JP2016005393A - Contactless power supply system - Google Patents

Abstract

An object of the present invention is to reduce a leakage magnetic field emitted during non-contact power transmission without separately providing a device for canceling the leakage magnetic field. In a non-contact power feeding system including a plurality of power feeding devices that independently perform non-contact power transmission, the system includes operation setting means for setting operations of the plurality of power feeding devices. In accordance with an instruction given from the operation setting means, a drive circuit that supplies each power transmission coil with a first AC current or a second AC current having a frequency substantially the same as that of the first AC current and having a predetermined phase difference. And the operation setting means reduces the difference between the number of power supply devices in which the first AC current is supplied to the power transmission coil and the number of power supply devices in which the second AC current is supplied to the power transmission coil. The operation of a plurality of power feeding devices is set in [Selection] Figure 1

Description

  The present invention relates to a contactless power supply system including a plurality of contactless power supply apparatuses that supply power in a contactless manner.

  2. Description of the Related Art In recent years, contactless power transmission technology that transmits power in a non-contact manner from a power transmission side to a power reception side has attracted attention. For example, a non-contact charging apparatus that uses this non-contact power transmission technology for charging a storage battery mounted on an electric vehicle or the like is being actively developed. In this non-contact charging device, electric power is transmitted from the power transmission side coil to the power reception side coil via the magnetic field generated by the power transmission side coil. In power transmission through such a magnetic field, a part of the magnetic field generated by the coil on the power transmission side becomes a leakage magnetic field, and this leakage magnetic field may adversely affect other electrical devices.

  In addition, with the widespread use of electric vehicles, the expansion of charging stations (charging stations) is also underway. In this charging station, a plurality of charging devices are often installed. Therefore, when a non-contact charging device is used as the charging device, it is more important to reduce the leakage magnetic field. In order to reduce such a leakage magnetic field, Patent Document 1 uses an external antenna (coil) that generates a magnetic field that cancels the leakage magnetic field generated by the feeder line. If this technology is applied, the leakage magnetic field emitted from the coil on the power transmission side can be reduced also in the contactless charging apparatus.

JP 2008-172947 A

  However, when applying the technique of Patent Document 1, a coil (antenna) for generating a magnetic field for canceling the leakage magnetic field must be provided separately. Furthermore, electric power for generating a magnetic field for canceling the leakage magnetic field is required, and power consumption increases. In addition, in a charging station (charging station) in which a plurality of non-contact charging devices are installed, the generated leakage magnetic field increases, so that the electric power for generating the magnetic field for canceling the leakage magnetic field further increases.

  Therefore, the present invention provides a non-contact power feeding system that can reduce a leakage magnetic field emitted during non-contact power transmission without separately providing a coil (antenna) that generates a magnetic field for canceling the leakage magnetic field. For the purpose.

  In order to solve the above-described problem, a contactless power supply system according to the present invention is a contactless power supply system including a plurality of power supply devices that each independently perform contactless power transmission, and includes a plurality of power supply devices. An operation setting unit configured to set an operation, and the plurality of power feeding devices have a first AC current or a frequency of the first AC current and a frequency substantially equal to each of the power transmission coils in accordance with an instruction given from the operation setting unit. A drive circuit that supplies a second alternating current that is the same and has a predetermined phase difference, wherein the operation setting means includes the number of power supply devices in which the first alternating current is supplied to the power transmission coil, and the second The operations of the plurality of power feeding devices are set such that the difference from the number of power feeding devices supplied with alternating current to the power transmission coil is reduced.

  In this configuration, the operations of the plurality of power feeding devices are set so that at least some components of the leakage magnetic field generated from each power feeding device cancel each other. Therefore, the leakage magnetic field generated from the plurality of power feeding devices can be reduced without providing a separate means for reducing the leakage magnetic field.

  It is preferable that the predetermined phase difference is approximately 180 degrees.

  By setting the phase difference between the first alternating current and the second alternating current to approximately 180 degrees, the leakage magnetic field generated from the plurality of power feeding devices can be more efficiently reduced.

  The drive circuit is configured to output a first AC voltage or a second AC voltage having the same frequency and a reverse phase as the first AC voltage, and the first AC current is the first AC voltage. The second AC current is a current based on the second AC voltage, and the second AC current is a current based on the second AC voltage.

  In this way, by outputting the first AC voltage or the second AC voltage from the drive circuit, the second AC based on the first AC current or the second AC voltage based on the first AC voltage. Current can be supplied to the power transmission coil. Therefore, the first alternating current or the second alternating current can be supplied to the power transmission coil by controlling the switching operation of the drive circuit.

  It is preferable that each of the power transmission coils is installed such that surfaces perpendicular to the magnetic field generated at the center of each of the power transmission coils of the plurality of power feeding devices are substantially parallel to each other.

  By installing a plurality of power transmission coils in this way, the leakage magnetic field generated from these power transmission coils is canceled more efficiently.

  At least one of the plurality of power supply devices includes a direction of a magnetic field generated when the first alternating current flows through a power transmission coil of the power supply device and a power transmission coil of any other power supply device. The direction of the magnetic field generated when the first alternating current flows may be reversed.

  Thus, the electric power feeder provided with the power transmission coil which generate | occur | produces the magnetic field of the direction opposite to other power transmission coils when the same alternating current flows may be included.

  The contactless power supply system according to the present invention is a contactless power supply system including a plurality of power supply devices that independently perform contactless power transmission, and the plurality of power supply devices have a frequency and a phase. A power supply device that generates a magnetic field in a first direction when the same alternating current is supplied and a power supply device that generates a magnetic field in a second direction opposite to the first direction are included, and the plurality of power supply devices include The number of power supply devices that generate the magnetic field in the first direction and the number of power supply devices that generate the magnetic field in the second direction are set so that a difference between them is small.

  In this configuration, the magnetic field in the first direction and the magnetic field in the second direction cancel each other. Therefore, the leakage magnetic field generated from the plurality of power feeding devices can be reduced without providing a separate means for reducing the leakage magnetic field.

  According to the non-contact power feeding system according to the present invention, it is possible to reduce the leakage magnetic field emitted during non-contact power transmission without separately providing a device for reducing the leakage magnetic field.

It is the schematic for demonstrating the structure of the non-contact electric power feeding system of this invention. It is the schematic circuit diagram which showed the power transmission coil, the power receiving coil, and these peripheral circuits. It is a wave form diagram for demonstrating the voltage applied to a power transmission coil. It is a wave form diagram which shows the voltage applied to a power transmission coil, and the electric current supplied to a power transmission coil. It is a wave form diagram for demonstrating the alternating voltage applied to a power transmission coil. It is a wave form diagram which shows the voltage applied to a power transmission coil. It is explanatory drawing for demonstrating operation | movement of the non-contact electric power feeding system of this invention. It is explanatory drawing for demonstrating arrangement | positioning of a power transmission coil. It is explanatory drawing for demonstrating arrangement | positioning of a power transmission coil. It is explanatory drawing for demonstrating arrangement | positioning of a power transmission coil.

  DESCRIPTION OF EMBODIMENTS Embodiments for carrying out the invention will be described with reference to the drawings. Note that the present invention is not limited by the contents described in the following embodiments. In the following description, the same reference numerals are used for the same elements or elements having the same functions, and redundant description is omitted.

  FIG. 1 is a schematic diagram illustrating a configuration of a contactless power feeding system according to the present embodiment. The non-contact power supply system 10 includes a non-contact power supply device 11, 12 and a control device 13 that controls the operation of the non-contact power supply device 11, 12. Each of the non-contact power feeding apparatuses 11 and 12 includes a power transmission coil. Vehicles 21 and 22 that receive electric power supplied from contactless power supply devices 11 and 12 include contactless power receiving devices 21a and 22a, respectively. Each of the non-contact power receiving devices 21a and 22a includes a power receiving coil. In this example, power transmission from the non-contact power feeding device 11 to the non-contact power receiving device 21a and power transmission from the non-contact power feeding device 12 to the non-contact power receiving device 22a are performed simultaneously. When power transmission is performed, the non-contact power feeding apparatuses 11 and 12 generate a magnetic field by the power transmission coil. This magnetic field generates an electromotive force in the receiving coils of the non-contact power receiving devices 21a and 22a. A current based on the electromotive force is supplied to the storage batteries in the vehicles 21 and 22. In addition, the power transmission coils of the non-contact power feeding apparatuses 11 and 12 have a plane perpendicular to the magnetic field generated at the center of the power transmission coil of the non-contact power feeding apparatus 11 and a magnetic field generated at the center of the power transmission coil of the non-contact power feeding apparatus 12. It is installed so that the vertical plane is almost parallel. And when the electric current of the same direction is sent through the power transmission coil of the non-contact electric power feeder 11, and the power transmission coil of the non-contact electric power feeder 12, it sets so that the magnetic field of the same direction may generate | occur | produce in each power transmission coil.

  Next, a drive circuit that supplies an alternating current to the power transmission coil and a power reception circuit that supplies power received by the power reception coil to the storage battery will be described with reference to FIG. Here, the driving circuit is a circuit incorporated in the non-contact power feeding device, and the power receiving circuit is a circuit incorporated in the non-contact power receiving device. The drive circuit is composed of switch elements SW1 to SW4. The switch element SW1 and the switch element SW2 are connected in series, and the input voltage Vin is applied to both ends thereof. Similarly, the switch element SW3 and the switch element SW4 are connected in series, and the input voltage Vin is applied to both ends thereof. One end of the capacitor Ct is connected to one end of the power transmission coil Lt, the other end of the power transmission coil Lt is connected to the connection point of the switch element SW3 and the switch element SW4, and the other end of the capacitor Ct is the switch element SW1 and the switch element SW2. Connected to the connection point. The current Idr flowing through the power transmission coil Lt is controlled by turning on and off the switch elements SW1 to SW4.

  The power receiving circuit includes a bridge diode Dr and a capacitor Co. One end of the receiving coil Lr is connected to one end of the capacitor Cr, the other end of the receiving coil Lr is connected to one input of the bridge diode Dr, and the other end of the capacitor Cr is connected to the other input of the bridge diode Dr. ing. A capacitor Co is connected between the output terminals of the bridge diode Dr. The current flowing through the receiving coil Lr is full-wave rectified by the bridge diode Dr and supplied to the capacitor Co. A load such as a storage battery is connected to the subsequent stage of the capacitor Co via a DCDC converter or the like.

  Next, the switching operation of the switch elements SW1 to SW4 will be described with reference to FIG. In the example shown in FIG. 3, the switch element SW1 and the switch element SW4 are turned on and off in synchronization. Similarly, the switch element SW2 and the switch element SW3 are turned on and off in synchronization. The voltage Vdr between the connection point of the switch element SW1 and the switch element SW2 and the connection point of the switch element SW3 and the switch element SW4 (voltage based on the connection point side of the switch element SW3 and the switch element SW4) is It changes based on on / off of SW1-4. As shown in FIG. 3, when the switch element SW1 and the switch element SW4 are turned on and the switch element SW2 and the switch element SW3 are turned off, the voltage Vdr becomes a positive voltage value whose absolute value is substantially equal to the input voltage Vin. On the other hand, when the switch element SW1 and the switch element SW4 are turned off and the switch element SW2 and the switch element SW3 are turned on, the voltage Vdr becomes a negative voltage value whose absolute value is substantially equal to the input voltage Vin.

  In the example illustrated in FIG. 1, the first alternating current is supplied to the power transmission coil included in the contactless power supply device 11, and the second alternating current is supplied to the power transmission coil included in the contactless power supply device 12. . The first alternating current and the second alternating current are alternating currents having the same frequency, and the second alternating current is set so that its phase is opposite to that of the first alternating current. Therefore, the leakage magnetic field generated from the power transmission coil provided in the non-contact power supply device 11 and the leakage magnetic field generated from the power transmission coil provided in the non-contact power supply device 12 act so as to cancel each other. The non-contact power feeding devices 11 and 12 supply the first alternating current or the second alternating current to the power transmission coil in accordance with an instruction given from the control device 13. The control device 13 performs operation settings as will be described later. In this operation setting, a non-contact power feeding device that supplies the first alternating current to the power transmission coil and a non-contact power feeding device that supplies the second alternating current to the power transmission coil are determined.

  Next, an AC voltage and an AC current (AC current supplied to the power transmission coil) output from the drive circuit will be described with reference to FIG. In this example, a first AC voltage Vdr and a second AC voltage Vdr ′ whose polarities are inverted at a predetermined cycle are shown. The frequencies of the first AC voltage Vdr and the second AC voltage Vdr ′ are set to substantially the same frequency. This frequency is set to about 10 kHz to 200 kHz. Note that the phase of the second AC voltage Vdr 'is opposite to the phase of the first AC voltage Vdr. That is, the phase of both is shifted by 180 ° (half cycle).

  The first AC current Idr shown in FIG. 4 is a current supplied to the power transmission coil when the first AC voltage Vdr is output from the drive circuit. On the other hand, the second AC current Idr 'is a current supplied to the power transmission coil when the second AC voltage Vdr' is output from the drive circuit. Here, the frequency of the first alternating current Idr and the second alternating current Idr 'is substantially the same frequency. The phase of the second alternating current Idr ′ is opposite to the phase of the first alternating current Idr. That is, the phase of both is shifted by 180 ° (half cycle).

  Since the first alternating current Idr and the second alternating current Idr ′ are in an opposite phase relationship, the leakage magnetic field generated by the power transmission coil to which the first alternating current Idr is supplied and the second alternating current Idr ′. The leakage magnetic fields generated by the power transmission coils to which the power is supplied cancel each other. Here, since the wavelength of the leakage magnetic field generated when the frequency of the first alternating current Idr and the second alternating current Idr ′ is 10 kHz to 200 kHz is about 30 km to 1.5 km, the first alternating current Idr is supplied. If the distance between the power transmission coil and the power transmission coil to which the second alternating current Idr ′ is supplied is sufficiently smaller than the wavelength of the leakage magnetic field, the leakage magnetic fields from the respective transmission coils generally cancel each other. become. The phase difference between the first alternating current Idr and the second alternating current Idr ′ is preferably approximately 180 ° (half cycle), but this phase difference is slightly shifted from 180 ° (half cycle). Even the leakage magnetic field is reduced.

Next, the fact that the leakage magnetic fields cancel each other will be described in more detail. The wave Ha of the leakage magnetic field generated by the power transmission coil to which the first alternating current Idr is supplied is given by the following equation.
Ha = A · sin (2πft−2πDa / λ) (1)
Here, A is the amplitude, f is the frequency of the leakage magnetic field, Da is the distance from the power transmission coil, and λ is the wavelength of the leakage magnetic field. Here, the amplitude A is a variable that changes based on the distance Da, and includes a component that is inversely proportional to the cube of the distance Da and a component that is inversely proportional to the square of the distance Da. Further, the equation (1) can be expanded as the following equation.
Ha = A {sin2πft · cos (2πDa / λ)
-Cos2πft · sin (2πDa / λ)} (2)
Here, when the frequency f of the leakage magnetic field is 200 kHz (the leakage magnetic field wavelength λ is 1500 m) and the distance Da from the power transmission coil is 100 m, cos (2πDa / λ) ≈1 and sin (2πDa / λ) ≈ It can be set to zero. Therefore, if the wavelength λ of the leakage magnetic field is sufficiently larger than the distance Da from the power transmission coil, the following approximate expression can be used for the wave Ha of the leakage magnetic field.
Ha≈A · sin2πft (3)

On the other hand, the leakage magnetic field wave Hb generated by the power transmission coil to which the second alternating current Idr ′ is supplied is given by the following equation. Since the second alternating current Idr ′ is out of phase with the first alternating current Idr by 180 ° (half cycle), “−π” is added to this equation.
Hb = B · sin (2πft−2πDb / λ−π)
= −B · sin (2πft−2πDb / λ) (4)
Here, B is the amplitude, f is the frequency of the leakage magnetic field, Db is the distance from the power transmission coil, and λ is the wavelength of the leakage magnetic field. Here, the amplitude B is a variable that changes based on the distance Db, and includes a component that is inversely proportional to the cube of the distance Db and a component that is inversely proportional to the square of the distance Db. Also, this equation (4) can be expanded as the following equation.
Hb = −B {sin 2πft · cos (2πDb / λ)
-Cos2πft · sin (2πDb / λ)} (5)
Here, when the frequency f of the leakage magnetic field is 200 kHz (the leakage magnetic field wavelength λ is 1500 m) and the distance Db from the power transmission coil is 100 m, cos (2πDb / λ) ≈1 and sin (2πDb / λ) ≈ It can be set to zero. Therefore, if the wavelength λ of the leakage magnetic field is sufficiently larger than the distance Db from the power transmission coil in this way, the following approximate expression can be used for the wave Hb of the leakage magnetic field.
Hb≈−B · sin2πft (6)

From equations (3) and (6), the leakage magnetic field generated by the power transmission coil supplied with the second AC current Idr ′ is added to the leakage magnetic field generated by the power transmission coil supplied with the first AC current Idr. The wave H of the leakage magnetic field when given is given by the following equation.
H≈ (A−B) sin2πft (7)
Here, A is a value determined according to the distance Da from the power transmission coil to which the first AC current Idr is supplied, and B is the distance Db from the power transmission coil to which the second AC current Idr ′ is supplied. It is a value determined according to. Therefore, at a point where the distance Da from the power transmission coil to which the first AC current Idr is supplied and the distance Db from the power transmission coil to which the second AC current Idr ′ is supplied differ according to the difference. Although there is a difference in the degree to which the leakage magnetic field is reduced, the leakage magnetic field can be reduced in most areas around the power transmission coil.

  Further, the switching elements SW1 to SW4 in FIG. 2 may perform a switching operation as shown in FIG. This switching operation is a switching operation when so-called phase shift PWM control is used. In this switching operation, there are a period in which the switch element SW1 and the switch element SW3 are on, and a period in which the switch element SW2 and the switch element SW4 are on, and the voltage output from the drive circuit in these periods is 0V. Become. These periods are inserted between a period in which the drive circuit outputs a positive voltage and a period in which a negative voltage is output. Therefore, in the first AC voltage Vdr generated by this phase shift PWM control, a period in which 0 V is output is interposed between a period in which a positive voltage is output and a period in which a negative voltage is output. To do.

  Even when the phase shift PWM control as shown in FIG. 5 is performed in the drive circuit, if the power transmission coil is driven by the first AC voltage Vdr and the second AC voltage Vdr ′ shown in FIG. , Leakage magnetic fields that cancel each other out can be generated. Also in this case, the first AC voltage Vdr and the second AC voltage Vdr 'are in opposite phases.

  Next, the operation of the non-contact power feeding system including six non-contact power feeding devices will be described with reference to FIG. This non-contact power feeding system includes non-contact power feeding devices 41 to 46. The power transmission coils of the non-contact power feeding devices 41 to 46 are installed so that the planes perpendicular to the magnetic field generated at the center of the power transmission coils are substantially parallel to each other. And when the electric current of the same direction is sent through the power transmission coil of the non-contact electric power feeders 41-46, it sets so that the magnetic field of the same direction may generate | occur | produce in those power transmission coils. In addition, illustration is abbreviate | omitted about the control apparatus which controls operation | movement of the non-contact electric power feeders 41-46. The non-contact power receiving devices 51 to 56 are devices mounted on a vehicle or the like, and the power transmitted from the non-contact power feeding devices 41 to 46 is transmitted to the non-contact power receiving devices 51 to 56.

  The power transmission coils provided in the non-contact power feeding devices 41 to 46 are set so that the first alternating current or the second alternating current is supplied. Here, the first alternating current and the second alternating current are in opposite phases. As described above, the first alternating current is a current based on the first alternating voltage, and the second alternating current is a current based on the second alternating voltage.

  In FIG. 7A, only power transmission from the non-contact power feeding device 43 to the non-contact power receiving device 53 is performed. That is, only the non-contact power feeding device 43 performs power transmission, and the other devices (non-contact power feeding devices 41, 42, 44 to 46) are stopped. At this time, the drive circuit of the non-contact power feeding device 43 outputs the first AC voltage, and the first AC current is supplied to the power transmission coil of the non-contact power feeding device 43.

In FIG. 7B, power transmission from the non-contact power feeding device 46 to the non-contact power receiving device 56 is newly started. Only the non-contact power feeding device 43 performs power transmission at the start time, and the operation status thereof is as follows.
Device where the drive circuit outputs the first AC voltage: 1 unit Device where the drive circuit outputs the second AC voltage: 0 units At this point, the drive circuit outputs the first AC voltage. The number of installed devices is one more than the number of devices whose drive circuit outputs the second AC voltage. Therefore, the control device gives an operation instruction to output the second AC voltage from the drive circuit to the non-contact power feeding device 46. In accordance with this instruction, the non-contact power feeding device 46 starts an operation of outputting the second AC voltage from the drive circuit, that is, an operation of supplying the second AC current to the power transmission coil.

In FIG. 7C, power transmission from the non-contact power feeding device 41 to the non-contact power receiving device 51 is newly started. The devices that perform power transmission at the time of the start are the non-contact power feeding device 43 and the non-contact power feeding device 46, and the operation status thereof is as follows.
A device in which the drive circuit outputs the first AC voltage: 1 unit A device in which the drive circuit outputs the second AC voltage: 1 unit At this time, the drive circuit outputs the first AC voltage. The number of devices and the number of devices whose drive circuit outputs the second AC voltage are the same. Therefore, the non-contact power feeding device 41 may perform an operation of outputting the first AC voltage from the drive circuit or an operation of outputting the second AC voltage from the drive circuit. In this example, the control device gives an operation instruction for outputting the first AC voltage from the drive circuit to the non-contact power feeding device 41. In accordance with this instruction, the non-contact power feeding device 41 starts an operation of outputting the first AC voltage from the drive circuit, that is, an operation of supplying the first AC current to the power transmission coil.

In FIG. 7D, power transmission from the non-contact power supply device 44 to the non-contact power reception device 54 is newly started. The devices that perform power transmission at the start time are the non-contact power feeding device 41, the non-contact power feeding device 43, and the non-contact power feeding device 46, and the operation status thereof is as follows.
Device in which the drive circuit outputs the first AC voltage: 2 units Device in which the drive circuit outputs the second AC voltage: 1 unit At this time, the drive circuit outputs the first AC voltage. The number of installed devices is one more than the number of devices whose drive circuit outputs the second AC voltage. Therefore, the control device gives an operation instruction to output the second AC voltage from the drive circuit to the non-contact power feeding device 44. In accordance with this instruction, the contactless power supply device 44 starts an operation of outputting the second AC voltage from the drive circuit, that is, an operation of supplying the second AC current to the power transmission coil.

In FIG. 7E, power transmission from the non-contact power supply device 45 to the non-contact power reception device 55 is newly started. The devices that perform power transmission at the time of the start are the non-contact power feeding device 41, the non-contact power feeding device 43, the non-contact power feeding device 44, and the non-contact power feeding device 46, and the operation status thereof is as follows.
Device where the drive circuit outputs the first AC voltage: 2 units Device where the drive circuit outputs the second AC voltage: 2 units At this point, the drive circuit outputs the first AC voltage. The number of devices and the number of devices whose drive circuit outputs the second AC voltage are the same. Therefore, the non-contact power feeding device 45 may perform the operation of outputting the first AC voltage from the drive circuit or the operation of outputting the second AC voltage from the drive circuit. In this example, the control device gives an operation instruction for outputting the first AC voltage from the drive circuit to the non-contact power feeding device 45. In accordance with this instruction, the non-contact power feeding device 41 starts an operation of outputting the first AC voltage from the drive circuit, that is, an operation of supplying the first AC current to the power transmission coil.

In FIG. 7F, power transmission from the non-contact power feeding device 42 to the non-contact power receiving device 52 is newly started. The devices that perform power transmission at the start time are the non-contact power feeding device 41, the non-contact power feeding device 43, the non-contact power feeding device 44, the non-contact power feeding device 45, and the non-contact power feeding device 46. It is like that.
Device with drive circuit outputting first AC voltage: 3 units Device with drive circuit outputting second AC voltage: 2 units At this time, the drive circuit outputs first AC voltage. The number of installed devices is one more than the number of devices whose drive circuit outputs the second AC voltage. Therefore, the control device gives an operation instruction to output the second AC voltage from the drive circuit to the non-contact power feeding device 42. In accordance with this instruction, the non-contact power feeding device 42 starts an operation of outputting the second AC voltage from the drive circuit, that is, an operation of supplying the second AC current to the power transmission coil.

  In this example, the control device has a difference between the number of non-contact power feeding devices whose driving circuit outputs a first AC voltage and the number of non-contact power feeding devices whose driving circuit outputs a second AC voltage. The operation of the non-contact power feeding device is controlled so that the number is one or less. In other words, when the number of non-contact power feeding devices performing power transmission is an even number, the operation of the non-contact power feeding device is controlled so that the number of both is the same, and the non-contact power feeding device performing power transmission When the number of devices is an odd number, the operation of the non-contact power feeding apparatus is controlled so that the difference between the numbers of both devices becomes one. However, the difference between the number of contactless power supply devices whose drive circuit outputs the first AC voltage and the number of contactless power supply devices whose drive circuit outputs the second AC voltage is two or more. However, it goes without saying that the effect of reducing the leakage magnetic field can be obtained if both are present.

  The control device gives a synchronization signal or a drive signal to the non-contact power supply devices 41 to 46, and the non-contact power supply devices 41 to 46 receive a first alternating current from the drive circuit based on the synchronization signal or the drive signal. An operation for outputting the voltage or an operation for outputting the second AC voltage from the drive circuit is performed. When the control device gives a synchronization signal to the non-contact power feeding devices 41 to 46, the non-contact power feeding devices 41 to 46 generate drive signals for driving the switch elements of the drive circuit in the respective devices. When the control device gives drive signals to the non-contact power feeding devices 41 to 46, the non-contact power feeding devices 41 to 46 drive the switch elements of the drive circuit by the given drive signals.

  For example, in FIG. 3, when the signal driving the switch elements SW1 and 4 is the signal S1 and the signal driving the switch elements SW2 and SW3 is the signal S2, the first AC corresponding to the voltage Vdr from the drive circuit. When outputting a voltage, the switch elements SW1 and SW4 are driven by the signal S1, and the switch elements SW2 and SW3 are driven by the signal S2. On the other hand, when outputting the second AC voltage corresponding to the voltage Vdr ′ from the drive circuit, the switch elements SW1, 4 are driven by the signal S2, and the switch elements SW2, 3 are driven by the signal S1. That is, the non-contact power feeding devices 41 to 46 can output the first AC voltage and the second AC voltage from the drive circuit based on the signals S1 and S2 as drive signals. .

  Next, the installation state of the power transmission coil will be described. In the example shown in FIG. 8, power transmission coils 71 to 73 having the same specifications (the coil winding directions are the same) are installed in a state where they are embedded in the ground 61. In this example, the ground 61 corresponds to an xy plane including the x axis and the y axis, and the power transmission coils 71 to 73 are arranged in the x axis direction. 8A shows a case when viewed from the y-axis direction, and FIG. 8B shows a case when viewed from the z-axis direction.

  In the example illustrated in FIG. 8, the magnetic field generated at the center of the power transmission coils 71 to 73 is perpendicular to the xy plane including the x axis and the y axis. With this setting, when a first AC current is passed through the power transmission coil 71 and a second AC current having a phase opposite to that of the first AC current is passed through the power transmission coil 72, the leakage magnetic field generated by the power transmission coil 71 and the power transmission The leakage magnetic fields generated by the coils 72 cancel each other. Similarly, when a first alternating current is passed through the power transmission coil 71 and a second alternating current is passed through the power transmission coil 73, the leakage magnetic field generated by the power transmission coil 71 and the leakage magnetic field generated by the power transmission coil 73 cancel each other. It ’s a good relationship.

  In the example illustrated in FIG. 9, power transmission coils 71 to 76 having the same specifications (the coil winding direction is the same) are arranged on the xy plane. Here, the power transmission coils 71 to 73 are arranged in the same manner as in FIG. 8, and the power transmission coils 74 to 76 are arranged next to the power transmission coils 71 to 73 with a predetermined interval in the y-axis direction. Moreover, the magnetic field generated at the center of the power transmission coils 71 to 76 is perpendicular to the xy plane. With this setting, when any two power transmission coils are selected from the power transmission coils 71 to 76, the first AC current is passed through one power transmission coil, and the second AC current is passed through the other power transmission coil, The leakage magnetic field generated by the power transmission coil and the leakage magnetic field generated by the other power transmission coil cancel each other. For example, when a first alternating current is passed through the power transmission coil 71 and a second alternating current is passed through the power transmission coil 76, the leakage magnetic field generated by the power transmission coil 71 and the leakage magnetic field generated by the power transmission coil 76 cancel each other. Become a relationship.

  In the example shown in FIGS. 8 and 9, the power transmission coils 71 to 76 having the same coil winding direction are used. For example, the coil winding direction of the power transmission coil 71 and the coil winding of the power transmission coil 74 are used. When the directions are opposite, the leakage magnetic field generated by the power transmission coil 71 and the leakage magnetic field generated by the power transmission coil 73 cancel each other when alternating currents having the same phase are passed through the power transmission coil 71 and the power transmission coil 72. Become a relationship.

  In addition, as shown in FIG. 10, when two power transmission coils 91 to 94 having the same specification (the coil winding direction is the same) are provided on two opposing wall surfaces 81 and 82, two power transmissions installed on different wall surfaces When alternating currents having the same phase are passed through the coils, the leakage magnetic fields generated by the power transmission coils cancel each other. That is, when an alternating current having the same phase is passed through the power transmission coil 91 installed on the wall surface 81 and the power transmission coil 93 installed on the surface 82, the direction of the magnetic field generated in the center of the power transmission coil 91 and the power transmission coil The direction of the magnetic field generated at the center of 93 is reversed. Accordingly, when alternating currents having the same phase are passed through the power transmission coil 91 and the power transmission coil 93, the leakage magnetic field generated by the power transmission coil 91 and the leakage magnetic field generated by the power transmission coil 93 cancel each other.

  Thus, depending on the difference in the specifications of the power transmission coil (difference in the winding direction of the coil) or the way of installation, the leakage magnetic fields may cancel each other when alternating currents having the same phase are passed. For example, a non-contact power feeding device including a power transmission coil having a first specification and a non-contact power feeding device including a power transmission coil having a second specification whose coil winding direction is opposite to that of the first specification. The leakage magnetic field can be reduced even if the system is configured such that alternating currents having the same phase flow through the first specification power transmission coil and the second specification power transmission coil. That is, the non-contact power feeding system is configured so that the number of the non-contact power feeding devices including the first specification power transmission coil and the number of the non-contact power feeding devices including the second specification power transmission coil are substantially equal, If alternating currents of the same phase flow through the power transmission coil of the non-contact power feeding device included in this non-contact power feeding system, the leakage magnetic field can be reduced.

  As mentioned above, although embodiment of the non-contact electric power feeding system concerning this invention was described, this invention is not limited to embodiment described above, In the range which does not deviate from the summary, various changes are added. be able to. Further, regarding the circuit configuration, structure, control method, and the like of the power transmission coil and drive circuit and the control device that constitute the non-contact power feeding device, various circuit configurations, structures, control methods, etc. that can be easily assumed by those skilled in the art may be used. it can. For example, as the power transmission coil, a spiral-shaped or solenoid-shaped coil, a coil that combines these coils, or a coil that combines these with other-shaped coils or capacitors can be used. Also for the drive circuit, a circuit configuration other than the full bridge configuration as shown in FIG. 2, for example, a half bridge configuration may be used. Further, a circuit for improving the power factor and a circuit for adjusting impedance may be added before the drive circuit or between the drive circuit and the power transmission coil.

  In this way, the non-contact power feeding system according to the present invention is configured by setting the leakage magnetic field generated from one non-contact power feeding device and the leakage magnetic field generated from another non-contact power feeding device to cancel each other. Various modifications and applications can be added without departing from the gist of reducing the leakage magnetic field of the non-contact power supply system as a whole.

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power feeding system, 11, 12 ... Non-contact electric power feeder, 13 ... Control apparatus, 21, 22 ... Vehicle, 21a, 22a ... Non-contact electric power receiving apparatus, 41-46 ... Non-contact electric power feeder 51-56 ... Non Contact power receiving device, 71-76 ... power transmission coil, 91-94 ... power transmission coil.

Claims (6)

A non-contact power feeding system including a plurality of power feeding devices each independently performing non-contact power transmission,
Comprising an operation setting means for setting operations of the plurality of power supply devices;
In accordance with an instruction given from the operation setting unit, each of the plurality of power feeding devices has a first AC current or a second phase having a predetermined phase difference and a frequency substantially the same as the first AC current. A drive circuit for supplying an alternating current is provided.
The operation setting means reduces the difference between the number of power supply devices in which the first alternating current is supplied to the power transmission coil and the number of power supply devices in which the second alternating current is supplied to the power transmission coil. An operation of the plurality of power feeding devices is set in the contactless power feeding system.   The contactless power feeding system according to claim 1, wherein the predetermined phase difference is approximately 180 degrees. The drive circuit is configured to output a first AC voltage or a second AC voltage having the same frequency and a reverse phase as the first AC voltage,
The first AC current is a current based on the first AC voltage, and the second AC current is a current based on the second AC voltage. The non-contact power feeding system described.   4. Each of the power transmission coils is installed such that surfaces perpendicular to the magnetic field generated at the center of each power transmission coil of the plurality of power feeding devices are substantially parallel to each other. The non-contact electric power feeding system of any one of.   At least one of the plurality of power supply devices includes a direction of a magnetic field generated when the first alternating current flows through a power transmission coil of the power supply device and a power transmission coil of any other power supply device. 5. The non-contact power feeding system according to claim 1, wherein a direction of a magnetic field generated when the first alternating current flows is reversed. 6. A non-contact power feeding system including a plurality of power feeding devices each independently performing non-contact power transmission,
The plurality of power supply devices generate a magnetic field in a second direction opposite to the first direction and a power supply device that generates a magnetic field in a first direction when an alternating current having the same frequency and phase is supplied. The number of power supply devices that include the power supply device and generate the magnetic field in the first direction and the number of power supply devices that generate the magnetic field in the second direction included in the plurality of power supply devices is reduced. A non-contact power feeding system characterized by being set to.

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