JP5158427B2 - Power extraction circuit for electrostatic induction type conversion element - Google Patents

Description

  The present invention relates to an electric power extraction circuit that can extract electric power with high efficiency from an electrostatic induction conversion element that converts kinetic energy generated by externally applied force such as vibration into electric energy.

  In recent years, attention has been paid to the development of electric energy generation technology that does not pollute the environment, and solar power generation, wind power generation, and the like have been put into practical use. In such technical development, development of an electrostatic induction conversion element that converts kinetic energy generated by externally applied force such as vibration into electric energy is also underway as another electric energy generation technique.

  The electrostatic induction conversion element is disclosed in, for example, an electrostatic induction conversion element disclosed in Japanese Patent Application Laid-Open No. 2006-180450 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2007-31551 (Patent Document 2). An electrostatic induction conversion element is known.

  As shown in FIG. 10, an electrostatic induction conversion element 10 disclosed in Japanese Patent Laid-Open No. 2006-180450 (Patent Document 1) includes an electret 11 formed by injecting electric charges near the surface of an insulating material. Located between the two conductors 12 and 13 and arranged in electrical contact with one conductor 12, the other conductor 13 faces the electret 11 at a predetermined interval, and the conductor 13 and the electret 11. Are configured to relatively move and convert kinetic energy into electrical energy. As a result, when the two conductors 12 and 13 are electrically connected to the load 14 and the conductor 13 is reciprocated in the direction of the arrow in the figure, for example, the electric charge (negative charge in the figure) injected into the electret 11 A positive charge is electrostatically induced, and a current flows through the load 14. Therefore, the electrostatic induction conversion element 10 having the above configuration functions as a generator.

  The electrostatic induction conversion element disclosed in Japanese Patent Application Laid-Open No. 2007-31551 (Patent Document 2) has been improved so that the distance between the substrates can be properly maintained when the opposing substrates move relative to each other. It has been applied. That is, as shown in FIGS. 11 and 12, two substrates 21 and 22 are arranged to face each other, and electrets 23 and conductors 24 are formed on the opposing surfaces of the substrates 21 and 22. Yes. The substrates 21 and 22 move relative to each other in the direction parallel to the opposing surface (the directions of arrows A and B in the figure), and the electret 23 moves relative to the conductor 24 as the substrates 21 and 22 move relative to each other. The electromotive force is generated in the conductor 24 by electrostatic induction. In order to maintain the distance between the substrates 21 and 22 appropriately, the electret 23 and the conductor 24 are attracted by the electret 23 and the conductor 24 facing each other, and the repulsion generated by the electret 23 facing each other. It is arranged to balance the force.

  When taking out electric power from such an electrostatic induction type conversion element, for example, an electric power taking out circuit as shown in FIG. 13 has been used. In FIG. 13, reference numeral 30 denotes a power extraction circuit, which includes a pair of input terminals 31 a and 31 b, a pair of output terminals 31 c and 31 d, resistors 32, 33 and 34, and a diode 35.

  The input terminal 31 a is connected to the conductor 13, and the input terminal 31 b is connected to the conductor 12. One end of the resistor 32 is connected to the input terminal 31a, and the other end of the resistor 32 is connected to the input terminal 31b and the output terminal 31d via the resistor 33. The other end of the resistor 32 is connected to the anode of a diode 35. The cathode of the diode 35 is connected to the output terminal 31 c and is connected to the output terminal 31 d via the resistor 34.

In the power extraction circuit 30, alternating current static electricity having a voltage of, for example, 80 V is generated between the electret 11 and the conductor 13 due to the reciprocating motion of the conductor 13, and current is applied to the resistors 32 and 33 connected in series. Flowing. The voltage generated between the electret 11 and the conductor 13 is divided by resistors 32 and 33 connected in series, and is rectified by a diode 35 after being set to a voltage of about 1 V to 5 V, for example. Since the resistance value between the electret 11 and the conductor 13 is several MΩ, the combined resistance values of the resistors 32 and 33 connected in series are also set to substantially the same value.
JP 2006-180450 A JP 2007-31551 A

  However, the electrical energy output from the electrostatic induction conversion element is an irregular alternating current component, the output is capacitive and the resistance value is very small (for example, several MΩ), and this is connected in series. Since the values of the resistors 32 and 33 are high impedance, many capacitance components are included. For this reason, since the capacitor components of the resistors 32 and 33 connected in series are connected in parallel to the capacitance between the electret 11 and the conductor 13, the power extraction efficiency is greatly reduced. Further, since a resistor 34 of about 100 kΩ is connected to the subsequent stage of the diode 35 so that current flows, the impedance on the anode side of the diode 35 is 100 kΩ while the cathode side impedance of the diode 35 is several MΩ. For this reason, there is a problem that the loss due to the resistor 34 becomes large and it is difficult to put it to practical use.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power extraction circuit capable of efficiently extracting electric power from an electrostatic induction conversion element.

  In order to achieve the above object, the present invention forms two substrates facing each other at a predetermined interval and capable of relative movement in a direction parallel to the facing surface, and at a predetermined position on the facing surface of at least one of the substrates. The electret, a conductor formed on the surface of the substrate facing the electret at a position facing the electret, and supporting the substrate so as to be capable of relative reciprocation in a predetermined linear direction parallel to the facing surface. A power extracting circuit for extracting electric power from an electrostatic induction conversion element that converts the kinetic energy of relative motion generated in the two substrates by an external force to be converted into electric energy and outputs the electric energy. A primary winding having one end conductively connected to the electret and the other end conductively connected to the conductor; and a secondary winding magnetically coupled to the primary winding. A stagger tuning circuit having a first stage transformer set to a tuning frequency and one or more transformers connected to one or more stages after the first stage transformer and set to a tuning frequency different from other transformers; A power extraction circuit including a pair of input terminals connected to both ends of the secondary winding of the last transformer of the stagger tuning circuit and a rectifier circuit having a pair of output terminals is proposed.

  In the power extraction circuit of the present invention, a tuning circuit is constituted by each of the transformers of each stage of the stagger tuning circuit, and the tuning frequencies of these tuning circuits are set to different frequencies.

  An alternating voltage generated between the electret and the conductor of the electrostatic induction conversion element is applied to the primary winding of the first stage transformer, and an alternating current flows through the primary winding. This alternating current generates a magnetic field in the primary winding, and this magnetic field crosses the secondary winding. As a result, a current is generated in the secondary winding by magnetic induction, and AC power having a voltage corresponding to the turn ratio with the primary winding is generated at both ends of the secondary winding. At this time, AC power having a frequency that matches the tuning frequency of the tuning circuit formed by the first stage transformer is most efficiently output to the secondary winding of the first stage transformer. In addition to the AC power of the frequency output from the previous transformer, AC power of a frequency that matches the tuning frequency of the tuning circuit formed by this transformer is output to the secondary winding of the other transformer in the subsequent stage. The Therefore, the AC power output from the secondary winding of the transformer at the final stage includes all AC power components having a frequency that matches the tuning frequency of the tuning circuit formed by each transformer. The AC power generated in the secondary winding of the final transformer is converted into DC power by the rectifier circuit and output.

  According to the power extraction circuit of the present invention, since the reactance of the transformer primary winding is connected in parallel to the capacitance between the electret and the conductor, the power loss is greatly increased as compared with the case where a conventional resistor is used. Thus, AC power can be obtained from the secondary winding, and this AC power can be converted into DC power by a rectifier circuit. Furthermore, since the AC power output from the secondary winding of the transformer at the final stage includes all of the AC power component having a frequency that matches the tuning frequency of the tuning circuit formed by each transformer, the electrostatic induction type Many irregular alternating current components of the electrical energy output from the conversion element can be extracted. Therefore, the practical application of using the electrostatic induction conversion element as a power supply is sufficiently possible.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 to 7 show an embodiment of the present invention. FIG. 1 is a block diagram showing a connection between an electrostatic induction conversion element and a power extraction circuit in an embodiment of the present invention. FIG. FIG. 3 is a transparent perspective view showing an electrostatic induction conversion element in one embodiment of the present invention, and FIG. 4 is an electrostatic induction conversion in one embodiment of the present invention. FIG. 5 is a plan view showing an electrostatic induction conversion element according to an embodiment of the present invention, FIG. 6 is a cross-sectional view taken along line AA in FIG. 5, and FIG. It is a figure which shows the electric system circuit of the electrostatic induction type conversion element in one Embodiment of invention. In these figures, 100 is a power extraction circuit, and 200 is an electrostatic induction conversion element.

  The power extraction circuit 100 includes a stagger tuning circuit 110, a rectifier circuit 160, a capacitor 102, and a resistor 103.

  The stagger tuning circuit 110 includes three transformers 120, 130, and 140 and capacitors 111 and 113 to 116.

  One end of the primary winding 121 of the transformer 120 is connected to a conductor 221 of an electrostatic induction conversion element 200, which will be described later, via an input terminal 101a, and the other end of the primary winding 111 of the transformer 110 is statically connected via an input terminal 101b. It is connected to the electret 231 of the electric induction conversion element 200. Further, the other end of the secondary winding 122 of the transformer 120 is connected to the input terminal 101b via the capacitor 111. A capacitor 123 is connected in parallel with the secondary winding 122 of the transformer 120. The capacitor 123 may use a stray capacitance. Capacitor 111 positions the reference potential of electrostatic induction conversion element 200 as the reference potential of power extraction circuit 100 and blocks direct current between primary winding 121 and secondary winding 122 of transformer 120.

  One end of the primary winding 131 of the transformer 130 is connected to one end of the secondary winding 122 of the transformer 120 via the capacitor 113, and the other end of the primary winding 131 of the transformer 130 is connected to the secondary of the transformer 120 via the capacitor 114. The other end of the winding 122 is connected. In addition, a capacitor 133 is connected in parallel with the primary winding 131 of the transformer 130 and a capacitor 134 is connected in parallel with the secondary winding 132. The capacitors 133 and 134 may use stray capacitance.

  One end of the primary winding 141 of the transformer 140 is connected to one end of the secondary winding 132 of the transformer 130 via the capacitor 115, and the other end of the primary winding 141 of the transformer 140 is connected to the secondary winding of the transformer 130 via the capacitor 116. The other end of the winding 132 is connected. A capacitor 143 is connected in parallel with the primary winding 141 of the transformer 140 and a capacitor 144 is connected in parallel with the secondary winding 142. The capacitors 143 and 144 may use stray capacitance.

  In this embodiment, as shown in FIG. 8, the tuning frequency f1 of the tuning circuit formed by the first stage transformer 120 is set to 70 Hz, and the tuning frequency f2 of the tuning circuit formed by the second stage transformer 130 is set. Is set to 30 Hz, and the tuning frequency f3 of the tuning circuit formed by the third stage transformer 140 is set to 150 Hz. Thereby, the kinetic energy in the range of 10 Hz to 200 Hz, which is the vibration frequency range fb of the reciprocating motion performed by the movable substrate 230 described later by the external force applied to the electrostatic induction conversion element 200, can be efficiently extracted as electric energy.

  Also, the tuning frequency of the tuning circuit formed by each transformer 120, 130, 140 can be easily adjusted to any frequency by adjusting the inductance value of the winding of each transformer 120, 130, 140 and the capacitance value of the capacitor connected in parallel to each winding. Can be set to

  Capacitors 113 and 114 are provided for isolation between the secondary winding 122 of the transformer 120 and the primary winding 131 of the transformer 130, and the capacitors 115 and 116 are the primary windings of the transformer 130 and the primary winding of the transformer 140. It is provided for isolation from the line 141. In this embodiment, the capacitors 113 to 116 are used to perform isolation between transformers, but isolation may be performed using a diode. Further, when a diode is used to perform isolation between transformers, it is preferable to use a compound diode having a low forward voltage in order to reduce loss and reduce a voltage that can be taken out.

  The rectifier circuit 160 includes two diodes 161 and 162. The anode of the diode 161 is connected to one end of the secondary winding 142 of the transformer 140, and the cathode of the diode 161 is connected to the cathode of the diode 162, the capacitor 102, one end of the resistor 103, and the output terminal 101c. The other end of the secondary winding 142 of the transformer 140 is connected to the anode of the diode 162, the capacitor 102, the other end of the resistor 103, and the output terminal 101d.

  The electrostatic induction conversion element 200 includes a rectangular parallelepiped housing 210 having a square upper surface. The housing 210 includes a fixed substrate 220 and a movable substrate 230, and the movable substrate 230 has one side of the upper surface. Are supported by springs 251 and 252 so as to be able to reciprocate in a predetermined linear direction parallel to the base plate, and the stationary substrate 220 and the movable substrate 230 reciprocate relatively to generate power.

  The bottom surface of the fixed substrate 220 is fixed to the inner bottom surface of the casing 210, and a comb-shaped conductor 221 is formed on the upper surface (opposing surface) of the fixed substrate 220. The comb-shaped conductor 221 is formed so that the comb teeth are orthogonal to the movable direction of the movable substrate 230 (C1 direction in FIG. 3). Further, the conductor 221 is electrically connected to an external electrode 212 provided on the outer bottom surface of the casing 210 via a wiring.

  The movable substrate 230 is supported by bearing balls 241 so that the bottom surface (opposing surface) faces the upper surface of the fixed substrate 220 in parallel with a predetermined interval. Further, a comb-shaped electret 231 and a conductor film 232 conductively connected to the electret 231 are formed on the bottom surface (opposing surface) of the movable substrate 230. The comb-shaped electret 231 is formed so that the comb teeth are orthogonal to the movable direction of the movable substrate 230 (C1 direction in FIG. 3).

  Further, a support member 241 extending in a direction orthogonal to the movable direction C1 is provided on the upper portion of the movable substrate 230, and the vertical pieces 431b at both ends of the support member 241 are fixed to two opposing sides of the movable substrate 230. Has been. The support member 241 is made of a conductor, and one vertical piece 431b is conductively connected to the conductor film 232.

  One end of each of the two springs 251 and 252 is connected to the center of the horizontal piece 431a of the support member 241. These springs 251 and 252 are arranged so that the expansion and contraction direction thereof coincides with the movable direction C1. Further, the other ends of the springs 251 and 252 are fixed to the inner surface of the casing 210. The support member 241 is electrically connected to a wiring 252a made of a conductor provided on the spring 252 and an external electrode 213 provided on the outer bottom surface of the housing 210 via the wiring. In this embodiment, the springs 251 and 252 are pantograph-shaped springs in which thin plate springs of plastic are arranged on each side of the rhombus. A coil spring or a torsion bar may be used as the springs 251 and 251.

  The electrostatic induction conversion element 200 having the above-described configuration is subjected to a force such as vibration from the outside, and when the movable substrate 230 reciprocates in the movable direction C1, the electric charge injected into the comb-shaped electret 231 (for example, negative) The positive charge is electrostatically induced in the comb-shaped conductor 221 of the fixed substrate 220 by the electric charge), and electric power can be taken out from the external electrodes 212 and 213. Therefore, the electrostatic induction conversion element 200 having the above configuration functions as a generator.

  In the power extraction circuit 100 configured as described above, an AC voltage generated between the electret 231 and the conductor 221 of the electrostatic induction conversion element 200 is applied to the primary winding 121 of the first stage transformer 120, and this primary winding 121. AC current flows through This alternating current generates a magnetic field in the primary winding 121, and this magnetic field crosses the secondary winding 122. As a result, a current is generated in the secondary winding 122 by magnetic induction, and AC power having a voltage corresponding to the turn ratio with the primary winding 121 is generated at both ends of the secondary winding 122. At this time, AC power having a frequency that matches the tuning frequency f1 of the tuning circuit formed by the first stage transformer 120 is most efficiently output to the secondary winding 122 of the first stage transformer 120.

  In addition, the secondary windings 132 and 142 of the other transformers 130 and 140 in the rear stage coincide with the tuning frequencies f2 and f3 of the tuning circuit formed by the transformers 130 and 140 in addition to the AC power of the frequency output from the transformers 120 and 130 in the previous stage. AC power with a frequency is output. Therefore, in the AC power output from the secondary winding 142 of the transformer 140 at the final stage, all of the AC power components having frequencies that match the tuning frequencies f1, f2, and f3 of the tuning circuit formed by the transformers 120, 130, and 140 are included. include. The AC power generated in the secondary winding 142 of the transformer 140 at the final stage is converted into DC power by the rectifier circuit 160 and output from the output terminals 101c and 101d.

  Since the DC output voltage after rectification has an unstable voltage value, it is preferable to stabilize the DC voltage by a charge circuit using a capacitor or the like.

  In addition, when the external force applied to the electrostatic induction conversion element 200 fluctuates, the voltage value output from the electrostatic induction conversion element 200 becomes too high and exceeds the withstand voltage of the first-stage transformer 120, thereby destroying the transformer 120. In order to avoid this, it is preferable to provide a shunt diode 104 in parallel with the primary winding 121 as shown in FIG. By providing the shunt diode 104 in this way, the shunt diode 104 becomes conductive when a voltage having a value equal to or higher than the withstand voltage value of the shunt diode 104 is output from the electrostatic induction conversion element 200, thereby protecting the transformer 120. .

  In the above embodiment, the shape of the conductor 221 and the shape of the electret 231 are comb-shaped, but the present invention is not limited to this.

The block diagram which shows the connection of the electrostatic induction type conversion element and electric power extraction circuit in one Embodiment of this invention The circuit diagram which shows the electric power extraction circuit in one Embodiment of this invention 1 is a perspective view showing an electrostatic induction conversion element according to an embodiment of the present invention. The principal part disassembled perspective view which shows the electrostatic induction type conversion element in one Embodiment of this invention. The top view which shows the electrostatic induction type conversion element in one Embodiment of this invention AA arrow direction sectional view in FIG. The figure which shows the electric system circuit of the electrostatic induction type conversion element in one Embodiment of this invention The figure which shows the frequency characteristic of the stagger tuning circuit in one Embodiment of this invention The circuit diagram which shows the other example of the electric power extraction circuit in one Embodiment of this invention The figure which shows the electrostatic induction type conversion element of a prior art example The figure which shows the electrostatic induction type conversion element of a prior art example The figure which shows the electrostatic induction type conversion element of a prior art example Circuit diagram showing conventional power extraction circuit

Explanation of symbols

  100 ... Power extraction circuit, 101a, 101b ... Input terminal, 101c, 101d ... Output terminal, 102 ... Capacitor, 103 ... Resistor, 104 ... Shunt diode, 110 ... Stagger tuning circuit, 111,113 to 116 ... Capacitor, 120 ... Transformer, 121 ... Primary winding, 122 ... Secondary winding, 130 ... Transformer, 131 ... Primary winding, 132 ... Secondary winding, 140 ... Transformer, 141 ... Primary winding, 142 ... Secondary winding, 160 ... Rectification Circuit, 161,162 ... Diode, 200 ... Static induction conversion element, 210 ... Case, 211 ... Bottom surface, 212,213 ... External electrode, 214 ... Bearing ball, 220 ... Fixed substrate, 221 ... Conductor, 230 ... Moving substrate, 231 ... Electret, 232 ... conductor film, 241 ... support member, 251,252 ... spring.

Claims (4)

Two substrates that face each other at a predetermined interval and are capable of relative movement in a direction parallel to the opposite surface, an electret formed at a predetermined position on the opposite surface of at least one substrate, and a substrate that faces the electret Force applied from the outside, having a conductor formed on the surface of the substrate at a position facing the electret, and a support means for supporting the substrate so as to be capable of relative reciprocation in a predetermined linear direction parallel to the facing surface. A power extraction circuit for extracting electric power from an electrostatic induction conversion element that converts the kinetic energy of relative motion generated in the two substrates into electric energy and outputs the electric energy;
A primary winding having one end conductively connected to the electret and the other end conductively connected to the conductor, and a secondary winding magnetically coupled to the primary winding and set to a predetermined tuning frequency A stagger tuning circuit having a first stage transformer and one or more transformers connected to one or more stages after the first stage transformer and set to a tuning frequency different from other transformers;
An electrostatic induction conversion element comprising: a rectifier circuit having a pair of input ends connected to both ends of a secondary winding of a transformer at the last stage of the stagger tuning circuit; and a pair of output ends. Power extraction circuit. The shunt diode that becomes conductive when the value of the voltage between both ends exceeds a predetermined withstand voltage value is connected in parallel to the primary winding of the first-stage transformer. A power extraction circuit of the electrostatic induction conversion element according to 1. The value of the resonance frequency of the resonance circuit formed by the capacitance formed between the electret and the conductor and the reactance of the primary winding of the transformer is set equal to the value of the predetermined vibration frequency in the reciprocating motion of the movable substrate. The power extraction circuit of the electrostatic induction conversion device according to claim 1, wherein: The static frequency according to claim 1, wherein a tuning frequency of a tuning circuit formed by a transformer of each stage of the stagger tuning circuit is set to a frequency within a range of a vibration frequency of a reciprocating motion of the movable substrate. A power extraction circuit for an electric induction type conversion element.

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