JP6315109B2 - Power supply device - Google Patents

Description

  The present invention relates to a power feeding device that feeds power to an external device using electromagnetic resonance coupling.

  Some power feeding systems are provided with a resonator including a coil and a capacitor in each of the power transmitting device and the power receiving device, and magnetically resonate each resonator to supply power from the power transmitting device to the power receiving device. When using magnetic field resonance, if the frequency characteristics of the respective resonators are deviated, the transmission power may be reduced. In Patent Document 1, even if the frequency characteristics of the resonator change due to the arrangement (distance) of the coils of the power transmitting device and the power receiving device by providing a resonance variable capacitor and adjusting the capacitance value of the resonator, A power transmission device is disclosed in which the peak of the frequency characteristic is matched with the frequency of the high frequency power so that the transmission power does not decrease.

JP2013-85350A

  However, as described in Patent Document 1, when a variable capacitor is provided, there is a problem that the cost is increased and the circuit is complicated. In addition, when the user touches the power transmission device or a metal such as a clip is placed on the power transmission device, stray capacitance occurs between the wiring pattern such as the coil of the power transmission device and the hand or metal, and the resonance frequency May fluctuate. In general, during normal operation at the design stage, the circuit constant is set so that the resonance frequency of the resonator of the power transmission device matches the resonance frequency of the resonator of the power reception device. When stray capacitance occurs, the resonance frequency characteristics cannot be adjusted, and there is a case where power cannot be supplied efficiently.

  Accordingly, an object of the present invention is to provide a power feeding device that does not reduce power feeding efficiency.

  The present invention provides a power feeding device that feeds power to an external device using electromagnetic resonance coupling, an inverter that converts an input DC voltage into an AC voltage, and an external device that is connected to an output side of the inverter and is provided in the external device A power supply resonance circuit having the same resonance frequency as the resonance circuit, wherein the power supply resonance circuit is an LC series resonance circuit in which a plurality of inductors and a plurality of capacitors are alternately connected in series.

  In this configuration, since the LC series resonance circuit is formed by a plurality of inductors and capacitors, the capacitance per capacitor is larger than when the LC series resonance circuit is formed by one capacitor. For this reason, even if the user touches the power feeding device to generate stray capacitance, the stray capacitance is relatively small compared to the capacitance of the capacitor of the LC series resonance circuit. As a result, fluctuations in the resonance frequency of the power supply resonance circuit can be suppressed, and a reduction in power supply efficiency can be prevented.

  In the present invention, each of the plurality of inductors preferably has the same inductance, and each of the plurality of capacitors preferably has the same capacitance.

  In this configuration, it is easy to set circuit constants for a plurality of inductors and capacitors.

  In the present invention, the inductor is a loop conductor for power feeding formed on a surface of an insulator substrate, and the capacitor is provided in the middle of the loop conductor, and the insulator covers the loop conductor. It is preferable to further include a protective film provided on the surface of the substrate.

  In this configuration, stray capacitance generated when the user's hand approaches the loop conductor can be reduced by the protective film.

  According to the present invention, it is possible to suppress fluctuations in the resonance frequency of the power supply resonance circuit, and it is possible to prevent power supply efficiency from being lowered.

The figure which shows the structure of the electric power feeder which concerns on this embodiment. Circuit diagram of power supply apparatus according to this embodiment The figure which shows the position where a stray capacitance is formed in LC series resonance circuit (A) is a diagram showing the resonance characteristics when stray capacitance is formed at the position shown in FIG. 3, and (B) is a diagram showing the capacitance component of the LC series resonance circuit with one capacitor as a comparison with (A). Diagram showing resonance characteristics when formed Circuit diagram of another example of power feeding device

  FIG. 1 is a diagram illustrating a configuration of a power feeding device 1 according to the present embodiment. FIG. 2 is a circuit diagram of the power feeding device 1 according to the present embodiment.

  The power feeding device 1 is a device that feeds power to the power receiving device 100 in a spatially separated place using electromagnetic resonance coupling. In the present embodiment, a mouse and a mouse pad are taken as an example, and the power receiving apparatus 100 will be described as a mouse, and the power feeding apparatus 1 will be described as a mouse pad that can perform wireless power feeding to the mouse.

  The power feeding device 1 includes a loop conductor 11 for power feeding formed on the surface of a substrate 10 made of an insulator, an inverter circuit 13 that inputs a DC voltage and converts it into an AC voltage, and a plurality of capacitors C1, C2, and C3. , C4, C5. The loop conductor 11 has an inductance component. And this inductance component comprises LC series resonance circuit 14 with capacitors C1-C5. The LC series resonance circuit 14 corresponds to a “feed resonance circuit” according to the present invention.

  The capacitors C1 to C5 have the same capacitance. The capacitors C1 to C5 are provided so that the inductance component of the loop conductor 11 is equally divided. Specifically, the capacitor C <b> 1 is connected between one end of the loop conductor 11 and one end of the inverter circuit 13. The capacitors C <b> 2 to C <b> 5 are provided in the middle of the loop conductor 11. Hereinafter, the inductance components of the loop conductor 11 divided by the capacitors C1 to C5 are referred to as L1, L2, L3, L4, and L5, respectively. Thus, the LC series resonance circuit 14 has a configuration in which the inductance components L1 to L5 and the capacitors C1 to C5 are alternately connected in series.

  Adjacent inductance components and capacitors form LC series circuits 141, 142, 143, 144, and 145. The LC series circuit 141 is formed by an inductance component L1 and a capacitor C1. The LC series circuit 142 is formed by an inductance component L2 and a capacitor C2. The LC series circuit 143 is formed by an inductance component L3 and a capacitor C3. The LC series circuit 144 is formed by an inductance component L4 and a capacitor C4. The LC series circuit 145 is formed by an inductance component L5 and a capacitor C5. As described above, the LC series resonance circuit 14 has a configuration in which a plurality of LC series circuits 141 to 145 are connected in series.

  As described above, the capacitors C1 to C5 have the same capacitance, and the inductance components L1 to L5 also have the same inductance. Suppose that the resonance frequency F of the LC series resonance circuit 14 is 1 / (2π√LC). In this case, the capacitances of the capacitors C1 to C5 are 5C, and the inductances of the inductance components L1 to L5 are L / 5. Then, each of the LC series circuits 141 to 145 has f = 1 / (2π√ (L / n · nC)) = 1 / (2π√LC), and has the same resonance frequency as the LC series resonance circuit 14. In this way, the inductance component of the loop-shaped conductor 11 is equally divided to form a plurality of LC series circuits 141 to 145 having the same resonance frequency as that of the LC series resonance circuit 14, whereby a plurality of inductance components L 1 to L 5 and a capacitor C 1 are formed. The circuit constants of .about.C5 can be easily set.

  The inverter circuit 13 converts the DC voltage input from the DC power supply 9 into an AC voltage. The frequency of this AC voltage is the same as the resonance frequency of the LC series resonance circuit 14. The AC voltage converted by the inverter circuit 13 is input to the loop conductor 11, and a current flows through the loop conductor 11. As a result, a magnetic field is generated in the loop-shaped conductor 11.

  A protective film 10A that covers the loop conductor 11 and the capacitors C2 to C5 is provided on the surface of the substrate 10 so that the user does not touch the loop conductor 11 directly. The substrate 10 and the protective film 10A correspond to a mouse pad body, and the power receiving device 100 that is a mouse is operated on the surface of the protective film 10A.

  The protective film 10A is, for example, a low dielectric constant resin (for example, a dielectric constant of about 3) such as polyimide resin, epoxy resin, or acrylic resin. By using the low dielectric constant resin, the stray capacitance generated when the user's hand approaches the loop conductor 11 can be reduced. When the stray capacitance is formed, the resonance characteristics of the LC series resonance circuit 14 may fluctuate. However, the influence on the resonance characteristics of the LC series resonance circuit 14 can be suppressed by reducing the stray capacitance.

  The power receiving device 100 includes a power receiving loop conductor 101, a capacitor 102, and a power receiving circuit 103. The power receiving loop conductor 101 and the capacitor 102 form an LC resonance circuit (an external resonance circuit according to the present invention), and the resonance frequency is the drive frequency of the inverter circuit 13 and the resonance frequency of the LC series resonance circuit on the power feeding device side. be equivalent to. The power receiving loop conductor 101 is interlinked with a magnetic flux generated by a current flowing through the loop conductor 11 formed on the substrate 10. Then, the loop-shaped conductor 11 and the power-receiving loop-shaped conductor 101 are coupled, so that power is fed from the power feeding device 1 to the power receiving device 100.

  Note that the drive frequency of the inverter 13, the resonance frequency of the LC series resonance circuit 14, and the resonance frequency of the LC resonance circuit of the power receiving apparatus 100 are “same”, but may not be completely coincident. If it is within the range where the LC series resonance circuit 14 and the LC resonance circuit of the power receiving apparatus 100 are coupled, they are included in the “same”.

  In the power supply device 1 configured as described above, when a user's hand touches the protective film 10A or a metal such as a clip is placed, stray capacitance is generated between the hand (or metal) and the loop conductor 11. Arise. This stray capacitance may affect the resonance characteristics of the LC series resonance circuit 14. Therefore, in the present embodiment, the LC series resonance circuit 14 is formed by a plurality of inductance components L1 to L5 and a plurality of capacitors C1 to C5. For this reason, compared with the case where the capacity | capacitance component of LC series resonance circuit is formed with one capacitor, the capacitance per capacitor C1-C5 is large. Thereby, even if stray capacitance occurs, the capacitance is relatively smaller than the capacitance of each of the capacitors C1 to C. As a result, fluctuations in the resonance characteristics of the LC series resonance circuit 14 can be suppressed.

  FIG. 3 is a diagram illustrating positions where stray capacitance is formed in the LC series resonance circuit 14. The position (A) is a preceding part of the inductance component L1 of the LC series circuit 141 (between the capacitor C1 and the inductance component L1), and the position (B) is a preceding part of the inductance component L3 of the LC series circuit 143. The position (C) is an intermediate portion of the inductance component L3 of the LC series circuit 143. The position (D) is a subsequent stage portion of the inductance component L3 of the LC series circuit 143. The position (E) is a subsequent stage portion of the inductance component L5 of the LC series circuit 145. FIG. 3 shows the stray capacitance Cp when the user touches the position (A) as an example.

  FIG. 4A is a diagram showing resonance characteristics when stray capacitance is formed at the position shown in FIG. FIG. 4B is a diagram showing resonance characteristics in the case where the capacitance component of the LC series resonance circuit is formed by one capacitor as a comparison with FIG. In the case of FIG. 4B, the capacitor is provided only at the position of the capacitor C1. 4A and 4B, the vertical axis represents the impedance when the LC series resonance circuit 14 side is viewed from the inverter circuit 13, and the horizontal axis represents the drive frequency of the inverter circuit 13.

  When the capacitance component of the LC series resonance circuit is formed by one capacitor, the resonance characteristics change depending on the position where the stray capacitance Cp is formed as shown in FIG. Specifically, as the position (E) moves from the position (A) to the position (A), the change in the resonance characteristics increases.

  On the other hand, when the LC series resonance circuit 14 is formed by connecting the LC series circuits 141 to 145 in series as in this embodiment, the stray capacitance Cp is formed anywhere in the positions (A) to (E). As shown in FIG. 4A, the combined equivalent circuit of the LC series circuits 141 to 145, that is, the resonance characteristics of the LC series resonance circuit 14 does not substantially change.

  In FIG. 4A, positions (A) and (B) overlap with each other because they have substantially the same characteristics. Further, since the positions (D) and (E) have substantially the same characteristics, they overlap.

  As described above, the LC series resonance circuit 14 includes the plurality of inductance components L1 to L5 and the plurality of capacitors C1 to C5, and the capacitance of the capacitors C1 to C5 is increased, thereby forming the stray capacitance Cp. Even so, the resonance characteristics of the LC series resonance circuit 14 can be prevented from changing. As a result, it is possible to prevent the power supply efficiency to the power receiving apparatus 100 from being lowered.

  Depending on the design of the power supply device, by dividing the inductance component into a plurality of inductance components L1 to L5, the self-resonance frequency of the inductance component of each loop conductor can be shifted to the high-frequency side, and the self-resonance frequency is driven. By preventing the frequency from approaching, the function as an inductor can be prevented from deteriorating.

  In this embodiment, the loop-shaped conductor 11 is formed on the surface of the substrate 10 and the protective film 10A is provided so as to cover the loop-shaped conductor 11, but the loop is formed on the inner side so as not to be exposed from the surface of the substrate 10. The conductor 11 may be formed. In this case, it is not necessary to provide the protective film 10A. Further, the line width of the loop-shaped conductor 11 may be reduced in order to reduce the stray capacitance Cp.

  In this embodiment, the loop conductor 11 is equally divided into five to form the inductance components L1 to L5 and the capacitors C1 to C5 are provided, but the inductance components and the number of capacitors are not limited to this. Further, the inductance components L1 to L5 may be different from each other, and the capacitances of the capacitors C1 to C5 may be different from each other. Each of the plurality of capacitors only needs to have a capacitance larger than the assumed stray capacitance Cp.

  FIG. 5 is a circuit diagram of another example of the power supply apparatus. As shown in FIG. 5, a configuration in which a series circuit of an inductance component L6 and a capacitor C6 is further connected in parallel to the inductance component L5 and the capacitor C5 connected in series may be used.

C1, C2, C3, C4, C5, C6 ... Capacitor Cp ... Stray capacitance L1, L2, L3, L4, L5, L6 ... Inductance component 1 ... Feeder 9 ... DC power supply 10 ... Substrate 10A ... Protective film 11 ... Loop shape Conductor 13 ... Inverter circuit 14 ... LC series resonance circuit (resonance circuit for power supply)
100: Power receiving device (external device)
101 ... Loop conductor for power reception 102 ... Capacitors 141, 142, 143, 144, 145 ... LC series circuit

Claims (6)

To an external device having an external resonant circuit, the power feeding device for feeding electricity by using electromagnetic resonance coupling,
An inverter that converts input DC voltage into AC voltage;
Connected to the output side of the inverter, a power supply resonance circuit having the same resonance frequency as before Kigai unit resonant circuit,
With
The power supply resonance circuit has a plurality of inductors and a plurality of capacitors, Ri said inductor and LC series resonant circuits der that the capacitor is alternately connected in series,
The capacitance of the capacitor is larger than the stray capacitance formed in the inductor ,
Power supply device. Each of the plurality of inductors has the same inductance,
Each of the plurality of capacitors, we have the same capacitance,
The power feeding device according to claim 1. The inductor is a loop conductor for feeding formed on the surface of an insulating substrate,
The capacitor is provided between the loop conductor and the loop conductor adjacent to each other ,
A protective film provided on the surface of the insulator substrate so as to cover the loop-shaped conductor;
The power feeding device according to claim 1 or 2.   The power feeding device according to claim 3, wherein the stray capacitance is a stray capacitance generated in the loop-shaped conductor in a state where a user's hand touches the protective film or a metal is placed.   5. The power feeding device according to claim 3, wherein a planar shape of the insulator substrate is a quadrangle, and a main portion of the loop-shaped conductor is configured by two conductors parallel to a first side of the quadrangle.   The power supply device according to claim 5, wherein the plurality of capacitors are arranged along a second side adjacent to the first side of the insulator substrate.

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