JP6085817B2 - Power transmission system - Google Patents

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.

Some proposals have been made on the specific configuration of the antenna used in the above-described magnetic resonance type wireless power transmission system. For example, Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2010-73976) discloses a structure of a communication coil provided in each of the power feeding circuit and the power receiving circuit of a wireless power transmission device that wirelessly transmits power from the power feeding circuit to the power receiving circuit. A printed circuit board made of a material having a relative dielectric constant greater than 1, a primary coil provided on the first layer of the printed circuit board and formed of a conductive pattern forming at least one loop, and a second layer of the printed circuit board And a resonance coil formed of a conductive pattern having a spiral shape. The communication coil structure of the wireless power transmission device is disclosed.
Special table 2009-501510 JP 2010-73976 A

  When the magnetic resonance type power transmission system as described above is used for power supply to vehicles such as an electric vehicle (EV) and a hybrid electric vehicle (HEV), a power transmission antenna is embedded in the ground and receives power. It is assumed that the antenna for use is laid out on the bottom of the vehicle.

  However, when the antenna having the structure described in Patent Document 1 is installed at the bottom of a vehicle made of a metal body, a magnetic field leaked from the antenna during power transmission enters the metal body, and current is induced in the metal body by the magnetic field. There was a problem of heating the bottom of the vehicle.

  Another problem is that the power transmission efficiency of the system is suppressed by the magnetic field that leaks from the antenna and enters the metal body during power transmission.

  Thus, in order to deal with each of the above problems, a power transmission system is required to have a configuration in which noise does not leak as much as possible. However, no specific proposal has been made so far. .

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. A power transmission system for transmitting electrical energy to a capacitor, wherein the power transmission system is provided between an inverter unit that generates power to be input to the primary resonator, the inverter unit, and the primary resonator, and at least a circuit unit A circuit unit including a coil, and the circuit unit coil and the primary resonator coil are connected in series, and a conductor wire circulation axis of the circuit unit coil is a conductor wire circuit of the primary resonator coil. The circuit unit coil and the primary resonator coil are arranged in parallel with the axis so that the direction of the magnetic flux generated by the circuit unit coil is opposite to the direction of the magnetic flux generated by the primary resonator coil. To place The features.

  The power transmission system according to the present invention is characterized in that the circuit unit coil is housed in a primary resonator case together with the primary resonator coil.

  In the power transmission system according to the present invention, the circuit unit is a matching unit.

  The power transmission system according to the present invention is arranged so that the conductor wire circumference axis of the circuit part coil included in the circuit part is parallel to the conductor wire circumference axis of the primary resonator coil and the current phase is reversed. Therefore, according to such a power transmission system according to the present invention, leakage of noise can be prevented, and even when a resonator is mounted on the bottom of the vehicle, the vehicle leaks from the resonator during power transmission. It is possible to reduce the magnetic field that enters the metal body at the bottom, without heating the bottom of the vehicle, and in addition, the power transmission efficiency of the system can be improved.

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 100 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 which shows the circuit structural example by the side of the power transmission system in the electric power transmission system 100 which concerns on embodiment of this invention. It is a figure which shows typically the physical structure of the primary resonator 150 in the electric power transmission system 100 which concerns on embodiment of this invention.

  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 stores programs that run 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).

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.

  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.

  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

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.

  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

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 present invention, the coil used in the circuit unit subsequent to the inverter unit 103 is used for noise cancellation. In the present embodiment, the conductor wire winding axis of the circuit unit coil included in the circuit unit is parallel to the conductor wire winding axis of the primary resonator coil 160 and the current phase is reversed. Yes. This makes it possible to reduce the leakage as described above, and to suppress the influence on the environment and the human body due to the leakage of the electromagnetic field. In addition, the coil of the circuit part of the subsequent stage of the inverter part 103 as described above, which is also used for noise cancellation, is expressed as a “circuit part coil” in the claims.

Hereinafter, a specific configuration will be described. FIG. 5 is a diagram for explaining the layout of the primary resonator coil 160 and the secondary resonator coil 260. FIG. 6 is a diagram illustrating a circuit configuration example on the power transmission system side in the power transmission system 100 according to the embodiment of the present invention, and FIG. 7 is a primary resonator 150 in the power transmission system 100 according to the embodiment of the present invention. It is a figure which shows typically a physical structure.

In the present invention, the conductor wire circulation axis of the circuit unit coil (310, 350) included in the circuit unit is parallel to the conductor wire circulation axis of the primary resonator coil 160, and the current phase is reversed. It is arranged. As shown in FIGS. 5 to 7, the coils Lb and Ld constituting the matching device 104 are housed in the primary resonator case 140 together with the primary resonator coil 160. The direction of the magnetic flux generated by the coils Lb and Ld is set to be opposite to the direction of the magnetic flux generated by the primary resonator coil 160.
As can be understood by referring to FIGS. 5 to 7, the coil arrangement in which the current phase of the circuit unit coils (310, 350) and the primary resonator coil 160 are reversed is the circuit unit coil (310, 350). It can be said that the direction of the magnetic flux generated by 350) is opposite to the direction of the magnetic flux generated by the primary resonator coil 160.

  Here, in order to specifically describe the coil Lb and the coil Ld, they are referred to as a first coil 310 and a second coil 350, respectively.

  FIG. 5 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.

  In the present embodiment, the primary resonator coil 160 includes a ferrite base material 161 and a coil winding 162 wound around the ferrite base material 161. The secondary resonator coil 260 includes the ferrite base material 261, It consists of a coil winding 262 wound around this ferrite substrate 261. In FIG. 5, only each coil is shown, and the primary resonator capacitor 170 is not shown.

  The first coil 310 includes, for example, a ferrite base material 311 and a coil winding 312 wound around the ferrite base material 311. The second coil 350 includes, for example, a ferrite base material 351 and a coil winding 352 wound around the ferrite base material 351.

  As shown in FIG. 6, the first coil 310 and the second coil 350 constitute a part of the matching unit 104, but in this embodiment, noise leaking from the primary resonator coil 160 is canceled. For this purpose, the primary resonator case 140 is housed in the primary resonator case 140 together with the primary resonator coil 160. FIG. 7 schematically shows a configuration in which the first coil 310 and the second coil 350 are accommodated in the primary resonator case 140.

  The first coil 310 and the second coil 350 have been described with reference to an example of a coil derived from a matching device. Coils constituting each circuit can also be used in the present invention.

  In this example, two coils are used for noise cancellation, but the number of coils used for noise cancellation is arbitrary.

  As described above, according to the power transmission system 100 of the present invention, leakage of noise can be prevented by the first coil 310 and the second coil 350 as described above, and even when a resonator is mounted on the bottom surface of the vehicle. It is possible to reduce the magnetic field that leaks from the resonator during power transmission and enters the metal body at the bottom of the vehicle, and does not heat the bottom of the vehicle, and in addition improves the power transmission efficiency of the system Can do.

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 161 ... Ferrite substrate 162 ... Coil winding 170 ... Primary resonator capacitor 201 ... -Secondary resonator 202 ... Rectification unit 203 ... Charging control unit 204 ... Battery 210 ... Main control unit 215 ... Interface unit 220 ... Communication unit 240 ... Secondary resonator Case 250 ... Secondary resonator 260 ... Secondary resonator coil 261 ... Ferrite substrate 262 ... Coil winding 270 ... Secondary resonator capacitor 310 ... First coil 311 ..Blow DOO substrate 312 ... coil winding 350 ... second coil 351 ... ferrite substrate 352 ... coil winding

Claims (3)

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,
An inverter unit for generating electric power to be input to the primary resonator;
A circuit unit provided between the inverter unit and the primary resonator and including at least a circuit unit coil;
The circuit unit coil and the primary resonator coil are connected in series,
The conductor wire circumferential axis of the circuit unit coil is parallel to the conductor wire circumferential axis of the primary resonator coil ,
The direction of the magnetic flux generated by the circuit unit coil is opposite to the direction of the magnetic flux generated by the primary resonator coil.
A power transmission system comprising the circuit unit coil and the primary resonator coil . The power transmission system according to claim 1, wherein the circuit unit coil is housed in a primary resonator case together with the primary resonator coil. The power transmission system according to claim 1, wherein the circuit unit is a matching unit.

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