JPH11188113A - Power transmission system, power transmission method and electric stimulation device provided with the power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably transmit power without destroying the resonance state of a coil even when the distance of transmission and reception coils fluctuates. SOLUTION: This system is provided with a transmission coil 21 and a reception coil 11 oppositely arranged holding skin between them, a variable capacitor 22 for constituting a resonance circuit by being connected to the transmission coil 21, a variable capacitor 12 for constituting the resonance circuit by being connected to the reception coil 11, voltage detection circuits 23 and 13 for respectively detecting voltage levels in the transmission coil 21 and the reception coil 11, a capacity control circuit 24 for inputting the voltage level detected in the voltage detection circuit 23 and varying the capacity of the variable capacitor 22 so that the detected voltage level takes a highest value at all times and a capacity control circuit 14 for inputting the voltage level detected in the voltage detection circuit 13 and varying the capacity of the variable capacitor 12 so that the detected voltage level takes the highest value at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a device having an opposing arrangement.
The present invention relates to a power transmission system and a power transmission method for transmitting electric energy between two coils using a pair of power supply coils. More specifically, the present invention is applied to a device for externally controlling various biological functions, for example, an electrical stimulation device for treating and reconstructing a function of a living body paralyzed by central nervous disorder such as stroke or spinal cord injury by electrical stimulation. The present invention relates to a power transmission system and a power transmission method to be performed. The power transmission here includes not only transmission of power but also transmission of control signals and the like.

[0002]

2. Description of the Related Art An electrical stimulator for treating and reconstructing the function of a paralyzed body with electrical stimulation is basically a stimulator that is implanted in the body to electrically stimulate a paralyzed part of a living body, And a device main body that transmits and drives electric power and signals to a stimulator implanted in the body. In such an electric stimulator, as a power transmission system for transmitting power or a signal from the main body to a stimulator embedded in the body, a power supply coil pair (for example, an air-core coil Power and signals from an external power supply coil to a power supply coil inside the body to transmit power and signals to a stimulator embedded in the body. Is known. As an example,
For example, Japanese Unexamined Patent Publication No. 5-317434 discloses a device provided with a non-contact type power supply coil.

[0003] The system disclosed in the above publication includes a first power supply coil completely embedded in a body together with an electrical stimulator, and a second power supply coil disposed in parallel with and opposed to the first power supply coil via the skin. And supplying the high-frequency power to a second power supply coil placed outside the body, so that the supplied high-frequency power is inductively transmitted to the first power supply coil in the body. And the first
Is converted into a desired frequency by the power supply coil.

[0004] In addition, Japanese Patent Application Laid-Open No. 4-285436 discloses a system for inductively transmitting power from an external sending coil to a target coil connected to an implanted capacitive element. Which can maintain the resonance coupling of the above.

[0005]

In the above-described power transmission system in which power transmission is performed between a pair of power supply coils arranged opposite to each other, power transmission is performed inductively with both coils in a resonance state. Will be However, in such a conventional system, since the resonance parameters of the transmitting and receiving coils are fixed and constant, for example, when the distance between the two coils changes or when the coils are shifted sideways, the mutual inductance of the two coils becomes large. Has changed,
The resonance state of the coil is lost. As a result, a problem arises in that the reception voltage at the reception side coil decreases, and a load circuit such as a stimulator connected to the reception coil does not operate.

An object of the present invention is to provide a power transmission system and a power transmission method capable of performing stable power transmission without disturbing the resonance state of the coil even if the distance between the transmitting and receiving coils fluctuates. is there. It is still another object of the present invention to provide an electric stimulator provided with the power transmission system.

[0007]

In order to achieve the above object, a first power transmission system according to the present invention includes a pair of power supply coils arranged opposite to each other, one of which is a transmission coil and the other is a reception coil. In a power transmission system in which power is transmitted inductively, a first variable capacitor connected to the transmission coil to form a resonance circuit, and a second variable capacitor connected to the reception coil to form a resonance circuit, A first voltage detecting means for detecting a voltage level in the transmitting coil, a second voltage detecting means for detecting a voltage level in the receiving coil, and a voltage level detected by the first voltage detecting means. An input, a first capacitance control unit that varies the capacitance of the first variable capacitor so that the detection voltage level always takes the maximum value, and a second voltage detection unit. And inputs the detected voltage level, and having a second capacity control means for varying the capacitance of the second variable capacitor to take always maximum voltage level said detectable, the.

A second power transmission system according to the present invention includes a pair of power supply coils disposed to face each other, one of which is a transmission coil, and the other of which is a reception coil. A first variable capacitor connected to the transmission coil to form a resonance circuit; a second variable capacitor connected to the reception coil to form a resonance circuit; and voltage detection means for detecting a voltage level in the reception coil. And capacitance control means for inputting the voltage level detected by the voltage detection means and varying the capacitances of the first and second variable capacitors so that the detected voltage level always takes the maximum value. It is characterized by having.

In the above case, a transmission coil and a reception coil which are different from the power supply coil pair and are arranged opposite to each other;
A first capacitor connected to the transmission coil to form a first resonance circuit; and a second capacitor connected to the reception coil.
A second capacitor constituting the resonance circuit of the above, a signal transmission unit which receives a control signal output from the capacitance control unit as an input, and supplies the input signal to the first resonance circuit, and the second resonance circuit And a signal receiving means for receiving the control signal received via the first variable capacitor and outputting the input control signal to the first variable capacitor.

[0010] An electrostimulation apparatus according to the present invention is an electrostimulation apparatus provided with any one of the above-described power transmission systems. Stimulating means for electrically stimulating the paralyzed portion; and control means connected to the transmitting coil and supplying power to the stimulating means from outside the body to control a stimulating operation.

According to a first power transmission method of the present invention, one of a pair of power supply coils disposed to face each other has a transmission coil,
In a power transmission method for inductively transmitting power using the other as a receiving coil, a voltage level in each of the transmitting coil and the receiving coil is detected, and the transmitting coil and the receiving coil are set so that each detected voltage level always takes a maximum value. Is characterized by controlling the resonance state.

According to a second power transmission method of the present invention, one of a pair of power supply coils disposed opposite to each other has a transmission coil,
In a power transmission method for inductively transmitting power using the other as a receiving coil, a voltage level in the receiving coil is detected, and a resonance state of the transmitting coil and the receiving coil is controlled such that the detected voltage level always takes a maximum value. It is characterized by doing.

(Operation) According to the present invention, a resonance circuit is constituted by the transmission coil and the first variable capacitor, and a resonance circuit is constituted by the reception coil and the second variable capacitor. Can be controlled by varying the capacity of each variable capacitor. Therefore, for example, even if the distance between the transmitting and receiving coils fluctuates and the mutual inductance of the transmitting and receiving coils changes, the resonance state of each resonance circuit can be controlled according to the change, and the power transmission between the transmitting and receiving coils is always performed. It can be performed in an optimal state.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing a schematic configuration of a power transmission system according to a first embodiment of the present invention. This power transmission system is applied to an electric stimulator for treating and reconstructing the function of a living body with electric stimulation, and a load circuit 3 for electrically stimulating a paralyzed part of the living body.
(Stimulation device), a power receiving unit 1 embedded in the body together with the load circuit 3, and a drive circuit 4 for transmitting power and signals to the load circuit 3 embedded in the body to control a stimulating operation (device main body) ) Is connected, and the power transmission unit 2 is provided outside the body together with the drive circuit 4.

The power receiving unit 1 includes an LC circuit (resonant circuit) including a receiving coil 11 for receiving power supplied from outside the body and a variable capacitor 12 connected in parallel to the receiving coil 11. A voltage detection circuit 13 for detecting a received voltage level, and a voltage level detected by the voltage detection circuit 13 are input, and the capacitance of the variable capacitor 12 is varied so that the detected voltage level always takes the maximum value. It has a capacity control circuit 14 and a rectifier circuit 15 for rectifying the voltage received by the receiving coil 11 from AC to DC.

The power transmitting unit 2 is disposed in parallel with and facing the receiving coil 11 embedded in the body.
An LC circuit (resonant circuit) including a transmitting coil 21 for inductively transmitting power to the transmission coil 1 and a variable capacitor 22 connected in parallel to the transmitting coil 21, and a voltage detecting circuit for detecting a voltage level transmitted by the transmitting coil 21 23 and the voltage detection circuit 2
3 has a capacitance control circuit 24 that receives the voltage level detected at 3 and changes the capacitance of the variable capacitor 22 so that the detected voltage level always takes the maximum value.

The transmitting and receiving coils 11 and 21 may be of any type as long as power can be inductively transmitted between the two coils. For example, various coils such as an air core coil and a magnetic core coil may be used. Can be.

In the power transmission system configured as described above, when power for driving the load circuit 3 is supplied from the drive circuit 4 to the transmission coil 21 of the power transmission unit 2, the transmission coil 21 transmits the power to the power reception unit. Power is inductively transmitted to one receiving coil 11. At this time, if the resonance circuits of the power receiving unit 1 and the power transmitting unit 2 are in a state of resonance at the frequency of the power carrier, most of the power supplied from the driving circuit 4 is used in the load circuit 3, If there is no resonance, it is wasted in the receiving coil 11 of the power receiving unit 1 and each circuit (voltage regulator) connected thereto. The power received by the receiving coil 11 is supplied to the load circuit 3 via the rectifier circuit 15.

Now, the power receiving unit 1 is switched to the frequency of the power carrier.
In addition, it is assumed that power transmission is performed in a state where each resonance circuit of the power transmission unit 2 resonates. Here, the transmission coil 2
When the distance 1 between the coil 1 and the receiving coil 11 changes, the mutual inductance of the transmitting and receiving coils changes, and the resonance parameter also changes. When the resonance parameter changes, the voltage level of the power carrier decreases, and the change in the voltage level is detected by each of the voltage detection circuits 13 and 23 of the power receiving unit 1 and the power transmitting unit 2.

When the voltage level decreases, the capacitance control circuit 1
4 varies the capacity of the variable capacitor 12 based on the output of the voltage detection circuit 13 so that the detected voltage level becomes the maximum value. Similarly, the capacitance control circuit 24 varies the capacitance of the variable capacitor 22 based on the output of the voltage detection circuit 23 so that the detected voltage level becomes the highest value. Thus, even if the mutual inductance of the transmitting and receiving coils changes, power transmission can be performed while always resonating at the frequency of the power carrier.

As described above, in the power transmission system of the present embodiment, the detection of the transmission voltage and the reception voltage is performed by the voltage detection units provided in the transmission unit and the reception unit, respectively. Since the capacitance of the capacitor of the resonance circuit is automatically corrected so as to maintain the resonance state, power transmission is performed in an optimum state.

In the above description, an example in which the present invention is applied to an apparatus for externally controlling a biological function has been described. However, the present invention is not limited to this.
The present invention can be applied to any device that can supply power by inductively transmitting electric energy using a pair of power supply coils.

(Embodiment 2) In the above-described first embodiment, the resonance state of the transmission and reception coil is controlled independently of the transmission unit and the reception unit. However, the voltage level of the reception coil is detected. Thus, the resonance state of the transmitting and receiving coil can be controlled based on the detection result.

FIG. 2 is a block diagram showing a schematic configuration of a power transmission system according to a second embodiment of the present invention. In the figure, the same components as those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals.

The power transmission system according to the present embodiment has the first
The voltage detection circuit 23 and the capacitance control circuit 24 on the power transmission unit 2 side of the embodiment are removed, and the capacitance control circuit 14 on the power reception unit 1 side changes the variable capacitor based on the voltage level detected by the voltage detection circuit 13. The capacities of 12 and 22 are respectively controlled. As a configuration for this, the transmission coil 17 and the capacitor 1
8 and a capacitance control circuit 14
Signal transmission circuit 19 for supplying the control signal sent from the power transmission unit 2 as a feedback signal (control signal for controlling the capacity of the variable capacitor 22 of the power transmission unit 2). Coil 27 and capacitor 28 arranged in parallel to and opposed to each other
And a feedback signal transmitted from the capacitance control circuit 14 which is received via the receiving coil 27, and the variable capacitor 2
2 and a feedback signal receiving circuit 29 that outputs the feedback signal to the control signal 2.

In the power transmission system configured as described above, power for driving the load circuit 3 from the drive circuit 4 is supplied to the transmission coil 21 of the power transmission unit 2 as in the case of the first embodiment. Then, power is inductively transmitted from the transmission coil 21 to the reception coil 11 of the power reception unit 1.
The power received by the receiving coil 11 is supplied to the load circuit 3 via the rectifier circuit 15.

Now, the power receiving unit 1 is switched to the power carrier frequency.
In addition, it is assumed that power transmission is performed in a state where each resonance circuit of the power transmission unit 2 resonates. Here, the transmission coil 2
When the distance 1 between the coil 1 and the receiving coil 11 changes, the mutual inductance of the transmitting and receiving coils changes, and the resonance parameter also changes. When the resonance parameter changes, the voltage level of the power carrier decreases, and this change in the voltage level is detected by the voltage detection circuit 13 of the power receiving unit 1.

When the voltage level decreases, the capacitance control circuit 1
Reference numeral 4 denotes a feedback signal transmission circuit which varies the capacitance of the variable capacitor 12 based on the output of the voltage detection circuit 13 so that the detected voltage level becomes the maximum value, and also varies the capacitance of the variable capacitor 22. Send to 19. The feedback signal transmitting circuit 19 that has received the feedback signal modulates the feedback signal at a predetermined frequency and transmits the modulated signal to the feedback signal receiving circuit 29 via each resonance circuit. The feedback signal receiving circuit 29 demodulates the received modulated signal and outputs the demodulated signal to the variable capacitor 22 as a control signal. Thus, the variable capacitor 22 is controlled by the capacity control circuit 14 of the power receiving unit 1.

As described above, based on the voltage level detected by the voltage detection circuit 13, the capacitance control circuit 14 of the power receiving unit 1 sets the variable capacitor 12, so that the detected voltage level becomes the maximum value. 22 is varied. Thereby, even if the mutual inductance of the transmitting and receiving coils 11 and 21 changes, power transmission can always be performed in a state of resonance at the frequency of the power carrier.

In the present embodiment, the signal transmission in the transmission coil 17 and the reception coil 27 is performed on the same principle as the inductive power transmission performed between the transmission coil 21 and the reception coil 11. The capacitors 18 and 28 to be connected to have a predetermined capacity according to the modulation frequency. In such a feedback system,
Since the resonance parameters are fixed, the transmitting and receiving coils 17, 2
Variations in the distance between the seven are expected to vary the voltage level of the received feedback signal, but this is not a problem since this variation does not directly affect the supply of power to the stimulator. In addition, since the portion for receiving the feedback signal is provided on the device main body side provided outside the body, an amplifier circuit or the like can be added, whereby fluctuations in the voltage level of the feedback signal can be avoided.

[0032]

According to the present invention configured as described above, the resonance state of the coil can be controlled according to the change in the mutual inductance of the transmitting and receiving coils, so that even if the distance between the transmitting and receiving coils fluctuates. In addition, there is an effect that stable power transmission can be performed without disturbing the resonance state of the coil.

Detecting the voltage level at the receiving coil,
In the invention in which the resonance state of the transmitting and receiving coil is controlled so that the voltage level always takes the maximum value, the receiving coil can be made to resonate more reliably at the frequency of the power carrier, and power transmission can be performed more stably. There is an effect that can be.

In the electric stimulator provided with the power transmission system of the present invention, since the power can be stably supplied to the stimulator implanted in the body, the received voltage at the receiving coil as in the prior art decreases. Thus, the problem that the load circuit such as the stimulator does not operate can be prevented, and a highly reliable electric stimulator can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a power transmission system according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of a power transmission system according to a second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 power receiving unit 2 power transmitting unit 3 load circuit 4 drive circuit 11, 27 receiving coil 12, 22 variable capacitor 13, 23 voltage detection circuit 14, 24 capacity control circuit 15 rectifier circuit 17, 21 transmission coil 18, 28 capacitor 19 feedback Signal transmission circuit 29 Feedback signal reception circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 392013648 Hidetoshi Matsuki 2-36-4 Yagiyama Honcho, Taihaku-ku, Sendai, Miyagi Prefecture (72) Inventor Seiichi Ishikawa 5-7-1 Shiba, Minato-ku, Tokyo NEC Within a stock company

Claims (8)

[Claims] 1. A power transmission system comprising a pair of power supply coils disposed opposite to each other, one of which is a transmission coil and the other of which is a reception coil, in which power is inductively transmitted, wherein the resonance circuit is connected to the transmission coil. A first variable capacitor connected to the receiving coil, a second variable capacitor connected to the receiving coil to form a resonance circuit, first voltage detecting means for detecting a voltage level in the transmitting coil, A second voltage detecting means for detecting a voltage level; and a voltage level detected by the first voltage detecting means as an input, and the first variable capacitor being controlled so that the detected voltage level always takes a maximum value. A first capacitance control means for varying the capacitance and a voltage level detected by the second voltage detection means are input, and the detected voltage level always takes the maximum value. And a second capacitance control means for varying the capacitance of the second variable capacitor. 2. The power transmission system according to claim 1, wherein the first capacitance control means controls a resonance circuit including the transmission coil and the first variable capacitor to resonate at a frequency of a power carrier. A power transmission system, wherein the second capacitance control means controls the resonance circuit including the receiving coil and the second variable capacitor to resonate at a frequency of a power carrier. 3. A power transmission system comprising a pair of power supply coils disposed opposite to each other, one of which is a transmission coil and the other of which is a reception coil, in which power is inductively transmitted, wherein the resonance circuit is connected to the transmission coil. A first variable capacitor, a second variable capacitor connected to the receiving coil to form a resonance circuit, a voltage detecting means for detecting a voltage level in the receiving coil, and a voltage detecting means for detecting the voltage level in the receiving coil. And a capacitance control means for varying the capacitances of the first and second variable capacitors so that the detected voltage level always takes the maximum value. . 4. The power transmission system according to claim 3, wherein the transmission coil and the reception coil, which are different from the power supply coil pair and are arranged opposite to each other, are connected to the transmission coil to form a first resonance circuit. A first capacitor to be connected, a second capacitor connected to the receiving coil to form a second resonance circuit, and a control signal output from the capacitance control means as inputs.
Signal transmitting means for supplying the input signal to the first resonance circuit; inputting the control signal received via the second resonance circuit, and outputting the input control signal to the first variable capacitor Power transmission system, further comprising: 5. An electric stimulating apparatus comprising the power transmission system according to claim 1, wherein the electric stimulating apparatus is embedded in a body together with the receiving coil, and receives power supply via the receiving coil. Stimulation means for electrically stimulating a paralyzed part of a living body, and control means connected to the transmission coil and supplying power to the stimulation means from outside the body to control a stimulation operation, Stimulator. 6. A power transmission method for inductively transmitting power between a pair of power supply coils disposed opposite to each other, using one as a transmission coil and the other as a reception coil, wherein a voltage level in the transmission coil and the reception coil is determined. A power transmission method, wherein the power transmission method detects each of the voltages and controls the resonance state of the transmission coil and the reception coil so that the respective detected voltage levels always take the maximum value. 7. A power transmission method for inductively transmitting power between a pair of power supply coils disposed opposite to each other, using one as a transmission coil and the other as a reception coil, comprising: detecting a voltage level in the reception coil; A power transmission method, wherein the resonance state of the transmission coil and the reception coil is controlled so that the detection voltage level always takes the maximum value. 8. The power transmission method according to claim 6, wherein the transmission coil and the reception coil are controlled to resonate at a frequency of a power carrier.