JP6860430B2 - Contactless power transfer system - Google Patents

Description

The present invention relates to a non-contact power transmission system in which electric power transmitted from an external coil provided on a road surface is received by a vehicle coil provided in a vehicle in a non-contact manner to charge a battery of the vehicle.

With the development of electric vehicles propelled by electric motors, such as electric vehicles, hybrid vehicles, fuel cell vehicles, and the like, technologies related to non-contact charging for non-contact charging the batteries of the electric vehicles have been advanced.

In order to efficiently perform non-contact charging, it is necessary to accurately align the external coil provided in the external charging station or the like with the vehicle coil provided in the vehicle (match the axes of both coils). There is.

For example, Patent Document 1 describes that a driver stops an electric vehicle near a position where a feeding coil is installed in order to perform accurate alignment (Patent Document 1 [0048]). At this time, a weak electric power smaller than the charging electric power is transmitted from the power feeding coil for alignment (the same [0049]). The amount of electric power related to the transmission of this weak electric power is referred to as the amount of electric power transmitted (the same [0053]). On the other hand, the electric vehicle receives the weak electric power by the power receiving coil, and obtains the electric energy of the received weak electric power (referred to as the electric energy received) (the same [0054]).

In the electric vehicle, the power transmission efficiency (received power amount / transmitted power amount) is calculated from the transmitted power amount and the received power amount during alignment, and at the time and position where the power transmission efficiency increases and reaches the maximum. The electric vehicle is stopped to complete the alignment (the same [0054] to [0057]).

Japanese Patent No. 5966407

However, Patent Document 1 has a problem that the power consumption of the entire system increases because it is necessary to continue transmitting weak power from the external coil during the alignment.

The present invention has been made in consideration of such a problem, and provides a non-contact power transmission system capable of reducing the power consumed for alignment using an external coil and a vehicle coil. The purpose is to do.

The non-contact power transmission system according to the present invention is a non-contact power transmission system that receives power transmitted from an external coil provided on a road surface in a non-contact manner by a vehicle coil provided in a vehicle to charge a vehicle battery. Is. Of the external coil or vehicle coil, the power transmission side control device that controls the transmission interval mode of the alignment power transmitted from one coil and the alignment power transmitted from one coil are transferred to the external coil or the vehicle coil. Among the vehicle coils, the power receiving side control device that receives power from the other coil and detects the voltage value generated by the received power as the received voltage value is provided, and the power transmission side control device and the power receiving side control device have the received voltage value. It is characterized in that the transmission interval mode is changed when the voltage threshold is exceeded.

According to the present invention, during alignment, the transmission interval mode of the alignment power transmitted from the external coil or the vehicle coil is changed, so that the power consumption is reduced while maintaining accurate alignment. it can. When the power for alignment is transmitted from the external coil, the power consumption of the outside, for example, the infrastructure side can be reduced, and when the power for alignment is transmitted from the vehicle coil, the continuous transmission mode is set. In comparison, it is possible to suppress a decrease in SOC of the vehicle battery.

In the above-mentioned non-contact power transmission system, the power transmission side control device preferably sets the power transmission interval mode to the intermittent power transmission mode before the received voltage value exceeds the voltage threshold value, and sets the power transmission side control device to the continuous power transmission mode after the power transmission interval value exceeds the voltage threshold value.

According to such a configuration, when the distance between one coil assigned to power transmission and the other coil assigned to power reception is long (the power reception voltage is less than the voltage threshold), the power transmission interval mode is set. Power saving can be achieved as an intermittent power transmission mode. When the distance between one coil assigned to power transmission and the other coil assigned to power reception becomes short (the power reception voltage is equal to or higher than the voltage threshold value), the continuous power transmission mode is set and accurate alignment is performed. Can contribute to.

In the above non-contact power transmission system, before the received voltage value exceeds the low voltage threshold lower than the voltage threshold, the transmission interval mode is set to the first intermittent power transmission mode, and after exceeding the low voltage threshold, power is transmitted up to the voltage threshold. It is preferable to set the interval mode to the second intermittent power transmission mode in which the power transmission interval is narrower than that of the first intermittent power transmission mode.

According to such a configuration, until the received voltage value reaches the voltage threshold value, in other words, until the distance becomes short, even if the interval is gradually narrowed, the alignment can be performed within a practically sufficient range. Therefore, the power consumption can be further reduced.

In the above non-contact power transmission system, after the received voltage value exceeds the low voltage threshold value, the power transmission interval mode is changed to the second intermittent power transmission mode in which the power transmission interval is narrower than that of the first intermittent power transmission mode until the voltage threshold is reached. When doing so, it is preferable to narrow the transmission interval as the received voltage value approaches the voltage threshold.

According to such a configuration, after the received voltage value exceeds the low voltage threshold value, the power transmission interval is narrowed as it approaches the voltage threshold value, so that the positioning distance can be grasped more accurately.

In the above-mentioned non-contact power transmission system, it is preferable to replace the received voltage value as a comparative value with the power value of the received voltage value or the transmission power efficiency of the transmitted / received power.

As a comparison value, even if the received voltage value is the power value of the received voltage value or the transmission power efficiency, the alignment process can be performed in the same manner.

According to such a configuration, during alignment, the transmission interval mode of the alignment power transmitted from one of the external coil or the vehicle coil is changed, so that accurate alignment can be maintained. , Power consumption can be reduced.

FIG. 1 is a system configuration diagram showing a non-contact power transmission system according to this embodiment. FIG. 2 is a characteristic diagram showing voltage value-distance information. FIG. 3 is the first half of the flowchart provided for explaining the operation of the non-contact power transmission system according to this embodiment. FIG. 4 is a latter half of a flowchart provided for explaining the operation of the non-contact power transmission system according to this embodiment. FIG. 5A is an explanatory diagram of a weak power transmission interval when the vehicle is far from the external coil, and FIG. 5B is an explanatory diagram of a weak power transmission interval when the vehicle is slightly far from the external coil. FIG. 6 is an explanatory diagram of a transmission interval of weak electric power when the vehicle is close to the external coil. FIG. 7A is an explanatory diagram showing a state in which weak electric power is transmitted from an external coil, and FIG. 7B is an explanatory diagram showing a state in which weak electric power is transmitted from a vehicle coil.

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

[Constitution]
FIG. 1 shows a schematic configuration of the non-contact power transmission system 10 according to this embodiment.

The non-contact power transmission system 10 is composed of a charging station 20 on the power supply side provided on the road surface (installation surface) 12 and an electric vehicle (simply referred to as a vehicle) 40 on the power receiving side. The battery 54 mounted on the electric vehicle 40 is non-contactly charged by the power supply from the charging station 20 after the alignment process.

The charging station 20 basically includes a power transmission circuit 22, an external control device 34, and an external 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 higher frequency transmission power (power supply power), and an external coil 28.

The external coil 28 is covered with the external pad 30 and arranged on the road surface (installation surface) 12.

The external control device 34 functions as a power transmission interval mode changing unit 27 or the like by reading and executing a program stored in the memory by a processor such as a CPU. The power transmission interval mode changing unit 27 changes the power conversion interval in the power converter 26, that is, the power transmission interval Tint.

The external control device 34 transmits a weak electric power having a constant strength for aligning the vehicle coil 44 and a charging electric power for charging the battery 54 from the external coil 28 with respect to the installation position of the external coil 28. The "weak power" means a power smaller than the "charging power" for charging the battery 54 after alignment.

The external communication device 36 is connected to the external control device 34 by a communication line. The external communication device 36 performs wireless communication with the vehicle-side communication device 68 of the electric vehicle 40.

The electric vehicle 40 basically includes a power receiving circuit 42, a battery 54, a vehicle-side control device 56, a vehicle-side communication device 68, a distance sensor 70, a display device 72, and a traveling device 74.

The power receiving circuit 42 includes a vehicle coil 44, a rectifier 48 that rectifies the received power (charging power, weak power), which is AC power received by the vehicle coil 44, and a voltage that detects a voltage generated by the received power (weak power). It includes a detector 50 and a contactor 52 that switches between electrical connection and disconnection between the power receiving circuit 42 and the battery 54. The vehicle coil 44 is covered with a vehicle side pad 46 and is arranged on the lower surface of the electric vehicle 40.

The voltage detector 50 detects the voltage generated on the output side of the rectifier 48 when receiving weak electric power. This voltage is called a weak voltage or an LPE (Low Power Excitation) voltage.

The battery 54 is made of a lithium ion battery or the like, and when the contactor 52 is connected and the external coil 28 and the vehicle coil 44 are magnetically coupled, the battery 54 is charged via the power receiving circuit 42.

The vehicle-side control device 56 is an ECU and manages a charging process including an alignment process. The vehicle-side control device 56 reads and executes a program stored in the memory 66 by a processor such as a CPU, so that the charge management unit 58, the differential value calculation unit 60, the vertical distance estimation unit 62, the horizontal distance estimation unit 64, and the threshold value are executed. It functions as a comparison unit 65.

The charge management unit 58 collectively manages the charge process.

The differential value calculation unit 60 is minute based on the weak voltage value (referred to as weak voltage value vlp) detected by the voltage detector 50 and the mileage x of the electric vehicle 40 detected by the distance sensor 70. The amount of change in the weak voltage value vlpe with respect to the mileage dx, that is, the position differential value d (vlpe) / dx is calculated.

The vertical distance estimation unit 62 sets the external coil 28 and the vehicle based on the weak voltage value vulpe, the position differential value d (vlp) / dx, and the voltage value-distance information (FIG. 2) stored in the memory 66. The vertical distance Z with the coil 44 is estimated. In a plan view, the vertical distance Z when the center position of the vehicle coil 44 coincides with the center position of the external coil 28 is referred to as a face-to-face distance. When the center position of the external coil 28 and the center position of the vehicle coil 44 match, the power receiving efficiency (weak power / transmitted power) of the weak power plpe becomes maximum, and the charging efficiency (received power / transmitted power) when charging the battery 54. Is also the maximum. Therefore, in the alignment process, it is targeted that the center positions (centers) of both the external coil 28 and the vehicle coil 44 match.

The horizontal distance estimation unit 64 is based on the weak voltage value vlp and the voltage value-distance information (FIG. 2) corresponding to the vertical distance Z, and the horizontal distance D between the external coil 28 and the vehicle coil 44 {in plan view. The linear distance connecting the center position (center) of the external coil 28 and the center position (center) of the vehicle coil 44} is estimated.

The threshold value comparison unit 65 compares the weak voltage value blpe with the threshold value (low voltage threshold blpel or voltage threshold blpeh), and when the weak voltage value vrpe exceeds the threshold value (low voltage threshold blpel or voltage threshold blpeh), it exceeds the threshold value. Notify the vehicle side communication device 68 of this.

The vehicle-side communication device 68 is connected to the vehicle-side control device 56 by a communication line. The vehicle-side communication device 68 performs wireless communication such as Wi-Fi (registered trademark) or Bluetooth (registered trademark) with the external communication device 36 of the charging station 20.

The traveling device 74 includes a driving force device that generates a driving force according to the operation of the accelerator pedal performed by the driver, a steering device that steers according to the operation of the steering wheel performed by the driver, and a brake performed by the driver. Includes a braking device that generates braking force in response to pedal operation. The driving force device includes an electric motor to which electric power is supplied from the battery 54 as a driving source.

The memory 66 of the vehicle-side control device 56 stores various programs, predetermined values, threshold values, and other numerical values, as well as characteristics indicating voltage value-distance information as shown in FIG. 2 as a map M. This voltage value-distance information is the distance (horizontal) between the reference portion of the external coil 28 (the center of the external coil 28 in this embodiment) and the reference portion of the vehicle coil 44 (the center of the vehicle coil 44 in this embodiment). It is a voltage value-distance characteristic showing the relationship between the distance D) and the weak voltage value vlpe corresponding to the distance (horizontal distance D).

More specifically, the voltage value-distance information shown in FIG. 2 is the vertical distance Z between the center of the external coil 28 and the center of the vehicle coil 44, and the center of the external coil 28 and the center of the vehicle coil 44. It is a voltage value-distance characteristic showing the relationship between the horizontal distance D between them and the weak voltage value vlpe corresponding to the vertical distance Z and the horizontal distance D.

When the electric vehicle 40 travels in the charging station 20 and aligns the vehicle coil 44 with respect to the external coil 28, the vertical distance Z does not change but the horizontal distance D changes.

In FIG. 2, the characteristics of the weak voltage value blpe-horizontal distance D corresponding to the three types of vertical distances Z1 to Z3 (Z1 <Z2 <Z3) are shown as a two-dimensional graph. As the vertical distance Z increases, the magnetic coupling becomes weaker, so that the weak voltage value vlpe becomes smaller. On the other hand, when the horizontal distance D is D = 0, the weak voltage value vulpe becomes the maximum weak voltage value vulpemax, and as the horizontal distance D increases from D = 0, the weak voltage value vulpe becomes smaller and becomes the minimum value at the distance D1. Become. Further, as the horizontal distance D increases from the distance D1, the weak voltage value vlpe increases, and becomes the weak voltage value vlpes which is the maximum value at the distance D2. Further, as the horizontal distance D increases from the distance D2, the weak voltage value vlpe becomes smaller, and when it cannot be detected, it becomes a 0 value.

As shown in FIG. 2, the characteristic of the weak voltage value vlpe-horizontal distance D is uniquely determined according to the vertical distance Z. Then, at the distance D2 where the weak voltage value vlp is the maximum weak voltage value vlpes, the maximum value (weak voltage value vlpes) is different for each vertical distance Z. That is, the maximum value (weak voltage value vlpes) of each characteristic is an eigenvalue of each characteristic. Therefore, when the vehicle coil 44 is aligned with respect to the external coil 28, when the weak voltage value flape becomes the weak voltage value flapes which is the maximum value, that is, when the position differential value d (vlpe) / dx becomes 0. The vertical distance Z can be estimated from the weak voltage value vlpe itself. Then, the characteristic of the weak voltage value vrpe-horizontal distance D corresponding to the estimated vertical distance Z is specified, and the horizontal distance D can be estimated by using the characteristic.

In each characteristic of the weak voltage value vlpe-horizontal distance D shown in FIG. 2, the position differential value d (vlpe) / dx becomes 0 when the horizontal distance D is D = 0, near D1 and near D2. It's time. Of these, the weak voltage value vlpe when the horizontal distance D is D = 0 is the maximum value among the characteristics. However, when the horizontal distance D is D = 0, it means that the positions of the center of the external coil 28 and the center of the vehicle coil 44 are already aligned. Therefore, in the alignment process, the maximum weak voltage value vlp (D = 0) is not used as a determination material for the vertical distance Z. The material used as the determination material for the vertical distance Z is that the position differential value d (vlpe) / dx starts to change when approaching the external coil 28 from a distance farther than the horizontal distance D3 (the horizontal distance D that starts to change is the horizontal distance D3). ) Is the weak voltage value vrpes (maximum value) at the position of the distance D2 where it first becomes 0.

[motion]
The alignment process performed on the electric vehicle 40 side will be described with reference to the flowcharts of FIGS. 3 and 4. The process described below is performed when the driver of the electric vehicle 40 turns on the start switch (not shown) of the alignment process.

As shown in FIG. 5A, for example, the charging station 20 is partitioned by a line 82. The driver 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 supplied from the vehicle-side control device 56 to the vehicle-side communication device 68.

In step S1, the charge management unit 58 instructs the vehicle-side communication device 68 to request the transmission of the weak power plpe. In response to this instruction, the vehicle-side communication device 68 performs pairing such as authentication with the external communication device 36, and transmits a transmission request signal of weak electric power plpe. The external control device 34 controls the power converter 26 in response to the power transmission request signal received by the external communication device 36 to start the transmission of the weak power plpe.

The power converter 26 converts AC power into a predetermined weak power plpe and supplies it to the external coil 28. Then, as shown in FIG. 5A, a weak power plpe of a constant power for alignment is transmitted from the external coil 28 to the outside. The power transmission interval Tint at this time is a relatively wide constant power transmission interval Ta.

When the position of the electric vehicle 40 (vehicle coil 44) is far from the external coil 28, the position information for each moment (minute time) is not required. Therefore, even if the power transmission interval Tin is set to a relatively wide power transmission interval Ta, the influence on the alignment is extremely small.

In step S2, the charge management unit 58 determines whether or not the weak voltage value vlpe generated in the voltage detector 50 by the weak power pullpe is equal to or higher than a predetermined value. As the electric vehicle 40 travels, the vehicle coil 44 approaches the external coil 28. When the vehicle coil 44 reaches a position (horizontal distance D3) where the weak electric power plpe of the external coil 28 can be received, the weak voltage value vlpe detected by the voltage detector 50 becomes equal to or higher than a predetermined value. When the weak voltage value vrpe is equal to or greater than a predetermined value (step S2: YES), the process proceeds to step S3. On the other hand, when the weak voltage value vlpe falls below a predetermined value (step S2: NO), the process of step S2 is repeated.

When shifting from step S2 to step S3, the differential value calculation unit 60 has a position differential value d (vlppe) based on the weak voltage value vlpe detected by the voltage detector 50 and the mileage x detected by the distance sensor 70. ) / Dx is calculated.

In step S4, the differential value calculation unit 60 determines whether or not the position differential value d (vlpe) / dx is 0. When the horizontal distance D between the center of the external coil 28 and the center of the vehicle coil 44 becomes the distance D2, the position differential value d (vlpe) / dx becomes 0. When the position differential value d (vlpe) / dx becomes 0 (step S4: YES), the process proceeds to step S5. On the other hand, when the position differential value d (vlpe) / dx is not 0 (step S4: NO), the process returns to the process of step S3.

When shifting from step S4 to step S5, the vertical distance estimation unit 62 sets the weak voltage value vlpes when the position differential value d (vlpe) / dx becomes 0 and the map M stored in the memory 66. The vertical distance Z is estimated based on this. For example, as shown in FIG. 2, when the weak voltage value vlp is the weak voltage value vlpes, the maximum value is the weak voltage value vlpes because of the characteristic of the weak voltage value vlpe-horizontal distance D of the vertical distance Z1. is there. In this case, the vertical distance estimation unit 62 estimates that the vertical distance Z is Z1. Then, the characteristic used in the subsequent processing is specified as the characteristic of the weak voltage value vlpe-horizontal distance D of the vertical distance Z1.

In step S6, the horizontal distance estimation unit 64 determines the characteristic of the weak voltage value vrpe-horizontal distance D (here, the characteristic of the vertical distance Z1) specified in step S5 and the weak voltage detected by the voltage detector 50. Based on the value vlp and, the horizontal distance D corresponding to the weak voltage value vlppe is estimated.

In step S7, the threshold value comparison unit 65 determines whether or not the weak voltage value vrpe exceeds the low voltage threshold value blpel, which is larger than the maximum weak voltage value vrpes.

When the low voltage threshold value vrpel is not exceeded (step S7: NO), the weak voltage value vulpe generated by the weak power lppe generated at the transmission interval Ta (FIG. 5A) and the weak voltage value vulpe specified in step S5. -The characteristic of the horizontal distance D (characteristic of the vertical distance Z1) and the estimation process of the horizontal distance D according to the characteristics are continued.

When the low voltage threshold value vlpell is exceeded (step S7: YES), the process proceeds to step S8. In step S8, the threshold value comparison unit 65 requests through the vehicle-side communication device 68 and the external communication device 36 to narrow the power transmission interval Tint as the horizontal distance D becomes shorter from D = Dl according to the horizontal distance D. Notify the external control device 34.

At this time, the power transmission interval mode changing unit 27 communicates the power transmission interval through the power converter 26 and the external coil 28 as the horizontal distance D becomes shorter from D = Dl (that is, as the weak voltage value vrpe approaches the voltage threshold vrpeh). As shown in FIG. 5B, Tin transmits a weak electric power plpe that gradually narrows from the transmission interval Ta to the transmission interval Tb and the transmission interval Tc (Ta> Tb> Tc). The power transmission interval Tint may be continuously narrowed so as to be the power transmission interval Tc from the power transmission interval Ta through the power transmission interval Tb.

Further, the charge management unit 58 causes the display device 72 to display the horizontal distance D estimated by the horizontal distance estimation unit 64. The driver operates the traveling device 74 while checking the display device 72 to continue traveling for aligning the center of the vehicle coil 44 with respect to the center of the external coil 28.

By narrowing the power transmission interval Tin stepwise or continuously as the position of the electric vehicle 40 approaches the external coil 28 in this way, real-time position information can be transmitted to the driver.

Next, in step S9, as in step S6, the horizontal distance estimation unit 64 uses the weak voltage value vrpe-horizontal distance D characteristic (vertical distance Z1 characteristic) specified in step S5 and the voltage detector 50. Based on the detected weak voltage value vrpe, the horizontal distance D (D = Dl to Dh) corresponding to the weak voltage value vrpe is estimated.

In step S10, the threshold value comparison unit 65 determines whether or not the weak voltage value blpe exceeds the voltage threshold blpeh (see FIG. 2) that exceeds the low voltage threshold vrpel.

If the voltage threshold voltage threshold is not exceeded (step S10: NO), the process returns to step S8, and the power transmission interval mode changing unit 27 externally externally weakens the power transmission interval Tint as the horizontal distance D becomes shorter. Power is transmitted from the coil 28.

Next, in step S9, as in step S6, the horizontal distance estimation unit 64 uses the weak voltage value vrpe-horizontal distance D characteristic (vertical distance Z1 characteristic) specified in step S5 and the voltage detector 50. Based on the detected weak voltage value vrpe, the horizontal distance D (D = Dl to Dh) corresponding to the weak voltage value vrpe is estimated.

In step S10, when the weak voltage value vlpe exceeds the voltage threshold value vlpeh (step S10: YES), the threshold value comparison unit 65 requests in step S11 to set the continuous power transmission mode in which the power transmission interval Tin becomes 0. , Notify the external control device 34 through the vehicle-side communication device 68 and the external communication device 36. At this time, the power transmission interval mode changing unit 27 continuously transmits the weak power plpe through the power converter 26 and the external coil 28, as shown in FIG.

Further, the charge management unit 58 causes the display device 72 to display the horizontal distance D estimated by the horizontal distance estimation unit 64. The driver operates the traveling device 74 while checking the display device 72 to continue traveling for aligning the center of the vehicle coil 44 with respect to the center of the external coil 28.

As described above, when the position of the electric vehicle 40 is close to the external coil 28, the horizontal distance estimation unit 64 is specified in step S5 in step S12 based on the accurate position information for each moment (minute time). Weak voltage value blpe-horizontal distance D (D) according to the weak voltage value vrpe based on the characteristics of the weak voltage value vulpe-horizontal distance D (for example, the characteristics of the vertical distance Z1) and the weak voltage value vulpe detected by the voltage detector 50. = Dh ~ 0) is estimated.

In step S13, the charge management unit 58 determines whether or not to start charging. When the alignment of the center of the vehicle coil 44 with respect to the center of the external coil 28 is completed, the driver stops the electric vehicle 40 and turns on the charging start switch (not shown). When the charging start switch is turned on (step S13: YES), a series of alignment processes is completed. On the other hand, if the charging start switch is not turned on (step S13: NO), the process returns to step S11.

The operation signal of the charging start switch is notified to the vehicle side control device 56. The charge management unit 58 instructs the vehicle-side communication device 68 to stop the weak power plpe and request the transmission of the charge power. The vehicle-side communication device 68 transmits a stop request signal for the weak power pull and a transmission request signal for the charging power to the external communication device 36. The external control device 34 controls the power converter 26 in response to the stop request signal received by the external communication device 36 to stop the transmission of the weak power plpe, and responds to the transmission request signal received by the external communication device 36. The power converter 26 is controlled to start transmission of charging power.

[Summary]
The non-contact power transmission system 10 according to this embodiment receives the electric power transmitted from the external coil 28 provided on the road surface 12 outside the electric vehicle 40 in a non-contact manner by the vehicle coil 44 provided on the electric vehicle 40. Then, the battery 54 of the electric vehicle 40 is charged.

The non-contact power transmission system 10 is an external control device as a power transmission side control device that controls a power transmission interval mode change unit 27 that changes the power transmission interval mode of the weak power pullpe, which is the power for alignment transmitted from the external coil 28. 34, a vehicle-side control device 56 as a power-receiving side control device that receives the transmitted weak power plpe with the vehicle coil 44 and detects the voltage value generated by the received power as a weak voltage value vlp, which is the received voltage value. To be equipped.

In this case, the external control device 34 and the vehicle side control device 56 coordinately change the power transmission interval mode from the intermittent power transmission mode to the continuous power transmission mode when the weak voltage value vrpe exceeds the voltage threshold value vrpeh (FIG. 2). doing.

In this way, during the alignment, the transmission interval mode of the weak power plpe, which is the alignment power transmitted from the external coil 28, is changed. Therefore, in the continuous transmission mode, accurate alignment is maintained. On the other hand, in the intermittent power transmission mode, the power consumption can be reduced.

According to the above embodiment, the power transmission interval Tin is set to the power transmission interval Tint = Ta (referred to as the first intermittent power transmission mode) from the time when the weak voltage value vrpe exceeds the low voltage threshold value vulpel until the voltage threshold value blpeh is reached. When the transmission interval Tc (referred to as the second intermittent transmission mode) is set to a narrow value, for example, the transmission interval Tc (Ta> Tb> Tc) is obtained from the transmission interval Ta via the transmission interval Tb. The transmission interval Tint is narrowed as it approaches the voltage threshold value vrpeh.

In this way, in the section where the transmission interval Tin is narrowed stepwise or continuously (the section from the horizontal distance Dl to the horizontal distance Dh), the section from the horizontal distance D3 to the horizontal distance Dl (transmission interval Tint = Ta) is set. In comparison, the alignment distance can be grasped more accurately.

[Modification 1]
In FIG. 2, the section of the continuous power transmission mode until the horizontal distance D is shorter than the horizontal distance Dh and the horizontal distance D becomes 0 is shorter than, for example, the power transmission interval Tc, in other words, compared with the power transmission interval Ta. The intermittent power transmission mode section may have an extremely short power transmission interval Tint (Tint <Tc and Tin << Ta).

[Modification 2]
Before the weak voltage value vrpe exceeds the low voltage threshold vrpel lower than the voltage threshold vrpeh, for example, in the first intermittent power transmission mode in which the transmission interval Tin takes Tin = Ta, after exceeding the low voltage threshold vrpel, until the voltage threshold vrpeh. May be set to a second intermittent power transmission mode having a power transmission interval Tin narrower than that of the first intermittent power transmission mode, for example, a power transmission interval Tb.

In this way, until the weak voltage value vlpe reaches the voltage threshold value vlpeh, in other words, until the horizontal distance D becomes close, even if the interval is gradually narrowed, it is possible to align within a practically sufficient range. Therefore, the power consumption can be further reduced.

[Modification 3]
In the above-described embodiment, as shown in FIG. 7A, the weak power plpe, which is the power for alignment, is transmitted from the external coil 28. However, the weak power plpe is as shown in FIG. 7B. The configuration may be changed so that power is transmitted from the coil of the electric vehicle 40 such as the vehicle coil 44 and received by the coil on the charging station 20 side such as the external coil 28.

When the weak power plpe, which is the power for alignment, is transmitted from the external coil 28, the power consumption of the outside, for example, the infrastructure side can be reduced. When power is transmitted from the vehicle coil 44, it is possible to suppress a decrease in SOC (State Of Charge) of the battery 54 of the electric vehicle 40 as compared with the continuous power transmission mode.

[Modification example 4]
In the above-described embodiment, the threshold value comparison unit 65 compares the weak voltage value vlp of the vehicle coil 44 as a comparison value with the voltage threshold value vlpeh or the low voltage threshold value vlpel as a reference value, but the present invention is limited to this. It is not something that can be done. For example, even if the weak voltage value vlp of the vehicle coil 44 as a comparison value is replaced with the power value of the weak voltage value vlpe which has a substantially linear relationship with the weak voltage value vlp, the alignment process can be performed in the same manner. it can. Alternatively, even if the weak voltage value vlp of the vehicle coil 44 as a comparison value is replaced with the transmission power efficiency of the power transmission / reception power (power value / transmission power value of the weak voltage value vlp), the alignment processing is performed in the same manner. be able to. In this case, as the power value as the comparison value or the reference value to be compared with the transmission power efficiency, the power threshold value corresponding to the voltage threshold value vrpeh or the low voltage threshold value vrpel or the threshold value of the transmission power efficiency is used.

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 without departing from the gist of the present invention.

10 ... Non-contact power transmission system 20 ... Charging station 27 ... Transmission interval mode change unit 28 ... External coil 34 ... External control device 36 ... External communication device 40 ... Electric vehicle 44 ... Vehicle coil 50 ... Voltage detector 56 ... Vehicle side control Device 60 ... Differential value calculation unit 62 ... Vertical distance estimation unit 64 ... Horizontal distance estimation unit 65 ... Threshold comparison unit 66 ... Memory 68 ... Vehicle side communication device

Claims (5)

A non-contact power transmission system that charges the battery of the vehicle by receiving the electric power transmitted from the external coil provided on the road surface in a non-contact manner by the vehicle coil provided in the vehicle.
A power transmission side control device that controls a power transmission interval mode of the power for alignment transmitted from one of the external coil or the vehicle coil.
The power for alignment transmitted from one of the coils is received by the other coil of the external coil or the vehicle coil, and the voltage value generated by the received power is detected as the received voltage value. Equipped with equipment,
The power transmission side control device and the power reception side control device have the maximum value of the power reception voltage value and the maximum value of the power reception voltage value obtained from the relationship between the power reception voltage value and the distance between the external coil and the vehicle coil. When the voltage threshold set between the maximum value and the maximum value is exceeded, the transmission interval mode is changed from the first intermittent transmission mode to the second intermittent transmission mode in which the transmission interval is narrower than the first intermittent transmission mode. Alternatively, a non-contact power transmission system characterized by changing to a continuous power transmission mode. In the non-contact power transmission system according to claim 1,
The power transmission side control device is
Wherein before receiving voltage value exceeds the voltage threshold, the power transmission interval mode in the first intermittent power transmission mode, after the above, the non-contact power transmission system, characterized by the continuous transmission mode. In the non-contact power transmission system according to claim 2.
Wherein before receiving voltage value exceeds a lower threshold voltage lower than the voltage threshold, the power transmission interval mode in the first intermittent power transmission mode, after exceeding the lower threshold voltage, until the voltage threshold, the power transmission interval mode non-contact power transmission system, characterized by a narrow second intermittent power transmission mode of the transmission intervals than said first intermittent power transmission mode. In the non-contact power transmission system according to claim 3.
After the incoming voltage value is above the low voltage threshold, until the said voltage threshold, when the narrow second intermittent power transmission mode of the transmission intervals than said transmission interval mode the first intermittent power transmission mode, A non-contact power transmission system characterized in that the transmission interval is narrowed as the received voltage value approaches the voltage threshold. In the non-contact power transmission system according to any one of claims 1 to 4.
A non-contact power transmission system characterized in that the received voltage value as a comparative value is replaced with the power value of the received voltage value or the transmission power efficiency of the transmitted / received power.

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