2.

The driver grasps the misalignment amount A2 by the notification of the display device 76 and / or the sound device 78. As shown in FIG. 5B, when the misalignment amount A2 of the secondary coil 44 with respect to the primary coil 28 becomes 0, the driver parks the electric vehicle 40 and starts charging. On the other hand, when the driver redoes the alignment operation, the processes after step S2 are executed again.

[Summary of 4 Embodiments]
In the non-contact power transmission system 10 according to the above-described embodiment, the vertical direction of the charging station 20 and the vehicle length direction of the electric vehicle 40 are substantially parallel, and the horizontal direction of the charging station 20 and the vehicle width direction of the electric vehicle 40. Power is transmitted from the primary coil 28 to the secondary coil 44 in a non-contact manner in a state of being substantially parallel to each other. The non-contact power transmission system 10 has a voltage detector 52 that detects the LPE voltage generated by the weak power transmitted from the primary coil 28 and received by the secondary coil 44, and the vertical of the secondary coil 44 with respect to the primary coil 28. The voltage value-positional deviation amount information In indicating the correspondence between the lateral misalignment amount A2 when the misalignment amount A1 in the direction is 0 and the voltage value V_LPE corresponding to the lateral misalignment amount A2. The storage device 70 to be stored, the maximum value determination unit 64 for determining the maximum value V_LPEmax of the LPE voltage that fluctuates with the running of the electric vehicle 40, the voltage value-positional deviation amount information In stored in the storage device 70, and the maximum. A deviation amount estimation unit 66 that estimates a lateral position deviation amount A2 corresponding to the maximum value V_LPEmax based on the maximum value V_LPEmax determined by the value determination unit 64 is provided.

According to the above configuration, the secondary coil 44 with respect to the primary coil 28 is based on the voltage value-positional deviation amount information In stored in the storage device 70 and the maximum value V_LPEmax of the LPE voltage detected by the voltage detector 52. The amount of misalignment A2 in the lateral direction can be easily estimated. Further, since the lateral displacement amount A2 of the secondary coil 44 with respect to the primary coil 28 can be estimated, the alignment of the primary coil 28 and the secondary coil 44 can be performed more accurately.

The non-contact power transmission system 10 includes a notification control unit 68 that notifies the lateral position deviation amount A2 estimated by the deviation amount estimation unit 66 by the display device 76 as a notification device and the sound device 78. According to the above configuration, it is possible to notify the occupant of the lateral displacement amount A2 of the secondary coil 44 with respect to the primary coil 28. Therefore, the occupant can easily align the primary coil 28 and the secondary coil 44.

The non-contact power transmission system 10 includes a distance sensor 80 that detects the mileage X of the electric vehicle 40. The maximum value determination unit 64 determines the voltage value V_LPE for a minute mileage X based on the voltage value V_LPE detected by the voltage detector 52 and the mileage X of the electric vehicle 40 detected by the distance sensor 80. The position differential value dV / dX, which is the amount of change, is calculated, and the voltage value V_LPE when the position differential value dV / dX becomes 0 is determined to be the maximum value V_LPEmax. According to the above configuration, the maximum value V_LPEmax of the LPE voltage can be calculated by a simple method such as calculating the position differential value dV / dX of the voltage value V_LPE. Therefore, the alignment of the primary coil 28 and the secondary coil 44 can be easily performed.

It should be noted that the non-contact power transmission system according to the present invention is not limited to the above-described embodiment, and of course, various configurations can be adopted without deviating from the gist of the present invention. For example, the non-contact power transmission system according to the present invention is a vehicle provided with a parking support device or an automatic parking device (Japanese Patent Laid-Open No. 2015-07426, etc.) that automatically controls at least one of steering, driving, and braking. Can also be used for.

10 ... Non-contact power transmission system 20 ... Charging station 28 ... Primary coil 34 ... Primary side control device 40 ... Electric vehicle 44 ... Secondary coil 52 ... Voltage detector 64 ... Maximum value determination unit 66 ... Deviation amount estimation unit 68 ... Notification control unit 70 ... Storage device 76 ... Display device 78 ... Sound device 80 ... Distance sensor

Claims (3)

From the primary coil to the secondary coil in a state where the vertical direction of the charging station and the vehicle length direction of the electric vehicle are substantially parallel, and the horizontal direction of the charging station and the vehicle width direction of the electric vehicle are substantially parallel. On the other hand, it is a non-contact power transmission system that transmits power in a non-contact manner.
A voltage detector that detects the voltage generated by the weak power transmitted from the primary coil and received by the secondary coil.
Correspondence between the lateral misalignment amount when the vertical misalignment amount of the secondary coil with respect to the primary coil is 0 and the voltage value according to the lateral misalignment amount. A storage device that stores voltage value-positional deviation amount information indicating the relationship,
A maximum value determination unit that determines the maximum value of the voltage that fluctuates as the electric vehicle travels,
The lateral displacement amount corresponding to the maximum value is estimated based on the voltage value-positional deviation amount information stored in the storage device and the maximum value determined by the maximum value determination unit. A non-contact power transmission system including a deviation amount estimation unit. In the non-contact power transmission system according to claim 1,
A non-contact power transmission system further comprising a notification control unit that notifies the lateral position deviation amount estimated by the deviation amount estimation unit by a notification device. In the non-contact power transmission system according to claim 1 or 2.
Further equipped with a distance sensor for detecting the mileage of the electric vehicle,
The maximum value determination unit determines the value of the voltage with respect to a minute mileage based on the value of the voltage detected by the voltage detector and the mileage of the electric vehicle detected by the distance sensor. A non-contact power transmission system characterized in that a position differential value which is an amount of change is calculated, and the value of the voltage when the position differential value becomes 0 is determined as the maximum value.

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