JP2016010168A - 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 effectively suppressing external leakage of an electric field in transmitting power using a magnetic field resonance system.SOLUTION: A resonator 30 used for a wireless power supply system for transmitting power on the basis of a magnetic field resonance system comprises: a resonant coil (winding coil) 41 having a predetermined resonant frequency; a support member 40 for supporting the resonant coil 41; and an electric field suppression part 42 disposed at a position that is inside the support member 40 or on the outer periphery of the support member 40 and differs from a surface vicinity region of the resonant coil 41. The electric field suppression part 42 is made from dielectric material having a first dielectric constant higher than that of material of the support member 40, and has a function for suppressing leakage of an electric field to the outside of the resonator 30.

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)

  In realizing a wireless power feeding system, there are problems such as electromagnetic interference generated by the resonator causes electromagnetic interference (EMI: Electro Magnetic Interference) to surrounding electronic devices and adverse effects on the human body. When power is transmitted between a pair of resonators in a wireless power feeding system, magnetic energy in a specific radiation direction mainly contributes to transmission, but a resonator that functions as an antenna resonates not only in a magnetic field but also in an electric field. From the viewpoint of EMI and human body protection, consideration for leaking electric fields is required. For example, a method of shielding an electric field radiated to the outside by forming a metal shield on each surface of a support member serving as a housing of the resonator can be considered. However, the metal shield is required to have a hermetic seal according to the wavelength of the transmission frequency, and a high degree of processing and molding technology is required for the metal workpiece, and the capacity of the metal material for the metal shield increases as the hermeticity increases. There is a problem that the weight of the resonator increases due to the increase.

  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 suppress leakage of an electric field that does not contribute to power transmission with a simple structure.

  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 position that is different from a region near the surface of the resonance coil inside or around the support member And an electric field suppressing portion made of a dielectric material having a first dielectric constant higher than the dielectric constant of the material of the support member.

  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. The electric field suppression portion made of a dielectric material having a first dielectric constant higher than the dielectric constant of the material of the support member is a region near the surface of the resonant coil in the support member. They are located at different positions. Therefore, since the electric field generated between the lines of the resonance coil during the operation of the resonator has a structure surrounded by the high dielectric constant electric field suppression unit, the leakage electric field to the outside can be suppressed. This makes it possible to take measures against EMI and human body protection of the wireless power feeding system with a simple structure without causing an increase in the weight of the resonator when a metal shield or the like is used.

  In the resonator of the present invention, the dielectric ceramic material is disposed in a region near the surface of the resonance coil and has a second dielectric constant that is higher than a dielectric constant of the material of the support member and lower than the first dielectric constant. The electric field concentration portion can be further provided. Such an electric field concentration portion concentrates the above-described electric field generated between the lines of the resonance coil on the low-loss dielectric ceramic material, so that the Q value of the resonance coil can be increased. Thereby, in addition to the effect of suppressing the leakage electric field to the outside described above, it is possible to improve the transmission efficiency of the wireless power feeding system using the resonance coil having a high Q value. Note that 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 the distance from the surface of the resonance coil is sufficiently smaller than the pitch between the linear conductors constituting the resonance coil. It is desirable that it is a region.

  The electric field concentrating portion described above may be disposed in the entire region near the surface of the resonance coil, or may be disposed in a part of the region near the surface of the resonance coil. In the case where a desired Q value of the resonator can be obtained even if the electric field concentrating portion is partially arranged, an increase in the weight of the resonator can be suppressed by reducing the dielectric ceramic material constituting the electric field concentrating portion.

As for the dielectric material which comprises an electric field suppression part, it is desirable for the dielectric loss tangent tan-delta to be 10 ^<-2 > or more. This is because if the dielectric loss tangent tan δ of the dielectric material is less than 10 ⁻² , the amount of attenuation of the electric field based on the loss of the electric field suppressing unit is insufficient. In addition, 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 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 side A power receiving side resonator coupled with a resonance coil by resonance of the magnetic field and receiving the electromagnetic field energy as AC power; and a circuit unit operated by the AC power received by the power receiving side resonator, the power transmission Each of the side resonator and the power receiving side resonator includes a resonance coil that mutually converts AC power and electromagnetic field energy of a predetermined resonance frequency, and a support member that supports the resonance coil An electric field made of a dielectric material having a first dielectric constant higher than the dielectric constant of the material of the support member, which is disposed at a position different from the region near the surface of the resonance coil, inside or around the support member. And a suppression unit.

  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 suppressing the leakage electric field to the outside can be obtained by the electric field suppressing unit.

  According to the present invention, in the resonator including the resonance coil and the support member, since the electric field suppression unit made of a dielectric material having a high dielectric constant is provided around the electric field generated between the lines of the resonance coil, leakage to the outside A wireless power feeding system that can effectively suppress an electric field and can take measures against EMI and human body protection with a simple structure can be realized.

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. FIG. 4 is a cross-sectional structure diagram of a resonator according to a first structure example. It is the top view which partially saw through the resonator which concerns on the 1st structural example. It is a cross-section figure of the resonator which concerns on the 2nd structural example. It is the top view which partially saw through the resonator concerning the 2nd structural example. It is a cross-section figure of the resonator which concerns on a 3rd structural example. It is the top view which partially saw through the resonator which concerns on a 3rd structural example.

  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 inductances L1 and L2 are determined depending on the size and the number of turns of the resonance coil portion, and the capacitances C1 and C2 are parasitic capacitances (stray capacitance) between the wirings of the resonance coil. It depends on you. 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 the Q value is not taken into account, it is difficult to transmit power when the distance between the pair of coils is increased. Since the value can be increased, 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, resonators (30 to 32) that are suitable for both the power transmission side resonator 13 and the power reception side resonator 20. ) Is assumed. First, the resonator 30 according to the first structural example will be described with reference to FIGS. 3 and 4. As for the first structural example, FIG. 3 shows a sectional structural view of the resonator 30, and FIG. 4 shows a top view of the resonator 30. The resonator 30 of the first structural example includes a disk-shaped support member 40, a spiral winding coil 41 (resonance coil of the present invention), and an electric field suppressing unit 42 disposed in the support member 40. It is prepared for. The resonator 30 transmits electromagnetic field energy mainly including a magnetic field to and from another resonator 30 disposed to face the transmission direction R shown in FIG. 4 shows the resonator 30 of FIG. 3 in a state where the upper surface portion 40a and the filling portion 40d of the support member 40 and the upper portion 42a and the bottom portion 42b of the electric field suppressing portion 42 are seen through.

  In the first structural example, the support member 40 has a role as a housing that supports the entire resonator 30, and is a disk-shaped member that is formed of a general resin material and has a predetermined thickness, for example. is there. 3 and 4, the support member 40 is divided into an upper surface portion 40a, a bottom surface portion 40b, a side surface portion 40c, and a filling portion 40d. The shape and structure of the support member 40 is not limited to the example of FIG. 4, but it is desirable that the support member 40 has a structure that can ensure a certain shape of the winding coil 41 and obtain sufficient mechanical strength. Inside the support member 40, the winding coil 41 and the electric field suppression part 42 are arranged in a fixed state. The winding coil 41 and the electric field suppressing part 42 are not in contact (separated). The filling portion 40d of the support member 40 may have a structure in which an internal space exists as long as the winding coil 41 can be fixed.

  The winding coil 41 is a linear conductor (for example, copper wire) that is disposed at a substantially central position in the thickness direction of the support member 40 and is wound in a spiral shape. As shown in FIG. 4, the winding coil 41 is formed with a predetermined wire diameter and a predetermined pitch between lines. However, the size of the winding coil 41, the number of turns, the wire diameter of the linear conductor, and the pitch between the wires can be appropriately determined according to design conditions such as the size of the resonator 30, the resonance frequency, and the Q value. In addition, in the example of FIG. 3, the linear conductor which comprises the winding coil 41 is represented by a circular cross section, However, A square cross section may be sufficient.

  Both ends of the winding coil 41 may be opened (open) or may be connected to circuit elements. In order to supply power to the resonator 30 with both ends of the winding coil 41 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 41, or a capacitor may be connected in parallel to both ends of the winding coil 41. By appropriately setting the capacitance value of such a capacitor, the resonance frequency and Q value of the resonator 30 can be adjusted.

The electric field suppressing portion 42 is a member formed of a ceramic material having a high dielectric constant, and is disposed between the entire top surface portion 40a, bottom surface portion 40b, and side surface portion 40c of the support member 40 and the filling portion 40d. The electric field suppressing part 42 is formed of a ceramic material having a dielectric constant higher than the dielectric constant of the support member 40 (first dielectric constant of the present invention). For example, a ceramic material having a relative dielectric constant ε exceeding 100 is used. It is desirable to use it. In addition, as a general resin material of the support member 40, for example, since the relative dielectric constant εr is about 2, the dielectric constant of the electric field suppressing unit 42 is set to a sufficiently high value. For example, barium titanate (εr> 1000, tan δ> 10 ⁻² ) can be used as the ceramic material of the electric field suppressing unit 42. As shown in FIG. 3, the electric field suppression part 42 is comprised by the upper part 42a, the bottom part 42b, and the side part 42c.

  The role of the electric field suppressing unit 42 is to suppress the electric field leaking in each direction of the resonator 30. Since the upper part 42a, the bottom part 42b, and the side part 42c of the electric field suppressing part 42 are disposed inside the upper surface part 40a, the bottom part 40b, and the side part 40c of the support member 40, respectively, The structure surrounds all directions. Since the electric field suppression unit 42 has a very high dielectric constant, the electric field radiated from the winding coil 41 in each direction converges inside the electric field suppression unit 42 and attenuates the electric field transmitted to the outside. The electric field which permeate | transmits and leaks outside can be suppressed. The upper portion 42a of the electric field suppressing unit 42 does not affect the magnetic field radiated from the winding coil 41 in the transmission direction R.

As described above, since the electric field suppressing unit 42 does not contribute to the transmission of the magnetic field energy of the resonator 30, there is no problem even if a ceramic material having a large loss is used. In this case, if the electric field suppression unit 42 is configured using a ceramic material having a certain amount of loss, the electric field energy passing through the electric field suppression unit 42 is consumed as heat, and the attenuation amount of the electric field transmitted through the electric field suppression unit 42 is reduced. Can be increased. From this point of view, it is desirable to configure the electric field suppressing portion 42 using a ceramic material having a dielectric loss tangent tan δ of 10 ⁻² or more like the aforementioned barium titanate. Further, the thicker the electric field suppressing unit 42, the higher the effect of suppressing electric field leakage. However, it is necessary to set the thickness of the electric field suppressing unit 42 in consideration of restrictions on the size and weight of the resonator 30. For example, it is desirable to set the thickness of the electric field suppressing part 42 to 0.5 mm or more.

  As described above, by adopting the first structural example, when the electromagnetic field energy is transmitted from the power transmission side resonator 13 to the power reception side resonator 20 by the magnetic field resonance method, the leakage electric field to the surroundings is sufficiently suppressed. Is possible. Therefore, it is possible to provide an effective EMI countermeasure means in the wireless power feeding system of the present embodiment, and it is possible to enhance effects such as safety to the human body and reduction of influence on surrounding devices. Further, when the metal shield is applied to the resonator 30, the structure of the airtight structure is complicated and the weight of the resonator 30 is increased. In this case, it is advantageous in that the structure of the resonator 30 is not complicated and the weight is increased.

  Next, a resonator 31 according to a second structure example will be described with reference to FIGS. FIG. 5 shows a cross-sectional structure diagram of the resonator 31 and FIG. 6 shows a top view of the resonator 31 with respect to the second structure example. 5 and 6 correspond to FIGS. 3 and 4 of the first structural example, respectively. Among the resonators 31 of the second structure example, the support member 40, the winding coil 41, and the electric field suppressing unit 42 are common to the resonator 30 of the first structure example, and therefore their descriptions are as follows. Omitted. On the other hand, the resonator 31 of the second structure example is different from the resonator 30 of the first structure example in that the electric field concentrating portion 43 made of a dielectric ceramic material is provided on both surfaces of the winding coil 41. Is a point.

As shown in FIG. 5, the electric field concentrating portion 43 is disposed in the entire surface vicinity region of the winding coil 41. That is, the electric field concentration portion 43 is arranged so as to sandwich the entire surface of both sides of the winding coil 41. Therefore, as shown in FIG. 6, the shape of the electric field concentration portion 43 in plan view is circular as a whole, and the center is opened in a circle. The dielectric ceramic material used for the electric field concentration portion 43 is at least a dielectric constant higher than the dielectric constant of the material of the support member 40 and lower than the dielectric constant of the electric field suppressing portion 42 (second dielectric constant of the present invention). have. Specifically, it is desirable to form the electric field concentration portion 43 using 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.

  The role of the electric field concentrating portion 43 is to increase the Q value of the winding coil 41 by concentrating the electric field generated between the windings of the winding coil 41 on the electric field concentrating portion 43 due to the difference in dielectric constant with the support member 40. It is in. As described above, since the magnetic field is mainly transmitted between the resonators 30, the electric field between the lines of the winding coil 41 does not contribute to the transmission, but the electric field between the lines of the winding coil 41 is actually supported. It is necessary to reduce the loss (mainly dielectric loss) when the member 40 passes through the resin material. Therefore, by arranging a dielectric material having a dielectric constant higher than that of the support member 40 in the region in the vicinity of the surface of the winding coil 41, the electric field is concentrated in the vicinity of the winding coil 41 (the density of electric lines of force is increased). Thus, the loss when the electric field passes through the support member 40 is reduced. If a resin material or the like is present between the winding coil 41 and the electric field concentration portion 43, an electric field passes through the resin material and loss occurs, so that the winding coil 41 and the electric field concentration portion 43 are in close contact as much as possible. It is desirable to arrange.

  As described above, by adopting the second structural example, the Q value of the winding coil 41 is increased by concentrating the electric field between the lines on the electric field concentration portion 43 arranged in the region near the surface of the winding coil 41. Therefore, good transmission efficiency can be realized in the wireless power feeding system of this embodiment. Further, in the second structure example, in addition to the electric field suppressing portion 42 similar to that in the first structural example, the above-described electric field concentration portion 43 is further provided, so that the electric field reduced by the electric field concentration portion 43 is further suppressed. Since it can suppress by the part 42, the suppression effect of the electric field leakage to the outside can be improved further. The electric field concentration part 43 and the electric field suppression part 42 are arranged at different positions. Since the electric field concentrating portion 43 is related to the Q value of the winding coil 41, unlike the electric field suppressing portion 42, it is desirable to use a ceramic material with a small loss.

  Next, a resonator 32 according to a third structure example will be described with reference to FIGS. FIG. 7 is a sectional structural view of the resonator 32 and FIG. 8 is a top view of the resonator 32 regarding the third structural example. 7 and 8 correspond to FIGS. 3 and 4 of the first structural example (FIGS. 5 and 6 of the second structural example), respectively. Here, FIG. 7 is a cross-sectional structure diagram taken along the line AA of FIG. Among the resonators 32 of the third structural example, the support member 40, the winding coil 41, and the electric field suppressing unit 42 are common to the resonators 30 and 31 of the first and second structural examples. These descriptions are omitted. On the other hand, the resonator 32 of the third structural example is similar to the second structural example in that the resonator 32 of the third structural example includes an electric field concentration portion 43 made of a dielectric ceramic material disposed on both surfaces of the winding coil 41. The structure of the concentrated portion 43 in plan view is different from that of the second structure example.

  Specifically, the electric field concentration portion 43 shown in FIG. 8 is arranged not in the entire surface vicinity region of the winding coil 41 but in a part thereof. In the example of FIG. 8, an electric field concentration portion 43 including three plate-like members arranged at predetermined positions in the circumferential direction of the winding coil 41 is shown. In this case, as shown in FIG. 7, electric field concentration portions 43 made up of six plate-like members are arranged across the surfaces on both sides of the winding coil 41. 7 shows a cross-sectional structure as viewed in the AA cross section of FIG. 8, and therefore shows a state in which the electric field concentration portion 43 is arranged only on the left side. Note that the number and arrangement of the plate-like members constituting the electric field concentrating portion 43 are not limited, and may be constituted by only one plate-like member.

  As described above, by adopting the third structural example, as in the second structural example, the effect of increasing the Q value of the winding coil 41 based on the concentration of the electric field by the electric field concentration unit 43 and the electric field suppression unit 42 are obtained. Thus, it is possible to obtain both of the effect of suppressing electric field leakage to the outside. Further, in the resonator 32 of the third structure example, the electric field concentration portion 43 is disposed only in a part of the surface vicinity region of the winding coil 41, so that the weight increase due to the dielectric ceramic material as compared with the second structure example. Can be suppressed. However, in order to ensure a sufficient Q value of the winding coil 41, it is desirable to set the area ratio of the electric field concentration portion 43 to the surface of the winding coil 41 to approximately 10% or more.

  In the present embodiment, the resonators 30 to 32 of the first to third structure examples have been described as examples. However, the resonators 30 to 32 are not limited to the first to third structure examples. Various structures can be adopted. For example, the electric field suppression unit 42 of the present embodiment is arranged such that the upper part 42a, the bottom part 42b, and the side part 42c cover the entire upper surface part 40a, the bottom part 40b, and the side part 40c of the support member 40. As long as the desired suppression effect of leakage is obtained, the electric field suppression part 42 may be arranged to partially cover the upper surface part 40a, the bottom surface part 40b, and the side surface part 40c of the support member 40.

  In addition, the electric field suppression unit 42 of the present embodiment does not include the electric field suppression unit 42 facing the transmission direction R when the power transmission side resonator 13 and the power reception side resonator 20 are coupled by an electric field in addition to a magnetic field. It is good also as a form. That is, it is good also as a form arrange | positioned so that the bottom part 42b and the side part 42c may cover the whole surface of the bottom face part 40b and the side part 40c of the supporting member 40, without providing the upper part 42a in the electric field suppression part 42. Also in this case, as long as the desired suppression effect of the electric field leakage is obtained, the electric field suppression portion 42 may be disposed so as to partially cover the bottom surface portion 40b and the side surface portion 40c of the support member 40.

  Moreover, the formation method of the ceramic material which comprises the electric field suppression part 42 of this embodiment is not restrict | limited, The mixed material which loaded ceramic powder on materials, such as rubber | gum, can be used in order to raise mechanical strength. Moreover, although the structural example using the spiral type winding coil 41 was demonstrated as the resonators 30-32 of this embodiment, you may use a helical type winding coil. Furthermore, although the electric field suppression part 42 of this embodiment is arrange | positioned inside the supporting member 40, even if the form arrange | positioned on the outer periphery of the supporting member 40 is employ | adopted as long as the desired suppression effect of an electric field leakage is acquired. Good. For example, only the filling part 40d is provided in the support member 40 of FIG. 3, and the electric field suppressing part 42 is exposed to the outside.

  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, 31, 32 ... Resonator 40 ... Supporting member 41 ... Winding coil 42 ... Electric field suppression part 43 ... Electric field concentration part

Claims (9)

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;
Electric field suppression made of a dielectric material having a first dielectric constant higher than the dielectric constant of the material of the support member, which is arranged at a position different from the region near the surface of the resonance coil, inside or around the support member And
A resonator comprising:   An electric field concentrating portion made of a dielectric ceramic material disposed in a region near the surface of the resonance coil and having a second dielectric constant that is higher than the dielectric constant of the material of the support member and lower than the first dielectric constant. The resonator according to claim 1.   The resonator according to claim 2, wherein the electric field concentrating portion is disposed in the entire surface vicinity region of the resonance coil.   The resonator according to claim 2, wherein the electric field concentration portion is disposed in a part of a region near the surface of the resonance coil. 5. The resonator according to claim 1, wherein the dielectric material of the electric field suppressing unit has a dielectric loss tangent tan δ of 10 ⁻² or more. The resonator according to claim 5, wherein the dielectric ceramic material of 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.   The resonator according to any one of claims 1 to 6, wherein the resonance coil is configured by a spiral wound 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;
Electric field suppression made of a dielectric material having a first dielectric constant higher than the dielectric constant of the material of the support member, which is arranged at a position different from the region near the surface of the resonance coil, inside or around the support member And
A wireless power feeding system comprising:   Each of the power transmission side resonator and the power reception side resonator is arranged in a region near the surface of the resonance coil, and has a second dielectric constant higher than a dielectric constant of a material of the support member and lower than the first dielectric constant. The wireless power feeding system according to claim 8, further comprising an electric field concentration portion made of a dielectric ceramic material having a rate.

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