KR101932854B1 - Apparatus and method for energy harvesting - Google Patents

Abstract

An energy harvesting apparatus and method are disclosed. The energy harvesting apparatus includes a piezoelectric element which is located in a container containing an aqueous solution and generates electric energy by a piezoelectric effect when an impact is applied, and a rotating body which is located in the container and rotates by micro-streaming, which is caused by micro bubbles that are vibrated by a sound wave, as a driving force, to apply the impact. It is possible to harvest electrical energy from acoustic energy.

Description

[0001] Apparatus and method for energy harvesting [0002]

The present invention relates to an energy harvesting apparatus and method.

In recent years, with the development of small radio devices such as micro sensors, micro robots, implantable medical devices, etc., the importance of developing a power supply for these small radio devices has increased .

In the case of implantable medical devices among small radio devices, a chemical battery has been mainly used as a power source in the past. However, chemical batteries have resulted in functional limitations in implantable medical devices due to their size, limited lifetime, and chemical side effects. Particularly, due to the limited lifespan of chemical batteries, patients using implantable medical devices have had to undergo surgical interventions at regular intervals to replace batteries in implantable medical devices inserted into the body.

Accordingly, energy harvesting technology has attracted attention as a power supply technology that can replace conventional chemical batteries. Energy harvesting technology is a power supply technology that harvests abandoned energy resources, accumulates harvested energy, and utilizes them when needed.

Energy harvesting techniques have been proposed for harvesting various energy sources such as solar heat, mechanical energy, temperature gradient, fluid flow, acoustics, and electromagnetic energy. Among the various energy resources, acoustic energy resources have a relatively low energy density compared to other energy resources, but they are a sustainable clean energy source and are widely available in our daily lives. come.

The present invention relates to an energy harvesting apparatus and method for harvesting electric energy from acoustic energy by using a micro bubble vibrating by a sound wave, as a power supply device for an implantable medical device will be.

According to an aspect of the present invention, an energy harvesting apparatus is disclosed.

An energy harvesting apparatus according to an embodiment of the present invention includes a piezoelectric element which is located in a vessel containing an aqueous solution and which generates electric energy by a piezoelectric effect when an impact is applied and a piezoelectric element which is located in the vessel, And a rotating body for rotating the microstreaming caused by the micro bubble to propel the impact.

The energy harvesting device is a power supply for an implantable medical device.

When the implantable medical device is inserted into a human body, a piezo actuator applied with a voltage generates the sound wave from the outside, and the sound wave has the same frequency as the resonance frequency of the fine bubble.

The piezoelectric element is a piezo cantilever that generates the electrical energy when mechanical deformation occurs due to the impact.

The rotating body is formed in the form of a central shaft and a toothed wheel. The rotor has a shaft hole formed at the center thereof and through which the central shaft is inserted, the rotating shaft being rotatable about the central shaft. And at least one micro-tube filled with the fine bubbles therein and coupled to the outer periphery of the rotor such that the open portion is directed outward.

When the micro bubbles repeatedly shrink and expand due to the sound waves, the micro-streaming occurs around the micro bubbles due to the difference in physical properties between the micro bubbles and the aqueous solution, and is ejected through the open part, Propulsion for rotation of the rotor is provided.

The piezoelectric element and the rotating body are arranged so that one end of the piezoelectric element and the outer periphery of the rotor overlap with each other, so that the rotating rotor applies the impact to the piezoelectric element.

A hydrophobic layer is formed inside the microtubes. The micro bubbles are placed inside the microtubes due to the action of the hydrophobic films, and are vibrated while maintaining the microtubes in the form of microtubes without being submerged by the aqueous solution .

And a rectifying circuit connected to the piezoelectric element and rectifying and storing the generated electric energy.

The rectifier circuit converts the alternating current electric energy generated by the piezoelectric element into a direct current (DC) form and stores the converted direct current in a capacitor.

According to another aspect of the present invention, there is disclosed a rotator for applying an impact to a piezoelectric element in a vessel containing an aqueous solution.

A rotating body according to an embodiment of the present invention is formed in the shape of a central shaft and a toothed wheel and has a shaft hole formed at a center thereof through which the shaft shaft is coupled so that the rotor rotates about the central shaft, And at least one micro tube which is formed in an open form and filled with micro bubbles therein and which is coupled to the outer periphery of the rotor so as to face the open part.

An energy harvesting apparatus and method according to an embodiment of the present invention harvests electric energy from acoustic energy using a micro bubble that is vibrated by a sound wave to generate a power supply of an implantable medical device Device. ≪ / RTI >

In addition, by using clean and sustainable acoustic energy, it is possible to replace an existing chemical battery used as a driving power source of a small sensor or a small electronic device, and it is possible to transmit and charge the power wirelessly.

1 illustrates a structure of an energy harvesting system according to an embodiment of the present invention.
2 is an exploded view of a rotating body of an energy harvesting apparatus according to an embodiment of the present invention.
3 is a diagram illustrating a driving concept of a micro bubble according to an embodiment of the present invention.
Fig. 4 is a diagram showing microstreaming caused by vibration of a fine bubble. Fig.
5 is a view showing an electric energy harvesting concept of an energy harvesting apparatus according to an embodiment of the present invention.
6 is a view illustrating a driving state of an energy harvesting apparatus according to an embodiment of the present invention.
7 shows a rectifying circuit according to an embodiment of the present invention.
8 is a graph of an experimental result obtained by measuring the accumulated electric energy using a rectifier circuit according to an embodiment of the present invention.
9 is a flow diagram illustrating an energy harvesting method in accordance with an embodiment of the present invention.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In this specification, the terms "comprising ", or" comprising "and the like should not be construed as necessarily including the various elements or steps described in the specification, Or may be further comprised of additional components or steps. Also, the terms "part," " module, "and the like described in the specification mean units for processing at least one function or operation, which may be implemented in hardware or software or a combination of hardware and software .

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a view showing a structure of an energy harvesting system according to an embodiment of the present invention, FIG. 2 is an exploded view of a rotating body of an energy harvesting apparatus according to an embodiment of the present invention, FIG. FIG. 4 is a view showing a microstreaming generated according to a vibration of a fine bubble, and FIG. 5 is a view showing a microbubble generated according to an embodiment of the present invention. FIG. 6 is a view illustrating a driving state of an energy harvesting apparatus according to an embodiment of the present invention, FIG. 7 is a diagram illustrating a rectifying circuit according to an embodiment of the present invention, and FIG. FIG. 8 is a graph of an experimental result obtained by measuring the accumulated electric energy using the rectifying circuit according to the embodiment of the present invention.

Referring to FIG. 1, an energy harvesting system according to an embodiment of the present invention includes an energy harvesting apparatus 100 and a piezo actuator 200.

Here, the energy harvesting apparatus 100 includes a piezocantilever 110 that generates electric energy by a piezoelectric effect when an impact is applied, and a microstreaming apparatus 110 that generates micro bubbles caused by a sound wave, And a rotating body 120 for rotating the piezoelectric cantilever 110 with an impulsive force to apply an impact to the piezoelectric cantilever 110. At this time, the rotating body 120 is placed in a vessel containing an aqueous medium for micro-streaming, so that the piezo cantilever 110 is also placed in the vessel containing the aqueous solution together with the rotating body 120 .

Then, the piezoelectric actuator 200 generates a sound wave that vibrates the fine bubble according to the application of the voltage. That is, the piezoelectric actuator 200 can generate a sound wave having the same frequency as the resonance frequency of the fine bubble.

For example, the energy harvesting device 100 may be applied as a power supply for an implantable medical device. Therefore, when the implantable medical device is inserted into a human body, the piezoelectric actuator 200 generates sound waves from the outside, and the sound waves are transmitted to the energy harvesting apparatus 100 in the body, whereby the energy harvesting apparatus 100 Electric energy can be generated from the sound waves generated by the piezoelectric actuator 200 and harvested.

The piezo cantilever 110 is a piezoelectric element for generating electric energy by a piezoelectric effect. Here, the piezoelectric effect is a phenomenon in which mechanical energy is generated when mechanical pressure is applied to the piezoelectric element, and mechanical deformation occurs when electrical energy is applied to the piezoelectric element. That is, the piezo cantilever 110 generates electrical energy when mechanical deformation (bending) occurs due to impact applied by the rotating body 120.

2, the rotating body 120 includes a central shaft 121, a bushing 122, a first rotor 123, a second rotor 124, a supporting portion 125, And a micro tube (126).

Referring to FIG. 2, the first rotor 123 and the second rotor 124 may be formed in the form of a toothed wheel, and a center shaft 121, to which a bushing 122 is coupled, A ball is formed. Here, the center shaft 121 is supported by the support portion 125. Thus, the first rotor 123 and the second rotor 124 can rotate about the central axis 121. [

The micro tube 126 is formed in such a manner that one end thereof is closed and the other end thereof is opened, and the micro bubble is filled therein. A hydrophobic layer may be formed in the micro tube 126 to stably generate and drive fine bubbles. That is, due to the action of the hydrophobic film, the fine bubble stably stays in the micro tube 126, and the micro bubble can stably vibrate while maintaining the shape of the micro tube 126 without being flooded by the aqueous solution.

The microtube 126 is disposed between the first rotor 123 and the second rotor 124 such that the opening portion is directed to the outer periphery of the first rotor 123 and the second rotor 124 Can be combined. That is, as shown in FIG. 2, the microtube 126 may be coupled to each of a plurality of points on the outer circumferential portion of the first rotor 123 and the second rotor 124, respectively.

 The microtube 126 is caused to rotate for the rotation of the first rotor 123 and the second rotor 124 by the micro-streaming caused by the vibration of the micro bubble, It can provide driving force.

The first rotor 123 and the second rotor 124 that rotate in this manner can apply an impact to the piezo cantilever 110. The piezoelectric cantilever 110 and the rotating body 120 may be disposed such that one end of the piezoelectric cantilever 110 and the outer circumferential portion of the first rotor 123 or the second rotor 124 overlap.

2, a pair of rotors 123 and 124 and a plurality of microtubes 126 are applied, but this is merely an example, and the rotors 123 and 124 And the number of microtubes 126 may be different.

3 is a view illustrating a concept of driving a fine bubble according to an embodiment of the present invention.

3, when a voltage is applied to the piezo actuator 200 in a state where the micro tube 126 is received in a container containing an aqueous medium, the micro bubble filled in the micro tube 126 is supplied to the piezo- And shrinks and expands due to the sound waves generated by the actuator 200 to vibrate. When the fine bubbles are vibrated, micro-streaming occurs around the fine bubbles due to the difference in physical properties between the fine bubbles forming the interface and the aqueous solution, and the fine micro bubbles are ejected through the open portion of the micro tube 126.

When the microtube 126 is received in a container containing an aqueous solution, the microbubbles filled in the microtube 126 maintain the shape of the microtube 126 because the hydrophobic film does not flood the inside of the microtube 126 .

FIG. 4 shows the micro-streaming caused by the vibration of the fine bubbles. As shown in FIG. 4, when a voltage is applied to the piezoelectric actuator 200, micro-streaming is caused by the vibration of the micro bubble, and the micro-stream can be ejected from the micro tube 126. The micro-streaming ejected from the micro-tube 126 is used as a driving force for rotating the rotating body 120, as described above.

FIG. 5 is a view showing an electric energy harvesting concept of an energy harvesting apparatus according to an embodiment of the present invention.

5, when a voltage is applied to the piezoelectric actuator 200, micro-streaming is caused by micro-bubble vibration caused by sound waves generated by the piezoelectric actuator 200, and the micro-stream is ejected from the micro-tube 126 . Rotors 123 and 124 are rotated by the ejected micro-streaming propulsion, and the piezo cantilever 110 is impacted while rotating. The piezo cantilever 110 subjected to the impact can generate mechanical deformation and generate electrical energy.

FIG. 6 shows a driving view of an energy harvesting apparatus 100 according to an embodiment of the present invention. 6, when a voltage is applied to the piezoelectric actuator 200, the rotors 123 and 124 are rotated by the vibration of the fine bubble caused by the acoustic waves generated by the piezoelectric actuator 200, , The rotors (123, 124) impact the piezo cantilever (110).

The energy harvesting apparatus 100 according to the embodiment of the present invention may further include a rectifying circuit for rectifying and storing electric energy generated by the piezo cantilever 110. [ The rectifier circuit may be connected to the piezo cantilever 110.

Fig. 7 shows a rectifying circuit according to the embodiment of the present invention. FIG. 8 shows a graph of an experimental result obtained by measuring the accumulated electric energy using the rectifier circuit shown in FIG.

The electric energy of the AC type generated by the piezo cantilever 110 can be converted into a DC form through the rectifying circuit shown in FIG. 7 and accumulated in a capacitor. The voltage magnitude with respect to each of the 0.1-V capacitor and the 1-V capacitor with which the electric energy generated by the piezo cantilever 110 is accumulated can be measured as shown in FIG.

9 is a flowchart illustrating an energy harvesting method according to an embodiment of the present invention.

In step S910, the piezo actuator 200 is energized.

In step S920, the piezoelectric actuator 200 to which the voltage is applied generates a sound wave having the same frequency as the resonance frequency of the fine bubble.

In step S930, microbubbles are vibrated by sound waves generated by the piezoelectric actuator 200, micro-streaming occurs due to micro-bubble vibration, and the micro-bubbles are ejected through the open part of the micro-tube 126. [

In step S940, the rotating body 120 rotates to apply impact to the piezo cantilever 110 by the driving force of the micro streaming which is ejected through the opening of the micro tube 126, so that the piezo cantilever 110 generates electric energy do.

In step S950, the generated electric energy is harvested by the rectifying circuit connected to the piezo cantilever 110. [

It will be apparent to those skilled in the art that various modifications, additions and substitutions are possible, without departing from the spirit and scope of the invention as defined by the appended claims. Should be regarded as belonging to the following claims.

100: energy harvesting device
110: Piezo cantilever (Piezocantilever)
120: rotating body
121: center axis
122: bushing
123: 1st electron
124: 2nd electron
125: Support
126: micro tube
200: Piezoactuator

Claims (11)

What is claimed is: 1. An energy harvesting apparatus used as a power supply for an implantable medical device,
A piezoelectric actuator which generates a sound wave and is located outside the human body;
A piezo cantilever which is located in a container containing an aqueous solution inserted into the human body and generates electrical energy by a piezoelectric effect when mechanical deformation occurs due to impact; And
A rotating body positioned in the vessel and rotating the micro-streaming caused by the micro bubbles caused by the sound waves to propel the impact;
And a rectifying circuit for converting the alternating current electric energy generated by the piezoelectric element into a direct current and accumulating it in a capacitor,
Wherein the sound wave has the same frequency as the resonance frequency of the fine bubble,
The rotating body has a central axis; A first rotor and a second rotor which are formed in the form of a gear wheel and have a shaft hole through which the center shaft is coupled to the center so as to rotate about the central axis; Wherein the second rotor is coupled between the first rotor and the second rotor, the one end of the first rotor being closed and the other end thereof being opened, the fine bubble being filled in the first rotor, And at least one microtube coupled to the outer peripheral portion such that the opening portion is directed outward,
When the micro bubbles repeatedly shrink and expand due to the sound waves, the micro-streaming occurs around the micro bubbles due to the difference in physical properties between the micro bubbles and the aqueous solution, and is ejected through the open part, A thrust for rotation of the rotor is provided,
Wherein at least one of the first rotor and the second rotor is disposed so that one end of the piezo cantilever overlaps with the outer periphery of the first rotor and the second rotor so that the rotating rotor applies the impact to the piezo cantilever,
Wherein when the implantable medical device including the energy harvesting device is inserted into a human body, the piezoactuator generates the sound wave outside the human body, and the generated sound waves cause the piezo cantilever and the rotator to move And generates the electric energy.




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