JP2005079786A - Power transmission system, power supply apparatus, power receiving apparatus, signal transmission system, signal transmission apparatus, and signal receiving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise a power transmission efficiency between a card reader/writer and a non-contact type card. <P>SOLUTION: A power transmission system includes the card reader/writer 110 for supplying a power, and a non-contact type card 112 for receiving a power from the card reader/writer in such a manner that a supply unit of the card reader/writer and a power receiver of the non-contact type card are disposed at opposed positions at a power transmission time and the power is transmitted in non-contact type. Further, the system includes a reactance correcting means for supplying the power from the card reader/writer to the non-contact type card through an electrode pair formed of a first electrode plate 212 of the card reader/writer and a second electrode plate 230 of the non-contact type card, to reduce a voltage drop due to the reactance of the electrode pair. The power transmission efficiency can be raised by such a constitution. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power transmission system, a power supply device, a power reception device, a signal transmission system, a signal transmission device, and a signal reception device.

  Conventionally, in mobile cards such as credit cards and cash cards, fixed data information such as user information and user ID (Identification) has been stored in a magnetic storage medium provided in the mobile card.

  In recent years, it has become possible to embed the above-mentioned semiconductor storage medium in a portable card by increasing the capacity and downsizing of the semiconductor storage medium, not only storing the above fixed data information, but also using the above-mentioned semiconductor storage medium. Advanced data information can be read and written.

  A portable card including such a semiconductor storage medium is covered with a non-conductive material from the viewpoints of corrosivity and water resistance or easy handling, and has an appearance in which metal terminals are not exposed. Such a portable card is also called a non-contact card because it can perform a desired operation even in a non-contact state with a separate device. For receiving power and transmitting / receiving signals required by the contactless card, a method of transmitting by means of electrode plates provided on both sides of the contactless card and the power or signal supply device (for example, Patent Document 1) is known.

Japanese Patent No. 2579980

  However, in the power transmission and signal transmission using the electrode plate as described above, a voltage drop due to the reactance caused by the pair of electrode plates occurs, and particularly in power transmission, the power efficiency is greatly affected. .

  The present invention has been made in view of the above-mentioned problems of conventional power transmission or signal transmission, and an object of the present invention is to reduce voltage drop due to reactance caused by the pair of electrode plates, and to transmit power. Another object is to provide a new and improved power transmission system, power supply device, power reception device, signal transmission system, signal transmission device, and signal reception device capable of efficiently performing signal transmission.

  In order to solve the above-described problem, according to a first aspect of the present invention, a power supply device that supplies power, and a power reception device that is configured separately from the power supply device and receives power from the power supply device. A power transmission system configured to transmit power in a non-contact manner, wherein the power supply unit and the power reception unit of the power reception device face each other and transmit power in a non-contact manner. The apparatus includes: a power generation unit that generates power; and a first electrode plate that is connected to the power generation unit and forms the one-side electrode plate of an electrode pair that functions as a capacitor; Is connected to the second electrode plate, which is the power receiving unit functioning as a capacitor by electrostatic coupling with the first electrode plate, and the power supplied via the second electrode plate is Power received The electrode pair of the first electrode plate and the second electrode plate forms part of a power transmission path; the power supply device or the power receiving device has a voltage drop due to reactance of the electrode pair. A power transmission system is further provided, further comprising reactance correction means for reducing. Here, the power receiving device may be a contactless card, and the power supply device may be a card reader / writer that reads data from and / or writes data to the contactless card. Here, the non-contact card includes a card in which an electrical element such as an integrated circuit is embedded in a non-conductive material and a metal terminal is not exposed on the surface, and an electrode is not connected to an electrode of another device. A card that can operate electrically even in contact. The non-contact type means that the devices can operate even if they are not in contact with each other, and includes that they operate in contact with each other.

  The electrode pair of the first electrode plate and the second electrode plate functions as a capacitor by electrostatic coupling, and becomes a power transmission path from the power supply device to the power receiving device. In addition, reactance correction means for canceling the reactance of the electrode pair can be provided in such a power transmission path to increase the power transmission efficiency.

  In order to solve the above problems, according to a second aspect of the present invention, the power receiving device is configured separately from a power receiving device that receives power, and the power receiving device and the power receiving device receive power during power transmission. A power supply device that is non-contact type and supplies power to the power receiving device in a non-contact manner; power generating means for generating power; one side of an electrode pair connected to the power generating means and functioning as a capacitor A first electrode plate serving as the supply unit forming the electrode plate; a voltage generated by reactance of an electrode pair formed by the first electrode plate and functioning as a capacitor between the power generation means and the first electrode plate; There is provided a power supply device comprising a reactance correction means for reducing a drop.

  With such a configuration, power can be transmitted to the power receiving device, which is the purpose of supplying power, via the electrode pair. In addition, reactance correction means for canceling the reactance of the electrode pair can be provided in the power transmission path including the power receiving device to increase the power transmission efficiency.

  Further, the reactance correction means includes any one of an inductor having a predetermined self-inductance; an active inductor capable of adjusting a self-inductance; a combination of an inductor having a predetermined self-inductance and a variable capacitor capable of adjusting a capacitance. It may be formed by.

  The electrode pair has a capacitive reactance and is usually represented negatively on the imaginary axis of impedance. Therefore, by connecting an inductor having a positive reactance in series with the power transmission path, it is possible to reduce the absolute value of the reactance and increase the power transmission efficiency.

  Further, by connecting an active inductor having positive reactance and adjustable self-inductance in series with the power transmission path, it is possible to increase the power transmission efficiency as described above. Furthermore, when the reactance of the electrode pair is not constant, it is possible to obtain the optimum power transmission efficiency by adjusting the active inductor.

  In addition, the power transmission efficiency can be increased in the same manner as described above by connecting a combination of an inductor having a greater reactance than the reactance of the electrode pair and a variable capacitor whose capacitance can be adjusted in series to the power transmission path. It becomes possible. Further, when the reactance of the electrode pair is not constant, the optimum power transmission efficiency can be obtained by adjusting the variable capacitor.

  Moreover, it is good also as providing the electric power adjustment means which adjusts the said reactance correction means according to the said electric power. Here, the power detection may be performed by directly measuring the power or by measuring the current under a constant voltage power source.

When the reactance correction means is formed by the active inductor, it is possible to obtain the minimum reactance in the self-inductance variable range of the active inductor by the power adjustment means. When the reactance is minimum, the impedance of the entire power transmission path is also minimum. Therefore, the power transmission efficiency at this point is maximized in the variable range of the self-inductance. The reactance is preferably 0, and the self-inductance L (H) at this time is L = 1 / L, where f (Hz) is the frequency of the power and C (F) is the capacitance of the electrode pair. ((2πf) ² × C).

Further, when the reactance correcting means is formed by a combination of the inductor having the predetermined self-inductance and the variable capacitor capable of adjusting the electrostatic capacity, the power adjusting means allows the variable capacitor in the variable capacitance range. A minimum reactance can be obtained. When the reactance is minimum, the impedance of the entire power transmission path is also minimum. Therefore, the power transmission efficiency at this point is maximized in the variable capacitance range. The reactance is preferably 0, and the capacitance Cd (F) of the variable capacitor at this time is defined as f (Hz), self-inductance L (H), and capacitance of the electrode pair. When C (F), Cd = 1 / ((2πf) ² × L) −C.

  Moreover, it is good also as providing the frequency adjustment means which adjusts the frequency of the electric power produced | generated by the said electric power production | generation means according to the said electric power.

  When the reactance correction means is formed of an inductor having a predetermined self-inductance, the frequency adjustment means can obtain the minimum reactance in the frequency variable range. When the reactance is minimum, the impedance of the entire power transmission path is also minimum. Therefore, the power transmission efficiency at this point is maximized in the frequency variable range. The reactance is preferably 0, and the frequency f (Hz) at this time is f = 1 / F, where C (F) is the capacitance of the electrode pair and L (H) is the self-inductance of the inductor. It is represented by (2π × √ (L × C)).

  Here, the inductor may be provided in the power supply apparatus, or may be provided in the power receiving apparatus. With this configuration, when the inductor is provided in common for a plurality of power receiving devices, the power supply device does not need to include an inductor. In addition, even when the self-inductances of the inductors provided in the plurality of power receiving devices are different from each other, optimal power transmission can be performed by the frequency adjusting means.

  In addition, two first electrode plates are provided in one power transmission path; each first electrode plate is connected to a hot side and a cold side of the power generating means, and is connected to a power receiving unit of the power receiving device. They may be formed side by side at opposing positions.

  In such power transmission, at least two electric circuits on the hot side and the cold side are necessary in the electric power transmission path between the power supply apparatus and the power receiving apparatus, and the two electric circuits are connected by the two first electrode plates. Can be formed.

  Further, the power generated by the power generation means may be AC power. The electrode pair formed by the first electrode plate functions as a capacitor by electrostatic coupling, but the capacitor has a characteristic of mainly passing AC power. Therefore, in order to efficiently perform the power transmission, it is desirable that the generated power is alternating current.

  The power supply device may be a card reader / writer that reads and / or writes data to and from the contactless card that is the power receiving device. With this configuration, power can be efficiently transmitted to the contactless card that is the power receiving apparatus.

  In order to solve the above problem, according to a third aspect of the present invention, the power supply device is configured separately from a power supply device that supplies power, and the power reception unit of the power reception device and the supply of the power supply device are transmitted during power transmission. A power receiving device that receives power from the power supply device in a contactless manner: a second electrode plate that is the power receiving unit that forms one side electrode plate of an electrode pair that functions as a capacitor; A power receiving means connected to the second electrode plate and receiving the power supplied through the second electrode plate; formed by the second electrode plate between the power receiving means and the second electrode plate; And a reactance correction unit that reduces a voltage drop due to reactance of the electrode pair functioning as a capacitor.

  With this configuration, power can be received from the power supply device that supplies power through the electrode pair. In addition, reactance correction means for canceling the reactance of the electrode pair can be provided in the power transmission path including the power supply device to increase power transmission efficiency.

  Further, the reactance correction means includes any one of an inductor having a predetermined self-inductance; an active inductor capable of adjusting the self-inductance; and an inductor having a predetermined self-inductance and a variable capacitor capable of adjusting the capacitance. It may be formed.

  The electrode pair has a capacitive reactance and is usually represented negatively on the imaginary axis of impedance. Therefore, by connecting an inductor having a positive reactance in series with the power transmission path, it is possible to reduce the absolute value of the reactance and increase the power transmission efficiency.

  Further, by connecting an active inductor having positive reactance and adjustable self-inductance in series with the power transmission path, it is possible to increase the power transmission efficiency as described above. Furthermore, when the reactance of the electrode pair is not constant, it is possible to obtain the optimum power transmission efficiency by adjusting the active inductor.

  In addition, the power transmission efficiency can be increased in the same manner as described above by connecting a combination of an inductor having a greater reactance than the reactance of the electrode pair and a variable capacitor whose capacitance can be adjusted in series to the power transmission path. It becomes possible. Further, when the reactance of the electrode pair is not constant, the optimum power transmission efficiency can be obtained by adjusting the variable capacitor.

  Moreover, it is good also as providing the electric power adjustment means which adjusts the said reactance correction means according to the said electric power. Here, the power detection may be performed by directly measuring the power or by measuring the current under a constant voltage power source.

When the reactance correction means is formed by the active inductor, it is possible to obtain the minimum reactance in the self-inductance variable range of the active inductor by the power adjustment means. When the reactance is minimum, the impedance of the entire power transmission path is also minimum. Therefore, the power transmission efficiency at this point is maximized in the variable range of the self-inductance. The reactance is preferably 0, and the self-inductance L (H) at this time is L = 1 / L, where f (Hz) is the frequency of the power and C (F) is the capacitance of the electrode pair. ((2πf) ² × C).

Further, when the reactance correcting means is formed by a combination of the inductor having the predetermined self-inductance and the variable capacitor capable of adjusting the electrostatic capacity, the power adjusting means allows the variable capacitor in the variable capacitance range. A minimum reactance can be obtained. When the reactance is minimum, the impedance of the entire power transmission path is also minimum. Therefore, the power transmission efficiency at this point is maximized in the variable capacitance range. The reactance is preferably 0, and the capacitance Cd (F) of the variable capacitor at this time is defined as f (Hz), self-inductance L (H), and capacitance of the electrode pair. When C (F), Cd = 1 / ((2πf) ² × L) −C.

  In addition, two second electrode plates are provided in one power transmission path; each second electrode plate is connected to each terminal of the power receiving means and is opposed to the supply unit of the power supply device. It may be formed side by side.

  In such power transmission, at least two electric circuits on the hot side and the cold side are required in the electric power transmission path between the power supply device and the power receiving device, and the two electric circuits are connected by the two second electrode plates. Can be formed.

  The power to be received may be AC power, and the power receiving means may include a rectifier circuit that rectifies the received AC power into DC power.

  The electrode pair formed by the second electrode plate functions as a capacitor by electrostatic coupling, but the capacitor has a characteristic of mainly passing AC power. Therefore, in order to efficiently perform the power transmission, it is desirable that the received power is alternating current. Further, the rectifier circuit can supply power to the semiconductor storage medium that requires DC power in the power receiving means.

  Further, the power receiving device may be a contactless card. A power receiving device formed as such a contactless card can include a miniaturized semiconductor storage medium and a small microcomputer, and can provide a device with excellent portability.

  The reactance correction means may be provided in both the power supply device and the power receiving device.

  In order to solve the above-described problem, according to a fourth aspect of the present invention, a signal transmission device for transmitting a signal and a signal reception for receiving a signal from the signal transmission device configured separately from the signal transmission device. A signal transmission system in which a transmission unit of the signal transmission device and a reception unit of the signal reception device are arranged to face each other at the time of signal transmission, and a signal is transmitted in a non-contact manner: the signal transmission The apparatus includes signal generation means for generating a signal, and a first electrode plate that is connected to the signal generation means and forms the one-side electrode plate of an electrode pair that functions as a capacitor, and is the transmission unit; Is a second electrode plate which is the receiving unit that functions as a capacitor by electrostatic coupling with the first electrode plate, and a signal transmitted through the second electrode plate is connected to the second electrode plate. Signal to receive An electrode pair of the first electrode plate and the second electrode plate forms a part of a signal transmission path; the signal transmitting device or the signal receiving device has a voltage drop due to a reactance of the electrode pair. There is provided a signal transmission system, further comprising reactance correction means for reducing. Here, the signal receiving device and the signal transmitting device may be a pair of: a non-contact type card; and a card reader / writer for reading and / or writing data with respect to the non-contact type card.

  The electrode pair of the first electrode plate and the second electrode plate functions as a capacitor by electrostatic coupling, and becomes a signal transmission path from the signal transmission device to the signal reception device. In addition, reactance correction means for canceling the reactance of the electrode pair can be provided in the signal transmission path to increase the signal transmission level.

  In addition, a signal transmitting apparatus having a configuration substantially the same as the power supply apparatus and having a transmission purpose as a signal, and a signal receiving apparatus having a configuration substantially the same as that of the power receiving apparatus and having a transmission purpose as a signal. Provided. Furthermore, the signal transmitting device and the signal receiving device can be configured as a single device.

  As described above, according to the present invention, in power transmission or signal transmission, it is possible to reduce the voltage drop due to the reactance of the electrode plate provided in the transmission path of each device, and to efficiently perform power transmission or signal transmission. It becomes.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is an image diagram showing a typical example of the power transmission system according to the first embodiment. In the present embodiment, a card reader / writer 110 is described as an example of the power supply device, and a non-contact card 112 is described as an example of the power receiving device.

  The power transmission system includes a card reader / writer 110 that is a power supply device and a contactless card 112 that is a power receiving device.

  The card reader / writer 110 has a structure capable of supporting the contactless card 112. By attaching the contactless card 112 to the card reader / writer 110, the card reader / writer 110 supply section and the contactless card 112 can be connected to each other. It has a mechanism in which the power receiving units face each other.

  As shown in FIG. 1, the card reader / writer 110 and the non-contact card 112 are configured separately. During operation of the non-contact card 112, that is, when power is transmitted from the card reader / writer 110 to the non-contact card 112, the non-contact card 112 is disposed at a position facing the card reader / writer 110, and power is supplied in a non-contact manner. Is transmitted.

  FIG. 2 is a block diagram showing the configuration of the card reader / writer 110 and the non-contact card 112 in the power transmission system.

  The card reader / writer 110 includes a power generation unit 210, a first electrode plate 212, a reactance correction unit 214, and a power adjustment unit 216.

  The power generation means 210 generates an AC power supply having a predetermined voltage and a predetermined frequency. In the power transmission using the electrode pair as in the present embodiment, the reactance represented by 1 / (j2πf × C) of the electrode pair shows a lower value as the frequency becomes higher. If the value is set high, efficient power transmission becomes possible.

  The first electrode plate 212 is formed of a metal material having a predetermined area, and is connected to one end (hot side) of the power generation means 210, and the other end (cold side). And the cold side first electrode plate 220 connected to. The first electrode plate 212 is provided in the power transmission path between the card reader / writer 110 and the non-contact card 112. That is, when the non-contact card 112 is attached to the card reader / writer 110, it is arranged to face the power receiving unit provided in the non-contact card 112.

  The reactance of the electrode pair formed by the supply unit of the card reader / writer 110 and the power reception unit of the contactless card 112 increases depending on the distance between the supply unit and the power reception unit. For this reason, the first electrode plate 212 is preferably formed at a position close to the non-contact card 112. Further, when the first electrode plate 212 is not exposed and formed, the surface of the card reader / writer 110 facing the non-contact card 112 is at least first made of a dielectric having a high relative dielectric constant, for example, a relative dielectric constant of 10. It may be formed so as to cover the electrode plate.

  The reactance correction unit 214 is provided between the power generation unit 210 and the first electrode plate 212, and reduces a voltage drop caused by the reactance of the electrode pair formed by the first electrode plate 212. Specifically, it is composed of one or two or more inductors, active inductors, or a combination of inductors and variable capacitors, and is inserted in series in the power transmission path. In FIG. 2, one of the two active inductors inserted as the reactance correction unit 214 has one end connected to the hot terminal of the power generation unit 210 and the other end connected to the hot-side first electrode plate 218, , One end is connected to the cold side of the power generation means 210 and the other end is connected to the cold side first electrode plate 220.

  The electrode pair has a capacitive reactance and is usually represented negatively on the imaginary axis of impedance. Therefore, the absolute value of the reactance can be lowered and the power transmission efficiency can be increased by the configuration of the inductor having the positive reactance.

  When the reactance correction unit 214 is composed of an active inductor or a combination of an inductor and a variable capacitor, the power adjustment unit 216 adjusts the active inductor and the variable capacitor according to the power generated by the power generation unit 210. Provide optimum power in the adjustment range.

  In the present embodiment, power is detected by inserting an ammeter 222 into the power transmission path and measuring the value of the current flowing through the ammeter 222. In such a configuration, the active inductor and the variable capacitor are adjusted within the adjustment range, and the point where the current value of the ammeter 222 is maximized is the minimum point of reactance and the maximum point of power.

  In this way, the power adjustment means 216 adjusts the active inductor and the variable capacitor to find the point where the current value of the ammeter 222 is maximized, and maintains the self-inductance or capacitance at this time.

  Such adjustment of the power adjusting means 216 is automatically performed, and when the current value of the ammeter 222 changes beyond a predetermined deviation, an operation for searching for the maximum power point is performed again. For example, when the contactless card 112 is replaced with another contactless card 112 during power transmission, or when the positional relationship of the contactless card during power transmission with the card reader / writer 110 changes. In this case, the reactance of the electrode pair formed by the first electrode plate 212 may change, and if the self-inductance of the active inductor is maintained, the power transmission efficiency may be deteriorated. In such a case, as described above, it is more suitable for the purpose to perform adjustment for searching for the maximum power point again.

The reactance adjusted by the power adjusting means 216 is preferably 0, and the self-inductance L (H) at this time is such that the frequency of the power is f (Hz) and the capacitance of the electrode pair is C ( F), L = 1 / ((2πf) ² × C).

Furthermore, the same effect as described above can be obtained even if the reactance correction means is formed of an inductor and a variable capacitor. Also in this case, the reactance is preferably 0, and the capacitance Cd (F) of the variable capacitor at this time is such that the frequency of the power is f (Hz), the self-inductance L (H), and the electrode pair. When the capacitance is C (F), it is expressed by Cd = 1 / ((2πf) ² × L) −C.

  Further, the non-contact card 112 in the present embodiment includes a second electrode plate 230 and a power receiving means 232.

  The second electrode plate 230 is formed of a metal material having a predetermined area, functions as a capacitor by electrostatic coupling with the first electrode plate at a position facing the first electrode plate 212, and serves as a hot-side first electrode. The hot-side second electrode plate 234 that is electrostatically coupled to the plate 218 and the cold-side second electrode plate 236 that is electrostatically coupled to the cold-side first electrode plate 220 are configured. The second electrode plate 230 is provided in the power transmission path between the card reader / writer 110 and the non-contact card 112. That is, when the non-contact type card 112 is attached to the card reader / writer 110, the card reader / writer 110 is disposed to face the supply unit.

  Here, if the power supplied from the card reader / writer 110 is AC power such as a sine wave, the corresponding electrode plates of the first electrode plate 212 and the second electrode plate 230 are different from the electrode pairs shown above. It does not matter if it becomes an electrode pair. That is, the hot side first electrode plate 218 and the cold side second electrode plate 236, and the cold side first electrode plate 220 and the hot side second electrode plate 234 are paired to form a part of the power transmission path. Is also possible.

  The power receiving unit 232 is connected to the second electrode plate 230 and receives power supplied through the second electrode plate 230. The received power is used as power for a load such as a semiconductor storage medium provided in the contactless card 112. When such a load that consumes power requires DC power, the power receiving means 232 may include a rectifier circuit that rectifies the received AC power into DC power.

(Power adjustment means 216)
Here, in order to deepen the understanding of the present embodiment, the adjustment of the power adjusting means 216 will be described in detail. The reactance correction unit 214 is formed of an active inductor, and the power adjustment unit 216 adjusts the self-inductance of the active inductor.

  FIG. 3 is an explanatory diagram for explaining the operation of the power adjusting means 216. Here, the horizontal axis 310 represents the frequency f (Hz), and the vertical axis 312 represents the reactance (Ω).

  At this time, the reactance due to the electrode pair formed by the first electrode plate 212 and the second electrode plate 230 changes as a curve 316 according to the power frequency f, and the reactance due to the active inductor depends on the power frequency f. It changes like a straight line 318. At this time, if the power frequency f is low, the absolute value of the reactance due to the electrode pair becomes larger than the absolute value of the reactance due to the active inductor, and the combined reactance increases in the negative direction. On the other hand, when the power frequency f is high, the absolute value of the reactance due to the active inductor becomes larger than the absolute value of the reactance due to the electrode pair, and the combined reactance increases in the positive direction.

  In the present embodiment, the self inductor of the active inductor can be adjusted, and the slope of the straight line 318 can be changed in the self inductor variable range 320 of FIG.

Here, the frequency of the power generated by the power generation unit 210 is constant f ₀ , and the power adjustment unit 216 cancels the reactance due to the electrode pair, that is, the self-inductance of the active inductor, that is, the slope of the straight line 318. Change. Thus the absolute value 322 is equal j2πfL and 1 / a (j2πfC) at power frequency _{f 0,} the reactance component becomes zero.

(Second Embodiment)
FIG. 4 is a block diagram showing configurations of the card reader / writer 110 and the non-contact card 112 according to the second embodiment in the power transmission system.

  The card reader / writer 110 includes a power generation unit 210, a first electrode plate 212, a reactance correction unit 214, and a frequency adjustment unit 350. The non-contact card 112 includes a second electrode plate 230 and power receiving means 232. Here, since the functions already described as the constituent elements in the first embodiment are substantially the same, the duplicate description is omitted.

  When the reactance correction unit 214 is composed of an inductor having a predetermined self-inductor, the frequency adjustment unit 350 adjusts the frequency of the power according to the power generated by the power generation unit 210 and adjusts the frequency range. Provide optimal power at.

  Also in this embodiment, the power is detected by inserting the ammeter 222 into the power transmission path and measuring the value of the current flowing through the ammeter 222. In such a configuration, the power frequency is adjusted within the adjustment range, and the point where the current value of the ammeter 222 is maximized is the minimum point of reactance and the maximum point of power. The frequency adjusting unit 350 finds a point where the current value of the ammeter 222 becomes maximum, and maintains the power frequency at this time.

  Such adjustment of the frequency adjusting means 350 is automatically performed, and when the current value of the ammeter 222 changes beyond a predetermined deviation, an operation for searching for the maximum power point is performed again. For example, when the contactless card 112 is replaced with another contactless card 112 during power transmission or when the position of the contactless card during power transmission with the card reader / writer 110 is changed. The reactance of the electrode pair formed by the first electrode plate 212 may change, and if the adjusted frequency is maintained, the power transmission efficiency may be deteriorated. In such a case, as described above, the purpose of adjusting the power transmission efficiency again is more suitable for the purpose.

  The reactance adjusted by the frequency adjusting means 350 is preferably 0, and the frequency f (Hz) at this time is the capacitance of the electrode pair C (F) and the self-inductance of the inductor L (H ), It is expressed by f = 1 / (2π × √ (L × C)).

  Here, the inductor may be provided in the card reader / writer 110 or may be provided in the non-contact card 112. With this configuration, when the inductor is provided in common for the plurality of contactless cards 112, the card reader / writer 110 does not need to include an inductor. Further, even when the self-inductances of the inductors provided in the plurality of non-contact cards 112 are different from each other as described above, it is possible to perform optimum power transmission by the frequency adjusting means 350.

  Further, the frequency adjusting unit 350 can be implemented in combination with the power adjusting unit 216 described in the first embodiment. In this case, it is possible to adjust the reactance value by the above-mentioned two means. For example, after the rough adjustment by the power adjustment means 216, fine adjustment by the frequency adjustment means 350, or non-contact type A large change in reactance due to replacement of the card 112 or the like can be handled by the power adjustment means 216, and a minute change in reactance during power transmission can be absorbed by the frequency adjustment means 350.

(Frequency adjusting means 350)
Here, in order to deepen the understanding of the present embodiment, the adjustment of the frequency adjusting means 350 will be described in detail. Here, the reactance correction means 214 is formed of an inductor having a predetermined self-inductance.

  FIG. 5 is an explanatory diagram for explaining the operation of the frequency adjusting means 350. Here, the horizontal axis 310 represents the frequency f (Hz), and the vertical axis 312 represents the reactance (Ω).

  At this time, the reactance due to the electrode pair formed by the first electrode plate 212 and the second electrode plate 230 changes as a curve 316 according to the power frequency f, and the reactance of the inductor having a predetermined self-inductance L is It changes like a straight line 370 according to the power frequency f. At this time, if the power frequency f is low, the absolute value of reactance due to the electrode pair becomes larger than the absolute value of reactance due to the inductor, and the combined reactance becomes larger in the negative direction. On the other hand, when the power frequency f is high, the absolute value of the reactance due to the inductor becomes larger than the absolute value of the reactance due to the electrode pair, and the combined reactance increases in the positive direction.

In the present embodiment, the frequency f _a of the power generated by the power generation unit 210 can be adjusted and can be changed in the frequency variable range 372 in FIG.

The frequency adjustment means 350, as the reactance due to the electrode pairs are canceled, to vary the power of the frequency f _a. Thus the absolute value 376 is equal j2πfL and 1 / a (j2πfC) at power frequencies _{f a,} the reactance component becomes zero.

(Third embodiment)
FIG. 6 is a block diagram showing configurations of the card reader / writer 110 and the non-contact card 112 according to the third embodiment in the power transmission system.

  The card reader / writer 110 includes a power generation unit 210 and a first electrode plate 212. The non-contact card 112 includes a second electrode plate 230, power receiving means 232, reactance correcting means 390, and power adjusting means 392. Here, since the functions already described as the constituent elements in the first embodiment are substantially the same, the duplicate description is omitted.

  In the present embodiment, the reactance correction unit 214 and the power adjustment unit 216 implemented in the card reader / writer 110 in the first embodiment are replaced with the reactance correction unit 390 and the power adjustment unit 392 of this embodiment while maintaining the functions as they are. There is no substantial functional difference in such means. The ammeter 394 also has a function equivalent to that of the ammeter 222 in the first embodiment. However, since the reactance correction unit 390 and the power adjustment unit 392 are provided in the non-contact card 112, the size is restricted.

(Fourth embodiment)
Hereinafter, an embodiment of the signal transmission system will be described as a fourth embodiment of the present application. Here, as in the first embodiment, the card reader / writer 110 and the non-contact type card 112 of FIG. 1 are used as typical examples, the card reader / writer 110 as an example of a signal transmission device, and an example of a signal reception device. A contactless card 112 is described.

  As shown in FIG. 1, the card reader / writer 110 and the non-contact card 112 are configured separately. When the contactless card 112 is operated, that is, when a signal is transmitted from the card reader / writer 110 to the contactless card 112, the contactless card 112 is disposed at a position facing the card reader / writer 110, and a signal is transmitted in a contactless manner. Is transmitted.

  FIG. 7 is a block diagram showing the configuration of the card reader / writer 110 and the non-contact card 112 in the signal transmission system.

  The card reader / writer 110 includes a signal generation unit 410, a first electrode plate 412, a reactance correction unit 414, and a signal adjustment unit 416. The non-contact card 112 includes a second electrode plate 430 and a signal receiving unit 432.

  In the present embodiment, the power that is the transmission purpose of the power transmission system in the first embodiment is replaced with a signal. The signal generation unit 410, the first electrode plate 412, the reactance correction unit 414, the signal of the present embodiment. The adjustment means 416, the ammeter 422, the second electrode plate 430, and the signal reception means 432 are the power generation means 210, the first electrode plate 212, the reactance correction means 214, the power adjustment means 216, and the ammeter, respectively, in the first embodiment. 222, the second electrode plate 230, and the power receiving means 232 have substantially the same functions. A duplicate description of such functions is omitted.

(Fifth embodiment)
FIG. 8 is a block diagram showing configurations of the card reader / writer 110 and the non-contact card 112 according to the fifth embodiment in the signal transmission system.

  The card reader / writer 110 includes a signal generation unit 410, a first electrode plate 412, a reactance correction unit 414, and a frequency adjustment unit 450. The non-contact card 112 includes a second electrode plate 430 and a signal receiving unit 432.

  In this embodiment, the power that is the transmission purpose of the power transmission system in the second embodiment is replaced with a signal. The signal generation means 410, the first electrode plate 412, the reactance correction means 414, and the frequency of this embodiment. The adjustment means 450, the ammeter 422, the second electrode plate 430, and the signal reception means 432 are the power generation means 210, the first electrode plate 212, the reactance correction means 214, the frequency adjustment means 350, and the second, respectively, in the first embodiment. The electrode plate 230 and the power receiving means 232 have substantially the same function. A duplicate description of such functions is omitted.

(Sixth embodiment)
FIG. 9 is a block diagram showing configurations of the card reader / writer 110 and the non-contact card 112 according to the sixth embodiment in the signal transmission system.

  The card reader / writer 110 includes a signal generation unit 410 and a first electrode plate 412. The non-contact card 112 includes a second electrode plate 430, a signal receiving unit 432, a reactance correcting unit 470, and a signal adjusting unit 472.

  In the present embodiment, the power that is the transmission purpose of the power transmission system in the third embodiment is replaced with a signal, and the signal generating means 410, the first electrode plate 412, the second electrode plate 430, and the like in the present embodiment. The signal receiving unit 432, the reactance correcting unit 470, the signal adjusting unit 472, and the ammeter 474 are respectively the power generating unit 210, the first electrode plate 212, the second electrode plate 230, the power receiving unit 232, and the reactance in the first embodiment. It has the same functions as the correcting unit 390, the power adjusting unit 392, and the ammeter 394.

  In such a signal transmission system, the signal to be transmitted is usually transmitted on a carrier wave having a high frequency such as 200 MHz. The signal transmission system is particularly effective when the frequency band of the base signal is narrower than the carrier wave.

In the fourth to sixth embodiments, the signal transmission system having substantially the same configuration as the power transmission system has been described. In such a signal transmission system, the card reader / writer 110 can be used as a signal transmitting device and the non-contact card 112 can be used as a signal receiving device as described above, but the reverse configuration can also be adopted. That is, the card reader / writer 110 is used as a signal receiving device, and the non-contact card 112 is used as a signal transmitting device. Further, such a card reader / writer 110 can be provided with both a signal transmitting device and a signal receiving device, and a non-contact card 112 can be provided with both the above devices. Furthermore, the power transmission system shown in the first to third embodiments can be further included as power for operating each device.
(Seventh embodiment)

  Hereinafter, the effect when the power transmission system is realized will be described with reference to FIGS. In this description, (1) a simple circuit that supplies power to a load resistor, (2) a capacitor that simulates an electrode pair formed by a first electrode plate 212 and a second electrode plate 230 in the power transmission path of the simple circuit. (3) The circuit of (2) above and the circuit of (2) further provided with reactance correction means are simulated, and the same power is applied to such a circuit, resulting in the load resistance at that time. Measure the voltage. Here, the higher the measured voltage, the higher the power transmission efficiency.

  FIG. 10 is a circuit diagram in which only the AC power source 510 as the power generation unit 210 and the rectifier circuit 512 as the power reception unit 232 are connected.

  The AC power source 510 generates AC power having a voltage of 5 V and a frequency of 200 MHz.

  The rectifier circuit 512 rectifies AC power from the AC power supply 510 into DC power, and supplies the DC power to a smoothing capacitor 514 that smoothes the voltage and a load resistor 516 that consumes power. At this time, the voltage generated at the test point (TP) 522 with respect to the card ground (CGND) 520 is measured.

  FIG. 11 is a plot showing voltage values measured in the above circuit. Here, the horizontal axis 550 shows the elapsed time, and the vertical axis 552 shows the measured TP voltage. In such a simple circuit, the TP voltage changes as shown by a curve 554 and finally reaches 3.7V.

  FIG. 12 is a circuit diagram in which a first electrode plate 212 and a second electrode plate 230 are added to the power transmission path of the circuit shown in FIG.

  Such a circuit includes an AC power supply 510, a rectifier circuit 512, a first capacitor 570, and a second capacitor 572. The first capacitor 570 and the second capacitor 572 simulate two electrode pairs formed by the first electrode plate 212 and the second electrode plate 230. Such a configuration is equivalent to providing a boundary 574 between the card reader / writer and the non-contact card between the electrode plates of both capacitors, and the AC power source 510 side is connected to the card reader / writer and the rectifier circuit. The 512 side can be regarded as a contactless card.

The size S of the electrode plates of the first capacitor 570 and the second capacitor 572 is 20 mm × 20 mm, the distance l between the electrode plates is 0.1 mm, and the vacuum dielectric constant ε ₀ is 8.86 × 10 ⁻¹² . In this case, the capacitance C is ε ₀ × S / l = 8.86 × 10 ⁻¹² × 0.0004 / 0.0001 = 3.544 × 10 ⁻¹¹ (F), and is a sine with a frequency of 200 MHz. The reactance -j / 2πfc for a wave signal is −j × 1 / (2π × 200 × 10 ⁶ × 3.544 × 10 ⁻¹¹ ) = − j22.45 (Ω).

  When a simulation is performed by inserting a capacitor having such a large reactance value, a voltage drop due to the reactance appears remarkably.

  FIG. 13 is a plot showing voltage values measured in the above circuit. Here, the horizontal axis 550 shows the elapsed time, and the vertical axis 552 shows the measured TP voltage. In a circuit in which such a capacitor is inserted, the TP voltage changes as shown by a curve 576 and finally becomes 1.7V. Even when compared with FIG. 11 in which no capacitor is inserted, the final value is lowered by 2.0 V, confirming that the voltage drop due to the reactance of the capacitor cannot be ignored.

  FIG. 14 is a circuit diagram in which reactance correction means is added to the power transmission path (on the non-contact card side) of the circuit shown in FIG.

  The circuit includes an AC power supply 510, a rectifier circuit 512, a first capacitor 570, a second capacitor 572, and a first inductor 580 and a second inductor 582 as reactance correction means. The first inductor 580 is inserted between the first capacitor 570 and the hot side terminal of the rectifier circuit 512, and the second inductor 582 is inserted between the second capacitor 572 and the cold side terminal of the rectifier circuit 512. The

  The reactance of the first capacitor 570 and the second capacitor 572 is canceled by the self-inductance of the first inductor 580 and the second inductor 582, and the power transmission efficiency can be increased.

  FIG. 15 is a plot showing voltage values measured in the circuit. Here, the horizontal axis 550 shows the elapsed time, and the vertical axis 552 shows the measured TP voltage. In a circuit in which such reactance correction means is inserted, the TP voltage changes as shown by a curve 584 and finally reaches 3.1V. As a result, it can be seen that this is an improvement compared to the final value of 1.7 V in FIG. Even if the reactance is canceled in this way, the reason why the voltage is not 3.7 V as shown in FIG. 11 is because of internal resistance and the like.

  FIG. 16 is a circuit diagram showing a case where reactance correction means for the power transmission path of the circuit shown in FIG. 14 is added to the card reader / writer side. At this time, the same result as shown in FIG. 15 is obtained.

  The above simulation confirms the necessity and effect of power transmission efficiency by reactance correction means.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  Although this embodiment is described assuming power transmission and signal transmission between a non-contact card and a card reader / writer, it can also be applied to short-distance, non-contact type power transmission such as a VTR rotary coupler. In addition, the power receiving device and the signal receiving device are not limited to the card shape, and the power supply device and the signal transmitting device are not limited to the reader / writer, and are mounted on portable or small electronic devices having other functions. It is also possible to do.

  The present invention can be applied to a power transmission system, a power supply device, a power reception device, a signal transmission system, a signal transmission device, and a signal reception device.

It is an image figure which shows the typical example of the electric power transmission system by 1st Embodiment. 1 is a block diagram illustrating a configuration of a power transmission system according to a first embodiment. It is explanatory drawing for demonstrating operation | movement of an electric power receiving means. It is the block diagram which showed the structure of the electric power transmission system by 2nd Embodiment. It is explanatory drawing for demonstrating operation | movement of an electric power receiving means. It is the block diagram which showed the structure of the electric power transmission system by 3rd Embodiment. It is the block diagram which showed the structure of the signal transmission system by 4th Embodiment. It is the block diagram which showed the structure of the signal transmission system by 5th Embodiment. It is the block diagram which showed the structure of the signal transmission system by 6th Embodiment. It is a circuit diagram explaining the effect at the time of implement | achieving an electric power transmission system. It is the plot figure which showed the voltage value of the transmitted electric power. It is a circuit diagram explaining the effect at the time of implement | achieving an electric power transmission system. It is the plot figure which showed the voltage value of the transmitted electric power. It is a circuit diagram explaining the effect at the time of implement | achieving an electric power transmission system. It is the plot figure which showed the voltage value of the transmitted electric power. It is a circuit diagram explaining the effect at the time of implement | achieving an electric power transmission system.

Explanation of symbols

110 Card reader / writer 112 Non-contact card 210 Power generation means 212 First electrode plate 214 Reactance correction means 216 Power adjustment means 230 Second electrode plate 232 Power reception means 350 Frequency adjustment means 410 Signal generation means 416 Signal adjustment means 432 Signal reception Means 512 rectifier circuit

Claims (31)

A power supply device that supplies power; and a power reception device that is configured separately from the power supply device and that receives power from the power supply device. During power transmission, the supply unit of the power supply device and the power reception device A power transmission system in which the power receiving unit of the device is placed at the opposite position and the power is transmitted in a contactless manner:
The power supply device includes power generation means for generating power,
A first electrode plate that is connected to the power generating means and forms the one-side electrode plate of the electrode pair that functions as a capacitor;
The power receiving device includes a second electrode plate serving as the power receiving unit that functions as a capacitor by electrostatic coupling with the first electrode plate;
Power receiving means connected to the second electrode plate and receiving power supplied via the second electrode plate;
An electrode pair of the first electrode plate and the second electrode plate forms part of a power transmission path;
The power transmission system, wherein the power supply device or the power receiving device further includes reactance correction means for reducing a voltage drop due to reactance of the electrode pair. The power receiving device is a contactless card;
The power transmission system according to claim 1, wherein the power supply device is a card reader / writer that reads and / or writes data to and from the contactless card. A power supply device configured separately from a power receiving device for receiving power, wherein a power supply unit and a power receiving unit of the power power receiving device are opposed to each other during power transmission and supply power to the power power receiving device in a contactless manner. :
Power generation means for generating power;
A first electrode plate that is connected to the power generating means and forms the one-side electrode plate of the electrode pair that functions as a capacitor;
Reactance correction means for reducing a voltage drop due to reactance of an electrode pair formed by the first electrode plate and functioning as a capacitor between the power generation means and the first electrode plate;
A power supply device comprising: The reactance correction means includes an inductor having a predetermined self-inductance;
Active inductor with adjustable self-inductance;
A combination of an inductor having a predetermined self-inductance and a variable capacitor with adjustable capacitance;
The power supply device according to claim 3, wherein the power supply device is formed of any one of the following.   The power supply apparatus according to claim 3, further comprising a power adjustment unit that adjusts the reactance correction unit according to the power.   The power supply apparatus according to claim 3, further comprising a frequency adjustment unit that adjusts a frequency of power generated by the power generation unit according to the power. Two first electrode plates are provided in one power transmission path;
Each first electrode plate is connected to a hot side and a cold side of the power generating means,
The power supply device according to claim 3, wherein the power supply device is formed side by side at a position facing a power reception unit of the power reception device.   The power supply apparatus according to claim 3, wherein the power generated by the power generation means is AC power.   4. The power supply apparatus according to claim 3, wherein the power supply apparatus is a card reader / writer that reads and / or writes data to and from a contactless card. A power receiving device configured separately from a power supply device that supplies power, wherein a power receiving unit and a supply unit of the power supply device face each other during power transmission and receive power from the power supply device in a contactless manner. :
A second electrode plate that is the power receiving unit forming one electrode plate of an electrode pair that functions as a capacitor;
Power receiving means connected to the second electrode plate and receiving power supplied via the second electrode plate;
Reactance correction means for reducing a voltage drop due to reactance of an electrode pair formed by the second electrode plate and functioning as a capacitor between the second electrode plate and the power receiving means;
A power receiving device comprising: The reactance correction means includes an inductor having a predetermined self-inductance;
Active inductor with adjustable self-inductance;
A combination of an inductor having a predetermined self-inductance and a variable capacitor with adjustable capacitance;
The power receiving device according to claim 10, wherein the power receiving device is formed of any one of the following.   The power receiving apparatus according to claim 10, further comprising a power adjusting unit that adjusts the reactance correcting unit according to the power. Two second electrode plates are provided in one power transmission path;
Each second electrode plate is connected to each terminal of the power receiving means,
The power receiving apparatus according to claim 10, wherein the power receiving apparatus is formed side by side at a position facing a supply unit of the power supply apparatus.   The power receiving apparatus according to claim 10, wherein the power to be received is AC power.   15. The power receiving apparatus according to claim 14, wherein the power receiving means includes a rectifier circuit that rectifies received AC power into DC power.   The power receiving device according to claim 10, wherein the power receiving device is a contactless card. A signal transmission device that transmits a signal, and a signal reception device that is configured separately from the signal transmission device and receives a signal from the signal transmission device, and at the time of signal transmission, the transmission unit of the signal transmission device and the signal reception A signal transmission system in which signals are transmitted in a contactless manner, with the receiving part of the device facing each other:
The signal transmission device includes signal generation means for generating a signal,
A first electrode plate that is connected to the signal generating means and that forms the one-side electrode plate of the electrode pair that functions as a capacitor;
The signal receiving device includes a second electrode plate which is the receiving unit that functions as a capacitor by electrostatic coupling with the first electrode plate;
Signal receiving means connected to the second electrode plate and receiving a signal transmitted through the second electrode plate;
An electrode pair of the first electrode plate and the second electrode plate forms part of a signal transmission path;
The signal transmission system according to claim 1, wherein the signal transmission device or the signal reception device further includes reactance correction means for reducing a voltage drop due to reactance of the electrode pair. The signal receiving device and the signal transmitting device are:
A contactless card; and a card reader / writer for reading and / or writing data to the contactless card;
The signal transmission system according to claim 17, wherein the signal transmission system is a pair. A signal transmission device configured separately from a signal reception device that receives a signal, wherein a transmission unit and the reception unit of the signal reception device face each other during signal transmission, and transmits a signal to the signal reception device in a contactless manner. :
Signal generating means for generating a signal;
A first electrode plate that is connected to the signal generating means and forms the one-side electrode plate of an electrode pair that functions as a capacitor;
Reactance correction means for reducing a voltage drop due to reactance of an electrode pair which is formed by the first electrode plate and functions as a capacitor between the signal generating means and the first electrode plate;
A signal transmission device comprising: The reactance correction means includes an inductor having a predetermined self-inductance;
Active inductor with adjustable self-inductance;
A combination of an inductor having a predetermined self-inductance and a variable capacitor with adjustable capacitance;
The signal transmission device according to claim 19, wherein the signal transmission device is formed by any one of the following.   The signal transmission device according to claim 19, further comprising a signal adjustment unit that adjusts the reactance correction unit according to the signal.   The signal transmission apparatus according to claim 19, further comprising frequency adjusting means for adjusting a frequency of a signal generated by the signal generating means in accordance with the signal. Two first electrode plates are provided in one signal transmission path;
Each first electrode plate is connected to each terminal of the signal generating means,
The signal transmission device according to claim 19, wherein the signal transmission device is formed side by side at a position facing a reception unit of the signal reception device.   The signal transmission device according to claim 19, wherein the signal generated by the signal generation means is an AC signal.   The signal transmission device according to claim 19, wherein the signal transmission device is a contactless card or a card reader / writer that reads and / or writes data to and from the contactless card. A signal receiving device configured separately from a signal transmitting device for transmitting a signal, wherein a receiving unit and a transmitting unit of the signal transmitting device face each other at the time of signal transmission and receive a signal from the signal transmitting device in a non-contact manner. :
A second electrode plate serving as the receiving unit for forming one electrode plate of the electrode pair functioning as a capacitor;
Signal receiving means connected to the second electrode plate and receiving a signal transmitted through the second electrode plate;
Reactance correction means for reducing a voltage drop due to reactance of an electrode pair formed by the second electrode plate and functioning as a capacitor between the second electrode plate and the signal receiving means;
A signal receiving device comprising: The reactance correction means includes an inductor having a predetermined self-inductance;
Active inductor with adjustable self-inductance;
A combination of an inductor having a predetermined self-inductance and a variable capacitor with adjustable capacitance;
27. The signal receiving device according to claim 26, wherein the signal receiving device is formed of any one of the following.   27. The signal receiving apparatus according to claim 26, further comprising a signal adjustment unit that adjusts the reactance correction unit according to the signal. Two of the second electrode plates are provided in one signal transmission path;
Each second electrode plate is connected to each terminal of the signal receiving means,
27. The signal receiving apparatus according to claim 26, wherein the signal receiving apparatus is formed side by side at a position facing a transmitting unit of the signal transmitting apparatus.   27. The signal receiving apparatus according to claim 26, wherein the received signal is an AC signal. 27. The signal receiving apparatus according to claim 26, wherein the signal receiving apparatus is a contactless card or a card reader / writer that reads and / or writes data to and from the contactless card.

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