JP2015220891A - Resonator and wireless power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resonator and a wireless power supply system, capable of easily achieving satisfactory transmission efficiency, using a magnetic field resonance method.SOLUTION: A resonator 30 for use in the wireless power supply system which transmits power based on the magnetic field resonance method includes: a resonance coil (winding coil) 32 having a predetermined resonant frequency; a support member 31 for supporting the resonance coil 32; and an electric field concentration part 33, which is composed of a dielectric ceramic material having permittivity higher than the permittivity of the material of the support member 31, and disposed in a part of a surface vicinity region of the resonance coil 32. Thus, an electric field between the lines of the resonance coil 32 is concentrated to the electric field concentration part 33 of high permittivity. This enables a reduced loss and an increased Q value of the resonance coil 32.

Description

  The present invention relates to a wireless power feeding system that uses a magnetic field resonance between resonators to transmit electric power from a power transmitting device to a power receiving device in a contactless manner.

  Conventionally, there is a demand for a wireless power feeding system that transmits power from a power transmission device to a power reception device in a contactless manner. As a technique for realizing a wireless power feeding system, a technique using electromagnetic induction, a technique using electromagnetic waves, and the like have been proposed. In recent years, as a technique applicable to a wireless power feeding system, a magnetic field resonance method in which electric power is transmitted from a power transmission device to a power reception device by using resonance of a magnetic field between resonators has attracted attention. For example, Patent Document 1 discloses a basic concept of a magnetic field resonance method in which electric power is transmitted from one resonator to the other resonator by resonance of magnetic fields of two resonators arranged to face each other at a predetermined distance. ing. Further, for example, Non-Patent Document 1 discloses a method for realizing a high Q value in a resonance coil as an antenna used in a magnetic field resonance method. Further, for example, Non-Patent Document 2 has theoretically studied the maximum transmission efficiency obtained in the magnetic field resonance method, and it is possible to improve the transmission efficiency by increasing the Q value of each resonator. It is shown. Further, for example, in Patent Document 2, an electric vehicle or a plug-in hybrid vehicle is assumed as an application target of a wireless power feeding system, and a magnetic resonance method is used to provide a wireless power feeding system in a vehicle from a resonance coil disposed in a lower portion of the vehicle. A technique for transmitting power to a resonance coil is disclosed.

Special table 2009-501510 JP 2009-106136 A

Tomoyuki Fujieda, Masami Suzuki, “Examination of low-loss antenna for magnetic field resonance power transmission”, PIONEER R & D, Vol. 21, no. 1/2012, p. 11-15 Hidetoshi Matsuki, et al., “Frontiers of Non-contact Power Transmission Technology”, CM Publishing, p. 7 (August 2009)

  The resonator in the above-described wireless power feeding system includes, for example, a resonance coil using a winding coil such as a copper wire, and a support member having mechanical strength for ensuring the shape of the resonance coil. When transmitting AC power using a resonator in a wireless power feeding system, in order to maintain good transmission efficiency, it is necessary to prevent the loss of the resonance coil from increasing and the Q value from decreasing. However, in the case of using the resonator having the above-described structure, the electric field generated by the potential difference between the coil wires passes through the support member, so that the support member acts as a dielectric, so that the loss of the resonance coil (dielectric loss) There is a problem that the Q value is lowered by the increase, and the transmission efficiency is lowered. On the other hand, as the material used for the support member, it is desirable to use a general resin material or the like in consideration of mechanical strength and cost. In this case, an increase in loss is unavoidable. As described above, in the conventional wireless power feeding system using the magnetic field resonance method, it is difficult to transmit power with high transmission efficiency using the resonator including the resonance coil and the support member.

  The present invention has been made to solve these problems, and an object of the present invention is to provide a resonator and a wireless power feeding system that can easily realize good transmission efficiency.

  In order to solve the above-described problems, a resonator according to the present invention is a resonator in a wireless power feeding system that transmits power from a power transmission side resonator to a power reception side resonator mainly using resonance of a magnetic field, A resonance coil that mutually converts alternating-current power and electromagnetic energy at a resonance frequency, a support member that supports the resonance coil, and a part of a region near the surface of the resonance coil, and a dielectric of the material of the support member And an electric field concentrating portion made of a dielectric ceramic material with a high dielectric constant having a dielectric constant higher than the dielectric constant.

  According to the resonator of the present invention, in the wireless power feeding system of the non-contact power transmission method (magnetic field resonance method) using magnetic field resonance, the resonance coil constituting each resonator on the power transmission side and the power reception side is the support member. In addition, an electric field concentration portion made of a dielectric ceramic material having a dielectric constant higher than that of the material of the support member is disposed in a part of the vicinity of the surface of the surface. Therefore, since the electric field generated between the lines of the resonance coil during the operation of the resonator passes through the dielectric ceramic material with relatively little loss, the Q value of the resonance coil can be increased. And when transmitting electromagnetic field energy between the resonators on the power transmission side and the power reception side using the resonance coil having a high Q value in this way, good transmission efficiency can be realized. The “region in the vicinity of the surface of the resonance coil” is a region that is in contact with the surface of the resonance coil or that the distance from the surface of the resonance coil is smaller than the line pitch of the winding coil that forms the resonance coil. desirable.

In the resonator of the present invention, it is desirable that the dielectric ceramic material constituting the electric field concentration portion has a relative dielectric constant εr of 8 or more and a dielectric loss tangent tan δ of 10 ⁻² or less. If the relative dielectric constant εr of the dielectric ceramic material is less than 8, the effect of increasing the Q value by concentrating the electric field between the lines of the resonant coil becomes insufficient, and the dielectric loss tangent tan δ of the dielectric ceramic material is 10 ^{−. This} is because when the ratio exceeds ² , the Q value decreases due to an increase in dielectric loss.

  In the resonator according to the present invention, it is desirable that the electric field concentrating portion described above is set in an area ratio of 10% or more in the area near the surface of the resonance coil. This is because the Q value decreases if the area of the electric field concentration portion is less than 10% in area ratio. However, even if the area of the electric field concentration portion is set to about 10% in area ratio, the desired Q value can be secured, so that the increase in weight due to the dielectric ceramic material can be suppressed while ensuring the mechanical strength of the resonator. Can do.

  In the resonator of the present invention, a variety of resonant coils can be used. For example, a resonance coil constituted by a spiral type winding coil or a resonance coil constituted by a helical type winding coil may be adopted.

  In order to solve the above-described problem, a wireless power feeding system according to the present invention is a wireless power feeding system that mainly transmits power from a power transmission device to a power reception device by using resonance of a magnetic field. A power source that supplies alternating-current power of a frequency, and a power-transmission-side resonator that resonates with the alternating-current power supplied from the power source and transmits the alternating-current power as electromagnetic energy, and the power receiving device includes the power transmission A power receiving side resonator coupled with a side resonance coil by resonance of the magnetic field and receiving the electromagnetic field energy as AC power, and a circuit unit that operates by the AC power received by the power receiving side resonator, Each of the power transmission side resonator and the power reception side resonator includes a resonance coil that mutually converts AC power and electromagnetic energy having a predetermined resonance frequency, and a support that supports the resonance coil. And an electric field concentration portion made of a dielectric ceramic material having a high dielectric constant and having a dielectric constant higher than that of the material of the support member, disposed in a part of a region near the surface of the resonance coil. Is done.

  According to the wireless power feeding system of the present invention, the resonator having the above characteristics can be applied to each of the power transmission side resonator of the power transmission device and the power reception side resonator of the power reception device. Therefore, in the power transmission device, the power transmission side resonator that resonates with the AC power supplied from the power supply transmits the electromagnetic field energy, and in the power reception device, the power reception side resonator receives the electromagnetic field energy and enters the subsequent circuit unit. Output AC power. For example, the wireless power feeding system of the present invention can be used for various applications such as power supply to vehicles such as electric vehicles and plug-in hybrid vehicles. The structure of the resonator in the wireless power feeding system of the present invention is as described above, and the same is true in that the effect of increasing the Q value of the resonance coil can be obtained by the concentration of the electric field on the electric field concentration portion.

  According to the present invention, in the resonator including the resonance coil and the support member, the electric field concentration portion made of the dielectric ceramic material having a high dielectric constant is provided in a part of the region near the surface of the resonance coil, so that loss is generated. It is possible to increase the Q value of the resonance coil by suppressing the above, and it is possible to realize a wireless power feeding system that can ensure good transmission efficiency between the resonators.

It is a block diagram which shows one structural example of the radio | wireless electric power feeding system to which this invention is applied. It is a figure which shows an example of the equivalent circuit of the power transmission side resonator and its related circuit part in a power transmission apparatus, and the power receiving side resonator and its related circuit part in a power receiving apparatus. It is a figure which shows the structural example of the resonator of this embodiment. It is a figure which illustrates typically the electric field which generate | occur | produces in the resonator of this embodiment. It is a figure which shows the result of having verified Q value of the winding coil of this embodiment by simulation. It is a figure which shows the result of having verified by simulation about the relationship between the area ratio and Q value which the area | region where the dielectric ceramic member as said electric field concentration part is arrange | positioned among the surface vicinity area | regions of the winding coil of this embodiment occupies. . It is a figure which shows the structural example of the resonator which concerns on one modification of this embodiment.

  Preferred embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below is an example of a form to which the technical idea of the present invention is applied, and the present invention is not limited by the content of the present embodiment.

  FIG. 1 is a block diagram showing a configuration example of a wireless power feeding system to which the present invention is applied. The wireless power feeding system illustrated in FIG. 1 is a system that transmits power from the power transmission device 1 to the power reception device 2 in a contactless (wireless) manner. For example, a wireless power feeding system that feeds power to the power receiving device 2 built in the vehicle in a non-contact manner from the power transmitting device 1 disposed on the ground or road surface can be given.

  As shown in FIG. 1, the power transmission device 1 includes an AC / DC converter 10, a high frequency power source 11, a matching circuit 12, a power transmission side resonator 13, a wireless communication unit 14, and a control unit 15. Is done. The power receiving device 2 includes a power receiving resonator 20, a matching circuit 21, a rectifier 22, a battery 23, a load circuit 24, a wireless communication unit 25, and a control unit 26.

  In the power transmission device 1, the AC / DC converter 10 converts AC power from a commercial power source or the like into DC power. The high frequency power supply 11 is an oscillator that generates high frequency power of a predetermined frequency using DC power supplied from the AC / DC converter 10. The matching circuit 12 performs impedance matching between the output side of the high frequency power supply 11 that supplies high frequency power and the power transmission side resonator 13 in the subsequent stage. The power transmission side resonator 13 is a resonator that receives high frequency power supplied via the matching circuit 12 and resonates at a predetermined frequency to generate electromagnetic field energy. The specific structure and operation of the power transmission side resonator 13 will be described later.

  In the power receiving device 2, the power receiving resonator 20 is a resonator that is magnetically coupled to the power transmitting resonator 13 of the power transmitting device 1 and resonates at the predetermined frequency based on the magnetic field resonance to generate high frequency power. . In the present embodiment, the power reception side resonator 20 may basically have the same structure as the power transmission side resonator 13 of the power transmission device 1. The matching circuit 21 performs impedance matching between the power-receiving-side resonator 20 and the subsequent rectifier 22. The rectifier 22 rectifies the high-frequency power supplied via the matching circuit 21 and converts it into DC power. The battery 23 that functions as a storage battery is a secondary battery that stores electric power supplied via the rectifier 22. The load circuit 24 is a circuit that operates in accordance with the discharge current supplied from the battery 23, and various components included in the attachment target of the power receiving device 2 are assumed.

  On the other hand, the control unit 15 of the power transmission device 1 controls the overall operation of the power transmission device 1. Similarly, the control unit 26 of the power receiving device 2 controls the overall operation of the power receiving device 2. Each control unit 15 and 26 includes, for example, a processor that executes processing determined by the wireless power feeding system, and a memory that stores data and programs. In addition, the wireless communication unit 14 of the power transmission device 1 and the wireless communication unit 25 of the power reception device 2 are respectively connected to the control units 15 separately from the transmission of power between the power transmission side resonator 13 and the power reception side resonator 20 described above. 26 is a means for transmitting necessary information to each other wirelessly, and includes, for example, a transmission / reception circuit and an antenna.

  Next, the structure and operation of the power transmission side resonator 13 and the power reception side resonator 20 in the wireless power feeding system of FIG. 1 will be described. In the present embodiment, each of the power transmission side resonator 13 and the power reception side resonator 20 includes a resonance coil that mutually converts AC power and electromagnetic field energy of a predetermined resonance frequency, and the power transmission side resonator 13 and the power reception side resonance. It is used in a state in which the container 20 is disposed facing each other at a relatively close distance and both are magnetically coupled. In such a state, magnetic field energy is mainly transmitted from the power transmission side resonator 13 to the power reception side resonator 20, and non-contact power transmission based on a so-called magnetic field resonance method becomes possible.

  FIG. 2 shows an example of an equivalent circuit of the power transmission side resonator 13 and the circuit portion related thereto in the power transmission device 1 and the power reception side resonator 20 and the circuit portion related thereto in the power reception device 2. In the power transmission device 1, the part of the series circuit of the oscillator 11a and the impedance Zo corresponds to the high frequency power supply 11 of FIG. 1, and the part of the series circuit of the inductance L1, the capacitor C1, and the resistor R1 is connected to the power transmission side resonator 13 of FIG. Correspondingly, both are connected. Further, in the power receiving device 2, the portion of the series circuit of the inductance L2, the capacitance C2, and the resistor R2 corresponds to the power receiving side resonator 20 in FIG. 1, and the circuit portion and the load (battery 23 or load circuit 24 in FIG. 1). Is connected. Thus, since the power transmission side resonator 13 and the power reception side resonator 20 are represented by the same equivalent circuit, they resonate (resonate) at the same resonance frequency by coupling of magnetic fields.

  In the power transmission side resonator 13 and the power reception side resonator 20, the inductance L is determined depending on the size and the number of turns of the resonance coil portion, and the capacitance C is determined depending on the parasitic capacitance (stray capacitance) between the wirings of the resonance coil. . In the equivalent circuit of FIG. 2, the circuit portions of the pair of power transmission side resonator 13 and the power reception side resonator 20 are expressed in the same manner as a circuit form in which a pair of coils generate electromagnetic induction. However, in the case of electromagnetic induction, since a magnetic material is used for the coil, the Q value becomes extremely low and transmission of power becomes difficult when the distance between the pair of coils is increased. Since the Q value of the resonance coil can be increased depending on the structure and material, even if the power transmission side resonator 13 and the power reception side resonator 20 are separated from each other to some extent, power can be efficiently transmitted by magnetic field coupling.

Here, the transmission efficiency η from the power transmission side resonator 13 to the power reception side resonator 20 is related to the fom (performance index) of the following equation (1).
fom = k (Q1 · Q2) ^1/2 (1)
Where k: coupling coefficient Q1: Q value of resonance coil of power transmission side resonator 13 Q2: Q value of resonance coil of power reception side resonator 20

In the equation (1), the coupling coefficient k depends on the interval (air gap) between the resonance coils of the power transmission side resonator 13 and the power reception side resonator 20, and decreases as the interval increases. That is, the transmission efficiency η can be improved as the above-described Q1 and Q2 become higher with respect to a given coupling coefficient k according to the restrictions on the arrangement of the resonance coils. In general, the Q value of the resonance coil at the angular frequency ω is given by equation (2).
Q = ωL / r (2)
Where L: inductance r: resistance

  In the equation (2), the resistance r is represented by the sum of losses such as dielectric loss, conductor loss, and radiation loss. In the present embodiment, the Q value of the resonance coil is improved by reducing the loss of the resonance coil based on the structure of the power transmission side resonator 13 and the power reception side resonator 20, which will be described in detail later.

  Next, the structure of the power transmission side resonator 13 and the power reception side resonator 20 of FIG. 1 is demonstrated. As described above, since the basic structures of the power transmission side resonator 13 and the power reception side resonator 20 are the same, in the following, a resonator 30 that is compatible with both the power transmission side resonator 13 and the power reception side resonator 20 is assumed. Will be described. First, a structural example of the resonator 30 of the present embodiment will be described with reference to FIG. A resonator 30 shown in FIG. 3 includes a disk-shaped support member 31, a spiral winding coil 32 (resonance coil of the present invention) made of a conductor inside the support member 31, and a surface of the winding coil 32. It is comprised with the dielectric ceramic member 33 (electric field concentration part of this invention) arrange | positioned in a one part area | region.

  In the structural example of FIG. 3, the support member 31 has a role as a housing that supports the entire resonator 30, and is formed of, for example, a general resin material. In the example of FIG. 3, the support member 31 is a disk-shaped member having a predetermined thickness, and a circular opening 31a is provided at the center. The shape and structure of the support member 31 are not limited to the example of FIG. 3, but it is desirable that the support member 31 has a structure that can ensure a certain shape of the winding coil 32 and obtain sufficient mechanical strength. A winding coil 32 and a dielectric ceramic member 33 are disposed inside the support member 31 in a fixed state. The inside of the support member 31 may be filled with, for example, a resin material, but a space may exist inside the support member 31.

  The winding coil 32 is arranged at a substantially central position in the thickness direction of the support member 31 and is constituted by a linear conductor (for example, copper wire) wound in a spiral shape. The size and number of turns of the winding coil 32, and the wire diameter and pitch between the linear conductors constituting the winding coil 32 are appropriately determined according to design conditions such as the size, resonance frequency, and Q value of the resonator 30. can do. The winding coil 32 is not limited to the structure arranged inside the support member 31, and may be arranged on the surface of the support member 31.

  Both ends of the winding coil 32 may be open (open) or may be connected to a circuit element. In order to supply power to the resonator 30 with both ends of the winding coil 32 open, for example, power may be supplied to the resonator 30 via a loop element arranged in the vicinity. Further, with respect to the resonator 30, a capacitor may be connected in series to one end of the winding coil 32, or a capacitor may be connected in parallel to both ends of the winding coil 32. By appropriately setting the capacitance value of such a capacitor, the resonance frequency and Q value of the resonator 30 can be adjusted.

The dielectric ceramic member 33 is a plurality of plate-like members formed of a ceramic material having a high dielectric constant, and is disposed in a part of the region near the surface of the winding coil 32. The material of the dielectric ceramic member 33 has a dielectric constant higher than at least the dielectric constant of the material of the support member 31. As a material of the dielectric ceramic member 33, it is desirable to use a dielectric ceramic material having a relative dielectric constant εr of 8 or more and a dielectric loss tangent tan δ of 10 ⁻² or less. In addition, as a general resin material of the support member 31, for example, the relative dielectric constant εr is about 2. Due to the difference in dielectric constant between the support member 31 and the dielectric ceramic member 33, the electric field generated between the windings of the winding coil 32 can be concentrated on the dielectric ceramic member 33 to increase the Q value of the winding coil 32. However, specific actions and effects will be described later.

  In the example of FIG. 3, as the dielectric ceramic member 33, three plate-like members arranged at predetermined positions in the circumferential direction of the winding coil 32 are shown, but the plate-like shape constituting the dielectric ceramic member 33 is shown. The number and arrangement of members are not limited. In this case, the dielectric ceramic member 33 may be composed of a single plate-like member. However, since the one or more plate-like members constituting the dielectric ceramic member 33 are of a size that covers the entire area near the surface of the winding coil 32, the weight reduction of the resonator 30 is hindered. It is desirable to have a size that covers a part of the area near the surface of the winding coil 32. Although omitted in FIG. 3, it is desirable to dispose the dielectric ceramic member 33 on the surfaces of both sides (upper and lower) of the winding coil 32 in order to enhance the effect of concentration of the electric field.

  The design conditions of the resonator 30 of this embodiment can be selected in various ways according to the form and application of the wireless power feeding system. For example, as a specific example of design conditions including the dimensional parameters of the winding coil 32, when the resonance frequency is 10 MHz, the number of turns is 6, the inner diameter of the coil is 200 mm, the pitch between lines is 1 mm, and the wire of the linear conductor having a circular cross section The diameter can be set to 0.96 mm. The thickness of the dielectric ceramic member 33 can be set to 5 mm, for example.

  Here, the electric field generated in the resonator 30 of this embodiment will be schematically described with reference to FIG. First, FIG. 4A shows an enlarged partial cross-sectional structure of the resonator 30 when the dielectric ceramic member 33 is not provided for comparison with the present embodiment. On the other hand, FIG. 4B shows an enlarged partial cross-sectional structure of a region where the dielectric ceramic member 33 is arranged in the structure of FIG. 3 of the present embodiment. 4A and 4B, the structure is the same except for the presence or absence of the dielectric ceramic member 33. That is, the winding coil 32 is fixed to substantially the center of the support member 31 in the thickness direction, and a plurality of linear conductors are arranged at regular intervals (interline pitch). In addition, although the linear conductor which comprises the coil 32 is represented by a circular cross section, a square cross section may be sufficient. The dielectric ceramic member 33 is arranged so as to sandwich the winding coil 32 from the upper surface and the lower surface.

  4A and 4B, the state of the electric field generated between the adjacent linear conductors of the winding coil 32 is indicated by arrows (electric lines of force), respectively. Usually, since the magnetic field is mainly used as the electromagnetic field energy transmitted between the resonators 30, the electric field between the wires of the winding coil 32 does not contribute to the transmission. However, in order to suppress a decrease in the Q value of the winding coil 32, it is necessary to reduce the loss (mainly dielectric loss) when the electric field between the lines of the winding coil 32 passes through the dielectric material. First, in FIG. 4A of the comparative example, the electric field between the wires of the winding coil 32 passes through the resin material of the support member 31, but since the dielectric constant of the resin material is low, the electric field spreads and is distributed. A relatively large loss occurs. On the other hand, in FIG. 4B of the present embodiment, the electric field between the wires of the winding coil 32 is concentrated inside the dielectric ceramic member 33 having a high dielectric constant, and becomes extremely small outside thereof. In this case, the higher the dielectric constant of the dielectric ceramic member 33, the stronger the concentration of electric field (density of electric lines of force) of the dielectric ceramic member 33, and the loss caused thereby can be reduced. However, in FIG. 4B, if a resin material or the like is present between the winding coil 32 and the dielectric ceramic member 33, an electric field passes through the resin material and loss occurs, so that the winding coil 32 and the dielectric ceramic are generated. It is desirable to arrange the member 33 in a state of being in close contact as much as possible. As described above, when the structure of FIG. 4B of the present embodiment is adopted, the loss of the electric field between the wires of the winding coil 32 is suppressed and the Q value thereof is compared with the structure of FIG. 4A of the comparative example. The effect of increasing

  FIG. 5 shows the result of verifying the Q value of the winding coil 32 of the present embodiment by simulation. In FIG. 5, under a predetermined condition, a structure S0 provided with only the winding coil 32, a structure S1 provided with the support member 31 and the winding coil 32 (structure shown in FIG. 4A), and the support member 31. , A structure in which the winding coil 32 and the dielectric ceramic member 33 are provided (structure of FIG. 4B), in which the relative dielectric constant εr of the material of the dielectric ceramic member 33 is set to εr = 10 and 30, respectively. With respect to S2 and S3, the respective Q values are compared. Of these, the structure S0 provided with only the winding coil 32 can ignore material loss, and the highest Q value can be obtained. Therefore, the quality of other structures can be judged based on this.

  The Q value of the structure S1 in FIG. 4A is significantly lower than the Q value of the structure S0. That is, as described above, the deterioration of the Q value due to the material loss of the support member 31 was confirmed. On the other hand, the Q values of the structures S2 and S3 in FIG. 4B according to the present embodiment are significantly improved from the Q value of the structure S1, and the decrease in the Q value compared to the structure S0 is relatively small. Stay on. It can also be seen that the structure S3 in the case of εr = 30 can obtain a higher Q value than the structure S2 in the case of εr = 10. Therefore, if the other conditions are the same, as described above, the effect of improving the Q value can be enhanced by increasing the dielectric constant of the dielectric ceramic member 33.

  Next, FIG. 6 shows, by simulation, the relationship between the area ratio and the Q value occupied by the above-described region where the dielectric ceramic member 33 as the electric field concentration portion is disposed in the region near the surface of the winding coil 32 of the present embodiment. The verified result is shown. For example, in the structure of FIG. 3 described above, the dielectric ceramic member 33 is arranged at an area ratio of about 30% of the region near the surface of the winding coil 32. The change in the Q value when the area ratio is increased or decreased. Is a problem. 6 shows a characteristic C0 (left end in FIG. 6) in the case where only the support member 31 and the winding coil 32 are provided (structure S1 in FIG. 5) for comparison of the Q value, and only the winding coil 32 is shown. The characteristic C3 (right end of FIG. 6) of the case where it is provided (structure S0 of FIG. 5) is shown. Then, within the range of 0 to 100% of the area ratio, the characteristic C1 of the dielectric ceramic member 33 with εr = 10 and the characteristic of the dielectric ceramic member 33 with εr = 30 in relation to the structures S2 and S3 in FIG. C2 is shown respectively. In the simulation of FIG. 6, the support member 31 is made of a general resin having εr = 2 and a winding coil 32 having a resonance frequency of about 10 MHz.

  As shown in FIG. 6, when the area ratio is lower than 10% in both the characteristics C1 and C2, the Q value is rapidly decreased. Also, when the area ratio is in the range of 10 to 100%, the Q value of both the characteristics C1 and C2 is stable, but the characteristic C2 with εr = 30 has a higher Q value than the characteristic C1 with εr = 10. I understand that Therefore, it is desirable to set the area ratio of the dielectric ceramic member 33 to 10% or more in the region near the surface of the winding coil 32, and the higher the dielectric constant of the dielectric ceramic member 33 within that range, the higher the Q value. Is advantageous. Further, when the area ratio is 100%, there is a problem that the weight of the dielectric ceramic material increases. Even if the area ratio is not 100%, a desired Q value can be secured if the area ratio is set to about 10%. Therefore, if the dielectric ceramic member 33 is disposed in a part of the surface vicinity region of the winding coil 32, the increase in weight due to the dielectric ceramic material can be suppressed while ensuring the mechanical strength of the resonator 30.

  As described above, by employing the resonator 30 of the present embodiment, the dielectric ceramic member 33 having a dielectric constant higher than that of the material of the support member 31 is arranged in a part of the region near the surface of the winding coil 32. By making it act as an electric field concentrator, a resonator 30 having a high Q value is realized, and transmission efficiency in the wireless power feeding system can be improved. In this case, since the area ratio of the dielectric ceramic member 33 occupying the region near the surface of the winding coil 32 should be about 10%, the weight of the resonator 30 is not increased, and the dielectric ceramic member 33 is cracked. Thus, it is possible to achieve a structure suitable for avoiding this problem and increasing the mechanical strength.

  3 to 6, the structural example using the spiral wound coil 32 as the resonator 30 of the present embodiment has been described. However, the structural example of the wound coil 32 has various modifications. FIG. 7 shows a structural example including a cylindrical support member 41, a helical winding coil 42, and a dielectric ceramic member 43 as a resonator 40 according to a modification of the present embodiment. Yes. The support member 41 is processed into a hollow shape, and a winding coil 42 is disposed on the side surface of the cylinder. A dielectric ceramic member 43 (four plate-like members in FIG. 7) is disposed in a partial region on the outer surface of the winding coil 42. The materials of the support member 41 and the dielectric ceramic member 43 and the relationship between the dielectric constants of the materials are the same as those of the resonator 30 of FIG.

  The size, the number of turns, the wire diameter of the linear conductor, the pitch between the wires, and the like of the winding coil 42 of the modified example of FIG. 7 are appropriately set according to the design conditions of the resonator 40 as in the winding coil 32 of FIG. Can be determined. The same applies to the point that the number and arrangement of the plate-like members constituting the dielectric ceramic member 43 are not restricted. Even when the modified example of FIG. 7 is adopted, as described with reference to FIG. 4, the electric field generated between the windings of the winding coil 42 is concentrated on the dielectric ceramic member 43 so that the winding coil 42 The effect of increasing the Q value is obtained.

  In addition, the support member 41 of the modification of FIG. 7 is not restricted to a cylindrical shape, For example, you may form in a rectangular shape. In this case, the winding coil 42 may be disposed along the side of the rectangular support member 41 having a rectangular cross section, and the dielectric ceramic 43 made of a plate member may be disposed at one or a plurality of predetermined locations outside the winding coil 42. . In this case, the inside of the support member 41 around which the winding coil 42 is wound is not limited to an air core shape, and a member having a predetermined dielectric constant may be inserted.

  The contents of the present invention have been specifically described above based on the present embodiment, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, the configuration example of FIG. 1 is shown as the wireless power supply system of the present embodiment, but the present invention is not limited to this, and as long as the resonator having the structural features of the present invention is used, wireless power supply having various configurations is possible. The present invention can be applied to a system. In addition, as a use of the wireless power supply system to which the present invention can be applied, reference is made to power supply to vehicles. For example, information terminals such as mobile phones and notebook PCs, TVs, home appliances, lighting devices, game devices, and medical devices The present invention can be applied to wireless power feeding systems for various uses such as industrial equipment. Further, the contents of the present invention are not limited by the above-described embodiment with respect to other points, and the contents disclosed in the above-described embodiment are not limited to the contents disclosed in the above-described embodiments as long as the effects of the present invention can be obtained. Is possible.

DESCRIPTION OF SYMBOLS 1 ... Power transmission apparatus 2 ... Power reception apparatus 10 ... AC / DC converter 11 ... High frequency power supply 12 ... Matching circuit 13 ... Power transmission side resonator 14 ... Wireless communication part 15 ... Control part 20 ... Power reception side resonator 21 ... Matching circuit 22 ... Rectifier DESCRIPTION OF SYMBOLS 23 ... Battery 24 ... Load circuit 25 ... Wireless communication part 26 ... Control part 30, 40 ... Resonator 31, 41 ... Support member 32, 42 ... Winding coil 33, 43 ... Dielectric ceramic member

Claims (8)

A resonator in a wireless power feeding system that mainly uses magnetic field resonance to transmit power from a power transmitting resonator to a power receiving resonator,
A resonant coil that mutually converts AC power and electromagnetic energy of a predetermined resonant frequency;
A support member for supporting the resonance coil;
An electric field concentration portion made of a dielectric ceramic material having a high dielectric constant and having a dielectric constant higher than the dielectric constant of the material of the support member, disposed in a part of a region near the surface of the resonant coil;
A resonator comprising: 2. The resonator according to claim 1, wherein the dielectric ceramic material has a relative dielectric constant εr of 8 or more and a dielectric loss tangent tan δ of 10 ⁻² or less.   3. The resonance according to claim 1, wherein the area where the electric field concentration portion is arranged in the area near the surface of the resonance coil is set to 10% or more by area ratio. 4. vessel.   The resonator according to any one of claims 1 to 3, wherein the resonance coil is configured by a spiral wound coil.   The resonator according to any one of claims 1 to 3, wherein the resonance coil is constituted by a helical winding coil. A wireless power feeding system that mainly uses magnetic field resonance to transmit power from a power transmitting device to a power receiving device,
The power transmission device is:
A power supply for supplying AC power of a predetermined frequency;
A power transmission-side resonator that resonates with the AC power supplied from the power source and transmits the AC power as electromagnetic energy;
With
The power receiving device is:
A power receiving side resonator coupled with the power transmitting side resonance coil by resonance of the magnetic field and receiving the electromagnetic field energy as AC power;
A circuit unit that operates by the AC power received by the power-receiving-side resonator;
With
Each of the power transmission side resonator and the power reception side resonator is:
A resonant coil that mutually converts AC power and electromagnetic energy of a predetermined resonant frequency;
A support member for supporting the resonance coil;
An electric field concentration portion made of a dielectric ceramic material having a high dielectric constant and having a dielectric constant higher than the dielectric constant of the material of the support member, disposed in a part of a region near the surface of the resonant coil;
A wireless power feeding system comprising: The wireless power feeding system according to claim 6, wherein the dielectric ceramic material has a relative dielectric constant εr of 8 or more and a dielectric loss tangent tan δ of 10 ⁻² or less. 8. The radio according to claim 6, wherein, of the region near the surface of the resonance coil, a region in which the electric field concentration portion is disposed is set to 10% or more in area ratio. Power supply system.

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