JP2014050302A - Non-contact power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power supply device capable of reducing the unnecessary radiation generated in non-contact power supply using a resonance technique.SOLUTION: The winding directions of respective coils are controlled so that the whole magnetic flux on the power transmission side generated when power is transmitted to an LC resonance part coil on the power transmission side via an external connection coil on the power transmission side, and the whole magnetic flux on the power reception side generated when power is transmitted to an LC resonance part coil on the power reception side via an LC resonance part coil on the power reception side cancel each other, and the unnecessary radiation generated from a non-contact power supply device can be reduced.

Description

  The present invention relates to a non-contact power supply apparatus capable of reducing unnecessary radiation (leakage electromagnetic field) in power transmission by non-contact power supply.

  In recent years, contactless power transmission that does not use a power cord or a power transmission cable has attracted attention as a power transmission method. In this non-contact power transmission, two techniques are mainly known: power transmission using electromagnetic induction and power transmission by a resonance method.

  Among these technologies, power transmission by the resonance method is a non-contact transmission technology in which a pair of resonance coils are resonated in an electromagnetic field and power is transmitted through the electromagnetic field, and a relatively large power such as several kW is several meters away. Can also be transmitted.

  Therefore, the electromagnetic field generated around the coil unit including the resonance coil may become electromagnetic noise for other electronic devices and the like, which may be an obstacle to the wireless communication device, for example. Further, when there is a conductor in the electromagnetic field, the conductor may be heated by electromagnetic induction by an electromagnetic field, which may cause a failure of the electronic device.

  Therefore, in power transmission using the resonance method, it is desired to suppress unnecessary radiation generated in directions other than the power transmission direction as much as possible.

  For example, in Patent Document 1, in order to make the leakage electromagnetic field as small as possible, when the high-frequency power supplied from the high-frequency power source is supplied from the primary self-resonant coil to the secondary self-resonant coil, the primary self-resonant coil and the secondary self-resonant coil are disclosed. A technique for setting a frequency so that currents in opposite directions flow through a coil is disclosed.

JP 2011-147213 A

  However, in the technique of Patent Document 1, the direction of the electromagnetic field generated from either the primary self-resonant coil or the secondary self-resonant coil is opposite to the direction of the electromagnetic field generated from the other coil. Therefore, although the leakage magnetic field generated between the primary self-resonant coil and the secondary self-resonant coil can be reduced, the electromagnetic field generated when the high-frequency power is supplied from the primary coil to the primary self-resonant coil or received power An electromagnetic field generated when the secondary self-resonant coil generates high-frequency power in the secondary coil may leak to the outside as unnecessary radiation.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a non-contact power feeding apparatus capable of reducing unnecessary radiation generated in non-contact power feeding using a resonance method.

  A contactless power supply device according to the present invention includes a power supply circuit, a power transmission side external connection coil to which power supplied from the power supply circuit is transmitted, and a power transmission side LC resonance unit magnetically coupled to the power transmission side external connection coil A coil, a power receiving side LC resonance part coil that is disposed opposite to the power transmission side LC resonance part coil and transmits the power, and a power receiving side external connection coil that is magnetically coupled to the power receiving side LC resonance part, A power receiving circuit through which the power is transmitted via the power receiving side external connection coil, and the winding direction of the power transmitting side LC resonance unit coil and the power receiving side LC resonance unit coil is opposite, and the power transmission side The winding direction of the LC resonance unit coil and the power transmission side external connection coil is the same, and the winding direction of the power reception side LC resonance unit coil and the power reception side external connection coil is the same. To do.

  According to this configuration, the entire power transmission side magnetic flux generated when power is transmitted to the power transmission side LC resonance unit coil via the power transmission side external connection coil, and the power reception side LC resonance unit via the power reception side LC resonance unit coil The magnetic flux generated on the power receiving side when the power is transmitted to the coils cancels each other, so that unnecessary radiation generated from the non-contact power feeding device can be reduced as a whole.

  ADVANTAGE OF THE INVENTION According to this invention, the non-contact electric power feeder which can reduce the unnecessary radiation generate | occur | produced in the non-contact electric power feeding using the resonance method can be provided.

It is a lineblock diagram of the non-contact electric supply device concerning the embodiment of the present invention. It is a figure which shows the change of the resonant frequency when the separation distance of the power transmission side LC resonance part coil and the power reception side LC resonance part coil is changed. The winding direction of the power transmission side LC resonance part coil and the power reception side LC resonance part coil is reversed, the winding direction of the power transmission side LC resonance part coil and the power transmission side external connection coil, and the power reception side LC resonance part coil and the power reception side external connection. It is a figure which shows the relationship between the power receiving part impedance and magnetic field intensity when the separation distance of the power transmission side LC resonance part coil and a power receiving side LC resonance part coil is 10 cm in the state which made the coil winding direction the same. The winding direction of the power transmission side LC resonance part coil and the power reception side LC resonance part coil are made the same, the winding direction of the power transmission side LC resonance part coil and the power transmission side external connection coil, and the power reception side LC resonance part coil and the power reception side external connection. It is a figure which shows the relationship between the power receiving part impedance and magnetic field intensity when the separation distance of the power transmission side LC resonance part coil and a power receiving side LC resonance part coil is 10 cm in the state which made the coil winding direction the same. The winding direction of the power transmission side LC resonance part coil and the power reception side LC resonance part coil are made the same, the winding direction of the power transmission side LC resonance part coil and the power transmission side external connection coil, and the power reception side LC resonance part coil and the power reception side external connection. It is a figure which shows the relationship between the power receiving part impedance and magnetic field intensity when the separation distance of the power transmission side LC resonance part coil and a power receiving side LC resonance part coil is 10 cm in the state which made the coil winding direction reverse. The winding direction of the power transmission side LC resonance unit coil and the power reception side LC resonance unit coil are reversed, and the winding direction of the power transmission side LC resonance unit coil and the power transmission side external connection coil is the same, the power reception side LC resonance unit coil and the power reception side It is a figure which shows the relationship between the power receiving part impedance and magnetic field intensity when the separation distance of the power transmission side LC resonance part coil and a power receiving side LC resonance part coil is 10 cm in the state which made the winding direction of the external connection coil reverse.

  FIG. 1 is a configuration diagram of a non-contact power feeding device 1 according to an embodiment of the present invention. A power transmission side external connection coil 103 is connected to the power supply circuit 102, and the power transmission side LC resonance coil 101 is magnetically coupled to the power transmission side external connection circuit 103. For example, a capacitor having a capacitance component is connected to the power transmission side LC resonance unit coil 101 to form the power transmission side LC resonance unit 11. The power transmission side LC resonator 10 and the power transmission side external connection coil 103 form a power transmission side LC resonator 10.

  A power receiving side external connection coil 203 is connected to the power receiving circuit 202, and a power receiving side LC resonance section coil 201 is magnetically coupled to the power receiving side external connection circuit 203. For example, a capacitor having a capacitance component is connected to the power reception side resonance unit coil 201 to form the power reception side LC resonance unit 21. The power receiving side LC resonator 20 and the power receiving side external connection coil 203 form a power receiving side LC resonator 20.

  The power transmission side LC resonance part coil 101 and the power reception side LC resonance part coil 201 are disposed so as to face each other, and are separated without being electrically connected.

  Reduction of unnecessary radiation in the non-contact power feeding device 1 is achieved as follows.

  The power supplied from the power supply circuit 102 to the power transmission side external connection coil 103 is supplied to the power transmission side LC resonance unit coil 101 that is magnetically coupled. At this time, since the winding direction of the power transmission side external connection coil 103 and the power transmission side LC resonance part coil 101 is the same, the power transmission side LC resonator 10 generates a magnetic flux only in one direction.

  Since the power received by the power transmission side LC resonance unit coil 101 magnetically resonates at the same resonance frequency as that of the power reception side LC resonance unit coil 201 that is spaced apart from the opposing position, this power is received.

  Next, the power receiving side LC resonance part coil 201 supplies the received power to the power receiving circuit 202 via the power receiving side external connection coil 203 magnetically coupled. At this time, the winding direction of the power receiving side external connection coil 203 and the power receiving side LC resonance unit coil 201 is the same, and the winding direction of the power receiving side LC resonance unit coil 201 and the power transmission side LC resonance unit coil 101 is opposite. Therefore, a magnetic flux is generated in the power receiving side LC resonator 20 in the direction opposite to that of the power transmitting side LC resonator 10.

  Therefore, the power transmission side LC resonator 10 and the power reception side LC resonator 20 are in opposite phases, and unnecessary radiation of the entire contactless power supply device 1 can be reduced.

  In FIG. 1, the power supply circuit 102 and the power transmission side external connection coil 103 are directly connected, but a circuit for converting impedance between them may be provided. Similarly, the power receiving circuit 202 and the power receiving side external connection coil 203 may be directly connected, or a circuit for converting impedance between them may be used. By passing through the circuit that converts the impedance, it is possible to absorb the power that has not been transmitted and returned to the power supply circuit by reflection and the resistance component of the coil so as not to become unnecessary radiation.

  Next, changes in the resonance frequency when the separation distance between the power transmission side LC resonance unit coil 101 and the power reception side LC resonance unit coil 201 is changed will be described with reference to FIG.

  In FIG. 2, the horizontal axis represents frequency, the vertical axis represents impedance, and the curve represents the frequency characteristics of impedance measured from the power transmission side external connection coil 103 or the power reception side external connection coil 203. 2A to 2D show the frequency characteristics of the impedance when the distance between the power transmission side LC resonator 10 and the power reception side LC resonator 20 gradually approaches from a state where the distance is long.

  FIG. 2A shows a state in which the power transmission side LC resonator 10 and the power reception side LC resonator 20 are sufficiently separated from each other and are not affected by the mutual LC resonators. Thus, in a state where the power transmission side LC resonator 10 and the power reception side LC resonator 20 are sufficiently separated from each other, the product of the coupling coefficient k and the coil Q (Quality Factor) is smaller than 1, and power transmission between the power transmission and reception coils is performed. Is not done enough.

  FIG. 2B shows that the power transmission side LC resonator 10 and the power reception side LC resonator 20 are close to each other, and the power transmission side LC resonator 10 and the power reception side LC resonator 20 are in a critically coupled state. The critical coupling state is a state in which the product of the coil Q and the coupling coefficient k is equal to 1, and it is known that good transmission can be performed.

  Furthermore, when the power transmission side LC resonator 10 and the power reception side LC resonator 20 are brought closer to each other, the resonance frequencies are gradually separated as shown in FIGS.

  2C and 2D show a state where the product of the coil Q and the coupling coefficient k is larger than 1. FIG. That is, when in the state of kQ> 1, the power transmitting / receiving LC resonator has two peaks, a low frequency peak 501 and a high frequency peak 502 centering on the self-resonant frequency indicated by the dotted line. This indicates that they are mutually influenced by the counterpart LC resonator.

  Of these two peak resonance frequencies, when the lower frequency is f1 and the higher frequency is f2, the power supply circuit 102 connected to the power transmission side LC resonator 10 has at least one of f1 and f2. AC power having a frequency component is transmitted to the power transmission side LC resonator 10.

[Example 1]
In the non-contact power feeding apparatus of FIG. 1, the power transmission side LC resonance unit coil 101 and the power reception side LC resonance unit coil 201 are planar coils configured with an inner diameter of 120 mm, an outer diameter of 260 mm, and a number of turns of seven. A 7 pF capacitor was connected. At this time, the winding direction of the power transmission side LC resonance part coil 101 and that of the power reception side LC resonance part coil 103 were reversed.

  As the power transmission side external connection coil 103, a coil having one turn (external connection coil) is on the same plane as the power transmission side LC resonance unit coil 101 and from the inner periphery of the power transmission side LC resonance unit coil 101. It arrange | positioned on the periphery 10 mm away in the winding-axis direction. At this time, the winding direction of the power transmission side external connection coil 103 was made the same as the winding direction of the power transmission side LC resonance coil 101.

  As the power receiving side external connection coil 203, a coil having one turn (external connection coil) is on the same plane as the power receiving side LC resonance unit coil 201 and from the inner periphery of the power reception side LC resonance unit coil 201. It arrange | positioned on the circumference 10 mm away in the winding axis direction. At this time, the winding direction of the power receiving side external connection coil 203 was the same as the winding direction of the power receiving side LC resonance coil 201.

  In this embodiment, the shape of the power transmission / reception side LC resonance part coil or the power transmission / reception side external connection coil is a spiral coil wound in a circular flat shape, but is not limited to this, and is rectangular or polygonal. Or a coil wound in a solenoid shape around a rod-shaped magnetic body or a cylindrical air core.

  In this embodiment, a single copper wire is used as the winding, but a stranded wire or a rectangular wire may be used, or a conductor pattern arranged on a circuit board may be used. The wire type of the winding is not limited to a copper wire, and may be an aluminum wire or an aluminum copper clad wire.

  In addition, the resonance frequencies of the power transmission side LC resonator 10 and the power reception side LC resonator 20 were set to be 12 MHz, respectively. And the separation distance of the power transmission side resonance part coil 101 and the power reception side resonance part coil was 10 cm so that the two peaks 501 and 502 of the resonance frequency shown by FIG.2 (c), (d) may appear.

  For the magnetic field strength (A / m), a loop antenna was used, and the maximum magnetic field strength (A / m) was measured on the circumference of a radius of 3 m from the power transmission side LC resonator 10. That is, the value of the magnetic field strength (A / m) indicates unnecessary radiation around the power transmission side LC resonator 10.

  In the non-contact power supply apparatus configured as described above, the power supply unit impedance (Z) is 0.1Ω to 200Ω, and the power reception unit impedance is in the range of 0.1Ω to 100Ω. FIG. 3 shows the result of measuring the magnetic field strength (unwanted radiation) (A / m) when 10 W of power is transmitted to the power receiving circuit 202.

  FIG. 3A shows the magnetic field strength (A / m) with respect to the impedance of the power receiving unit when power is transmitted / received using the lower resonance frequency f1 of the two peak resonance frequencies. ) Shows the magnetic field strength (A / m) with respect to the power receiving section impedance when power is transmitted and received using the higher resonance frequency f2 of the two peak resonance frequencies.

  As can be seen from the results of FIGS. 3 (a) and 3 (b), the power transmission unit impedance (Z) was low, and the magnetic field strength (A / m) at the power reception unit impedance of about 10Ω was the weakest. The value of the magnetic field strength (A / m) can be regarded as a magnetic flux leaked as unnecessary radiation because the magnetic flux generated in the power transmission side LC resonator 10 and the magnetic flux generated in the power reception side LC resonator 20 cancel each other. At this time, it is understood that the magnetic field strength (A / m) becomes weaker when power is transmitted and received at f2 than at the resonance frequency f1.

[Comparative Example 1]
The winding direction of the power transmission side LC resonance part coil 101 and the power reception side LC resonance part coil 201 is made the same, the winding direction of the power transmission side LC resonance part coil 101 and the power transmission side external connection coil 103 and the power reception side LC resonance part coil 201. In the state where the winding direction of the power receiving side external connection coil 203 is the same, the power transmission unit impedance (Z) is in the range of 0.1Ω to 200Ω and the power reception unit impedance is in the range of 0.1Ω to 100Ω, as in the first embodiment. FIG. 4 shows the result of measuring the magnetic field strength (unwanted radiation) (A / m) when power of 10 W is transmitted from the power supply circuit 102 to the power receiving circuit 202 while changing the impedance value.

  FIG. 4A shows the magnetic field strength (A / m) with respect to the impedance of the power receiving unit when power is transmitted / received using the lower resonance frequency f1 of the two peak resonance frequencies. ) Shows the magnetic field strength (A / m) with respect to the power receiving section impedance when power is transmitted and received using the higher resonance frequency f2 of the two peak resonance frequencies.

In Comparative Example 1, since the winding direction of all the coils is the same, between any of the power transmission side LC resonance unit coil, the power reception side LC resonance unit coil, the power transmission side external connection coil, and the power reception side external connection coil However, there is no relationship that cancels out the magnetic flux.

  Therefore, as compared with Example 1, the magnetic field strength (A / m) is higher regardless of whether the resonance frequency is f1 or f2. However, it is understood that the magnetic field strength (A / m) is weaker when power is transmitted and received at f2 than at the resonance frequency f1 as in the first embodiment.

[Comparative Example 2]
Next, the winding direction of the power transmission side LC resonance part coil 101 and the power reception side LC resonance part coil 201 are made the same, the winding direction of the power transmission side LC resonance part coil 101 and the power transmission side external connection coil 103, and the power reception side LC resonance. In the state where the winding direction of the power coil 201 and the power receiving side external connection coil 203 is opposite, the power transmission impedance (Z) is 0.1Ω to 200Ω and the power reception impedance is 0.1Ω to the same as in the first embodiment. FIG. 5 shows the result of measuring the magnetic field strength (unwanted radiation) (A / m) when 10 W of power is transmitted from the power supply circuit 102 to the power receiving circuit 202 while changing the impedance value in the range of 100Ω.

  FIG. 5A shows the magnetic field strength (A / m) with respect to the power receiving unit impedance when power is transmitted and received using the lower resonance frequency f1 of the two peak resonance frequencies. ) Shows the magnetic field strength (A / m) with respect to the power receiving section impedance when power is transmitted and received using the higher resonance frequency f2 of the two peak resonance frequencies.

  In Comparative Example 2, the power transmission side LC resonance coil 101 and the power reception side LC resonance coil have the same winding direction, and the power transmission side external connection coil 103 and the power reception side external connection coil 203 are both power transmission / reception LC resonance part coils. The winding direction is the opposite of. In other words, since the winding direction of the power transmission / reception LC resonance part coil and the power transmission / reception external connection coil is opposite, the magnetic flux generated in both is partially canceled, but the magnetic flux that is not canceled becomes unnecessary radiation. It is thought that it leaks.

  Compared to Example 1, the magnetic field strength (A / m) is higher in both cases where the resonance frequency is f1 or f2 as in Comparative Example 1. However, it is understood that the magnetic field strength (A / m) is weaker when power is transmitted and received at f2 than at the resonance frequency f1 as in the first embodiment.

[Comparative Example 3]
The winding direction of the power transmission side LC resonance unit coil and the power reception side LC resonance unit coil are reversed, and the winding direction of the power transmission side LC resonance unit coil and the power transmission side external connection coil is the same, the power reception side LC resonance unit coil and the power reception side In the state where the winding direction of the external connection coil is reversed, the magnetic field strength (unnecessary radiation) when power of 10 W is transmitted from the power supply circuit 102 to the power receiving circuit 202 while changing the impedance value as in the first embodiment. ) (A / m) is shown in FIG.

  FIG. 6A shows the magnetic field strength (A / m) with respect to the impedance of the power receiving unit when power is transmitted / received using the lower resonance frequency f1 of the two peak resonance frequencies. ) Shows the magnetic field strength (A / m) with respect to the power receiving section impedance when power is transmitted and received using the higher resonance frequency f2 of the two peak resonance frequencies.

  In Comparative Example 3, the winding direction of the power transmission LC resonance unit coil 101, the power transmission external connection coil 103, and the power reception side external connection coil 203 is the same, and only the winding direction of the power reception side LC resonance unit coil 201 is reversed. Therefore, although the magnetic fluxes generated in both directions are partially canceled, it is considered that the magnetic flux that is not canceled leaks as unnecessary radiation.

  Compared with Example 1, the magnetic field strength (A / m) is higher in both cases where the resonance frequency is f1 or f2, as in Comparative Examples 1 and 2. However, it is understood that the magnetic field strength (A / m) is weaker when power is transmitted and received at f2 than at the resonance frequency f1 as in the first embodiment. As described with reference to FIG. 3, when power transmission / reception between the power transmission side LC resonator 10 and the power reception side LC resonator is performed at a distance where two resonance frequency peaks appear, f2 having a high resonance frequency is used. This shows that the effect of the present invention can be obtained more.

  In this way, by controlling the winding direction of the power transmission side LC resonance unit coil, the power reception side LC resonance unit coil, and each external connection coil, the effect of canceling the generated magnetic flux can be obtained, and unnecessary radiation can be reduced. The

  As described above, the non-contact power supply device according to the present invention can be used regardless of a low-power product or a high-power product, power supply to an electric vehicle or a hybrid vehicle, a mobile phone, a mobile phone, a portable information device, a home appliance, It is useful for power supply to drive systems such as machine tools, industrial transfer equipment, machine tools, and large-sized moving vehicles, and power supply between vehicles.

DESCRIPTION OF SYMBOLS 10 Power transmission side LC resonator 11 Power transmission side LC resonance part 20 Power reception side LC resonator 21 Power reception side LC resonance part 101 Power transmission side LC resonance part coil 102 Power supply circuit 103 Power transmission side external connection coil 201 Power reception side LC resonance part coil 202 Power reception circuit 203 Power receiving side external connection coil

Claims (1)

A power circuit;
A power transmission side external connection coil to which power supplied from the power supply circuit is transmitted;
A power transmission side LC resonance part coil magnetically coupled to the power transmission side external connection coil;
A power receiving side LC resonance unit coil that is arranged opposite to the power transmission side LC resonance unit coil and transmits the power;
A power receiving side external connection coil magnetically coupled to the power receiving side LC resonance unit;
A power receiving circuit through which the power is transmitted via the power receiving side external connection coil,
Winding directions of the power transmission side LC resonance part coil and the power reception side LC resonance part coil are opposite,
The winding direction of the power transmission side LC resonance part coil and the power transmission side external connection coil is the same,
The non-contact power feeding device, wherein a winding direction of the power receiving side LC resonance part coil and the power receiving side external connection coil is the same.

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