JP2014197932A - Power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission system which suppresses generation of noise and reduces leakage of noise.SOLUTION: A power transmission system transmits electric energy to a secondary resonator 250 including a secondary resonator coil 260 through an electromagnetic field having a predetermined frequency generated by a primary resonator 150 including a primary resonator coil 160, where the primary resonator coil 160 is arranged on the ground and the secondary resonator coil 260 is arranged on the bottom surface of a vehicle. The power transmission system comprises a noise cancel resonator 300 which includes a noise cancel resonator coil 310 and has a resonant frequency higher than the predetermined frequency by a shift frequency determined depending on the degree of coupling between the primary resonator coil 160 and the noise cancel resonator coil 310. The noise cancel resonator coil 310 is arranged at a position where the distance between the secondary resonator coil 260 and circumference of the vehicle is short.

Description

  The present invention relates to a power transmission system that transmits and receives power wirelessly by a magnetic resonance method.

  In recent years, development of technology for transmitting electric power (electric energy) wirelessly without using a power cord or the like has become active. Among wireless transmission methods, there is a technique called magnetic resonance as a technology that has attracted particular attention. This magnetic resonance method was proposed by a research group of Massachusetts Institute of Technology in 2007, and a technology related to this is disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-501510.

  A magnetic resonance wireless power transmission system efficiently transmits energy from a power transmission side antenna to a power reception side antenna by making the resonance frequency of the power transmission side antenna and the resonance frequency of the power reception side antenna the same. One of the major features is that the power transmission distance can be several tens of centimeters to several meters.

  When such a magnetic resonance wireless power transmission system is used in a power supply station of a vehicle such as an electric vehicle, a power receiving antenna is mounted on the bottom of the vehicle, and the power receiving antenna is connected to the power receiving antenna. A method of feeding power from a power transmission antenna embedded on the ground can be considered. In such a power transmission mode, it is difficult to completely electromagnetically couple between the power transmission side antenna and the power reception side antenna, and noise emitted from the antenna is generated. This may cause a temperature rise.

  Therefore, in the wireless power transmission system, it is necessary to consider a measure for reducing noise generated from the antenna.

As a technique for reducing high-frequency noise, for example, Patent Document 2 (Japanese Patent Laid-Open No. 2010-87024) discloses a conductor having a loop-shaped closed path, a closed path, and an electric circuit in the vicinity of a noise generation source. It is disclosed to provide a resonant circuit composed of a capacitor that is connected electrically.
Special table 2009-501510 JP 2010-87024 A

  In the prior art described in Patent Document 2, the noise reduction effect is increased by combining the resonance frequency of the LC resonator for noise cancellation with the frequency of the noise source to be removed.

  However, even if the resonance frequency of the noise canceling resonator is combined with the frequency of the noise source as a noise countermeasure particularly in a wireless power transmission system using a magnetic resonance type magnetic resonance antenna, the noise reduction effect is not necessarily large. There was no problem.

Further, the prior art described in Patent Document 2 has been a problem because there is no disclosure about the optimal arrangement of the noise canceling resonator.

  In order to solve the above problem, a power transmission system according to the present invention has a secondary resonance coil having a secondary resonator coil via an electromagnetic field having a predetermined frequency generated by the primary resonator having the primary resonator coil. An electrical energy is transmitted to the device, the primary resonator coil is disposed on the ground, and the secondary resonator coil is a power transmission system disposed on a bottom surface of the vehicle, and includes a noise canceling resonator coil, A noise canceling resonator having a resonance frequency higher than the predetermined frequency by a shift frequency determined in accordance with a degree of coupling between the primary resonator coil and the noise canceling resonator coil; It is characterized in that the distance between the next resonator coil and the periphery of the vehicle is short.

  The power transmission system according to the present invention transmits electrical energy to a secondary resonator having a secondary resonator coil via an electromagnetic field having a predetermined frequency generated by the primary resonator having the primary resonator coil. The power transmission system includes a noise canceling resonator coil, and has a resonance frequency higher than the predetermined frequency by a shift frequency determined according to a degree of coupling between the secondary resonator coil and the noise canceling resonator coil. A noise canceling resonator is provided, and the noise canceling resonator coil is disposed at a location where the distance between the secondary resonator coil and the periphery of the vehicle is short.

  In the power transmission system according to the present invention, the predetermined frequency is a frequency of a fundamental wave of an electromagnetic field generated by the primary resonator.

  In the power transmission system according to the present invention, the predetermined frequency is a harmonic frequency of an electromagnetic field generated by the primary resonator.

  The power transmission system according to the present invention is characterized in that the harmonics are odd harmonics.

  The power transmission system according to the present invention is characterized in that the harmonics are even harmonics.

In the power transmission system according to the present invention, when a mutual inductance component between the primary resonator coil and the noise canceling resonator coil is L _m ,
The shift frequency is

であることを特徴とする。

It is characterized by being.

  The power transmission system according to the present invention is characterized in that a Q value of the noise canceling resonator coil is 50 or more.

The power transmission system according to the present invention includes a noise canceling resonator coil, and has a resonance frequency that is higher than the predetermined frequency by a shift frequency determined according to the degree of coupling between the primary resonator coil and the noise canceling resonator coil. In addition, the noise canceling resonator coil of the noise canceling resonator is disposed at an optimal position. Therefore, according to the present invention, wireless power transmission using a magnetic resonance type magnetic resonance antenna in particular is used. It is possible to suppress noise generation in the system and reduce noise leakage.

1 is a block diagram of a power transmission system according to an embodiment of the present invention. It is a figure which shows the inverter part of an electric power transmission system. It is a figure which shows the equivalent circuit of the electric power transmission system 100 which concerns on embodiment of this invention. It is a figure explaining the installation form of the primary resonator and the secondary resonator in the electric power transmission system which concerns on embodiment of this invention. It is a figure explaining the layout of a primary resonator coil and a secondary resonator coil. It is a figure explaining the coupling between the noise cancellation resonator which concerns on embodiment of this invention, and the primary resonator which is a noise source. It is a figure which superimposes and shows the figure of the frequency dependence of transmission efficiency, and the frequency dependence of noise emissivity. It is a figure which shows typically the mode of the electric current and electric field in a 1st extreme value frequency (frequency at the time of a magnetic wall condition coupling | bonding). It is a figure which shows typically the mode of the electric current and electric field in a 2nd extreme value frequency (frequency at the time of an electric wall condition coupling | bonding). It is a conceptual diagram explaining that noise reduction efficiency improves with a noise cancellation resonator. It is a figure explaining the example of a layout of a noise cancellation resonator coil.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a power transmission system according to an embodiment of the present invention. In the present embodiment, an example will be described in which the primary resonator 150 is used as a power transmission-side antenna and a secondary resonator 250 is used as a power-receiving antenna.

  As a power transmission system using the antenna of the present invention, for example, a system for charging a vehicle such as an electric vehicle (EV) or a hybrid electric vehicle (HEV) is assumed. Since the electric power transmission system transmits electric power to the vehicle as described above in a non-contact manner, the electric power transmission system is provided in a stop space where the vehicle can be stopped. The user of the vehicle stops the vehicle in a stop space where the power transmission system is provided, and makes the secondary resonator 250 mounted on the vehicle and the primary resonator 150 face each other, thereby causing the power transmission system. Receives power from.

  In the power transmission system, when power is efficiently transmitted from the primary resonator 150 on the power transmission system 100 side to the secondary resonator 250 on the power receiving system 200 side, the resonance frequency of the primary resonator 150, 2 By making the resonance frequency of the next resonator 250 the same, energy is efficiently transferred from the power transmission side antenna to the power reception side antenna.

  The AC / DC conversion unit 101 in the power transmission system 100 is a converter that converts an input commercial power source into a constant direct current. The output from the AC / DC converter 101 is boosted to a predetermined voltage by the voltage controller 102. Setting of the voltage generated by the voltage control unit 102 can be controlled from the main control unit 110.

The inverter unit 103 generates a predetermined AC voltage from the voltage supplied from the voltage control unit 102 and inputs it to the matching unit 104. FIG. 2 is a diagram illustrating an inverter unit of the power transmission system. For example, as shown in FIG. 2, the inverter unit 103 includes four field effect transistors (FETs) composed of Q _{A to} Q _D connected in a full bridge system.

In the present embodiment, between the connection portion T1 between the switching elements Q _A and Q _B connected in series and the connection portion T2 between the switching elements Q _C and Q _D connected in series. The matching device 104 is connected to the switching element Q _A.
When the switching element Q _D is on, the switching element Q _B and the switching element Q _C are off. When the switching element Q _B and the switching element Q _C are on, the switching element Q _A and the switching element Q _D are off. As a result, a rectangular wave AC voltage is generated between the connection portion T1 and the connection portion T2. In the present embodiment, the range of the frequency of the rectangular wave generated by the switching of each switching element is about 20 kHz to several 1000 kHz.

Drive signals for the switching elements Q _{A to} Q _D constituting the inverter unit 103 as described above are input from the main control unit 110. The frequency for driving the inverter unit 103 can be controlled from the main control unit 110.

  The matching unit 104 is composed of a passive element having a predetermined circuit constant, and receives an output from the inverter unit 103. The output from the matching unit 104 is supplied to the primary resonator 150. The circuit constants of the passive elements constituting the matching unit 104 can be adjusted based on a command from the main control unit 110. The main control unit 110 instructs the matching unit 104 so that the primary resonator 150 and the secondary resonator 250 resonate. The matching unit 104 is not an essential configuration.

  The primary resonator 150 includes a primary resonator coil 160 having an inductive reactance component and a primary resonator capacitor 170 having a capacitive reactance component, and is mounted on the vehicle so as to face each other. By resonating with the secondary resonator 250, the electrical energy output from the primary resonator 150 can be sent to the secondary resonator 250. The primary resonator 150 and the secondary resonator 250 function as a magnetic resonance antenna unit in the power transmission system 100.

  The main control unit 110 of the power transmission system 100 is a general-purpose information processing unit that includes a CPU, a ROM that holds a program that runs on the CPU, and a RAM that is a work area of the CPU. The main control unit 110 operates in cooperation with the components connected to the main control unit 110 shown in the figure.

  The communication unit 120 is configured to perform wireless communication with the vehicle-side communication unit 220 so that data can be transmitted to and received from the vehicle. Data received by the communication unit 120 is transferred to the main control unit 110, and the main control unit 110 can transmit predetermined information to the vehicle side via the communication unit 120.

  Next, a configuration provided on the vehicle side will be described. In the system on the power receiving side of the vehicle, the secondary resonator 250 receives electric energy output from the primary resonator 150 by resonating with the primary resonator 150. Such a secondary resonator 250 is attached to the bottom surface of the vehicle.

  The secondary resonator 250 includes a secondary resonator coil 260 having an inductive reactance component and a secondary resonator capacitor 270 having a capacitive reactance component.

  The AC power received by the secondary resonator 250 is rectified by the rectification unit 202, and the rectified power is stored in the battery 204 through the charge control unit 203. The charging control unit 203 controls the storage of the battery 204 based on a command from the main control unit 210. More specifically, the output from the rectifying unit 202 is stepped up or down to a predetermined voltage value in the charge control unit 203 and stored in the battery 204. In addition, the charging control unit 203 is configured to be able to perform remaining amount management of the battery 204 and the like.

  The main control unit 210 is a general-purpose information processing unit that includes a CPU, a ROM that holds programs that run on the CPU, and a RAM that is a work area of the CPU. The main controller 210 operates in cooperation with the components connected to the main controller 210 shown in the figure.

  The interface unit 215 is provided in the driver's seat of the vehicle and provides predetermined information to the user (driver) or accepts an operation / input from the user. A touch panel, a speaker, and the like. When a predetermined operation by the user is executed, the interface unit 215 sends the operation data to the main control unit 210 for processing. Further, when providing predetermined information to the user, display instruction data for displaying the predetermined information is transmitted from the main control unit 210 to the interface unit 215.

  Further, the vehicle-side communication unit 220 is configured to perform wireless communication with the power transmission-side communication unit 120 and to transmit and receive data to and from the power transmission-side system. Data received by the communication unit 220 is transferred to the main control unit 210, and the main control unit 210 can transmit predetermined information to the power transmission system side via the communication unit 220.

  In the power transmission system, a user who wants to receive power inputs the information indicating that charging is performed from the interface unit 215 by stopping the vehicle in the stop space where the power transmission side system as described above is provided. Receiving this, the main control unit 210 obtains the remaining amount of the battery 204 from the charge control unit 203 and calculates the amount of power necessary for charging the battery 204. The calculated amount of power and information to request power transmission are transmitted from the vehicle side communication unit 220 to the communication unit 120 of the power transmission side system. The main control unit 110 of the power transmission side system that has received the information controls the voltage control unit 102, the inverter unit 103, and the matching unit 104 to transmit power to the vehicle side.

  Next, circuit constants (inductance component and capacitance component) of the primary resonator 150 and the secondary resonator 250 configured as described above will be described. FIG. 3 is a diagram showing an equivalent circuit of the power transmission system 100 according to the embodiment of the present invention.

  In the power transmission system 100 according to the present invention, the circuit constants (inductance component, capacitance component) of the primary resonator 150 and the circuit constants of the secondary resonator 250 are intentionally different from each other, so that the transmission efficiency can be improved. To improve.

In the equivalent circuit shown in FIG. 3, the inductance component of the primary resonator 150 is L ₁ , the capacitance component is C ₁ , the resistance component is Rt ₁ , the inductance component of the secondary resonator 250 is L ₂ , and the capacitance component is C ₂ , the resistance component is Rt ₂ , and the mutual inductance between the primary resonator 150 and the secondary resonator 250 is M. The resistance component Rt ₁ and the resistance component Rt ₂ are internal resistances such as conductive wires, and are not intentionally provided. R represents the internal resistance of the battery 204. The coupling coefficient between the primary resonator 150 and the secondary resonator 250 is indicated by K.

In the present embodiment, the primary resonator 150 is a series resonator having an inductance component L ₁ and a capacitance component C ₁ , and the secondary resonator 250 is an inductance component L ₂ and a capacitance component C ₂ . Consider a series resonator.

  First, in the magnetic resonance type power transmission, when power is efficiently transmitted from the primary resonator 150 on the power transmission system 100 side to the secondary resonator 250 on the power receiving side system 200 side, By making the resonance frequency and the resonance frequency of the secondary resonator 250 the same, energy is efficiently transferred from the power transmission side antenna (primary resonator 150) to the power reception side antenna (secondary resonator 250). Like to do. The condition for this can be expressed by the following formula (1).

これを、インダクタンス成分がＬ₁、キャパシタンス成分がＣ₁、インダクタンス成分がＬ₂、キャパシタンス成分がＣ₂のみの関係で示すと、下式（２）に要約することができる。

This can be summarized by the following equation (2) when the inductance component is L ₁ , the capacitance component is C ₁ , the inductance component is L ₂ , and the capacitance component is C ₂ only.

また、１次共振器１５０のインピーダンスは下式（３）により、また、２次共振器２５０のインピーダンスは下式（４）により、表すことができる。なお、本明細書においては、下式（３）及び下式（４）によって定義される値をそれぞれの共振器のインピーダンスとして定義する。

Further, the impedance of the primary resonator 150 can be expressed by the following equation (3), and the impedance of the secondary resonator 250 can be expressed by the following equation (4). In the present specification, values defined by the following expressions (3) and (4) are defined as impedances of the respective resonators.

磁気共鳴方式の電力伝送システム１００の受電側システムにおいて、電池２０４が定電圧充電モードに移行すると、電池２０４の電圧が一定なので、充電電力によって入力インピーダンスが変化する。電池２０４への充電電力が大きければ入力インピーダンスは低く、充電電力が小さければ入力インピーダンスは高くなる。受電側における２次共振器２５０は、効率の面から、電池２０４の充電電力に応じた入力インピーダンスに近いインピーダンスに設定することが望ましい。

In the power receiving side system of the magnetic resonance type power transmission system 100, when the battery 204 shifts to the constant voltage charging mode, the voltage of the battery 204 is constant, so the input impedance changes depending on the charging power. If the charging power to the battery 204 is large, the input impedance is low, and if the charging power is small, the input impedance is high. The secondary resonator 250 on the power receiving side is desirably set to an impedance close to the input impedance corresponding to the charging power of the battery 204 in terms of efficiency.

  On the other hand, the input impedance to the primary resonator 150 viewed from the power source on the power transmission side is better as it is higher in terms of efficiency. This is because a loss occurs in proportion to the square of the current due to the internal resistance of the power supply.

  From the above, the relationship of the following equation (5) is satisfied between the impedance of the primary resonator 150 expressed by the equation (3) and the impedance of the secondary resonator 250 expressed by the equation (4). It is desirable that

これを、インダクタンス成分がＬ₁、キャパシタンス成分がＣ₁、インダクタンス成分がＬ₂、キャパシタンス成分がＣ₂のみの関係で示すと、下式（６）に要約することができる。

This can be summarized by the following equation (6) when the inductance component is L ₁ , the capacitance component is C ₁ , the inductance component is L ₂ , and the capacitance component is C ₂ only.

本発明に係る電力伝送システム１００においては、１次共振器１５０の回路定数と、２次共振器２５０の回路定数とが上記の式（２）及び式（６）を満たすようにされているために、受電側システムで電池２０４の充電を行う場合に、効率的な電力伝送を行うことが可能となる。

In the power transmission system 100 according to the present invention, the circuit constant of the primary resonator 150 and the circuit constant of the secondary resonator 250 satisfy the above formulas (2) and (6). In addition, when the battery 204 is charged by the power receiving side system, efficient power transmission can be performed.

  Further, the relationship with the internal impedance of the battery 204 will also be mentioned. In the power receiving side system, as a condition for efficiently charging the battery 204, the impedance of the secondary resonator 250 and the impedance of the battery 204 can be matched.

  That is, in the present embodiment, in addition to the conditions of the expressions (2) and (6), the impedance between the secondary resonator 250 of the expression (4) and the impedance R of the battery 204 is

の関係を持たせることで、受電側システムで電池２０４の充電を行う場合、システム全体として、効率的な電力伝送を行うことを可能としている。

Thus, when the battery 204 is charged in the power receiving side system, efficient power transmission can be performed as the entire system.

  Next, countermeasures against noise leakage in the power transmission system 100 configured as described above will be described.

  As described so far, the power transmission system 100 according to the present embodiment is used to charge a vehicle-mounted battery such as an electric vehicle (EV) or a hybrid electric vehicle (HEV). FIG. 4 is a diagram illustrating an installation form of the primary resonator 150 and the secondary resonator 250 in the power transmission system according to the embodiment of the present invention.

  As shown in FIG. 4, the primary resonator coil 160 and the primary resonator capacitor 170 constituting the primary resonator 150 are housed in the primary resonator case 140 and are disposed on the ground. On the other hand, the secondary resonator coil 260 and the secondary resonator capacitor 270 constituting the secondary resonator 250 are housed in the secondary resonator case 240 and attached to the bottom surface of the vehicle.

  When power transmission is performed in the power transmission system 100 in the above situation, a region is generated in the peripheral portion where the primary resonator 150 and the secondary resonator 250 are not opposed to each other but the electromagnetic field strength is high. As a result, noise leaks.

  Such an electromagnetic field leaked from the resonator during power transmission can enter the metal part of the vehicle and heat it, or can leak from between the bottom of the vehicle and the ground, affecting the environment and the human body. It is not preferable because of its properties.

  Therefore, in the power transmission system 100 according to the present invention, it is possible to reduce the leakage as described above by disposing the noise canceling resonator 300 in the vicinity of the primary resonator 150 that is an antenna on the power transmission side. It is possible to suppress the influence on the environment and the human body due to leakage of the electromagnetic field.

  FIG. 5 is a diagram for explaining the layout of the primary resonator coil 160 and the secondary resonator coil 260.

  FIG. 5A is a diagram illustrating a primary resonator case 140 in which the primary resonator 150 is accommodated and a secondary resonator case 240 in which the secondary resonator 250 is accommodated. In this figure, only the primary resonator coil 160 of the primary resonator 150 is shown, and the primary resonator capacitor 170 is not shown. Similarly, only the secondary resonator coil 260 of the secondary resonator 250 is shown, and the secondary resonator capacitor 270 is not shown.

Further, the noise canceling resonator 300 used in the present invention is configured by a series connection of a noise canceling resonator coil 310 having an inductance component L _n and a noise canceling resonator capacitor 320 having a capacitance component C _n . In FIG. 5A, only the noise canceling resonator coil 310 is shown, and the noise canceling resonator capacitor 320 is not shown.

  FIG. 5B schematically illustrates the primary resonator coil 160, the secondary resonator coil 260, and the noise canceling resonator coil 310 shown in FIG. 5A. The primary resonator coil 160 is disposed in the virtual plane P1, and the secondary resonator coil 260 is disposed in the virtual plane P2. Further, the noise canceling resonator coil 310 is arranged in the vicinity of the primary resonator coil 160 and included in the virtual plane P1.

  The primary resonator coil 160 and the noise canceling resonator coil 310 are in the same virtual plane P1, and the direction of the magnetic field generated by the primary resonator coil 160 and the magnetic field generated by the noise canceling resonator coil 310 are the same. The noise canceling resonator coil 310 is arranged so as to be parallel to this direction.

  Furthermore, in the present embodiment, the noise canceling resonator coil 310 is included in a plane (virtual plane P1) where a magnetic field is generated from the primary resonator coil 160 to the outside of the primary resonator coil 160, and 1 It is characterized by being arranged outside the next resonator coil 160.

Here, the noise cancellation resonator 300 will be described in more detail. The noise canceling resonator 300 used in the present invention is particularly suitable for noise countermeasures in a wireless power transmission system using a magnetic resonance type magnetic resonance antenna, but is not limited to a noise source such as the above power transmission system, It is possible to improve noise reduction efficiency for various noise sources.

  FIG. 6 is a diagram illustrating coupling between the noise canceling resonator 300 according to the embodiment of the present invention and the primary resonator 150 that is a noise source.

  In FIG. 6, the primary resonator 150 is used as an antenna for power transmission in the power transmission system, and the primary resonator 150 generates an electromagnetic field having a predetermined fundamental frequency. Electric power is transmitted by the magnetic resonance method. The mutual inductance between the primary resonator 150 and the secondary resonator 250 is M.

The primary resonator 150 is composed of a series connection of a primary resonator coil 160 having an inductance component L ₁ and a primary resonator capacitor 170 having a capacitance component C ₁ .

On the other hand, the noise canceling resonator 300 is composed of a series connection of a noise canceling resonator coil 310 having an inductance component L _n and a noise canceling resonator capacitor 320 having a capacitance component C _n . It is assumed that the electromagnetic field (noise) leaking from the primary resonator 150 without contributing to power transmission is removed.

L _m is a mutual inductance between the primary resonator coil 160 and the noise canceling resonator coil 310.

  The noise canceling resonator 300 actually has a closed structure at the terminal portion (2), but in FIG. 6, it is recognized as a power transmission circuit from the primary resonator 150 to the noise canceling resonator 300. The characteristics of the noise canceling resonator 300 will be described.

  FIG. 7 is a diagram showing the frequency dependence of the transmission efficiency, the noise emissivity, and the frequency dependence in the power transmission circuit of FIG. 6 as described above. In FIG. 7, the horizontal axis indicates the frequency, and S21 on the vertical axis indicates the power passing through the terminal (2) when a signal is input from the terminal (1).

As shown in FIG. 7, in the frequency characteristic of the power transmission efficiency in the power transmission circuit of FIG. 6, there are two frequencies that give two extreme values. The extreme frequency with the lower frequency is defined as the first extreme frequency, and the extreme frequency with the higher frequency is defined as the second extreme frequency. In the figure, f _o indicates the resonance frequency of the noise canceling resonator 300.

  When the primary resonator 150 is driven at the first extreme frequency which is the lower extreme frequency and power is transmitted, the primary resonator coil 160 of the primary resonator 150 and the noise cancel resonance The noise canceling resonator coil 310 of the resonator 300 is coupled under a magnetic wall condition.

  On the other hand, when the primary resonator 150 is driven at the second extreme frequency, which is the higher extreme frequency, and power is transmitted, the primary resonator coil 160 of the primary resonator 150 and noise The noise canceling resonator coil 310 of the canceling resonator 300 is coupled with an electric wall condition.

Hereinafter, the primary resonator coil 160 of the primary resonator 150 and the noise canceling resonator 300 will be described.
The concept of the electric wall and magnetic wall generated on the plane of symmetry between the noise canceling resonator coil 310 will be described.

  FIG. 8 is a diagram schematically showing the state of current and electric field at the first extreme frequency (frequency at the time of magnetic wall condition coupling). At the first extreme frequency, the current flowing through the primary resonator coil 160 and the current flowing through the noise canceling resonator coil 310 have substantially the same phase, and the positions where the magnetic field vectors are aligned are the primary resonator coil 160 and the noise. Near the center of the cancel resonator coil 310. This state is considered as a magnetic wall in which the direction of the magnetic field is perpendicular to the plane of symmetry between the primary resonator coil 160 and the noise canceling resonator coil 310.

  As shown in FIG. 8, when the primary resonator 150 and the noise cancellation resonator 300 are coupled under a magnetic wall condition, the magnetic field from the primary resonator coil 160 enters the noise cancellation resonator coil 310. It will be in such a state.

  Moreover, FIG. 9 is a figure which shows typically the mode of the electric current and electric field in a 2nd extreme value frequency (frequency at the time of an electric wall condition coupling | bonding). At the second extreme frequency, the current flowing through the primary resonator coil 160 and the current flowing through the noise canceling resonator coil 310 are almost opposite in phase, and the position where the magnetic field vectors are aligned is the primary resonator coil 160 or noise. Near the symmetry plane of the cancel resonator coil 310. This state is considered as an electrical wall in which the direction of the magnetic field is horizontal with respect to the plane of symmetry between the primary resonator coil 160 and the noise canceling resonator coil 310.

  As shown in FIG. 9, when the primary resonator 150 and the noise canceling resonator 300 are coupled under an electric wall condition, the magnetic field from the primary resonator coil 160 and the magnetic field from the noise canceling resonator 300 are used. However, it will be in a state where they are rejected on the symmetry plane.

  Regarding the concepts of the electric wall and the magnetic wall as described above, Takehiro Imura and Yoichi Hori “Transmission Technology by Electromagnetic Resonance Coupling”, IEEE Journal, Vol. 129, no. 7, 2009, or Takehiro Imura, Hiroyuki Okabe, Toshiyuki Uchida, Yoichi Hori “Studies on magnetic field coupling and electric field coupling of non-contact power transmission as seen from the equivalent circuit” IEEE Trans. IA, Vol. 130, no. What is described in 1,2010 etc. is used in this specification.

  Here, the frequency characteristic of the noise radiation from the primary resonator 150 indicated by the one-dot chain line in FIG. 7 takes a minimum value at the first extreme value frequency (frequency at the time of magnetic wall condition coupling), and the second extreme value frequency. It can be seen that the maximum value is obtained at (frequency at the time of electrical wall condition coupling).

Because of the above characteristics, in the present invention, the frequency of the electromagnetic field (noise) generated by the primary resonator 150 is exactly the first extreme value frequency f _m (frequency at the time of magnetic wall condition coupling). in relationship as to set the resonant frequency f _c of the noise canceling resonator 300.

More specifically, the resonance frequency f _c of the noise cancellation resonator 300 is equal to the primary resonator 15.
A shift frequency f _s determined according to the degree of coupling k (lower case) between the primary resonator coil 160 and the noise canceling resonator coil 310 from a predetermined frequency of the electromagnetic field where 0 is generated (referred to as f _{m in} this embodiment). Set the resonance frequency higher.

The shift frequency f _s depends on the primary resonator coil 160 and the noise canceling resonator coil 310.
In other words, the shift frequency f _s is also determined by the mutual inductance L _m between the primary resonator coil 160 and the noise canceling resonator coil 310, The shift frequency f _s can be obtained by the following equation (8).

以上より、ノイズキャンセル共振器３００の共振周波数ｆ_cは、下式（９）により求め
るようにする。

From the above, the resonance frequency f _c of the noise canceling resonator 300 as determined by the following equation (9).

ノイズキャンセル共振器３００の共振周波数ｆ_cを上記のように設定することで、ノイ
ズ源である１次共振器１５０の１次共振器コイル１６０とノイズキャンセル共振器コイル３１０とは磁気壁条件で結合することとなり、これにより、図７のノイズ放射の周波数特性でも示されるように、ノイズキャンセル共振器３００が効率的に、１次共振器１５０から放射されるノイズを除去することができるようになる。

The resonance frequency f _c of the noise canceling resonator 300 by setting as described above, coupled with the magnetic wall conditions the primary resonator coil 160 and the noise canceling resonator coil 310 of the primary resonator 150 is a noise source As a result, the noise canceling resonator 300 can efficiently remove the noise radiated from the primary resonator 150, as shown in the frequency characteristics of noise radiation in FIG. .

  According to the noise canceling resonator 300 used in the present invention, the noise reduction effect is great particularly in a noise countermeasure in a wireless power transmission system in which a magnetic resonance type magnetic resonance antenna is used.

  Since the noise canceling resonator 300 used in the present invention has a passive configuration with respect to noise, it is desirable that the characteristics of the noise canceling resonator 300 be approximately equal to the level of the antiphase wave of noise. Further, it is desirable to reduce the loss in the noise canceling resonator 300 as much as possible, and it has been experimentally confirmed that the noise reduction effect is large when the Q value of the noise canceling resonator 300 is 50 or more.

  By the way, the frequency of the electromagnetic field generated from the primary resonator 150 which is a noise source includes a noise component of a harmonic of the fundamental wave in addition to the fundamental wave. There is a need to remove by 300.

  As harmonics as described above, harmonics obtained by the following equation (10) are generated from the primary resonator 150 in a system that emits odd harmonics of the frequency that drives the primary resonator 150. The resonance frequency of the noise cancellation resonator 300 is preferably determined by the following equation (11).

（ただし、ｎは自然数）

(Where n is a natural number)

（ただし、ｎは自然数）
また、高調波として、１次共振器１５０を駆動する周波数の偶数倍の高調波が放射されすい系では、１次共振器１５０から下式（１２）により求められる高調波が発生するので、ノイズキャンセル共振器３００の共振周波数は、下式（１３）により定められるものとするとよい。

(Where n is a natural number)
Further, in the system in which even-numbered harmonics that drive the primary resonator 150 are radiated as harmonics, the harmonics obtained from the primary resonator 150 according to the following equation (12) are generated. The resonance frequency of the cancel resonator 300 may be determined by the following equation (13).

（ただし、ｎは自然数）

(Where n is a natural number)

（ただし、ｎは自然数）
これまで説明したように、本発明で用いるノイズキャンセル共振器３００のノイズキャンセル共振器コイル３１０においては、１次共振器１５０の１次共振器コイル１６０と磁気壁条件で結合するようにすることで、ノイズ低減効果を狙うようにしているが、この原理を模式的に説明する。

(Where n is a natural number)
As described above, in the noise canceling resonator coil 310 of the noise canceling resonator 300 used in the present invention, it is coupled with the primary resonator coil 160 of the primary resonator 150 under a magnetic wall condition. The noise reduction effect is aimed at, but this principle will be schematically explained.

  FIG. 10 is a conceptual diagram illustrating that noise reduction efficiency is improved by the noise canceling resonator 300 according to the embodiment of the present invention. As described above, the primary resonator coil 160 and the noise canceling resonator coil 310 are coupled to each other under a magnetic wall condition. Further, the primary resonator coil 160 and the noise canceling resonator coil 310 are in the same virtual plane P1, and the direction of the magnetic field generated by the primary resonator coil 160 and the magnetic field generated by the noise canceling resonator coil 310 are the same. The noise canceling resonator coil 310 is arranged so as to be parallel to this direction.

  Furthermore, in the present embodiment, the noise canceling resonator coil 310 is included in a plane (virtual plane P1) where a magnetic field is generated from the primary resonator coil 160 to the outside of the primary resonator coil 160, and 1 It is characterized by being arranged outside the next resonator coil 160.

  FIG. 10A shows a case where the primary resonator coil 160 of the primary resonator 150 and the noise cancel resonator coil 310 of the noise cancel resonator 300 are coupled under a magnetic wall condition. The magnetic field from the primary resonator coil 160 enters the noise canceling resonator coil 310. Based on this, the magnetic field generated at the point X also enters the noise canceling resonator coil 310. It will be. Therefore, as surrounded by a dotted line, the magnetic field from the primary resonator coil 160 and the magnetic field entering the noise canceling resonator coil 310 cancel each other, and a noise canceling effect occurs.

  On the other hand, FIG. 10B shows a case where the primary resonator coil 160 of the 150 primary resonators and the noise canceling resonator coil 310 of the noise canceling resonator 300 are coupled under an electric wall condition. In this case, the magnetic field from the primary resonator coil 160 and the magnetic field from the noise canceling resonator 300 are in a state of mutual exclusion, but based on this, a magnetic field entering the point X is generated. Will be. Therefore, as surrounded by a dotted line, the magnetic field from the primary resonator coil 160 and the magnetic field from the noise canceling resonator coil 310 work to strengthen each other and amplify the noise. Become.

  As described above, the power transmission system 100 according to the present invention includes the noise canceling resonator coil 310, and a shift determined according to the degree of coupling between the primary resonator coil 160 and the noise canceling resonator coil 310 from the predetermined frequency. Since the noise canceling resonator 300 having a resonance frequency higher by the frequency is provided, and the noise canceling resonator coil 310 of the noise canceling resonator 300 is arranged at an optimal position, according to the present invention, the magnetic resonance method of the present invention is particularly effective. Noise generation can be suppressed and noise leakage can be reduced in a wireless power transmission system using a magnetic resonance antenna.

  In the embodiment described above, the noise canceling resonator 300 has been described based on the example of being disposed on the primary resonator coil 160 side. However, the noise canceling resonator 300 is not limited to the secondary resonator 250. The secondary resonator coil 260 may be arranged in the vicinity.

  More specifically, in such an embodiment, a secondary resonator having a secondary resonator coil 260 via an electromagnetic field having a predetermined frequency generated by the primary resonator 150 having the primary resonator coil 160. 250 is a power transmission system that transmits electric energy to 250, and includes a noise canceling resonator coil 310, and depending on the degree of coupling between the secondary resonator coil 260 and the noise canceling resonator coil 310 from the predetermined frequency. A noise canceling resonator 300 having a resonance frequency higher by a determined shift frequency is provided, and the direction of the magnetic field generated by the secondary resonator coil 260 is parallel to the direction of the magnetic field generated by the noise canceling resonator coil 310. As described above, the noise canceling resonator coil 310 is disposed.

  Further, the noise canceling resonator coil 310 is included in a plane (virtual plane P2) where a magnetic field is generated from the secondary resonator coil 260 to the outside of the secondary resonator coil 260, and the secondary resonance Arranged outside the coil 260.

  Even in the embodiment in which the noise canceling resonator 300 as described above is arranged in the vicinity of the secondary resonator coil 260 of the secondary resonator 250, the same effect as that of the previous embodiment can be obtained. .

  Further, in the present invention, the noise canceling resonator 300 is arranged both near the primary resonator coil 160 of the primary resonator 150 and near the secondary resonator coil 260 of the secondary resonator 250. May be.

  According to the present invention as described above, it is possible to suppress noise generation and reduce noise leakage particularly in a wireless power transmission system using a magnetic resonance type magnetic resonance antenna.

  Next, in the power transmission system 100 according to the present invention, a more preferable arrangement of the noise canceling resonator coil 310 when viewed from the vertical direction will be described.

  FIG. 11 is a diagram for explaining a layout example of the noise canceling resonator coil 310. FIG. 11 shows that the vehicle is stopped in a stop space where the primary resonator 150 is installed, and the secondary resonator 250 mounted on the vehicle and the primary resonator 150 are opposed to each other so that the electric power is transmitted in the power transmission system 100. It is a figure which shows the layout of each coil at the time of performing transmission, and has shown what looked at other structures, such as a vehicle, transparently from the perpendicular | vertical upper direction.

In the example of FIG. 11A, the secondary resonator 250 is mounted in a substantially central portion of the vehicle, and the distance between the secondary resonator 250 and the periphery of the vehicle is the distance between the front and the secondary resonator 250. a d ₁ between a d ₂ between the right and the second resonator 250, a d ₃ between the rear and the secondary resonator 250, the left and the secondary resonator 250 And d ₄ , and distance d ₁ compared to distance d ₂ and distance d ₄
And the distance d ₃ can be set sufficiently long.

  In such a case, noise is generated between the right side and the secondary resonator 250 where the distance between the secondary resonator 250 and the periphery of the vehicle is short, and between the left side and the secondary resonator 250. A cancel resonator coil 310 is arranged.

  When the distance between the facing portion of the primary resonator 150 and the secondary resonator 250 and the vehicle peripheral portion is long, a region where the electromagnetic field intensity is high is covered by the vehicle main body, and noise from the vehicle peripheral portion is detected. Leakage is small, but when the distance between the facing portion and the vehicle peripheral edge is short, the area where the electromagnetic field strength is high is covered with the vehicle main body. Noise leakage increases. Therefore, in the present embodiment, the power transmission system is configured by disposing the noise canceling resonator coil 310 at a location where the distance between the facing portion of the primary resonator 150 and the secondary resonator 250 and the vehicle peripheral portion is short. As a whole, efficient noise leakage is prevented.

In the example of FIG. 11B, the secondary resonator 250 is mounted on the front portion of the vehicle. The distance between the secondary resonator 250 and the periphery of the vehicle is the distance between the front and the secondary resonator 250. a d ₁ between a d ₂ between the right and the second resonator 250, a d ₃ between the rear and the secondary resonator 250, the left and the secondary resonator 250 an d ₄ between, than the distance d ₁ and distance d ₂ and a distance d _4, the distance d ₃ indicates a situation that can be set sufficiently long.

  In such a case, for example, between the front and the secondary resonator 250 where the distance between the secondary resonator 250 and the periphery of the vehicle is short, and the right side and the secondary resonator 250. In the meantime, noise canceling resonator coils 310 are arranged at three positions between the left side and the secondary resonator 250.

  Thus, as in the case of FIG. 11 (A), the distance between the opposing portion of the primary resonator 150 and the secondary resonator 250 and the vehicle peripheral portion is short, and the region where the electromagnetic field strength is high is the vehicle main body portion. The noise canceling resonator coil 310 is arranged at a place where the covered distance is also short, so that efficient noise leakage can be prevented as the entire power transmission system 100.

DESCRIPTION OF SYMBOLS 100 ... Power transmission system 101 ... AC / DC conversion part 102 ... Voltage control part 103 ... Inverter part 104 ... Matching device 110 ... Main control part 120 ... Communication part 140- Primary resonator case 150 ... Primary resonator 160 ... Primary resonator coil 170 ... Primary resonator capacitor 201 ... Secondary resonator 202 ... Rectifier 203 ... Charging control unit 204 ... battery 210 ... main control unit 215 ... interface unit 220 ... communication unit 240 ... secondary resonator case 250 ... secondary resonator 260 ... 2 Secondary resonator coil 270... Secondary resonator capacitor

Claims (8)

Electric energy is transmitted to a secondary resonator having a secondary resonator coil via an electromagnetic field having a predetermined frequency generated by the primary resonator having the primary resonator coil, and the primary resonator coil is grounded. The secondary resonator coil is a power transmission system disposed on the bottom surface of the vehicle,
A noise canceling resonator coil, comprising a noise canceling resonator having a resonance frequency higher than the predetermined frequency by a shift frequency determined according to a degree of coupling between the primary resonator coil and the noise canceling resonator coil;
The power transmission system according to claim 1, wherein the noise canceling resonator coil is disposed at a location where a distance between the secondary resonator coil and a periphery of the vehicle is short. A power transmission system for transmitting electrical energy to a secondary resonator having a secondary resonator coil via an electromagnetic field having a predetermined frequency generated by the primary resonator having the primary resonator coil, wherein the energy transfer resonance system A noise canceling resonator having a resonance frequency higher than the predetermined frequency by a shift frequency determined according to a degree of coupling between the secondary resonator coil and the noise canceling resonator coil,
The power transmission system according to claim 1, wherein the noise canceling resonator coil is disposed at a location where a distance between the secondary resonator coil and a periphery of the vehicle is short. The power transmission system according to claim 1, wherein the predetermined frequency is a frequency of a fundamental wave of an electromagnetic field generated by the primary resonator. The power transmission system according to claim 1, wherein the predetermined frequency is a harmonic frequency of an electromagnetic field generated by the primary resonator. The power transmission system according to claim 4, wherein the harmonic is an odd harmonic. The power transmission system according to claim 4, wherein the harmonic is an even harmonic. When the mutual inductance component between the primary resonator coil and the noise canceling resonator coil is L _m ,
The shift frequency is

The power transmission system according to claim 1, wherein the power transmission system is a power transmission system. The power transmission system according to claim 1, wherein a Q value of the noise canceling resonator coil is 50 or more.

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