JP2012038887A - Power transmission coil, and non-contact power transmission and communication system using power transmission coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission coil, and a non-contact power transmission device and a communication system using the power transmission coil which is comprised of a loop coil or spiral coil suitable for small packaging, and capable of suppressing radiation of harmonics of an operation frequency and frequency components other than the operation frequency.SOLUTION: A power transmission coil includes a basic coil part 100 which is a spiral-shaped coil formed on a plane substrate 102, and a tip open stub 101. The basic coil part 100 is provided with an input connection part 104 for inputting electric power from a power transmission device, and an output connection part 105 for outputting electric power. The tip open stub 101 is connected, with its one end, to a stub connection part 103 in the proximity of the input connection part 104 of the basic coil part 100, and comprised of a linear conductor placed along the inside of the basic coil part 100.

Description

  The present invention comprises a power receiving device provided in a portable electronic device or the like and a power transmitting device provided in a power feeding device or the like. Between the two devices and the function of transmitting electric power from the power transmitting device to the power receiving device by electromagnetic induction. The present invention relates to a power transmission coil used in a non-contact power transmission and communication system having a function of performing non-contact data communication, and a non-contact power transmission and communication system using the power transmission coil.

  In recent years, with the miniaturization of electronic components, portable electronic devices typified by mobile phones and portable music players have been widely spread due to the reduction in size and weight. Generally, charging a secondary battery or a capacitor built in a portable electronic device is performed by bringing the charging terminal of the portable electronic device into contact with the charging terminal installed on the charging stand (cradle) of the charging device. In other words, the secondary battery or the capacitor of the portable electronic device is charged by supplying power from a charging stand.

  However, in the charging method in which the charging terminals are connected in contact with each other, charging may not be possible due to dirt on the charging terminals or intrusion of foreign matter between the charging terminals, so recently contactless power using the principle of electromagnetic induction Many supply systems are used, and the demand for non-contact power transmission devices used therefor is increasing. In a non-contact power transmission device, generally, a power transmission coil of a power transmission device and a power reception coil of a power reception device are arranged in close proximity to each other, and power is transmitted via electromagnetic coupling between the power transmission coil and the power reception coil. It is. Further, non-contact power transmission and communication having a function of communicating the required power on the power receiving side, data indicating stoppage of power transmission in the event of abnormality, data such as ID authentication between power transmitting and receiving devices via the power transmitting coil and the power receiving coil A system has been developed.

  In such a system, a loop coil or a spiral coil is suitable as a power transmission coil and a power reception coil for compact mounting. However, in general, when power is transmitted using a loop coil or spiral coil, the current flowing through the power transmission coil may include harmonic components of the power transmission frequency and other frequency components generated in the power transmission circuit. The electromagnetic radiation noise of the frequency will occur. Therefore, in order to perform stable power supply and communication, a power transmission coil consisting of a loop coil and a spiral coil that suppresses the generation of radiation noise is realized, and signals of frequency components other than the system operating frequency are radiated from the power transmission coil. It is necessary to suppress as much as possible.

  Conventionally, there is a method using a stub as means for suppressing propagation of a signal having a specific frequency component. For example, Patent Document 1 discloses a means for taking measures against interference by providing a tip open stub (open stub) at a signal input / output end in a wireless communication apparatus using a coil as an antenna. FIG. 14 is a configuration explanatory view showing an RFID tag as a wireless communication device using a conventional coil described in Patent Document 1 as an antenna. According to this, this wireless communication device is a wireless communication device corresponding to signals in two frequency bands, and operates as an antenna with an induction electromagnetic field in a low frequency band and connected to the IC chip 208, and has a high frequency. It has two antennas, an antenna 206 that operates in the band electromagnetic field and is connected to the IC chip 207. Then, by installing an open stub 201 at the input / output terminal of the IC chip 208 connected to the coil 200 that operates in the induction electromagnetic field, a structure that suppresses interference from the antenna 206 that operates in the radiation electromagnetic field is realized. Degradation of communication performance is reduced.

  In addition, as another conventional structure combining an open stub and an antenna, a method of installing an open stub for matching has been reported. For example, Patent Document 2 discloses a structure in which an open stub is provided on an antenna used in a vehicle-mounted wireless communication device to perform impedance matching of the antenna. FIG. 15 is an explanatory diagram three-dimensionally showing the structure of the antenna and the matching stub described in Patent Document 2. As shown in FIG. According to this, the reflection of the signal propagating through the linear antenna does not occur at the boundary between the two linear antennas 300 arranged on the front surface of the substrate and the connection line 309 arranged on the back surface and connecting them. In addition, impedance matching is performed by a matching stub 301 provided at the boundary.

JP 2009-288874 A JP 2009-100445 A

  In the conventional example of Patent Document 1, when two types of antennas that are integrated and operate in different frequency bands are used, an open-ended stub is provided at an input / output terminal for a coil antenna that operates in a low frequency band. Measures against electromagnetic interference for frequency signals. Further, in the conventional example of Patent Document 2, impedance matching of the connection line at the boundary of the antenna connection portion is performed by the open end stub. However, as described above, in non-contact power transmission and communication systems, it is required to suppress as much as possible the emission of frequency components other than the operating frequency of the system from the power transmission coil. This technology cannot be applied as it is.

  Accordingly, an object of the present invention is a power transmission coil that includes a loop coil or a spiral coil suitable for small packaging, and that can suppress the emission of harmonic components of the operating frequency and frequency components other than the operating frequency, and the same. A contactless power transmission device and a communication system are provided.

  In order to solve the above problems, a power transmission coil according to the present invention includes a power transmission device including a power transmission coil and a power transmission circuit for supplying power to the power transmission coil, and a power reception coil including a power reception coil that can be electromagnetically coupled to the power transmission coil. A power transmission coil used in a non-contact power transmission and communication system that performs non-contact power transmission and communication via electromagnetic coupling between the power transmission coil and the power reception coil, and has a loop shape or a spiral shape And a tip open stub made of a linear conductor disposed along at least one of the coils, the tip open stub having one end connected to a part of the coil. And

  Here, the conductor has a frequency of 30 MHz or more and 1000 MHz or less and a quarter of the wavelength corresponding to at least one frequency of an electric signal or its harmonic component generated in at least a part of the power transmission circuit. It is desirable that the length be.

  Further, the coil and the open end stub are formed on the surface or inside of a substrate mainly made of a magnetic material, a substrate made mainly of a dielectric, or a substrate made mainly of a magnetic material and a dielectric. It may be formed.

  Further, the substrate may be a multilayer substrate in which conductor layers are arranged in a multilayer shape, and at least a part of the open end stub may be formed in a conductor layer different from the conductor layer in which the coil is formed. .

  A non-contact power transmission and communication system according to the present invention is characterized by using any one of the above-described power transmission coils.

  As described above, the power transmission coil of the present invention is a loop-shaped or spiral-shaped coil having a tip-open stub connected to a part of the coil, and a signal of a harmonic component of an operating frequency or other desired frequency component. Is removed by the open-end stub, so that a countermeasure against electromagnetic interference is applied to the power transmission coil to prevent generation of unnecessary radiation noise from the power transmission coil.

  That is, in the power transmission coil of the present invention and the non-contact power transmission and communication system using the same, the desired frequency that interferes with the system while maintaining the original power transmission operation and communication operation at the operation frequency of the power transmission coil. It is possible to set a stop band to In addition, since the frequency which becomes this interference exists between 30 or more and 1000 MHz or less in normal non-contact electric power transmission and a communication system, this invention blocks the interference wave.

  According to the power transmission coil and the non-contact power transmission and communication system using the power transmission coil of the present invention, it is possible to reduce the power supplied to the power transmission coil by setting the stop band to a desired frequency.

  Further, in the power transmission coil of the present invention, since the open end stub is arranged along the coil pattern of the power transmission coil, it is possible to provide a miniaturized harmonic suppression type power transmission coil without increasing the overall shape of the power transmission coil. Is possible.

  Moreover, in the power transmission coil of the present invention, a plurality of open end stubs having different lengths can be arranged, so that a plurality of stop bands can be set.

  Therefore, according to the present invention, a power transmission coil comprising a loop coil or a spiral coil suitable for small mounting and capable of suppressing radiation of harmonic components of the operating frequency and frequency components other than the operating frequency, and non-contact using the same It is possible to provide power transmission and a communication system.

The top view explaining 1st Embodiment of the power transmission coil by this invention. The perspective view explaining 1st Embodiment of the power transmission coil by this invention. The figure which shows the permeation | transmission characteristic of the Example of the power transmission coil of 1st Embodiment. The figure which shows the reflective characteristic of the Example of the power transmission coil of 1st Embodiment. The top view explaining 2nd Embodiment of the power transmission coil by this invention. The top view explaining 3rd Embodiment of the power transmission coil by this invention. The top view explaining 4th Embodiment of the power transmission coil by this invention. The top view explaining 5th Embodiment of the power transmission coil by this invention. The top view explaining 6th Embodiment of the power transmission coil by this invention. The top view explaining 7th Embodiment of the power transmission coil by this invention. The perspective view explaining 8th Embodiment of the power transmission coil by this invention. The perspective view explaining 9th Embodiment of the power transmission coil by this invention. The perspective view explaining 10th Embodiment of the power transmission coil by this invention. Structure explanatory drawing which shows the radio | wireless communication apparatus which used the conventional coil as an antenna. Explanatory drawing which shows the structure of the conventional antenna and the matching stub three-dimensionally.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a plan view for explaining a first embodiment of a power transmission coil according to the present invention, and FIG. 2 is a perspective view for explaining a first embodiment of a power transmission coil according to the present invention. The power transmission coil of the present embodiment includes a power transmission device having a power transmission coil and a power transmission circuit for supplying power to the power transmission coil, and a power reception device having a power reception coil that can be electromagnetically coupled to the power transmission coil. It is a power transmission coil used for non-contact power transmission and a communication system which performs power transmission and communication in a non-contact manner through electromagnetic coupling between a power transmission coil and the power receiving coil. 1 and 2, the power transmission coil of the present embodiment includes a basic coil unit 100 that is a spiral coil formed on a flat substrate 102 and one open-end stub 101. The basic coil unit 100 is provided with an input connection unit 104 that inputs power from the power transmission device and an output connection unit 105 that outputs power. The open-ended stub 101 is a stub adjacent to the input connection unit 104 of the basic coil unit 100. One end of the connecting portion 103 is connected, and the connecting portion 103 is made of a linear conductor disposed along the inner side of the basic coil portion 100.

  Next, in order to confirm the effect of this invention, the result of having designed and evaluated one specific example of the power transmission coil of 1st Embodiment is demonstrated. The basic coil portion 100 of the power transmission coil of the present embodiment has an overall outer shape of 20 mm × 40 mm, a coil pattern width of 0.5 mm, a coil pattern interval of 1.5 mm, and a winding number of 4 turns, and an operating frequency of 13.56 MHz. The power transmission coil is assumed to be

  As the planar substrate 102, a dielectric substrate (FR-4) having a shape of 22 mm × 42 mm × 0.27 mm is used, and a copper foil having a thickness of 0.016 mm is used as a ground plane on the back surface of the substrate.

  The open end stub 101 having a width of 0.5 mm is connected from the stub connection portion 103 near the input connection portion 104 by the same conductor on the same plane as the basic coil portion 100 described above.

  In this embodiment, three kinds of lengths of the open end stub 101 are used. That is, due to the wavelength shortening effect due to the dielectric constant of the planar substrate 102, the electrical length is 340 mm long with a quarter wavelength at a frequency of 100 MHz, 200 mm long with a quarter wavelength at 180 MHz, and 450 MHz. Three types with a length of 80 mm that would be λ / 4 were used. For comparison, a conventional power transmission coil having no open end stub was also evaluated.

  In the power transmission coil designed as described above, the electromagnetic field simulation of the transmission characteristic S21 and the reflection characteristic S11 was performed from the observation voltage at the input connection unit 104 and the output connection unit 105. The result of the transmission characteristic is shown in FIG. 3, and the result of the reflection characteristic is shown in FIG. FIG. 3 is a diagram illustrating the transmission characteristics of an example of the power transmission coil according to the first embodiment. FIG. 4 is a diagram illustrating the reflection characteristics of an example of the power transmission coil according to the first embodiment. As shown in FIG. 3 and FIG. 4, it can be confirmed that the conventional power transmission coil has no reflection in all frequency bands from 10 MHz to 1000 MHz and transmits all. On the other hand, in the power transmission coil of the present embodiment, due to the effect of the open end stub 101, transmission is reduced and reflection is increased at an odd multiple of the frequency at which the electrical length of the open end stub 101 corresponds to ¼ wavelength. It can be confirmed that a stop band is generated. In addition, at an operating frequency of 13.56 MHz, transmission of −0.1 dB or more and reflection of −20 dB or less are obtained, and it can be confirmed that the transmission line has a very small reflection characteristic.

  From the above, by using the power transmission coil of the present embodiment, it operates as a normal power transmission coil with a small reflection at the operating frequency of 13.56 MHz, and a large reflection in the stop band caused by the effect of the open-end stub 101. Thus, it was confirmed that no current flows through the power transmission coil section, and that it is possible to suppress harmonic radiation noise generated from the coil section.

  As described above, according to the present invention, a power transmission coil in which harmonic radiation noise is reduced is obtained, and by using this power transmission coil, a non-contact power transmission and communication system capable of performing stable power supply and communication are provided. can get.

  FIG. 5 is a plan view for explaining a second embodiment of the power transmission coil according to the present invention. In the first embodiment, the tip open stub is connected from the vicinity of the input connection portion 104. In this embodiment, the tip open stub 111 is connected to the stub in the vicinity of the output connection portion 105 as shown in FIG. One end of the portion 113 is connected and arranged along the inside of the basic coil portion 100. Other configurations are the same as those of the first embodiment. By adopting such a configuration, it is possible to reflect load fluctuations in an unnecessary frequency band, a backflow of electric signals, and the like by the output connection unit 105, and to suppress harmonic radiation noise generated from the coil unit.

  FIG. 6 is a plan view for explaining a third embodiment of the power transmission coil according to the present invention. In the first embodiment, the tip open stub 121 is connected from the vicinity of the input connection portion 104 and is disposed along the inner side of the basic coil portion 100. However, in this embodiment, the tip open stub 121 is the basic coil. It is arranged along the outside of the part 100 and connected at the stub connection part 123 near the input connection part 104. Other configurations are the same as those of the first embodiment.

  FIG. 7 is a plan view for explaining a fourth embodiment of the power transmission coil according to the present invention. In the first embodiment, only one open end stub is arranged. However, in the present embodiment, the open end stub 131 connected from the stub connection portion 133 near the input connection portion 104 and the output connection portion are provided. Two open end stubs are connected to the open end stub 135 connected from the stub connecting part 134 in the vicinity of 105. These two open end stubs are arranged along the inner side of the basic coil unit 100. Other configurations are the same as those of the first embodiment. In this way, a plurality of open end stubs may be arranged. By adopting such a configuration, load fluctuations and electrical signals in unnecessary frequency bands are reflected by both the input connection unit 104 and the output connection unit 105, and harmonic radiation noise generated from the coil unit is suppressed. Can do.

  FIG. 8 is a plan view for explaining a fifth embodiment of the power transmission coil according to the present invention. In the present embodiment, the open-ended stub 141 connected from the stub connection part 143 near the input connection part 104 and disposed along the inner side of the basic coil part 100, and the basic coil part 100 connected from the stub connection part 143 are connected. It has two tip open stubs with tip open stubs 145 arranged along the outside. Other configurations are the same as those of the first embodiment. With such a configuration, two open-end stubs can be connected, so that the reflection performance of unnecessary signals can be improved.

  FIG. 9 is a plan view for explaining a sixth embodiment of the power transmission coil according to the present invention. In the present embodiment, the tip open stub 151 connected from the stub connection part 153 near the output connection part 105 of the basic coil part 100 and disposed along the inner side of the basic coil part 100 is connected from the stub connection part 153. It has two tip open stubs with a tip open stub 155 arranged along the outside of the basic coil unit 100. Other configurations are the same as those of the first embodiment.

  FIG. 10 is a plan view for explaining a seventh embodiment of the power transmission coil according to the present invention. In the present embodiment, the open-ended stub 161 connected from the stub connection part 163 near the input connection part 104 and disposed along the inner side of the basic coil part 100, and the basic coil part 100 connected from the stub connection part 163 are connected. It has two tip open stubs with a tip open stub 165 arranged along the outside. Other configurations are the same as those of the first embodiment. In the fifth embodiment, a configuration is shown in which the lengths of the plurality of tip-opening stubs are the same, but in this embodiment, as shown in FIG. 10, the tip-opening stub 161 and the tip-opening stub are shown. At 165, the length is different. In this way, a plurality of open end stubs having different lengths may be arranged. By adopting such a configuration, two open end stubs having different lengths can be connected to each other, so that it is possible to cope with a case where there are many unnecessary signal frequencies.

  FIG. 11 is a perspective view for explaining an eighth embodiment of a power transmission coil according to the present invention. In the present embodiment, the flat substrate 107 is a substrate in which a conductor layer is disposed on the front surface and the back surface, and the open end stub 171 is a conductor on the back surface different from the surface conductor layer on which the basic coil unit 100 is formed. Formed in layers. The tip open stub 171 is connected from the stub connection part 173 near the input connection part 104 and pulled out to the back surface, and is arranged along the basic coil part 100 on the front surface. Other configurations are the same as those of the first embodiment. In this way, the open end stub may be disposed on the back surface of the flat substrate 107. By adopting such a configuration, the distance between the conductors of the basic coil unit 100 and the open-ended stub 171 can be reduced. Therefore, when other parts are arranged in the center of the power transmission coil, the basic coil unit 100 In addition, it is desirable because a distance between the open end stub 171 and other parts can be increased to prevent electromagnetic influence.

  FIG. 12 is a perspective view for explaining a ninth embodiment of a power transmission coil according to the present invention. In the present embodiment, the planar substrate 107 is a substrate in which a conductor layer is disposed on the front surface and the back surface, and is connected from the stub connection portion 183 near the input connection portion 104 and is a basic coil on the same plane as the basic coil portion 100. There are two tip open stubs, a tip open stub 181 arranged along the outside of the portion 100 and a tip open stub 185 connected to the stub connection part 184 drawn out on the back surface and formed on the back surface. Other configurations are the same as those of the first embodiment.

  FIG. 13 is a perspective view for explaining a tenth embodiment of a power transmission coil according to the present invention. In the present embodiment, the planar substrate 108 is a multilayer substrate in which conductor layers are disposed on the front surface, the back surface, and the inside, and is connected from the stub connection portion 193 near the input connection portion 104 of the basic coil portion 100. 100 is connected to the open end stub 191 arranged along the inner side of the basic coil unit 100 on the same plane as the 100 and the stub connection part 194 drawn from the vicinity of the input connection part 104 to the inner layer surface and the back surface, and arranged on the inner layer surface. The front end open stub 195 and the front end open stub 196 connected from the stub connecting portion 194 and formed on the back surface are provided. Other configurations are the same as those of the first embodiment. As described above, a multilayer substrate in which conductor layers are arranged in a multilayer shape as a planar substrate may be used, and a part or all of the open-ended stub may be formed on a conductor layer different from the conductor layer on which the basic coil portion is formed. Good. With such a configuration, a plurality of open end stubs having different lengths can be connected to each other, so that it is possible to cope with a case where the frequency of unnecessary signals is very large.

  In each of the above embodiments, as the planar substrates 102, 107, 108, a dielectric substrate such as an FPC or FR-4 substrate or a magnetic substrate such as ferrite can be used, and the system operating frequency is low. It is desirable to be composed of a material that is a loss. Moreover, you may comprise with the composite material which combined the dielectric material which has several different material constants, or a magnetic body.

  Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments and examples, and there are design changes that do not depart from the gist of the present invention. Is included in the present invention. That is, various changes and modifications that can be naturally made by those skilled in the art are also included in the present invention.

  The power transmission coil, contactless power transmission, and communication system of the present invention can be used for mobile terminal devices such as mobile phones, digital cameras, headsets, digital videos, game controller devices, and charging devices thereof. Moreover, it is applicable also to the apparatus which requires large electric power, such as a motor vehicle, and its charging device.

100 Basic coil section
101, 111, 121, 131, 135, 141, 145, 151, 155, 161, 165, 171, 181, 185, 191, 195, 196 Open end stub
102, 107, 108 Planar substrate
103, 113, 123, 133, 134, 143, 153, 163, 173, 183, 184, 193, 194 Stub connection
104 Input connection
105 Output connection
200 coils
201 Open stub
206 Antenna
207, 208 IC chip
300 linear antenna
301 Stub for alignment
309 connection line

Claims (5)

  A power transmission device having a power transmission coil and a power transmission circuit for supplying power to the power transmission coil; and a power reception device having a power reception coil that can be electromagnetically coupled to the power transmission coil, and an electromagnetic wave between the power transmission coil and the power reception coil. A power transmission coil used in a non-contact power transmission and communication system that performs non-contact power transmission and communication through coupling, and is arranged along a loop-shaped or spiral-shaped coil and at least one of the coils A power transmission coil comprising: a tip open stub made of a linear conductor, the tip open stub having one end connected to a part of the coil.   The frequency of 30 MHz or more and 1000 MHz or less and a quarter of the wavelength corresponding to the frequency of at least one of the electric signal or its harmonic component generated in at least a part of the power transmission circuit is defined as the length of the conductor. The power transmission coil according to claim 1, wherein:   The coil and the open-end stub are formed on the surface or inside of a substrate made mainly of a magnetic material, a substrate made mainly of a dielectric, or a substrate made mainly of a magnetic material and a dielectric. The power transmission coil according to claim 1, wherein the power transmission coil is provided.   The substrate is a multilayer substrate in which conductor layers are arranged in a multilayer shape, and at least a part of the tip open stub is formed in a conductor layer different from the conductor layer in which the coil is formed. The power transmission coil according to claim 3.   A non-contact power transmission and communication system using the power transmission coil according to any one of claims 1 to 4.

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