WO2014069331A1

WO2014069331A1 - Contactless power feeding device

Info

Publication number: WO2014069331A1
Application number: PCT/JP2013/078845
Authority: WO
Inventors: 浩之阿部田
Original assignee: 日産自動車株式会社
Priority date: 2012-10-31
Filing date: 2013-10-24
Publication date: 2014-05-08
Also published as: JP2016007087A

Abstract

A contactless power feeding device comprises a coil (12) which contactlessly transmits and receives power to and from a partner coil (22) using magnetic coupling, a first capacitor (13i), and a second capacitor (13o). The coil is wound into a swirl shape in a prescribed planar surface. The first capacitor is serially connected with the inner terminal of the coil. The second capacitor is serially connected with the outer terminal of the coil. When the inner diameter of the coil is Di and the outer diameter of the coil is Do, the ratio of the electrostatic capacitance Ci of the first capacitor to the electrostatic capacitance Co of the second capacitor satisfies a formula (1). Ci/Co = (2Di + Do) / (2Do + Di) … (1)

Description

Non-contact power feeding device

The present invention relates to a non-contact power feeding device.

2. Description of the Related Art Conventionally, a non-contact power supply device that supplies power in a non-contact manner by magnetic coupling of a pair of coils is known (Patent Document 1). Application of this non-contact power supply apparatus to an electric vehicle such as an electric vehicle is being promoted. For example, one coil connected to an AC power supply is installed in a parking space such as a power supply stand, and the other coil connected to a battery is installed in an electric vehicle. And by using the coil on the parking space side as the primary coil and the coil on the electric vehicle side as the secondary coil, the AC power source on the parking space side is transferred to the battery on the vehicle side via one coil and the other coil. Power can be supplied.

JP 2011-72074 A

However, in the non-contact power feeding device, the leakage current becomes a noise source, and radiation noise may appear around the non-contact power feeding device.

The present invention has been made in view of such circumstances, and an object of the present invention is to effectively suppress radiation noise in a non-contact power supply apparatus that transfers power in a non-contact manner.

A non-contact power feeding device according to one embodiment of the present invention includes a coil that performs non-contact power transfer with a counterpart coil by magnetic coupling, a first capacitor, and a second capacitor. ing. The coil has a structure wound spirally within a predetermined plane. The first capacitor is connected in series with the inner terminal of the coil. The second capacitor is connected in series with the outer terminal of the coil. When the inner diameter of the coil is Di and the outer diameter of the coil is Do, the ratio between the capacitance Ci of the first capacitor and the capacitance Co of the second capacitor is set to satisfy the relationship (1). Has been.

FIG. 1 is a block diagram schematically illustrating a configuration of a contactless power feeding system according to the embodiment. FIG. 2 is an explanatory diagram showing the concept of leakage current. FIG. 3 is a circuit diagram schematically showing the configuration of the non-contact power feeding system of FIG. FIG. 4A is a graph showing the relationship between the capacitance ratio and leakage current, and FIG. 4B is a graph showing the relationship between the capacitance ratio and radiation noise.

With reference to FIG. 1, the structure of the non-contact electric power feeding system which concerns on embodiment is demonstrated. The non-contact power supply system includes a power supply device 100 that is a ground-side unit, and an electric vehicle (hereinafter simply referred to as “vehicle”) 200 that includes the vehicle-side unit. The non-contact power supply system supplies power from the power supply apparatus 100 in a non-contact manner and charges a battery 28 provided in the vehicle 200. In the embodiment, an example in which a non-contact power feeding device is applied to the power feeding device 100 and the vehicle 200 will be described.

The power feeding device 100 is installed in a charging stand or the like having a parking space for the vehicle 200 and supplies power to the vehicle 200. The power supply apparatus 100 is mainly configured by a power control unit 11, a power transmission coil 12, a wireless communication unit 14, and a control unit 15.

The power control unit 11 is a circuit for converting AC power transmitted from the AC power source 300 into high-frequency AC power and transmitting it to the power transmission coil 12. The power control unit 11 includes a rectifying unit 111, a PFC (Power Factor Correction) circuit 112, an inverter 113, and a sensor 114.

The rectifying unit 111 is a circuit that is electrically connected to the AC power supply 300 and rectifies the AC power output from the AC power supply 300. The PFC circuit 112 is a circuit for improving the power factor by shaping the output waveform from the rectifying unit 111, and is connected between the rectifying unit 111 and the inverter 113. The inverter 113 is a power converter including a PWM control circuit having a switching element such as a smoothing capacitor or IGBT. The inverter 113 converts DC power into high-frequency AC power based on a control signal from the control unit 15 and supplies it to the power transmission coil 12. The sensor 114 is connected between the PFC circuit 112 and the inverter 113, and detects a current and a voltage flowing between the PFC circuit 112 and the inverter 113.

The power transmission coil 12 is a coil for supplying power to the power reception coil 22 mounted on the vehicle 200 in a non-contact manner, and has a structure in which a conductive wire made of a conductor such as metal is wound in a spiral shape in a predetermined plane. have. The power transmission coil 12 is provided at a destination such as a parking space where the vehicle 200 is parked. Specifically, the power transmission coil 12 is provided so as to be positioned directly below the power reception coil 22 while keeping a distance from the power reception coil 22 when the vehicle 200 is parked at an appropriate parking position in the parking space. . In other words, when the vehicle 200 is parked at a specified position in the parking space, the vehicle 200 faces the power receiving coil 22 on the vehicle 200 side. The power transmission coil 12 is wound around a coil axis in a direction parallel to the road surface in the parking space. As the winding shape, a circular shape (including an ellipse) or a polygonal shape can be adopted.

The wireless communication unit 14 performs bidirectional communication with the wireless communication unit 24 mounted on the vehicle 200. The frequency of the electromagnetic wave used for communication between the wireless communication unit 14 and the wireless communication unit 24 is set to be higher than the frequency used in the vehicle peripheral device such as an intelligent key (registered trademark). For this reason, even if it communicates between the radio | wireless communication part 14 and the radio | wireless communication part 24, a vehicle peripheral device is hard to receive the interference by the said communication. For communication between the wireless communication unit 14 and the wireless communication unit 24, for example, various wireless LAN methods are used, and communication methods suitable for long distances are used.

The control unit 15 has a function of controlling the power supply apparatus 100. Specifically, the control unit 15 controls the power control unit 11, the power transmission coil 12, and the wireless communication unit 14. The control unit 15 transmits a control signal to start power supply to the vehicle 200 side or receives power from the vehicle 200 side through communication between the wireless communication unit 14 and the wireless communication unit 24. Receive control signals. The control unit 15 performs switching control of the inverter 113 based on the detection current of the sensor 114 and controls electric power supplied from the power transmission coil 12. As the control unit 15, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface can be used.

The vehicle 200 includes, as a vehicle-side unit, a power receiving coil 22, a wireless communication unit 24, a charging control unit 25, a rectifying unit 26, a relay unit 27, a battery 28, an inverter 29, a motor 30, and a notification unit. 32.

The power receiving coil 22 is a coil for receiving power in a non-contact manner from the power transmitting coil 12 on the power supply apparatus 100 side, and has a structure in which a conductive wire made of a conductor such as metal is wound in a spiral shape within a predetermined plane. Yes. The power receiving coil 22 is provided, for example, at a target location such as a bottom surface (chassis) of the vehicle 200, particularly between the rear wheels. When the vehicle 200 is parked at a specified position in the parking space, the power receiving coil 22 faces the power transmitting coil 12 on the power supply apparatus 100 side.

The wireless communication unit 24 performs bidirectional communication with the wireless communication unit 14 provided on the power supply apparatus 100 side. The rectifying unit 26 is connected to the power receiving coil 22 and is configured by a rectifying circuit that rectifies AC power received by the power receiving coil 22 into direct current. The relay unit 27 includes a relay switch that is turned on and off under the control of the charging control unit 25. The relay part 27 can isolate | separate the strong electric system containing the battery 28 and the weak electric system containing the receiving coil 22 and the rectifier 26 which become a charge circuit part by turning off the said relay switch.

The battery 28 is a power source of the vehicle 200, and is configured by electrically connecting a plurality of secondary batteries, for example. The inverter 29 is a power converter including a PWM control circuit having a switching element such as an IGBT. The inverter 29 converts the DC power output from the battery 28 into AC power based on the control signal, and supplies the AC power to the motor 30. The motor 30 is composed of, for example, a three-phase AC motor, and is a drive source for driving the vehicle 200.

The notification unit 32 includes a display device of a navigation system, a warning lamp, and a speaker provided at a position where a driver such as an instrument panel in the vehicle can see. The notification unit 32 outputs light, an image, sound, or the like to the user based on the control by the charge control unit 25.

The charging control unit 25 has a function of controlling the charging of the battery 28. For example, the charging control unit 25 controls the wireless communication unit 24 and the notification unit 32. The charging control unit 25 receives a control signal for starting power supply from the power supply apparatus 100 side through communication of the wireless communication unit 24 and the wireless communication unit 14, or receives a control signal for receiving power from the vehicle 200 side. Or send to.

Although not shown, the charging control unit 25 is connected to a controller that controls the entire vehicle 200 via a CAN communication network. The controller manages the switching control of the inverter 29 and the state of charge (SOC) of the battery 28. When the charging control unit 25 determines full charging based on the SOC of the battery 28 obtained from the controller, the charging control unit 25 transmits a control signal to the power supply apparatus 100 to end charging.

In the non-contact power feeding system according to the present embodiment, high-frequency power is transmitted between the power transmission coil 12 and the power receiving coil 22 in a non-contact state by electromagnetic induction. In other words, when a voltage is applied to the power transmission coil 12, magnetic coupling occurs between the power transmission coil 12 and the power reception coil 22, and power is supplied from the power transmission coil 12 to the power reception coil 22.

In such a non-contact power supply system, for example, in the power supply apparatus 100 that is a ground-side unit, power is supplied from the AC power supply 300, and thus a leakage current is generated. This leakage current flows in a closed loop as indicated by a broken line (LC) in FIG. Then, due to this leakage current, this becomes a noise source and radiation noise may appear in the surroundings. Here, the leakage current due to the power supply apparatus 100 is a small amount. However, if the configuration such as the AC power supply 300 or the power supply apparatus 100 is large, the area of the closed loop through which the leakage current flows increases, so that the level of radiation noise increases. In addition, radiation noise caused by leakage current is generated not only by the ground unit, but also by the vehicle 200.

FIG. 3 is a circuit diagram schematically showing a configuration of the non-contact power feeding system according to the present embodiment. In the present embodiment, a pair of capacitors, specifically, a first capacitor 13 i and a second capacitor 13 o are connected to the power transmission coil 12 in order to suppress the generation of radiation noise due to leakage current. Yes. Here, the first capacitor 13 i is connected in series with the inner terminal of the power transmission coil 13, while the second capacitor 13 o is connected in series with the outer terminal of the power transmission coil 13.

Here, the first capacitor 13i and the second capacitor 13o are set so that the capacitance ratio satisfies the equation (1).

In the formula (1), Ci is the capacitance of the first capacitor 13i, and Co is the capacitance of the second capacitor 13o. Di is the inner diameter of the power transmission coil 12, and Do is the outer diameter of the power transmission coil 12.

Hereinafter, the concept of setting the capacitance ratio (Ci / Co) will be described. First, the leakage current is obtained by equation (2).

In equation (2), I _total indicates the total leakage current due to the power transmission coil 12. Here, ω is a constant corresponding to the current frequency of the power transmission coil 12, and ε is a dielectric constant between the power transmission coil 12 and the casing that houses the power transmission coil 12. d is the distance between the coil and the bottom surface of the housing, W is the outer diameter of the wire of the power transmission coil 12, and k is the total number of windings of the power transmission coil 12. Vi is the voltage at the inner terminal of the power transmission coil 12, and Vo is the voltage at the outer terminal of the power transmission coil 12.

Here, when Vo = G · Vi, the expression (2) can be expressed by the expression (3).

When the value in the parenthesis on the right side shown in the equation (3) is 0, I _total is 0. G when I _total is 0 is expressed by the equation (4).

The power transmission coil 12 is a planar coil wound in a spiral shape within a predetermined plane. In this case, W satisfies the relationship shown in equation (5).

Then, when this equation (5) is substituted into equation (4), “G” is expressed by equation (6).

Further, from Vo = G · Vi, “G” is also expressed by equation (7).

Thus, based on the equations (6) and (7), the capacitance ratio (Ci / Co) of the first capacitor 13i and the second capacitor 13o is expressed by the equation (1).

Similarly, a pair of capacitors, specifically, a first capacitor 23 i and a second capacitor 23 o are connected to the power receiving coil 22 in order to suppress the generation of radiation noise due to leakage current. Here, the first capacitor 23 i is connected in series with the inner terminal of the power receiving coil 22, while the second capacitor 23 o is connected in series with the outer terminal of the power receiving coil 22. In this case, the first capacitor 23i and the second capacitor 23o are set so that the capacitance ratio (Ci / Co) satisfies the relationship expressed by the above-described equation (1).

4A is a graph showing the relationship between the capacitance ratio (Ci / Co) and leakage current, and FIG. 4B shows the capacitance ratio (Ci / Co), radiation noise, and It is a graph which shows the relationship. FIG. 4A shows the measured value (La) and the calculated value (Lc) of the leakage current. “Fc” in FIGS. 4A and 4B indicates a capacitance ratio determined by the equation (1). As shown in FIG. 4A, it can be seen that the measured value (La) and the calculated value (Lc) of the leakage current are most suppressed in the capacitance ratio (Fc) defined by the equation (1). . Further, as shown in FIG. 4B, it can be seen that the radiation noise is most suppressed in the capacitance ratio (Fc) defined by the equation (1).

As described above, in the present embodiment, the coils (12, 22) that transfer power in a contactless manner with the counterpart coil (22, 12) by magnetic coupling are wound in a spiral shape within a predetermined plane. Have a structure. The first capacitor (13i, 23i) is connected in series with the inner terminal of the coil, and the second capacitor (13o, 23o) is connected in series with the outer terminal of the coil. The ratio (Ci / Co) between the capacitance Ci of the first capacitor and the capacitance Co of the second capacitor is set to satisfy the above equation (1).

According to such a configuration, the capacitors are connected in series to both ends of the coil, and the capacitance ratio of the pair of capacitors is appropriately set. Thereby, since generation | occurrence | production of a leakage current can be suppressed, radiation noise can be suppressed effectively.

Here, in the present embodiment, the coil having the above characteristics is applied to the power transmission coil 12 arranged in the power supply apparatus 100 that supplies power to the vehicle 200 on which the power receiving coil 22 of the other party is mounted.

According to such a configuration, the power supply apparatus 100 in which the power receiving coil 22 is arranged has a large facility scale, and therefore there is a tendency that the area of the closed loop in which leakage current flows is large and radiation noise tends to increase. Therefore, radiation noise can be effectively suppressed by applying the above configuration to the power transmission coil 12 of the power supply apparatus 100.

In this embodiment, the coil having the above characteristics is also applied to the power receiving coil 22 mounted on the vehicle 200.

Since a leakage current is also generated in the power receiving coil 22 on the vehicle 200 side, radiation noise is generated. Since the configuration on the vehicle 200 side is smaller than that of the power supply apparatus 100, the influence of radiation noise is also small. However, by applying the above configuration to the power receiving coil 22 on the vehicle 200 side, radiation noise in the vehicle 200 can be suppressed, and radiation noise in the entire non-contact power feeding system can be suppressed.

As mentioned above, although the non-contact electric power feeding apparatus concerning embodiment of this invention was demonstrated, it cannot be overemphasized that a various deformation | transformation is possible within the scope of the invention, without this invention being limited to embodiment mentioned above. Absent.

The entire content of Japanese Patent Application No. 2012-239753 (filing date: October 31, 2012) is incorporated herein by reference.

DESCRIPTION OF SYMBOLS 100 Electric power feeder 12 Power transmission coil 13i, 23i 1st capacitor | condenser 13o, 23o 2nd capacitor | condenser 200 Vehicle (electric vehicle)
22 Power receiving coil 300 AC power supply

Claims

A coil having a structure wound in a spiral shape within a predetermined plane, and transferring power in a contactless manner with a counterpart coil by magnetic coupling;
A first capacitor connected in series with an inner terminal of the coil;
A second capacitor connected in series with the outer terminal of the coil,
When the capacitance of the first capacitor is Ci, the capacitance of the second capacitor is Co, the inner diameter of the coil is Di, and the outer diameter of the coil is Do, the static capacity of the first capacitor is A non-contact power feeding device, wherein a ratio of a capacitance to a capacitance of the second capacitor satisfies the formula (1).
The coil is disposed in a ground-side unit that supplies electric power to the electric vehicle on which the counterpart coil is mounted, and when a voltage is applied by the electric power supplied from a power source, the coil is magnetized between the counterpart coil. The non-contact power feeding apparatus according to claim 1, wherein electric power is supplied to the coil of the other party by generating a general coupling.
The coil is mounted on the electric vehicle, and when a voltage is applied to the counterpart coil arranged in the ground side unit that supplies power to the electric vehicle, the coil is magnetically connected to the counterpart coil. The contactless power feeding device according to claim 1, wherein power is supplied by generating coupling.