JP6399351B2 - Power transmission device, vehicle equipped with power transmission device and wireless power transmission system - Google Patents

Description

  The present disclosure relates to a power transmission device that transmits AC power in a contactless manner by electromagnetic induction between a power transmission coil and a power reception coil, a vehicle equipped with the power transmission device, and a wireless power transmission system.

  Various mobile devices such as mobile phones are widespread. The power consumption of mobile devices continues to increase due to functional and performance improvements and content diversification. When the power consumption of a mobile device that operates with a battery of a predetermined capacity increases, the operation time of the mobile device becomes shorter. A wireless power transmission system has attracted attention as a technique for supplementing the limitation of battery capacity. The wireless power transmission system transmits AC power from a power transmission device to a power reception device in a non-contact manner by electromagnetic induction between a power transmission coil in the power transmission device and a power reception coil in the power reception device. In particular, a wireless power transmission system using a resonant power transmission coil and a power reception coil can maintain high transmission efficiency even when the positions of the power transmission coil and the power reception coil are shifted from each other. For this reason, the resonance type wireless power transmission system is applied to various fields.

  In recent years, a system in which a power transmission device that charges a mobile device (power receiving device) such as a mobile phone in a contactless manner is installed in a vehicle has begun to spread. Such a system allows a mobile device to be contactlessly charged in a car. It is desirable to make the power transmission device as thin as possible so as not to occupy many places.

JP 2008-205215 A

  However, in the related art, since the power transmission device is reduced in thickness to increase the loss of the power transmission coil and the transmission efficiency is lowered, a power transmission device that transmits AC power with high efficiency has been demanded.

  A power transmission device according to an aspect of the present disclosure is a power transmission device that transmits AC power in a contactless manner to a power reception device including a power reception coil, and is input from a power transmission surface that transmits power to the power reception device and a DC power source A power transmission circuit that converts the DC power into AC power, and 2N (N is a natural number of 2 or more) planar coils provided on the power transmission surface side inside the power transmission device and having different inductance values, And at least one power transmission coil that transmits the AC power output from the power transmission circuit to the power reception coil. In the 2N planar coils, when i = 1 to N, among the 2N planar coils, the planar coil having the i-th highest inductance and the planar coil having the lowest i-th inductance are A coil group connected in series is configured, and each of the coil groups is connected in parallel.

  A power transmission device according to another aspect of the present disclosure is a power transmission device that transmits AC power in a contactless manner to a power reception device including a power reception coil, and includes a power transmission surface that transmits power to the power reception device, and a DC power source. A power transmission circuit that converts input DC power into AC power, and M (M is a natural number of 3 or more) planar coils that are provided on the power transmission surface side inside the power transmission device and have different inductance values, And at least one power transmission coil that transmits the AC power output from the power transmission circuit to the power receiving coil. The M planar coils have two or more coil groups including a coil group in which two or more planar coils selected in an order different from the magnitude order of the inductance values are connected in series as a set; Each of the coil groups is connected in parallel.

  A power receiving device according to still another aspect of the present disclosure is a power receiving device that receives AC power in a non-contact manner from a power transmitting device including a power transmission coil, and is input from the power receiving surface that receives power from the power transmitting device and the power receiving surface A power receiving circuit that converts alternating current power into direct current power, and 2N (N is a natural number of 2 or more) planar coils that are provided on the power receiving surface side inside the power receiving device and have different inductance values. And at least one power receiving coil that outputs the AC power input from the surface to the power receiving circuit. In the 2N planar coils, when i = 1 to N, among the 2N planar coils, the planar coil having the i-th highest inductance and the planar coil having the lowest i-th inductance are A coil group connected in series is configured, and each of the coil groups is connected in parallel.

  A power receiving device according to still another aspect of the present disclosure is a power receiving device that receives AC power in a non-contact manner from a power transmitting device including a power transmission coil, and is input from the power receiving surface that receives power from the power transmitting device and the power receiving surface A power receiving circuit for converting AC power into DC power, and M planar coils (M is a natural number of 3 or more) provided on the power receiving surface side inside the power receiving device and having different inductance values. And at least one power receiving coil that outputs the AC power input from the surface to the power receiving circuit. The M planar coils have two or more coil groups including a coil group in which two or more planar coils selected in an order different from the magnitude order of the inductance values are connected in series as a set; Each of the coil groups is connected in parallel.

  Note that these comprehensive or specific aspects may be realized by a system, method, integrated circuit, computer program, or recording medium. Any of the system, apparatus, method, integrated circuit, computer program, and recording medium may be used. It may be realized by various combinations.

  According to the said aspect, the thin power transmission apparatus which transmits alternating current power with high efficiency can be provided.

It is a figure which shows an example of the wireless power transmission system mounted in the vehicle. It is a disassembled perspective view which shows the some planar coil which has the structure similar to the laminated coil disclosed by patent document 1. FIG. FIG. 3 is an equivalent circuit diagram of the laminated coil shown in FIG. 2. It is sectional drawing which shows an example of a wireless power transmission system provided with a power transmission apparatus and a power receiving apparatus. It is sectional drawing which shows an example of a wireless power transmission system provided with a power transmission apparatus and a power receiving apparatus which has a magnetic body. It is sectional drawing which shows an example of a wireless power transmission system provided with the power transmission apparatus which has a metal housing | casing, and a power receiving apparatus. It is a perspective view which shows the power transmission coil which has the planar coils L1 to L4. FIG. 3 is an equivalent circuit diagram of the power transmission coil shown in FIG. 2. It is a block diagram which shows an example of a wireless power transmission system. It is a block diagram which shows an example of a power transmission circuit. 3 is a cross-sectional view of a power transmission coil according to Embodiment 1. FIG. FIG. 3 is an exploded perspective view of a power transmission coil in the first embodiment. FIG. 3 is an equivalent circuit diagram of the power transmission coil in the first embodiment. 6 is an exploded perspective view of a power transmission coil in Embodiment 2. FIG. 6 is an equivalent circuit diagram of a power transmission coil in Embodiment 2. FIG. 6 is an exploded perspective view of a power transmission coil in Embodiment 3. FIG. 6 is an equivalent circuit diagram of a power transmission coil according to Embodiment 3. FIG. It is a graph which shows the characteristic of the power transmission coil in Embodiment 1 (Example 1) and Embodiment 3 (Example 2). FIG. 6 is an exploded perspective view of a power transmission coil according to a fourth embodiment. FIG. 10 is an equivalent circuit diagram of a power transmission coil in the fourth embodiment. It is a disassembled perspective view which shows an example of the power transmission coil from which the winding number of each planar coil differs. FIG. 20 is an equivalent circuit diagram of the power transmission coil shown in FIG. 19. It is a perspective view which shows an example of the power transmission coil formed by overlapping two plane coils on the same plane. It is an equivalent circuit diagram which shows the modification which connected the planar coil La in series with the power transmission coil in Embodiment 1. It is an equivalent circuit diagram which shows the modification which connected the planar coil Lb in parallel with the power transmission coil in Embodiment 1. FIG. FIG. 10 is a perspective view showing a power transmission device in a fifth embodiment. FIG. 10 is a perspective view illustrating a state where a power receiving device is placed on a power transmitting device according to a fifth embodiment. FIG. 10 is a perspective view showing another state in which a power receiving device is placed on a power transmitting device in a fifth embodiment. FIG. 10 is a diagram illustrating a schematic configuration of a power transmission device according to a fifth embodiment. It is a figure which shows an example of a wireless power transmission system. It is a figure which shows an example of a vehicle provided with a power transmission apparatus. It is sectional drawing which shows the structural example of a receiving device provided with the several planar coil laminated | stacked.

(Knowledge that became the basis of this disclosure)
The present inventors have found that the following problems occur with respect to the power transmission apparatus described in the “Background Art” column.

  FIG. 1 is a perspective view showing an example of a wireless power transmission system mounted on a vehicle. This system includes a power transmission device 100 mounted in an in-vehicle console box 400 and a power reception device 200. The power transmission device 100 includes at least one power transmission coil having a plurality of planar coils stacked vertically to a power transmission surface that transmits power to the power reception device.

  Patent document 1 is disclosing the laminated coil unit used for a wireless power transmission system. This laminated coil unit has a plurality of planar air-core coils. Each coil is composed of a spiral conductive pattern formed on an insulating substrate, and is laminated in the thickness direction of the insulating substrate.

  FIG. 2 is an exploded perspective view showing a plurality of planar coils having the same configuration as the laminated coil disclosed in Patent Document 1. FIG. 3 is a diagram showing an equivalent circuit of the plurality of planar coils shown in FIG. In this laminated coil, a thin substrate such as a flexible substrate is used as an insulating substrate. One planar coil in which a conductor pattern (0.035 mm) is spirally formed on a flexible substrate is produced. Four planar coils are produced by the same method as described above, and the planar coils are electrically connected as shown in FIGS. 2 and 3 in a state where the four planar coils are laminated. Of the four planar coils, two are connected in series and the remaining two are also connected in series. These two pairs of planar coils are connected in parallel. Patent Document 1 describes that with such a configuration, it is possible to provide a power transmission apparatus that is thin and has an improved Q factor (Quality Factor).

  FIG. 4A is a cross-sectional view schematically illustrating an example of a wireless power transmission system. The power transmission device 100 in this example includes a power transmission antenna 110 and a power transmission circuit 140. The power receiving device 200 includes a power receiving antenna 210, a power receiving circuit 220, and a secondary battery 230. The power transmission antenna 110 includes a power transmission coil including a plurality of planar coils as shown in FIG. 2 and a resonance capacitor (not shown). As shown in FIG. 4A, in the power transmission device 100 in which neither a magnetic body nor a metal is disposed in the vicinity of the power transmission antenna 110, generally, the number of turns and the size of the conductor pattern of each planar coil are substantially the same. In some cases, their inductance values are approximately the same. However, in an actual wireless power transmission system, the inductance value of each planar coil included in the power transmission antenna 110 is often different. For example, as shown in FIG. 4B, a magnetic body 250 may be loaded on the power receiving device 200. Since the power receiving device 200 is required to be thinner, such a magnetic body 250 is loaded in the vicinity of the power receiving antenna 210 in order to reduce eddy current loss of the power receiving coil in the power receiving antenna 210.

  In such a configuration, the magnetic body 250 in the power receiving device 200 is positioned in the vicinity of the power transmission coil in a state where the power transmitting device 100 and the power receiving device 200 are disposed facing each other (for example, during power transmission). As a result, the inductance values of the plurality of planar coils constituting the power transmission coil are different from each other.

  The same thing can happen when the casing of the power transmission device 100 is made of metal as shown in FIG. 4C. In this case, generally, the inductance of the planar coil closer to the metal casing 125 is lower.

  When the power receiving device 200 loaded with the magnetic body 250 as shown in FIG. 4B is opposed to the power transmitting device 100 having a laminated coil similar to that disclosed in Patent Document 1, the amount of heat generation is high. It has been found that the transmission efficiency decreases. The present inventors analyzed this cause as follows.

  The present inventors created a group of planar coils L1 to L4 as shown in FIG. 5 and arranged the power receiving device 200 loaded with the magnetic body 250 facing the power transmission surface 130. Table 1 shows the results of analyzing the characteristics of the inductance L and AC resistance R of the planar coils L1 to L4 in this state.

As shown in Table 1, it can be seen that each inductance value is changed from a larger value to a smaller value in the order of the planar coil far from the planar coil close to the magnetic body 250, that is, in the order of L4 to L1. Here, a general-purpose electromagnetic field analysis simulator was used for the analysis. As analysis conditions, each planar coil was formed on a glass epoxy resin (FR4) substrate by a copper pattern. The outer diameter of each planar coil was 45 mm, the line width was 0.5 mm, the pitch between the lines was 1 mm, the number of turns was 10 turns, the copper thickness was 70 um, and the distance between the copper pattern surfaces of each layer was 0.2 mm. For the magnetic material, the relative magnetic permeability was 200, and the size was 50 × 50 × 1 mm ³ . The distance from the surface of the copper pattern on the power transmission surface side of the power transmission coil to the surface of the magnetic material loaded on the power receiving device was 2 mm. The analysis frequency was 150 kHz. An unillustrated aluminum plate (50 × 50 × 0.5 mm ³ ) simulating a heat radiating plate was disposed immediately above the magnetic body.

  FIG. 6 is an equivalent circuit diagram showing electrical connection of the planar coils L1 to L4. As shown in FIG. 6, the planar coils L1 and L2 are connected in series, and the planar coils L3 and L4 are connected in series. These two planar coil pairs are connected in parallel. The planar coils L1 to L4 are in a coupled state with each other. When the inductance values of the planar coils L1 to L4 are represented by L1 to L4, respectively, L1 <L2 <L3 <L4.

  Here, a plurality of coils connected in series will be referred to as a “coil group”. For example, in the example shown in FIG. 6, the planar coils L1 and L2 are the first coil group, and the planar coils L3 and L4 are the second coil group. The combined inductance value of the first coil group is obtained by combining the smallest inductance value L1 and the second smallest inductance value L2 among the four inductance values. The combined inductance value of the second coil group is obtained by combining the largest inductance value L4 and the second largest inductance value L3 among the four inductance values. Therefore, the combined inductance value of the first coil group is smaller than the combined inductance value of the second coil group.

  As described above, in the configuration of the planar coil disclosed in Patent Document 1, there is a difference between the combined inductance value of the first coil group connected in parallel and the combined inductance value of the second coil group. . Due to this difference, when AC power is transmitted, the balance between the impedance of the first coil group and the impedance of the second coil group is lost. When the impedance balance is lost, the loss of current flowing through the stacked planar coils increases. As a result, it was found that heat is generated in the first coil group having a lower impedance, and the transmission efficiency is lowered.

  In the above example, the power receiving device loaded with the magnetic material is disposed so as to face the inductance value of the first coil group connected in parallel and the inductance value of the second coil group. I found that there was a difference. However, there is a difference between the inductance value of the first coil group connected in parallel and the inductance value of the second coil group regardless of whether or not the power receiving device loaded with the magnetic material is arranged. Under similar conditions, similar problems can arise.

  Based on the above technical knowledge, the present inventors diligently studied a technique for reducing the amount of heat generation and improving the transmission efficiency by paying attention to the inductance of the planar coil. The inventors of the present invention have come up with the following aspects of the invention in order to reduce the loss due to the current flowing in the stacked planar coils and improve the transmission efficiency while reducing the thickness of the power transmission device. .

A power transmission device according to an aspect of the present disclosure is provided.
A power transmitting device that transmits AC power in a contactless manner to a power receiving device including a power receiving coil,
A power transmission surface for transmitting power to the power receiving device;
A power transmission circuit for converting DC power input from a DC power source into AC power;
2N (N is a natural number greater than or equal to 2) planar coils provided on the power transmission surface side inside the power transmission device and having different inductance values, and the AC power output from the power transmission circuit to the power reception coil And at least one power transmission coil for transmitting power,
The 2N planar coils are:
When i = 1 to N, among the 2N planar coils,
The i-th planar coil having the highest inductance and the i-th planar coil having the lowest inductance are connected in series, and
Each of the coil groups is connected in parallel,
According to the above aspect, in the 2N planar coils inside the power transmission apparatus, the value of the combined inductance of each of the coil groups connected in parallel (a plurality of planar coils connected in series) becomes a close value. Averaged.

  Specifically, when i = 1 to N, among the 2N planar coils, a planar coil having the i-th highest inductance value and a planar coil having the lowest i-th inductance value are connected in series. By configuring the connected coil groups, the combined inductance values of the coil groups are averaged so as to be close to each other.

  As a result, the balance of the resistance value among the coil groups connected in parallel is suppressed from being lost, so that the loss of current flowing in the planar coil can be reduced. As a result, unnecessary heat generation can be reduced and transmission efficiency can be improved.

A power transmission device according to another aspect of the present disclosure is provided.
A power transmitting device that transmits AC power in a contactless manner to a power receiving device including a power receiving coil,
A power transmission surface for transmitting power to the power receiving device;
A power transmission circuit for converting DC power input from a DC power source into AC power;
Including M planar coils (M is a natural number of 3 or more) having different inductance values provided on the power transmission surface side inside the power transmission device, and receiving the AC power output from the power transmission circuit to the power receiving coil And at least one power transmission coil for transmitting power,
The M planar coils have two or more coil groups including a coil group in which two or more planar coils selected in an order different from the magnitude order of the inductance values are connected in series as a set;
Each of the coil groups is connected in parallel.

  According to the said aspect, the inductance value of M plane coils inside a power transmission apparatus differs. The M planar coils include two or more coil groups in which two or more planar coils selected in an order different from the order of magnitude of inductance values are connected in series as a set.

  As a result, the value of the combined inductance of each of the coil groups can be made relatively close.

  Accordingly, it is possible to suppress the balance of the resistance values from being lost between the coil groups connected in parallel, and thus it is possible to reduce the loss of current flowing through the planar coil. As a result, unnecessary heat generation can be reduced and transmission efficiency can be improved.

  Moreover, in the said aspect, it is not necessary to laminate | stack a planar coil so that the inductance value of each planar coil may be in order of L1 <L2 <L3 <L4 from one surface of a power transmission antenna to the other surface.

  Hereinafter, embodiments of the present disclosure will be described. In addition, in each following embodiment, the same code | symbol is attached | subjected about the same component. In the following description, descriptions of overlapping items may be omitted.

(Embodiment 1)
[1. overall structure]
FIG. 7 is a block diagram illustrating a schematic configuration of the wireless power transmission system according to the first embodiment of the present disclosure. This wireless power transmission system includes a power transmission device 100 and a power reception device 200. Electric power is transmitted from the power transmitting antenna 110 in the power transmitting apparatus 100 to the power receiving antenna 210 in the power receiving apparatus 200 in a contactless manner.

  The power receiving device 200 includes a power receiving antenna 210 having a power receiving coil 212, resonant capacitors 214a and 214b, a power receiving circuit 220, and a secondary battery 230. The power receiving coil 212 and the resonant capacitors 214a and 214b constitute a series and parallel resonant circuit. The power receiving circuit 220 rectifies and outputs the AC power received by the power receiving coil 212. The secondary battery 230 is charged with the DC power output from the power receiving circuit 220. The energy stored in the secondary battery 230 is consumed by a load (not shown).

  The power receiving circuit 220 may include various circuits such as a rectifier circuit, a frequency conversion circuit, a constant voltage / constant current control circuit, and a modulation / demodulation circuit for communication. It is configured to convert the received AC energy into DC energy or low frequency AC energy available to the load. Various sensors for measuring the voltage / current output from the power receiving coil 212 may be included in the power receiving circuit 220.

  The power transmission device 100 includes a power transmission antenna 110 including a power transmission coil 112, a resonance capacitor 114, and a power transmission circuit 140. The power transmission coil 112 is connected in series with the resonance capacitor 114. The resonant capacitor 114 is connected to the power transmission circuit 140.

  For example, the power transmission coil 112 may have a configuration in which a plurality of thin flat coils formed of a substrate pattern are stacked. In addition, a winding coil using a copper wire, a litz wire, a twisted wire, or the like can be used. The resonant capacitors 114, 214a, and 214b may be provided as necessary. The self-resonant characteristic of each coil may be used in place of these capacitors.

  The power transmission circuit 140 includes, for example, a full-bridge inverter or an oscillation circuit such as a class D or class E. FIG. 8 shows an example in which the power transmission circuit 140 includes a full-bridge inverter and a control circuit 150 that controls the inverter. The power transmission circuit 140 may have various sensors for measuring a modulation / demodulation circuit for communication and voltage / current. The power transmission circuit 140 is connected to an external direct current (DC) power supply 300. DC power input from the DC power supply 300 is converted into AC power and output. This AC power is sent to the space by the power transmission coil 112.

  For example, the frequency at the time of power transmission is set to the same value as the resonance frequency of the power transmission resonator constituted by the power transmission coil 112 and the resonance capacitor 114. However, it is not limited to this. For example, it may be set to a value in the range of about 85 to 115% of the resonance frequency. The frequency band of power transmission can be set to a value within the range of 100 kHz to 200 kHz, for example, but may be set to a value outside this range.

  The DC power source 300 includes a commercial power source, a primary battery, a secondary battery, a solar cell, a fuel cell, a USB (Universal Serial Bus) power source, a high-capacity capacitor (for example, an electric double layer capacitor), and a voltage converter connected to the commercial power source. Or a combination thereof.

  The power transmission circuit 140 includes a control circuit 150 that is a processor that controls the operation of the entire power transmission apparatus 100. The control circuit 150 can be realized by a combination of a CPU and a memory storing a computer program, for example. The control circuit 150 may be a dedicated integrated circuit configured to realize the operation of the present embodiment. The control circuit 150 performs power transmission control (power transmission state adjustment) by the power transmission circuit 140.

  The control circuit 150 may include a communication circuit that performs communication with the power receiving apparatus 200. For example, the communication circuit can obtain information indicating fluctuations in the impedance of the load of the power receiving device 200. Based on the information, the control circuit 150 can instruct the power transmission circuit 140 to change the power transmission parameter so that, for example, a constant voltage is supplied to the load. Such power transmission parameters can be, for example, frequency, phase difference between a pair of switching elements of the inverter, or input voltage of the inverter. When adjusting the input voltage, the power transmission circuit 140 may include a DC / DC converter between the DC power supply 300 and the inverter. By changing these power transmission parameters, the voltage supplied to the load can be changed.

  The power transmission device 100 may include elements other than the above-described components. For example, a power receiving coil 212 by the control circuit 150 or a display element that displays the detection result of the foreign matter may be provided. Such a display element may be a light source such as an LED. Further, an oscillating circuit for detecting foreign matter and a detection coil may be provided.

  The configuration of power reception device 200 is not limited to that shown in FIG. As long as it has the receiving coil 212 which receives at least one part of the energy sent from the power transmission coil 112, the structure may be designed arbitrarily.

[2. Configuration of power transmission coil]
Next, the structure of the power transmission coil 112 in this embodiment is demonstrated. As shown in FIGS. 4A to 4C, the power transmission coil 112 is provided on the power transmission surface 130 side inside the power transmission device 100. Here, the power transmission surface 130 means a surface of the power transmission device 100 that faces the power reception device 200 during a power transmission operation. The power transmission coil 112 includes 2N (N is a natural number of 2 or more) planar coils having different inductance values. The AC power output from the power transmission circuit 140 is sent to the power receiving coil 212 by 2N planar coils. The 2N planar coils in the present embodiment, when i = 1 to N, are the i-th planar coil having the highest inductance and the i-th planar coil having the lowest inductance among the 2N planar coils. A group of coils connected in series is configured. Each of these coil groups is connected in parallel. The 2N planar coils can be realized by, for example, a multilayer substrate in which 2N substrates each having a conductor pattern wound on an insulating substrate or a dielectric substrate are stacked. In the present embodiment, 2N planar coils are stacked vertically on the power transmission surface 130. Here, “stacked perpendicular to the power transmission surface 130” means that when 2N planar coils are viewed from a direction perpendicular to the power transmission surface 130, at least some of the planar coils overlap each other. Means that Hereinafter, the detailed configuration of the power transmission coil 112 will be described by taking N = 2 as an example.

  FIG. 9 is a diagram illustrating a partial cross section of the power transmission coil 112 in the present embodiment. In this example, four planar coils in the case of N = 2 are configured by a four-layer substrate. The power transmission coil 112 is realized by a multilayer substrate in which a planar coil formed by winding a copper pattern 160 on a glass epoxy resin 170 as an insulating substrate is laminated. The inductance values of the planar coils are different from each other.

  FIG. 10 is an exploded perspective view of the power transmission coil 112 in the present embodiment. The planar coils in each layer are connected by through holes. Both ends of the power transmission coil 112 are connected to the terminal 180. Here, the layer of the planar coil L1 farthest from the power transmission surface 130 is referred to as a first layer, and hereinafter referred to as a second layer to a fourth layer in order. A through hole connecting the inner end of the first layer planar coil L1 and the inner end of the fourth layer planar coil L4, the inner end of the second layer planar coil L2, and the inner end of the third layer planar coil L3 The through-holes connecting the two are arranged so as not to conduct each other.

  FIG. 11 is an equivalent circuit diagram of the power transmission coil 112 in the present embodiment. Although not shown, each of the planar coils L1 to L4 is in a coupled state. As shown in FIGS. 10 and 11, planar coils L1 and L4 connected in series constitute a first coil group, and planar coils L2 and L3 connected in series constitute a second coil group. Yes. The first coil group and the second coil group are connected in parallel. As shown in FIG. 11, the order of the magnitudes of the inductance values of the planar coils L1 to L4 is L1 <L2 <L3 <L4. Therefore, the inductance value of the first coil group constituted by the planar coil L4 having the first largest inductance value and the planar coil L1 having the first smallest inductance value, and the planar coil L3 and the inductance value having the second largest inductance value. The inductance value of the second coil group constituted by the second smallest planar coil L2 is substantially the same value. Therefore, it can suppress that the balance of the impedance of each of the first coil group and the second coil group is lost. As a result, the loss reduction effect of the power transmission coil in parallel connection is improved.

  In order to verify the effect of this embodiment, the inventors connect four planar coils L1 to L4 as shown in FIG. 10 under the same conditions as the analysis described with reference to FIG. The characteristics of the power transmission coil of Example 1 were analyzed. On the other hand, the characteristics of the power transmission coil were also analyzed for a comparative example in which four planar coils L1 to L4 were connected as shown in FIG. Table 2 shows the analysis results of the combined inductance L and AC resistance R of the power transmission coil in Example 1 and the comparative example.

  As shown in Table 2, although the value of the inductance L is not substantially changed, the value of the AC resistance R is reduced by 4.1% in the first embodiment compared to the comparative example. From this, it can be seen that the configuration of the present embodiment can suppress unnecessary heat generation and improve transmission efficiency.

(Embodiment 2)
FIG. 12 is an exploded perspective view illustrating a configuration of the power transmission coil 112 according to the second embodiment of the present disclosure. FIG. 13 is an equivalent circuit diagram of the power transmission coil 112 in the present embodiment. The power transmission coil 112 in the present embodiment is different from the first embodiment in that N = 3, that is, six planar coils. Hereinafter, the same reference numerals are given to components common to or corresponding to those of the first embodiment, and description of common matters will not be repeated.

  The power transmission coil 112 in the present embodiment employs a 6-layer 3-parallel configuration in order to further reduce the loss from the first embodiment. As shown in FIGS. 12 and 13, the power transmission coil 112 in the present embodiment has six planar coils L1 to L6. The planar coils L1 and L6 are connected in series and constitute a first coil group. The planar coils L2 and L5 are connected in series and constitute a second coil group. The planar coils L3 and L4 are connected in series and constitute a third coil group. The first to third coil groups are connected in parallel. The order of the inductance values of the plurality of planar coils L1 to L6 is L1 <L2 <L3 <L4 <L5 <L6. Therefore, the first coil group includes the planar coil L6 having the first largest inductance value and the planar coil L1 having the first smallest inductance value. The second coil group includes a planar coil L5 having the second largest inductance value and a planar coil L2 having the second smallest inductance value. The third coil group includes a planar coil L4 having the third largest inductance value and a planar coil L3 having the third smallest inductance value. For this reason, the inductance values (combined inductance values) of the first to third coil groups are substantially the same.

  Thus, also in this embodiment, it can suppress that the balance of the impedance of each of the first to third coil groups is lost. As a result, the loss reduction effect of the power transmission coil 112 in parallel connection is improved.

  In this embodiment, N = 3, but N = 4 or N> 4. A further loss reduction effect can be expected by increasing the number of layers and the number of parallel connections within the allowable range of the thickness of the power transmission coil 112.

(Embodiment 3)
Next, a third embodiment of the present disclosure will be described. The power transmission coil 112 in the present embodiment includes M (M is a natural number of 3 or more) planar coils having different inductance values. The M planar coils have two or more coil groups including a coil group in which two or more planar coils selected in an order different from the order of magnitude of inductance values are connected in series. Each of the two or more coil groups is connected in parallel. Here, “the order different from the order of the magnitude of the inductance value” means an order in which at least a part of the order different from the order of the magnitude of the inductance value is included. As an example, assuming that M ≧ 4, a planar coil having the highest inductance, a planar coil having the second highest inductance, and a planar coil having the fourth highest inductance form one coil group. To do. In this case, the arrangement of the flat coil having the second highest inductance and the fourth flat coil having the highest inductance is different from the arrangement of the large and small inductances. Therefore, this order corresponds to “an order different from the order of the inductance values”. Hereinafter, this embodiment will be described by taking M = 4 as an example.

  FIG. 14 is an exploded perspective view showing the configuration of the power transmission coil 112 when M = 4. FIG. 15 is an equivalent circuit diagram of the power transmission coil 112. As shown in FIGS. 14 and 15, the power transmission coil 112 in the present embodiment has four planar coils L1 to L4. The planar coils L1 and L3 are connected in series and constitute a first coil group. The planar coils L2 and L4 are connected in series and constitute a second coil group. The first and second coil groups are connected in parallel. The order of the inductance values of the planar coils L1 to L4 is L1 <L2 <L3 <L4. Therefore, the inductance value of the first coil group configured by the planar coils L1 and L3 and the inductance value of the second coil group configured by the planar coils L2 and L4 are averaged. That is, the inductance values of the first and second coil groups are averaged by connecting the planar coils in an order different from the order of the inductance values in series. Therefore, it can suppress that the balance of the impedance of each of the first coil group and the second coil group is lost. As a result, the loss reduction effect of the power transmission coil 112 in parallel connection is improved.

  In order to verify the effect of this embodiment, the inventors connect four planar coils L1 to L4 as shown in FIG. 14 under the same conditions as the analysis described with reference to FIG. The characteristics of the power transmission coil of Example 2 were analyzed. Table 3 shows the analysis results of the combined inductance L and AC resistance R of the power transmission coil in Example 2 and the above-described comparative example.

  As shown in Table 3, the value of the inductance L is not substantially changed, but the value of the AC resistance R is reduced by 5.1% in Example 2 compared to the comparative example. From this, it can be seen that the configuration of the present embodiment can suppress unnecessary heat generation and improve transmission efficiency.

  FIG. 16 is a graph showing a result of comparison between the characteristics of the power transmission coil in the present embodiment and the first embodiment and the characteristics of the power transmission coil in the comparative example. It can be seen that the AC resistance R is particularly reduced by changing the connection of each of the planar coils L1 to L4 from the connection in the comparative example.

(Embodiment 4)
FIG. 17 is an exploded perspective view illustrating a configuration of the power transmission coil 112 according to the fourth embodiment of the present disclosure. FIG. 18 is an equivalent circuit diagram of the power transmission coil 112 in the present embodiment. The power transmission coil 112 in the present embodiment is different from that in the third embodiment in that M = 6, that is, six planar coils. Hereinafter, description of matters common to the third embodiment will not be repeated.

  As shown in FIGS. 17 and 18, the power transmission coil 112 in the present embodiment has six planar coils L1 to L6. The planar coils L1, L4, and L6 are connected in series and constitute a first coil group. The planar coils L2, L3, and L5 are connected in series and constitute a second coil group. The first and second coil groups are connected in parallel. In this example, the order of the inductance values of the planar coils L1 to L6 is L1 <L2 <L3 <L4 <L5 <L6. Therefore, the first coil group includes the planar coil L1 having the first smallest inductance value, the planar coil L4 having the fourth smallest inductance, and the planar coil L6 having the sixth smallest inductance. The first coil group includes a planar coil L2 having the second smallest inductance value, a planar coil L3 having the third smallest value, and a planar coil L5 having the fifth smallest value. For this reason, the inductance values of the first and second coil groups are averaged and become close values. Therefore, it can suppress that the balance of the impedance of the first coil group and the second coil group is lost. As a result, the loss reduction effect of the power transmission coil in parallel connection is improved.

  In the present embodiment and the third embodiment, at least one set of planar coils is selected in an order different from the order of inductance values among a plurality of planar coils connected in series constituting each of the plurality of coil groups. Yes. Thereby, the inductance value of the coil group is averaged. For example, in the configuration shown in FIG. 18, the planar coil L2 and the planar coil L3 constituting the second coil group are connected in the order of the inductance value, but the planar coil L3 and the planar coil L5 have the inductance value. They are connected in an order different from the order. For this reason, the inductance values of the first and second coil groups are averaged, and the loss reduction effect is improved.

  In this embodiment, M = 6, but N ≧ 7 may be acceptable. A further loss reduction effect can be expected by increasing the number of layers and the number of parallel connections within the allowable range of the thickness of the power transmission coil 112.

(Modification)
In the embodiment described above, it is assumed that the power receiving device 200 loaded with the magnetic body 250 is disposed to face the power transmitting device 100. However, the present disclosure is not limited to such a case. The technique of the present disclosure is effective in any situation where a difference occurs in the inductance of a plurality of planar coils included in the power transmission coil 112. As an example of such a situation, there is a case where at least one of the size and the number of turns of each planar coil is different.

  FIG. 19 is an exploded perspective view showing an example of the power transmission coil 112 in which the number of turns of each planar coil is different. FIG. 20 is an equivalent circuit diagram of the power transmission coil 112. As illustrated in FIG. 19, the power transmission coil of the present disclosure can be applied even when the size and the number of turns of each planar coil are different. In the power transmission coil 112 shown in FIG. 19, the number of turns of the planar coils L2 and L3 is smaller than that of the planar coils L1 and L4. The planar coil L2 has a reduced number of outer turns, and the planar coil L3 has a reduced number of inner turns. The order of the magnitudes of the inductance values of the planar coils L1 to L4 when the power receiving device loaded with a magnetic material is disposed opposite to the power transmission coil 112 is L2 <L3 <L1 <L4.

  In this example, as shown in FIGS. 19 and 20, the first coil group is configured by connecting planar coils L1 and L3 in series. A second coil group is configured by connecting the planar coils L2 and L4 in series. The first and second coil groups are connected in parallel. Therefore, the first coil group includes the planar coil L1 having the second largest inductance value and the planar coil L3 having the third largest inductance value. The second coil group includes a planar coil L4 having the first largest inductance value and a planar coil L2 having the fourth largest inductance value. For this reason, the inductance values of the first and second coil groups are substantially the same value. Therefore, it can suppress that the balance of the impedance of each of the first coil group and the second coil group is lost. As a result, the loss reduction effect of the power transmission coil 112 in parallel connection is improved.

  FIG. 21 is a perspective view showing an example of a power transmission coil formed by overlapping two planar coils on the same plane. Thus, two or more (two in the example of FIG. 21) planar coils formed on the same plane may be laminated over a plurality of layers. In this example, 2N planar coils are divided into layer units. Each layer is provided with a plurality of planar coils. Each layer is stacked vertically on the power transmission surface 130. Even in such a configuration, the loss reduction effect of the power transmission coil 112 can be improved by connecting the planar coils in consideration of the order of the inductance values. An equivalent circuit diagram of the power transmission coil 112 shown in FIG. 21 is the same as FIG.

  Further, a new planar coil may be further stacked on the plurality of planar coils in each of the above-described embodiments, and connected in series or in parallel.

  FIG. 22A is an equivalent circuit diagram illustrating a modification in which a planar coil La is newly connected in series to the power transmission coil 112 in the first embodiment. FIG. 22B is an equivalent circuit diagram illustrating a modification in which the planar coil Lb is newly connected in parallel to the power transmission coil 112 according to the first exemplary embodiment. 22A and 22B are effective when the inductance needs to be finely adjusted in the circuit design of the wireless power transmission system. Not only the configuration of the first embodiment, but also a new planar coil may be added to the configurations of the second to fourth embodiments or the modified example. Although not shown, the number of newly added planar coils may not be one. For example, one may be added in series and in parallel, two in series, or two in parallel.

  In addition, although the said modification was demonstrated mainly based on the structure of Embodiment 1, it is not restricted to this. Similar modifications are possible in other embodiments.

(Embodiment 5)
Next, Embodiment 5 according to a power transmission device 100 including a plurality of power transmission coils 112 will be described.

  FIG. 23A to FIG. 23C are diagrams illustrating the appearance and operation of the power transmission device 100 according to the fifth embodiment. The power transmission device 100 is a wireless charger and has a flat plate structure. As illustrated in FIG. 23A, the power transmission device 100 includes a plurality of power transmission coils 112 (in this example, seven power transmission coils 112a to 112g) arranged in a line. Each power transmission coil has a configuration in which a plurality of planar coils in any of the above-described embodiments are stacked. Each power transmission coil has a shape that is short in the arrangement direction (lateral direction in the figure) and long in a direction perpendicular to the arrangement direction. Although not shown, the power transmission device 100 also includes a power transmission circuit that supplies AC power to each power transmission coil, and a control circuit that controls a connection state between the power transmission circuit and each power transmission coil.

  When the power receiving device 200 including the power receiving coil 212 comes close to the power transmitting device 100, the control circuit electrically connects the two power transmitting coils closest to the power receiving coil 212 and the power transmitting circuit. For example, in the state shown in FIG. 23B, only two power transmission coils 112c and 112d are connected to the power transmission circuit. In the state shown in FIG. 23C, only two power transmission coils 112f and 112g are connected to the power transmission circuit. In this example, power is always supplied to two power transmission coils, but the number of power transmission coils that are simultaneously supplied may be other than two. The number of power transmission coils fed simultaneously may be a number smaller than the total number of power transmission coils.

  FIG. 24 is a block diagram illustrating a schematic configuration of the power transmission device 100 according to the present embodiment. Constituent elements common or corresponding to those in FIG. 7 are denoted by the same reference numerals, and description of common matters will not be repeated.

  The power transmission device 100 includes a plurality of power transmission coils 112, a plurality of switches 190, a resonance capacitor 114, and a power transmission circuit 140. The power transmission circuit 140 includes a control circuit 150. The plurality of switches 190 are connected to the plurality of power transmission coils 112, respectively. Here, “connected” means connected so as to be electrically conductive. The plurality of power transmission coils 112 are connected in parallel to the power transmission circuit 140 via the plurality of switches 190. One end of each power transmission coil is connected to one electrode of the capacitor 114. The other electrode of the capacitor 114 is connected to the power transmission circuit 140. Each of the plurality of switches 190 is connected to a terminal of the plurality of power transmission coils 112 to which the capacitor 114 is not connected. This is because the voltage fluctuation is large between the capacitor 114 and the plurality of power transmission coils 112.

  The control circuit 150 detects the relative position of the power receiving coil 212 with respect to the plurality of power transmitting coils 112. In addition to this, a foreign object such as a metal adjacent to the power transmission coil 112 may be detected. Detection of the position of the power receiving coil 212 and detection of foreign matter can be performed based on measured values of parameters that vary with impedance changes such as voltage, current, frequency, and inductance on the circuit. More specifically, the control circuit 150 turns on the plurality of switches 190 in order by a fixed number (for example, two), and measures any of the above parameters each time. When a value deviating from the specified range is measured, it can be determined that the power receiving coil 212 or a foreign object exists in the vicinity of the power transmitting coil that is feeding at that time. In order to enable such detection, the control circuit 150 may include a detection circuit (not shown). In the present disclosure, the detection of the power receiving coil 212 and the detection of foreign matter are not limited to a specific method, and can be performed by any known method.

  The control circuit 150 in the present embodiment selects two power transmission coils to be used for power transmission according to the relative position of the power reception coil 212 with respect to the plurality of power transmission coils 112. And the conduction | electrical_connection state of the some switch 190 is switched so that alternating current power may be supplied from the power transmission circuit 140 only to two selected power transmission coils. As a result, AC energy is sent from the two selected power transmission coils to the space.

  In the present embodiment, the power transmission device 100 has a plurality of power transmission coils. Thereby, the range which can be transmitted is expanded compared with the structure which has a single power transmission coil. For this reason, the power receiving apparatus 200 can be easily aligned.

(Other embodiments)
The technology of the present disclosure is not limited to the above-described embodiment, and various modifications can be made. Hereinafter, examples of other embodiments will be described.

  FIG. 25 is a diagram illustrating a configuration example of a wireless power transmission system that transmits power from a wall in a contactless manner to a robot 500 used in a hospital or the like. In this example, the power transmission device 100 is embedded in the wall. The robot 500 includes components similar to those of the power receiving device 200 illustrated in FIGS. 4A to 4C or 7. Furthermore, the electric motor 240 for a drive and the some wheel 270 for a movement are provided. With such a system, for example, electric power can be transmitted from a wall in a non-contact manner to a robot 500 in a hospital, and charging can be performed automatically without borrowing a person. Instead of the robot 500, a similar configuration may be applied to an electric vehicle such as an electric vehicle.

  FIG. 26 is a block diagram schematically illustrating a vehicle 600 equipped with the power transmission device 100 according to the present disclosure. The vehicle 600 includes the power transmission device 100 inside a console box 400 shown in FIG. Thereby, the user can charge an electronic device such as a mobile phone in the vehicle 600.

  In the above embodiment, the power transmission coil has a plurality of stacked planar coils, but the power receiving coil may have a plurality of similar planar coils. Also in the power receiving device, it is effective to apply the coil configuration of the present disclosure because the inductance values of the plurality of planar coils may be different from each other.

  FIG. 27 is a cross-sectional view illustrating an example of a wireless power transmission system including such a power receiving device 200. In this example, the power receiving device 200 includes a power receiving surface 260 that receives power from the power transmitting device 100, a power receiving circuit 220 that converts received AC power into DC power, and at least a power receiving surface 260 provided inside the power receiving device 200. One power receiving coil (a part of the power receiving antenna 210). The at least one power receiving coil includes 2N (N is a natural number of 2 or more) planar coils having different inductance values, and outputs AC power input from the power receiving surface 260 to the power receiving circuit 220. When 2 = 1 planar coils, i = 1 to N, among the 2N planar coils, the planar coil having the i-th highest inductance and the planar coil having the i-th lowest inductance are connected in series. A connected coil group is configured. Each of these coil groups is connected in parallel. Here, the “power receiving surface” means the surface of the power receiving device 200 that faces the power transmitting surface 130 of the power transmitting device 100 during power reception.

  Instead of the above configuration, the at least one power receiving coil includes M planar coils having different inductance values (M is a natural number of 3 or more), and the M planar coils are arranged in order of the inductance values. May have two or more coil groups including a coil group in which two or more planar coils selected in different orders are connected in series as a set. Also in this case, each of the two or more coil groups is connected in parallel.

  In the example illustrated in FIG. 27, the power transmission device 100 includes a magnetic body 120 on the opposite side of the power transmission surface 130 with respect to the power transmission coil. For this reason, the inductance values of the plurality of stacked planar coils in the power receiving antenna 210 tend to be higher as they are closer to the magnetic body 120. Therefore, it is effective to apply the configuration of the plurality of stacked planar coils in any one of the above embodiments to the power receiving coil in the power receiving antenna 210. In this example, the power transmission coil in the power transmission antenna 110 may include a plurality of stacked planar coils in any of the above embodiments, or may be a conventional power transmission coil. The power transmission device 100 may not have the magnetic body 120.

  As described above, the present inventors have conceived the following aspects of the invention in order to reduce the loss of current flowing in the stacked planar coils and improve the transmission efficiency.

(1) A power transmission device according to the first aspect of the present disclosure includes:
A power transmitting device that transmits AC power in a contactless manner to a power receiving device including a power receiving coil,
A power transmission surface for transmitting power to the power receiving device;
A power transmission circuit for converting DC power input from a DC power source into AC power;
2N (N is a natural number greater than or equal to 2) planar coils provided on the power transmission surface side inside the power transmission device and having different inductance values, and the AC power output from the power transmission circuit to the power reception coil And at least one power transmission coil for transmitting power,
The 2N planar coils are:
When i = 1 to N, among the 2N planar coils,
The i-th planar coil having the highest inductance and the i-th planar coil having the lowest inductance are connected in series, and
Each of the coil groups is connected in parallel,
According to the above aspect, in the 2N planar coils inside the power transmission apparatus, the value of the combined inductance of each of the coil groups connected in parallel (a plurality of planar coils connected in series) becomes a close value. Averaged.

  Specifically, when i = 1 to N, among the 2N planar coils, a planar coil having the i-th highest inductance value and a planar coil having the lowest i-th inductance value are connected in series. By configuring the connected coil groups, the combined inductance values of the coil groups are averaged so as to be close to each other.

  As a result, the balance of the resistance value among the coil groups connected in parallel is suppressed from being lost, so that the loss of current flowing in the planar coil can be reduced. As a result, unnecessary heat generation can be reduced and transmission efficiency can be improved.

(2) The power transmission device according to the second aspect of the present disclosure is the power transmission device according to the first aspect of the present disclosure.
When N is 2, a planar coil having the first highest inductance value and a planar coil having the first lowest inductance value are connected in series, the planar coil having the second highest inductance value, and the inductance value second. A low planar coil is connected in series.

  According to the above aspect, in the four planar coils stacked inside the power transmission device, the combined inductance value of each of the coil groups connected in parallel (a plurality of planar coils connected in series) becomes a close value. Is averaged as

(3) The power transmission device according to the third aspect of the present disclosure is the power transmission device according to the first or second aspect of the present disclosure.
A magnetic body is provided inside the power transmission device on the side opposite to the power transmission surface side of the power transmission coil.

  According to the above aspect, eddy current loss in the power transmission coil can be reduced.

(4) The power transmission device according to the fourth aspect of the present disclosure is the power transmission device according to any one of the first to third aspects of the present disclosure.
The 2N planar coils are a multilayer substrate in which 2N substrates each having a conductor pattern wound on an insulating substrate or a dielectric substrate are stacked.

  According to the said aspect, thickness reduction of a power transmission apparatus can be achieved.

(5) The power transmission device according to the fifth aspect of the present disclosure is the power transmission device according to any one of the first to fourth aspects of the present disclosure.
The at least one power transmission coil includes a plurality of power transmission coils.

  According to the said aspect, when a some power transmission coil is arranged in the direction parallel to a power transmission surface, the area which can be transmitted can be expanded.

(6) The power transmission device according to the sixth aspect of the present disclosure is the power transmission device according to any one of the first to fifth aspects of the present disclosure.
The power transmission coil includes a first additional planar coil connected in series with the 2N planar coils, or a second additional planar coil connected in parallel with the 2N planar coils.

  According to the above aspect, the inductance can be easily adjusted when it is necessary to finely adjust the inductance in circuit design.

(7) The power transmission device according to the seventh aspect of the present disclosure is the power transmission device according to any one of the first to sixth aspects of the present disclosure.
The 2N planar coils are stacked perpendicular to the power transmission surface.

  According to the said aspect, it is easy to connect each planar coil based on the order of the magnitude | size of an inductance value.

(8) The power transmission device according to the eighth aspect of the present disclosure is the power transmission device according to any one of the first to sixth aspects of the present disclosure.
The 2N planar coils are divided into layer units,
Each layer is provided with a plurality of planar coils,
Each of the layers is stacked perpendicular to the power transmission surface.

  According to the said aspect, since several planar coils can be arrange | positioned at each layer, a power transmission coil can be made thin.

  (9) The vehicle according to the ninth aspect of the present disclosure is equipped with the power transmission device according to any one of the first to eighth aspects of the present disclosure.

  According to the said aspect, charging to an electronic device can be performed with high electric power transmission efficiency within a vehicle.

  (10) A wireless power transmission system according to a tenth aspect of the present disclosure includes the power transmission device according to any one of the first to eighth aspects of the present disclosure, and the power reception device.

  According to the above aspect, a wireless power transmission system including a thin power transmission device with high power transmission efficiency can be realized. Such a wireless power transmission system may be, for example, a medical robot or a transport robot system.

(11) A power transmission coil according to an eleventh aspect of the present disclosure is:
A power transmission coil used in a power transmission device that transmits AC power in a contactless manner to a power reception device including a power reception coil,
In the power transmission device,
A power transmission surface for transmitting power to the power receiving device;
A power transmission circuit for converting DC power input from a DC power source into AC power;
And at least one power transmission coil that transmits the AC power output from the power transmission circuit to the power reception coil, and
The power transmission coil is:
2N (N is a natural number of 2 or more) planar coils provided on the power transmission surface side inside the power transmission device,
The 2N planar coils are:
When i = 1 to N, among the 2N planar coils, the planar coil having the i-th highest inductance and the planar coil having the i-th lowest inductance are connected in series. And
Each of the coil groups is connected in parallel.

  According to the said aspect, the effect similar to a 1st aspect can be acquired.

  (12) A power transmission antenna according to the twelfth aspect of the present disclosure includes the power transmission coil according to the eleventh aspect of the present disclosure and a resonance capacitor.

  According to the said aspect, the effect similar to a 1st aspect can be acquired.

(13) A power transmission device according to a thirteenth aspect of the present disclosure includes:
A power transmitting device that transmits AC power in a contactless manner to a power receiving device including a power receiving coil,
A power transmission surface for transmitting power to the power receiving device;
A power transmission circuit for converting DC power input from a DC power source into AC power;
Including M planar coils (M is a natural number of 3 or more) having different inductance values provided on the power transmission surface side inside the power transmission device, and receiving the AC power output from the power transmission circuit to the power receiving coil And at least one power transmission coil for transmitting power,
The M planar coils have two or more coil groups including a coil group in which two or more planar coils selected in an order different from the magnitude order of the inductance values are connected in series as a set;
Each of the coil groups is connected in parallel.

  According to the said aspect, the inductance value of M plane coils inside a power transmission apparatus differs. The M planar coils include two or more coil groups in which two or more planar coils selected in an order different from the order of magnitude of inductance values are connected in series as a set.

  As a result, the value of the combined inductance of each of the coil groups can be made relatively close.

  Accordingly, it is possible to suppress the balance of the resistance values from being lost between the coil groups connected in parallel, and thus it is possible to reduce the loss of current flowing through the planar coil. As a result, unnecessary heat generation can be reduced and transmission efficiency can be improved.

  Moreover, in the said aspect, it is not necessary to laminate | stack a planar coil so that the inductance value of each planar coil may be in order of L1 <L2 <L3 <L4 from one surface of a power transmission antenna to the other surface.

(14) A power transmission device according to a fourteenth aspect of the present disclosure is the power transmission device according to the thirteenth aspect of the present disclosure.
Each of the M planar coils is stacked in order of increasing or decreasing inductance value.

  According to the said aspect, it is easy to connect each planar coil based on the order of the magnitude | size of an inductance value.

(15) A power transmission device according to a fifteenth aspect of the present disclosure is the power transmission device according to the thirteenth or fourteenth aspect of the present disclosure.
The M planar coils are stacked perpendicular to the power transmission surface.

  According to the said aspect, it is easy to connect each planar coil based on the order of the magnitude | size of an inductance value.

(16) A power transmission device according to a sixteenth aspect of the present disclosure is the power transmission device according to the thirteenth aspect of the present disclosure.
The M planar coils are divided into layers,
Each layer is provided with a plurality of planar coils,
Each of the layers is stacked perpendicular to the power transmission surface.

  According to the said aspect, since several planar coils can be arrange | positioned at each layer, a power transmission coil can be made thin.

(17) A power transmission device according to a seventeenth aspect of the present disclosure is the power transmission device according to any one of the thirteenth to sixteenth aspects of the present disclosure.
Inside the power transmission device, a magnetic body is provided on the side opposite to the power transmission surface side of the power transmission coil.

  According to the above aspect, eddy current loss in the power transmission coil can be reduced.

(18) A power transmission device according to an eighteenth aspect of the present disclosure is the power transmission device according to any one of the thirteenth to seventeenth aspects of the present disclosure.
The M planar coils are multilayer substrates obtained by stacking the M substrates on which a conductive pattern is wound on an insulating substrate or a dielectric substrate.

  According to the said aspect, thickness reduction of a power transmission apparatus can be achieved.

(19) A power transmission device according to a nineteenth aspect of the present disclosure is the power transmission device according to any one of the thirteenth to eighteenth aspects of the present disclosure.
The at least one power transmission coil includes a plurality of power transmission coils.

  According to the said aspect, when a some power transmission coil is arranged in the direction parallel to a power transmission surface, the area which can be transmitted can be expanded.

(20) A power transmission device according to a twentieth aspect of the present disclosure is the power transmission device according to any one of the thirteenth to nineteenth aspects of the present disclosure.
The power transmission coil includes a third additional planar coil connected in series with the M planar coils, or a fourth additional planar coil connected in parallel with the M planar coils.

  According to the above aspect, the inductance can be easily adjusted when it is necessary to finely adjust the inductance in circuit design.

  (21) A vehicle according to a twenty-first aspect of the present disclosure is equipped with the power transmission device according to any one of the thirteenth to twentieth aspects of the present disclosure.

  According to the said aspect, charging to an electronic device can be performed with high electric power transmission efficiency within a vehicle.

  (22) A wireless power transmission system according to a twenty-second aspect of the present disclosure includes the power transmission device according to any one of the thirteenth to sixteenth aspects of the present disclosure, and the power receiving device.

  According to the above aspect, a wireless power transmission system including a thin power transmission device with high power transmission efficiency can be realized. Such a wireless power transmission system may be, for example, a medical robot or a transport robot system.

(23) A power transmission coil according to a twenty-third aspect of the present disclosure,
A power transmission coil used in a power transmission device that transmits AC power in a contactless manner to a power reception device including a power reception coil,
In the power transmission device,
A power transmission surface for transmitting power to the power receiving device;
A power transmission circuit for converting DC power input from a DC power source into AC power;
At least one power transmission coil that transmits the AC power output from the power transmission circuit to the power reception coil;
A magnetic body provided on the side opposite to the power transmission surface side of the power transmission coil inside the power transmission device,
The power transmission coil is:
Including M (M is a natural number of 3 or more) planar coils provided on the power transmission surface side inside the power transmission device and having different inductance values;
The M planar coils have two or more coil groups including a coil group in which two or more planar coils selected in an order different from the magnitude order of the inductance values are connected in series as a set;
Each of the coil groups is connected in parallel,
According to the said aspect, the effect similar to a 13th aspect can be acquired.

  (24) A power transmission antenna according to a twenty-fourth aspect of the present disclosure includes the power transmission coil according to the twenty-third aspect of the present disclosure and a resonance capacitor.

  According to the said aspect, the effect similar to a 13th aspect can be acquired.

(25) A power receiving device according to a twenty-fifth aspect of the present disclosure includes:
A power receiving device that receives AC power in a contactless manner from a power transmitting device including a power transmission coil,
A power receiving surface for receiving power from the power transmission device;
A power receiving circuit that converts AC power input from the power receiving surface into DC power;
The power receiving device includes 2N (N is a natural number of 2 or more) planar coils having different inductance values provided on the power receiving surface side inside the power receiving device, and the AC power input from the power receiving surface is supplied to the power receiving circuit. And at least one power receiving coil for outputting,
The 2N planar coils are:
When i = 1 to N, among the 2N planar coils,
The i-th planar coil having the highest inductance and the i-th planar coil having the lowest inductance are connected in series, and
Each of the coil groups is connected in parallel.

  According to the said aspect, the power receiving apparatus which has an effect similar to a 1st aspect is realizable.

(26) A power receiving coil according to a twenty-sixth aspect of the present disclosure includes:
A power receiving coil used in a power receiving device that receives AC power in a contactless manner from a power transmitting device including a power transmitting coil,
The power receiving device includes
A power receiving surface for receiving power from the power transmission device;
A power receiving circuit that converts AC power input from the power receiving surface into DC power;
The power receiving device includes 2N (N is a natural number of 2 or more) planar coils having different inductance values provided on the power receiving surface side inside the power receiving device, and the AC power input from the power receiving surface is supplied to the power receiving circuit. And at least one receiving coil for outputting,
The power receiving coil is
The 2N planar coils are:
When i = 1 to N, among the 2N planar coils,
The i-th planar coil having the highest inductance and the i-th planar coil having the lowest inductance are connected in series, and
Each of the coil groups is connected in parallel.

  According to the above aspect, the same effect as in the 25th aspect can be obtained.

  (27) A power receiving antenna according to a twenty-seventh aspect of the present disclosure includes the power receiving coil according to the twenty-sixth aspect of the present disclosure and a resonance capacitor.

  According to the above aspect, the same effect as in the 25th aspect can be obtained.

(28) A power receiving device according to a twenty-eighth aspect of the present disclosure includes:
A power receiving device that receives AC power in a contactless manner from a power transmitting device including a power transmission coil,
A power receiving surface for receiving power from the power transmission device;
A power receiving circuit that converts AC power input from the power receiving surface into DC power;
The power receiving device includes M planar coils (M is a natural number of 3 or more) having different inductance values provided on the power receiving surface side inside the power receiving device, and the AC power input from the power receiving surface is supplied to the power receiving circuit. And at least one power receiving coil for outputting,
The M planar coils have two or more coil groups including a coil group in which two or more planar coils selected in an order different from the magnitude order of the inductance values are connected in series as a set;
Each of the coil groups is connected in parallel.

  According to the said aspect, the power receiving apparatus which has an effect similar to a 13th aspect is realizable.

(29) A power transmission coil according to a twenty-ninth aspect of the present disclosure,
A power receiving coil used in a power receiving device that receives AC power in a contactless manner from a power transmitting device including a power transmitting coil,
The power receiving device includes
A power receiving surface for receiving power from the power transmission device;
A power receiving circuit that converts AC power input from the power receiving surface into DC power;
The power receiving device includes M planar coils (M is a natural number of 3 or more) having different inductance values provided on the power receiving surface side inside the power receiving device, and the AC power input from the power receiving surface is supplied to the power receiving circuit. And at least one receiving coil for outputting,
The M planar coils are:
Having two or more coil groups including a coil group in which two or more planar coils selected in an order different from the magnitude order of the inductance values are connected in series as a set;
Each of the coil groups is connected in parallel,
According to the above aspect, the same effect as in the 28th aspect can be obtained.

  (30) A power transmission antenna according to a thirtieth aspect of the present disclosure includes the power receiving coil according to the twenty-ninth aspect of the present disclosure and a resonance capacitor.

  According to the above aspect, the same effect as in the 28th aspect can be obtained.

  The power transmission device and the wireless power transmission system according to the present disclosure are widely applicable to, for example, applications that charge or supply power to electric vehicles, AV devices, batteries, medical devices, and the like.

DESCRIPTION OF SYMBOLS 100 Power transmission device 110 Power transmission antenna 112 Power transmission coil 114 Resonance capacitor 120 Magnetic body 125 Metal housing 130 Power transmission surface 140 Power transmission circuit 150 Control circuit 160 Copper pattern 170 Glass epoxy resin 180 Terminal 190 Switch 200 Power reception device 210 Power reception antenna 212 Power reception coil 214a, 214b Resonant capacitor 220 Power receiving circuit 230 Secondary battery 240 Electric motor for driving 250 Magnetic body 270 Wheel 300 DC power supply 400 Console box 500 Hospital robot 600 Vehicle

Claims (12)

A power transmitting device that transmits AC power in a contactless manner to a power receiving device including a power receiving coil,
A power transmission surface for transmitting power to the power receiving device;
A power transmission circuit for converting DC power input from a DC power source into AC power;
2N (N is a natural number greater than or equal to 2) planar coils provided on the power transmission surface side inside the power transmission device and having different inductance values, and the AC power output from the power transmission circuit to the power reception coil And at least one power transmission coil for transmitting power,
The 2N planar coils are:
When i = 1 to N, among the 2N planar coils,
The i-th planar coil having the highest inductance and the i-th planar coil having the lowest inductance are connected in series, and
Each of the coil groups is connected in parallel,
Power transmission device. When N is 2, a planar coil having the first highest inductance value and a planar coil having the first lowest inductance value are connected in series, the planar coil having the second highest inductance value, and the inductance value second. A low planar coil is connected in series,
The power transmission device according to claim 1. Provided a magnetic body on the opposite side to the power transmission surface side of the power transmission coil inside the power transmission device,
The power transmission device according to claim 1 or 2. The 2N planar coils are multilayer substrates in which 2N substrates each having a conductive pattern wound on an insulating substrate or a dielectric substrate are stacked.
The power transmission device according to any one of claims 1 to 3. The at least one power transmission coil includes a plurality of power transmission coils;
The power transmission device according to any one of claims 1 to 4. The power transmission coil includes a first additional planar coil connected in series with the 2N planar coils, or a second additional planar coil connected in parallel with the 2N planar coils.
The power transmission device according to any one of claims 1 to 5. The 2N planar coils are stacked perpendicular to the power transmission surface,
The power transmission device according to any one of claims 1 to 6. The 2N planar coils are divided into layer units,
Each layer is provided with a plurality of planar coils,
Each of the layers is stacked perpendicular to the power transmission surface,
The power transmission device according to any one of claims 1 to 3 .   A vehicle equipped with the power transmission device according to claim 1. A wireless power transmission system comprising the power transmission device according to claim 1 and the power reception device. A power transmission coil used in a power transmission device that transmits AC power in a contactless manner to a power reception device including a power reception coil,
In the power transmission device,
A power transmission surface for transmitting power to the power receiving device;
A power transmission circuit for converting DC power input from a DC power source into AC power;
And at least one power transmission coil that transmits the AC power output from the power transmission circuit to the power reception coil, and
The power transmission coil is:
2N (N is a natural number of 2 or more) planar coils provided on the power transmission surface side inside the power transmission device,
The 2N planar coils are:
When i = 1 to N, among the 2N planar coils, the planar coil having the i-th highest inductance and the planar coil having the i-th lowest inductance are connected in series. And
Each of the coil groups is connected in parallel,
Power transmission coil.   A power transmission antenna comprising the power transmission coil according to claim 11 and a resonance capacitor.

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