JP6308310B2 - Contactless power supply - Google Patents

Description

  The present invention relates to a non-contact power supply apparatus that supplies power in a non-contact manner to a load provided in a power receiving apparatus.

  For example, a non-contact power supply device has been proposed in order to supply electric power in a non-contact manner to a load such as a battery mounted on a vehicle. The non-contact power supply device includes a power transmission coil unit including a power transmission coil and a resonance capacitor, and a power conversion unit that supplies power for power transmission to the power transmission coil unit. In many cases, the power transmission coil unit and the power conversion unit are provided at remote locations, and the two are electrically connected via a power supply cable.

  On the other hand, in the inverter device (power conversion circuit) provided in the power conversion unit, the impedance on the output side needs to be inductive in order to reduce the loss of the semiconductor element. In Patent Document 1, an inductor (inductive element) and a variable capacitor are provided on the output side of the inverter device in the power conversion unit, and impedance matching is performed with the inductor using the variable capacitor to induce the impedance on the output side. It is disclosed to make it.

  However, when an inductor is provided on the output side of the inverter device, the voltage generated in the power supply cable for connecting the power conversion unit and the power transmission coil unit rises, so that it is necessary to take measures against high voltage.

Special table 2012-504387 gazette

  As described above, when an inductor (inductive element) is provided on the output side of the inverter device, the voltage generated in the power supply cable for connecting between the power conversion unit and the power transmission coil unit is increased. The problem arises that measures must be taken.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a non-contact power feeding device capable of reducing a voltage generated in a power supply cable. is there.

  A non-contact power feeding device according to an aspect of the present invention includes a power transmission-side resonance circuit that resonates with the power reception-side resonance circuit with respect to a power reception device having a power-receiving-side resonance circuit, and transmits power without contact. The apparatus includes a power transmission coil and a power transmission side capacitor, and includes a power transmission coil unit that transmits power to the power receiving apparatus. A power conversion unit that includes a power conversion circuit that outputs AC power, and that includes a series connection circuit of an inductive element and a power output side capacitor, and that supplies power to the power transmission coil unit via a connection wire; Have. The capacity of the power output side capacitor is set so that the frequency of the AC power output from the power conversion circuit matches the resonance frequency due to the inductance of the inductive element and the electrostatic capacity of the power output side capacitor. Further, the combined capacitance of the power transmission side capacitor and the power output side capacitor is set so as to coincide with the capacitance of the resonance capacitor to be installed on the power transmission coil as the power transmission side resonance circuit.

It is a block diagram which shows the structure of the non-contact electric power feeder which concerns on 1st Embodiment of this invention, and its peripheral device. It is explanatory drawing which shows the structure at the time of the non-contact electric power feeder which concerns on embodiment of this invention mounted in the vehicle. It is a circuit diagram showing the composition of the non-contact electric supply device concerning a 1st embodiment of the present invention. It is a circuit diagram which shows the structure of the non-contact electric power feeder which concerns on a comparative example. In the non-contact electric power feeder which concerns on 1st Embodiment of this invention, it is a characteristic view which shows the change of the voltage which arises in a power supply cable. In the non-contact electric power feeder which concerns on a comparative example, it is a characteristic view which shows the change of the voltage which arises in an electric power supply cable. It is a circuit diagram which shows the structure of the non-contact electric power feeder which concerns on the modification of 1st Embodiment of this invention. It is a circuit diagram which shows the structure of the non-contact electric power feeder which concerns on 2nd Embodiment of this invention.

[Description of First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a contactless power supply device 101 according to an embodiment of the present invention and a power receiving device 102 to which power is supplied from the contactless power supply device 101.

  The non-contact power supply apparatus 101 includes, for example, a power transmission coil unit 11 provided on the ground of a parking space of a vehicle, and a power conversion unit 13 connected to the power transmission coil unit 11 via power supply cables 12a and 12b (connection wires). It is equipped with. The power receiving device 102 is provided in, for example, an electric vehicle, and includes a power receiving coil unit 21, a rectifier 22, and a battery 23. The power receiving coil unit 21 includes a resonance coil L31 and a resonance capacitor C31. The resonance coil L31 and the resonance capacitor C31 constitute a “power-receiving-side resonance circuit”.

  That is, as shown in FIG. 2, since the power transmission coil unit 11 is provided on the ground 103 of the parking space, when the electric vehicle V1 is stopped in the parking space, it is disposed on the bottom surface of the electric vehicle V1. The power receiving coil unit 21 and the power transmitting coil unit 11 face each other. Accordingly, when power is supplied to the power transmission coil unit 11 in this state, power is transmitted from the power transmission coil unit 11 to the power receiving coil unit 21 in a contactless manner. The power received by the power receiving coil unit 21 is rectified by the rectifier 22 and then charged to the battery 23.

  A power conversion unit 13 shown in FIG. 1 includes an inverter device 31 (power conversion circuit) including a bridge circuit of a semiconductor switch, and a reactance circuit including a direct connection of an inductor L1 (inductive element) and a capacitor C1 (power output side capacitor). 32. The inductor L1 is installed to make the impedance on the rear stage side of the inverter device 31 inductive. In addition, the capacitor C1 plays a part of a capacitor for forming a resonance circuit with a power transmission coil L11 (details will be described later) provided in the power transmission coil unit 11. The capacitor C2 and the power transmission coil L11 provided in the power transmission coil 11 and the capacitor C1 provided in the reactance circuit 32 constitute a “power transmission side resonance circuit”.

  Further, on the upstream side of the power conversion unit 13, a converter and a smoothing capacitor that convert alternating current of a commercial power source (not shown) (for example, 100 V, 50 Hz) into direct current are provided. Hereinafter, the capacitance of the capacitor C1 is indicated by the same symbol C1, and the inductance of the inductor L1 is indicated by the same symbol L1.

  The inverter device 31 generates AC power having a desired frequency by switching on and off a plurality of semiconductor switches, and outputs the AC power to the power transmission coil unit 11 via the two power supply cables 12a and 12b. To do.

The power transmission coil unit 11 includes a series connection circuit of a power transmission coil L11 and a capacitor C2 (power transmission side capacitor). The capacitance of the capacitor C2 is also indicated by the same symbol C2. The combined capacitance of the capacitor C1 provided in the reactance circuit 32 and the capacitor C2 provided in the power transmission coil unit 11 is the same as that of the power transmission side resonance circuit including the power transmission coil L11 and the power reception side resonance circuit including the power reception coil L31. It is set to be equal to the capacity of a resonance capacitor necessary for resonating between them (this is C0). That is, the relationship of the following formula (1) is established.
1 / C0 = (1 / C1) + (1 / C2) (1)

  FIG. 3 is a circuit diagram of the non-contact power feeding apparatus 101 according to the present embodiment, and FIG. 4 is a circuit diagram of the non-contact power feeding apparatus 201 according to a comparative example of the present embodiment. Hereinafter, the operation of the non-contact power feeding apparatus 101 according to the present embodiment will be described in comparison with a comparative example.

  As shown in FIG. 4, in the non-contact power feeding apparatus 201 according to the comparative example, the reactance circuit 132 provided in the power conversion unit 113 is only the inductor L1, and the power transmission coil unit 111 includes the power transmission coil L11 and the resonant capacitor. A capacitor C0 is provided. The resonance capacitor C0 has the same capacitance C0.

  As described above, by providing the inductor L1, the impedance on the rear stage side of the inverter device 31 is made inductive. Providing the inductor L1 increases the impedance on the rear stage side of the power conversion unit 113, so that the voltage generated between the two power supply cables 12a and 12b increases. Therefore, it is necessary to increase the withstand voltage between the power supply cables 12a and 12b, which increases the scale of the apparatus and causes problems such as noise.

On the other hand, as shown in FIG. 3, in the non-contact power feeding apparatus 101 according to the present embodiment, the reactance circuit 32 is provided with an inductor L1 and a capacitor C1 (power output side capacitor), which are connected in series. Yes. And when the frequency of the alternating current power output from the inverter apparatus 31 is set to f1, the inductance L1 and the electrostatic capacitance C1 are set so that the following (2) Formula may be materialized.

  That is, the resonance frequency by the inductance L1 and the capacitance C1 is set to be the frequency f1. And the impedance of the back | latter stage side of the power conversion unit 13 can be made small by setting the electrostatic capacitance C1 based on (2) Formula mentioned above. Therefore, the voltage generated between the two power supply cables 12a and 12b can be reduced.

  Further, as described above, the capacitor C1 (power output side capacitor) has the relationship of the above expression (1) with the capacitor C2 (power transmission side capacitor) provided in the power transmission coil unit 11. That is, the combined capacitance of the power transmission side capacitor C2 and the power output side capacitor C1 is set so as to coincide with the capacitance of the resonance capacitor C0 to be installed with respect to the power transmission coil L11 as the power transmission side resonance circuit. Yes. Therefore, since the power transmission coil L11 can be resonated by the two capacitors C1 and C2, the power generated in the inverter device 31 can be stably transmitted to the power receiving device 102 (see FIG. 1) in a non-contact manner. .

  FIG. 5 is a waveform diagram showing a simulation result of the voltage generated between the two power supply cables 12a and 12b provided in the non-contact power feeding apparatus 101 according to the present embodiment shown in FIG. 3, and FIG. It is a wave form diagram which shows the simulation result of the voltage which arises between the two electric power supply cables 12a and 12b provided in the non-contact electric power feeder 201 which concerns on the shown comparative example. 5 and 6, the resonant capacitor C0 is divided into two capacitors C1 and C2, and the capacitor C1 (power output side capacitor) is used as the power as in this embodiment. By installing in the conversion unit 13, it can be seen that the voltage peak generated between the two power supply cables 12a and 12b is reduced to almost half as compared with the case where the capacitor C0 is not divided. That is, the peak value of the curve q1 shown in FIG. 5 is about half of the peak value shown in the curve q2 shown in FIG.

  Thus, in the non-contact power feeding apparatus 101 according to the present embodiment, the capacitor C1 is installed in the reactance circuit 32, and the above-described equation (2) is obtained by the capacitance of the capacitor C1 and the inductance of the inductor L1. It is going to be established. As a result, the voltage generated between the two power supply cables 12a and 12b for connecting the power conversion unit 13 and the power transmission coil unit 11 can be reduced. For this reason, it is not necessary to improve the pressure | voltage resistant performance between the two electric power supply cables 12a and 12b. As a result, it is possible to suppress an increase in the scale of the apparatus and to reduce the cost.

[Description of Modified Example of First Embodiment]
Next, a modification of the first embodiment will be described. FIG. 7 is a circuit diagram showing a configuration of a non-contact power feeding apparatus 101a according to a modification. The modification is different from the non-contact power feeding apparatus 101 shown in FIG. 3 in that two capacitors C11 and C12 are provided in a reactance circuit 32a provided in the power conversion unit 13a. The combined capacitance of the capacitors C11 and C12 is set to be equal to the capacitance of the capacitor C1 shown in FIG. A “power output side capacitor” is configured by parallel connection of two capacitors C11 and C12.

  Even in such a configuration, the voltage generated between the two power supply cables 12a and 12b can be reduced, as in the first embodiment described above, so that it is not necessary to improve the pressure resistance performance. For this reason, the enlargement of the apparatus can be suppressed, and the cost can be reduced. Further, since two (a plurality) of small-capacitance capacitors can be configured, the capacitors can be arranged in a distributed manner.

[Description of Second Embodiment]
Next, a second embodiment of the present invention will be described. The contactless power supply device according to the second embodiment is divided into two parts for the capacitor C2 provided in the power transmission coil unit 11 shown in FIG. 3 in contrast to the contactless power supply device 101 shown in the first embodiment. And the inductor L1 and the capacitor C1 provided in the reactance circuit 32 are divided into two parts.

  As shown in FIG. 8, the non-contact power feeding apparatus 101b according to the second embodiment includes a reactance circuit 32b including a series connection circuit of an inductor L21 and a capacitor C13 and a series connection circuit of an inductor L22 and a capacitor C14. . The inductors L21 and L22 have the same inductance, and the capacitors C13 and C14 have the same capacitance.

  The power transmission coil unit 11b includes a power transmission coil L11 and capacitors C21 and C22 connected to both ends of the power transmission coil L11. The capacitors C21 and C22 have the same capacitance. Here, the capacitors C13 and C14 constitute a “power output side capacitor”, and the capacitors C21 and C22 constitute a “power transmission side capacitor”.

  That is, the power conversion unit 13b includes inductors L21 and L22 (inductive elements) between the two output units of the inverter device 31 (power conversion circuit) and the two electric wires (power supply cables 12a and 12b), respectively. And a series connection circuit of capacitors C13 and C14 (power output side capacitors).

  The combined inductance of the two inductors L21 and L22 is set to be equal to the inductance of the inductor L1 (see FIG. 3) shown in the first embodiment. The combined capacitance of the two capacitors C13 and C14 is set to be equal to the capacitance of the capacitor C1 (see FIG. 3) shown in the first embodiment. Further, the combined capacitance of the two capacitors C21 and C22 is set to be equal to the capacitance of the capacitor C2 (see FIG. 3) shown in the first embodiment.

  Therefore, the above-described equations (1) and (2) are established. For this reason, the voltage which arises between the two electric power supply cables 12a and 12b can be reduced similarly to 1st Embodiment. There is no need to increase the withstand voltage between the two power supply cables 12a and 12b, the scale of the apparatus can be suppressed, and the cost can be reduced.

  In this way, in the non-contact power supply apparatus 101b according to the second embodiment, the voltage generated between the two power supply cables 12a and 12b can be reduced as in the first embodiment described above, so that the withstand voltage performance is improved. There is no need. For this reason, the enlargement of the apparatus can be suppressed, and the cost can be reduced. Furthermore, the voltage between the two power supply cables 12a and 12b and the ground can be stabilized.

  As mentioned above, although the non-contact electric power feeder of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is replaced with the thing of the arbitrary structures which have the same function. be able to.

  For example, in each of the above-described embodiments, a non-contact power supply device that supplies power to a load such as a battery mounted on a vehicle in a non-contact manner has been described, but the present invention is not limited to this, and other loads may be used. The present invention can also be applied when power is supplied in a non-contact manner.

11, 11b Power transmission coil unit 12a, 12b Power supply cable (connection wire)
13, 13a, 13b Power conversion unit 21 Power receiving coil unit 22 Rectifier 23 Battery 31 Inverter device 32, 32a, 32b Reactance circuit 101, 101a, 101b Non-contact power feeding device 102 Power receiving device 103 Ground 111 Power transmission coil unit 113 Power conversion unit 132 Reactance Circuit 201 Non-contact power supply device C0 Resonance capacitor C1 capacitor (Power output side capacitor)
C2 capacitor (capacitor on the power transmission side)
L1 Inductor L11 Power transmission coil L31 Power reception coil V1 Electric vehicle

Claims (3)

A non-contact power feeding device that has a power transmission side resonance circuit that resonates with the power reception side resonance circuit with respect to a power reception device having a power reception side resonance circuit, and that transmits power in a non-contact manner,
A power transmission coil unit having a power transmission side capacitor and transmitting power to the power receiving device;
A power conversion circuit for outputting AC power, and a series connection circuit of an inductive element and a power output side capacitor, connected to the power transmission coil unit via a connecting wire, and supplying power to the power transmission coil unit A power conversion unit to supply,
The capacity of the power output side capacitor is set so that the frequency of the AC power output from the power conversion circuit matches the resonance frequency of the inductance of the inductive element and the capacitance of the power output side capacitor. ,
Furthermore, the combined capacitance of the power transmission side capacitor and the power output side capacitor is set to coincide with the capacitance of a resonance capacitor to be installed on the power transmission coil as the power transmission side resonance circuit. A non-contact power feeding device characterized by comprising: The power conversion unit includes a plurality of power output side capacitors, and a combined capacitance of a combined capacitance of each power output side capacitor and a capacitance of the power transmission side capacitor is the power transmission side resonance. The non-contact power feeding device according to claim 1, wherein the non-contact power feeding device is set to coincide with a capacitance of a resonance capacitor to be installed as a circuit with respect to the power transmission coil. The power conversion unit includes a series connection circuit of an inductive element and a power output side capacitor between the two output portions of the power conversion circuit and the two wires constituting the connection wire, respectively.
The resonance frequency due to the combined inductance of the two inductive elements and the combined capacitance of the two power output capacitors is set to match the frequency of the AC power output from the power conversion circuit. ,
The combined capacitance of the combined capacitance of the two power output side capacitors and the capacitance of the power transmission side capacitor is the resonance capacitor to be installed on the power transmission coil as the power transmission side resonance circuit. The non-contact power feeding device according to claim 2, wherein the non-contact power feeding device is set so as to coincide with a capacitance.

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