JP2009017769A - Vibration type generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration type generator which realizes, for example, the method of securing a high generating efficiency under the environment having an arbitrary vibrating frequency, by so performing substantially actively the movement control of its inner mass as to make the movement of its inner mass synchronize intentionally with external vibrations. <P>SOLUTION: The vibration type generator so controls its inner mass as to be able to perform a high-efficiency generation even in an arbitrary environmental vibrations, by making the movement of its inner mass synchronize actively with environmental vibrations. The movement control of its inner mass is performed in the form of consuming no energy at least in a long-term average or is performed in the form of consuming no energy even in an individual elemental control. As an especial example, when so controlling the generator as to proportion the reaction of its inner mass exerting on its main body to the velocity of its main body, its generating performance becomes same as the performance of a pendulum which is present in the resonance state occurring at an arbitrary frequency interposed between the upper-limit and lower-limit frequencies defined on its design. The generator comprises a sensor of its movement state, a controlling circuit, a controlling element of modulating its movement, an inner mass or a plurality of inner masses, an energy converter, and an output circuit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a power generation device that converts vibration energy into electrical energy, and generates power from a change in acceleration of a generator body caused by an external environment rather than compression force or tensile force applied thereto, that is, relative to the environment. The present invention relates to a vibration power generator having an internal mass that does not use motion.

As a method of mechanical vibration energy conversion that generates electric power from time-varying acceleration, a vibration-powered wristwatch using an internal mass that performs a conventional rotational motion (for example, see Non-Patent Document 1), or translation of an internal mass supported by a spring There is a proposal of a method for generating power by movement (for example, see Non-Patent Document 2). That is, such a vibration power generation technique in which a kinetic mass in a generator behaves passively is well known regardless of the presence or absence of a resonance state.

In addition to this, there are proposals for a variable capacity vibration power generation apparatus using a mechanical resonator (for example, see Patent Document 1) and proposals for a device in which a vibration power generation apparatus and an accelerometer are integrated (for example, see Patent Document 2). is there. In the former, the inventors have recognized that the resonance-type vibration power generation device has low efficiency except in the vicinity of the resonance frequency, and a method for simultaneously using a plurality of resonators having different resonance frequencies is described as a solution. Has been. In the latter invention, the mass that moves in the power generator is actively controlled by a digital computer, which is used to improve the accuracy of acceleration measurement.

Turning to large-scale vibration generators, there are many inventions that convert vibration energy of water surface waves into electrical energy in the ocean wave power generation field. The power generation method using the relative motion that occurs between the land or the shallow sea floor and the ocean wavefront accounts for the overwhelming majority in the applicant's survey results. In particular, the invention described in Patent Document 3 shows that energy can be extracted with a high efficiency of 90% from the water surface wave energy of a fixed frequency. Is considered a high-level device to be compared with. However, since the frequency spectrum of an actual ocean wave is greatly widened, the power generation according to the above-described invention must be extremely low in a situation where practical application is expected. This point has been recognized by the applicant of Patent Document 3, and an invention corresponding to ocean wave motion of a non-constant frequency by active control of a power generator has been reported (see Patent Document 4). It describes a method for improving the coupling between ocean wave motion and generator motion by controlling the apparent hardness of the generator.

  JP 2005-137071 PR   JP 2006-329800 A   U.S. Pat. No. 3,928,967   U.S. Pat. No. 4,134,023

Journal of the Japan Watch Association, No. 120, 1987, pages 40-48 Sensors and Actuators A, vol. 52, (1996), 8-11 (Sensors and Actuators A, vol. 52, 1996, pp 8-11).

The transition to alternative energy is one of the important trends from the present to the future. Among them, the role of mechanical energy in society is increasing in importance as seen in wind power generation and ocean wave power generation, and may become one of the major energy sources in the future. On the other hand, the penetration of decentralized information systems and sensor networks into society will be a major trend in the near future. There are many network nodes used in the network, so there is a problem with realistic energy supply methods due to their dispersion, and an autonomous energy procurement method using vibration energy as well as thermal energy and light energy is proposed.・ Researched. As a large flow that includes these two trends, diversification of the scale of power generation equipment is expected. The present invention maximizes the utilization efficiency of mechanical vibration energy, which is expected to be used in the future, regardless of the size of the power generation device, when generating power from time-varying acceleration. Furthermore, the present invention not only does not depend on the scale of the power generation apparatus, but also has a generality that does not depend on any specific method of converting mechanical electric energy.

In order to realize power generation that makes use of the potential of mechanical energy resources, a highly efficient mechanical-electrical energy conversion mechanism is required. However, the conventional technology has many problems and is not suitable for high-efficiency power generation based on real mechanical energy resources with a wide spectrum. Several cases are considered here. First, when considering a conventionally proposed or used small power generator, Non-Patent Documents 1 and 2 describe a power generation method based on the movement of a passive internal mass in a power generator, but the former used a resonator. There is no efficiency amplification. In the latter, power generation efficiency is improved under resonance conditions, but since it is a purely passive element, such an advantage cannot be enjoyed at operating frequencies other than the resonance frequency. In fact, it is widely recognized that an increase in power generation efficiency at the resonance point of a resonator is accompanied by the price of a narrower power generation frequency bandwidth. For example, the applicants of Patent Document 1 have proposed a method of generating power corresponding to the broadband vibration spectrum of the environment by including a plurality of resonators having different resonance frequencies. However, it should be noted that this solution increases the size and mass of the generator as the bandwidth is increased. As an index of superiority or inferiority in the design of vibration power generators, the amount of power generation per mass in a given environment must be considered.

The present invention realizes a method of widening the power generation possible frequency bandwidth while enjoying the advantage of increasing the power generation efficiency at the resonance point. It is done by actively controlling the motion of the mass inside the generator. Patent Document 2 describes a method of simultaneously performing power generation and acceleration measurement while exerting the influence calculated by a computer on the motion of the internal mass. However, in the present invention, the goal is to measure acceleration while generating power, and there is no description regarding improvement of power generation efficiency by active control.

In Patent Document 4, it is pointed out that the power generation device shown therein has the maximum efficiency at the resonance frequency, and in order to efficiently generate power from the wide energy frequency spectrum band of ocean waves, the apparent Q of the harmonic oscillator A method for improving performance by reducing the value is described. However, in this method, there is a problem that it is not possible to enjoy the benefit of resonance as much as the Q value is reduced.

で与えられる。この状況はとりわけＭＥＭＳ（Ｍｉｃｒｏ Ｅｌｅｃｔｒｏｍｅｃｈａｎｉｃａｌ Ｓｙｓｔｅｍｓ）技術に代表されるような超小型発電技術分野において発電量に厳しい限界を課している。本発明ではこの限界の制限を受けない方法を実現する。Therefore, the object of the present invention is to drastically eliminate the trade-off problem between the energy conversion efficiency of the resonator and the energy conversion frequency bandwidth that existed conventionally in the vibration energy utilization technology in general, and realize high power generation with high bandwidth. There is. In fact, in the case of a passive harmonic oscillator, the maximum power generation amount is only the mass m of the oscillator, the resonance frequency ₀ , and the vibration amplitude spectral density in the environment (having a dimension of the length squared per unit frequency) A ² only. Strictly limited. In fact, if the power generation amount is P, this is

Given in. This situation imposes strict limits on the amount of power generation, particularly in the field of microminiature power generation technology represented by MEMS (Micro Electromechanical Systems) technology. The present invention implements a method that is not subject to this limitation.

To briefly explain the summary of typical inventions among the inventions disclosed by the present application in order to achieve the above object, it is as follows.

That is, typical vibration power generators of the present invention include a motion state detector, a control circuit that outputs an internal mass control signal, a control element that controls motion, an internal mass that moves within the power generator, and an energy conversion device. And an output circuit. The motion state detector is composed of an accelerometer and a control circuit including one or a plurality of integrators, and outputs necessary ones of the motion states of the power generation device such as position, speed, and acceleration. The control circuit calculates how and at what timing the motion of the internal mass is controlled. The control element for controlling the motion corrects the motion of the internal mass according to the signal output from the control circuit. The internal mass is an object element having an appropriate inertial mass that can move inside the power generator. The energy conversion device is a mechanoelectric conversion element that converts a part of the kinetic energy of the internal mass into electric energy. The output circuit shapes the output of the energy conversion device into a voltage, current, or cross-flow shape suitable for the application.

The motion state detector is preferably, for example, one that time-integrates the output of the accelerometer and outputs a speed signal.

The motion state detector is suitable, for example, as long as the speed signal is not negatively fed back to correct the acceleration signal so that the speed signal does not drift on a long-time scale that exceeds a certain time constant. The reciprocal of this time constant is one of the factors that can provide the lower limit operating frequency of the vibration power generator of the present invention. Note that the lower limit operating frequency may be limited by the size of the generator set.

ここにａ、Ｔはそれぞれ計測された加速度および充分に大きな時定数である。この両辺を微分することにより粘性流体中の質点の運動方程式への類似が明らかであり、そのことから更に、Ｔ以下のタイムスケールでは出力が加速度の積分を与える一方でＴ以上のタイムスケールでは出力がドリフトしないようにゼロ近辺にとどまることが分かる。従って下限動作周波数を下げるために大きなＴが望ましいが、積分中の第二項が加速度計の誤差やノイズとコンパラブルなほど小さくなってはならない。More specifically, it is preferable that the output speed signal v is described by the following integral equation.

Here, a and T are the measured acceleration and a sufficiently large time constant, respectively. By differentiating both sides, the similarity to the equation of motion of the mass point in a viscous fluid is clear, and further, the output gives the integral of acceleration at the time scale below T, while the output at the time scale above T It can be seen that it stays near zero so that it does not drift. Therefore, a large T is desirable to lower the lower limit operating frequency, but the second term during integration should not be so small that it is comparable to accelerometer errors and noise.

The control circuit uses the speed information to maximize the product of the speed and the force that the external environment exerts on the power generator, that is, the work rate that the environment exerts on the power generator under a given situation. Any is suitable. Note that the force that the external environment exerts on the power generation device is equal in magnitude to the reaction force that the power generation device exerts on the external environment, the latter depending on the state of motion of the internal mass.

One special case is especially worth mentioning here. In this special configuration, the control circuit exerts a force proportional to the velocity signal on the internal mass through the control element. Such control is naturally performed in the harmonic oscillator in the resonance state, which is the essence of the increase in power generation efficiency in the resonance state. In other words, by performing this control artificially, the motion of the external environment and the motion of the internal mass can be synchronized in the same manner as the harmonic oscillator in the resonance state regardless of the frequency.

Especially when the scale of the generator is large, the power generation efficiency can be further improved if there is knowledge about the environmental movement. Therefore, when possible, it is desirable that the control circuit maximizes the amount of power generation in consideration of side information obtained by other sensors in addition to the signal from the motion state detector. For example, such a sensor provides information that optically monitors the ocean wave waveform to assist the control circuit in calculating what force is applied to the generator after a period of time.

The control circuit may be a simple analog circuit or a general-purpose computer depending on the situation. These motion state detectors and control circuits consume energy, but when the device is scaled up, such energy behaves as a constant term and is always negligible for the amount of power generated. In practice, however, the energy consumption of the motion state detector and the control circuit must be considered in the design, especially when the power generator is a small micro energy source.

The control element is preferably an electromechanical energy conversion element using electromagnetic interaction, electrostatic interaction, or the like that controls the movement of the internal mass.

The control element delivers internal mass and energy. In the case where energy is also transferred, an element that can keep energy loss as low as possible is preferable because it does not behave as a constant as described above when the device is scaled up. In addition, a design for obtaining net energy from the control element is also conceivable. In this case, the control element also serves as an energy conversion device described later.

The internal mass may be designed to hang it inside the device with a spring, roll on the rail, or float using diamagnetism, but only the possibility of movement is essential. It is preferable that an optimal method that suits the purpose is selected. However, it is desirable that the frictional force and internal mechanical loss be as small as possible.

The energy conversion device is preferably an electromechanical energy conversion element using electromagnetic interaction or electrostatic interaction based on a material such as a magnetic material or a ferroelectric material. It should be noted that if the size limitation of the power generation device is not taken into consideration, the energy conversion of the motion of the internal mass, that is, the effective coefficient of friction due to power generation, is paradoxically better. Here, the braking force F _F by running friction is the product of the velocity v of-the internal mass. The reason why it is desirable to have a small value is obvious from the similarity to the harmonic oscillator in the resonance state. However, the effective friction due to energy conversion must be greater than the internal friction of the device itself. Further, it is necessary to quantitatively control how much mechanical energy is converted into electrical energy per unit time.

Electromechanical energy conversion using electret materials is particularly suitable for the realization of the present invention. The reason is that the internal mass and the energy delivered can be stored in the capacitor naturally. The electrostatic energy stored in the capacitor is low loss compared to the magnetic energy stored in the coil. When electret material is applied to the internal mass element, an external force can be applied to the internal mass by applying a voltage to the nearby electrode, and the movement of the internal mass can be obtained as a current flowing between the electrodes. I can do it.

ここにσ、ｗ、Ｖ、ε、ｇ、ｄはそれぞれエレクトレット膜の表面電荷密度、エレクトレット膜の運動方向に垂直な方向の実効的な長さ（電気機械エネルギー変換機構が複数個集積されている場合それに応じて実効的長さも大きくなる）、エレクトレット膜の比誘電率、エレクトレット膜表面と対向電極間のギャップ距離、そしてエレクトレット膜の厚さである。また、電極間に流れる電流Ｉは

で与えられる。ここにｖは内部質量の運動速度である。Actually, when the voltage is V, the external force F is given by the following equation.

Here, σ, w, V, ε, g, and d are the surface charge density of the electret film and the effective length in the direction perpendicular to the movement direction of the electret film (a plurality of electromechanical energy conversion mechanisms are integrated. The effective length also increases accordingly), the dielectric constant of the electret film, the gap distance between the electret film surface and the counter electrode, and the thickness of the electret film. The current I flowing between the electrodes is

Given in. Here, v is the motion speed of the internal mass.

When the electret electromechanical energy conversion is used, if a charge source / sink circuit from an internal capacitor with a variable voltage is realized as a control element, the internal capacitor, that is, the energy storage device in the circuit is gradually energized by performing appropriate control. Can be stored. Although this patent does not disclose a specific circuit scheme, the fact that such a circuit is physically possible is that parallel plate capacitors with sufficiently charged variable electrode spacing can be used for this purpose. it is obvious. Since the attractive force between the flat plates can be canceled by another force (for example, a force by an auxiliary spring), the output voltage can be adjusted while controlling the electrode interval without consuming energy.

The power output of the energy conversion device can be direct current, alternating current, or any other waveform, and the output impedance can also vary depending on the physical principle of the energy conversion device. In addition to shaping the power output from the energy conversion device, the output circuit is preferably combined with an energy storage device to realize stable continuous or intermittent power supply to the outside.

According to the present invention, there is an effect of removing an undesirable frequency selectivity which has been a problem in the resonance type vibration power generation device in the prior art. Note that the same goal can be achieved by using multiple oscillators with different resonant frequencies in parallel, but this solution does not allow an increase in power generation per unit mass. In a vibration power generator, the amount of power generated per unit mass should be taken into account when developing an evaluation index for design superiority or inferiority.

が適切である。ここにＰ、ｍ、Ｃ、ω_ａはそれぞれ発電量（仕事率）、内部質量素子の質量（複数個の場合はその和）、環境中の振動のｒ．ｍ．ｓ．（平均からのずれの２乗平均の平方根）振幅、環境中の振動振幅の２乗のスペクトルの平均周波数である。発電量は内部質量素子の質量や外部振動エネルギーを増やすと当然大きくなるので、発電装置の性能を比較するには単純な発電量の比較では不十分であり、このような数値指標の使用が助けになる。ただし、この指標は外部環境の振動スペクトルの形に依存することに注意すべきであり、違うスペクトルに対するγ値の比較にはあまり意味がない。にもかかわらず、特定の発電装置がどのようなスペクトルに適しており他のスペクトルに適さないかなどを判断する材料にはなると考えられる。Dimensionless as evaluation index or performance index of vibration generator

Is appropriate. Here, P, m, C, and ω _a are the power generation amount (power), the mass of the internal mass element (the sum in the case of a plurality of elements), and the r. m. s. (Root mean square of deviation from the mean) Amplitude, average frequency of spectrum of square of vibration amplitude in environment. The amount of power generation naturally increases as the mass of the internal mass element and external vibration energy increase, so a simple comparison of the power generation amount is not sufficient to compare the performance of the power generation equipment. become. However, it should be noted that this index depends on the shape of the vibration spectrum of the external environment, and it does not make much sense to compare γ values for different spectra. Nevertheless, it can be considered as a material for determining what kind of spectrum a specific power generation device is suitable for and what is not suitable for another spectrum.

For example, as an example of a small generator placed in a relatively quiet place, considering the case of m = 100 g (for example, about 5 cc of tungsten), c = 10 μm, and ω _a = 100 Hz, the power generation amount P is calculated from the equation (5). It can be seen that γ · 10 μW. That is, in order to obtain, for example, 1 mW, which is a practical power generation amount, it is desirable to obtain at least about 100 as a γ value for a natural broadband spectrum. The control circuit needs to operate with only a part of this power output, but the recent emergence and widespread use of ultra-low power active electronic devices such as nW level FETs make these numbers realistic. It should be noted that the present invention is significantly easier to apply than the above example when a larger power generation device is used in a natural / artificial environment with greater vibrational energy. On the other hand, when it is applied to micro power generation using MEMS technology or the like, the control circuit should be simplified, that is, its power consumption can be reduced, even if performance is slightly sacrificed.

で与えられる。ここにμ_０は外部振動速度ｖに比例した内部質量に加える力Ｆ＝μ_０ｖの表式に現れる比例係数である。そもそも共振の有無がないためにγ値が外部振動周波数ω_ａに極めて弱い依存性を持つことがわかる。これが本発明の最も顕著な帰結である。比例係数μ_０大きいほどＱ値の大きな振動子同様に高性能になるが、内部質量の運動距離が長くなるので発電機のサイズの上限が考慮されなくてはならない。この制限を満たす限りにおいて、μ_０を大きく設定することにより広帯域にわたって高性能の発電装置を構成することが出来る。First, when evaluating a generator using a conventional harmonic oscillator for a single-color delta function-type external vibration spectrum, if the frequency of the external vibration matches the natural frequency of the harmonic oscillator, the γ value is maximum. It becomes equal to the Q value of the vibrator. The meaning of maximum is because this is the upper limit, and the γ value usually decreases due to internal energy loss. This represents the fact that an oscillator with a high Q value can generate power more efficiently for regular external excitation. However, the γ value decreases rapidly if the resonance condition is deviated even a little. On the other hand, in the case of the device described in the present invention, the γ value is maximum.

Given in. Here, μ ₀ is a proportional coefficient appearing in the expression of force F = μ ₀ v applied to the internal mass proportional to the external vibration speed v. In the first place, since there is no resonance, it can be seen that the γ value has _a very weak dependence on the external vibration frequency ωa. This is the most significant consequence of the present invention. The larger the proportionality coefficient μ ₀ is, the higher the performance is as in a vibrator having a large Q value, but the movement distance of the internal mass becomes longer, so the upper limit of the size of the generator must be considered. As long as this restriction is satisfied, a high-performance power generator can be configured over a wide band by setting μ ₀ large.

となる。前者ではＱ値が表式から消えているのに対して、後者では単色励起の場合と本質的に同等な性能指数が得られている。実用上重要な顕著な違いであると言える。尚、周波数スペクトルの指数５が自然である根拠は幾つかあるが、その議論は本発明において特段の重要性はない。The above results are further clarified by evaluating the γ value for a broad-band external vibration spectrum that is closer to the actual environmental vibration. For example, in the case of a spectrum that is proportional to the inverse fifth power of the frequency (a cutoff frequency is set at the low frequency end in order to suppress the divergence of the total energy), the γ value of the power generator using the conventional harmonic oscillator has an upper limit of 0. .994, which is not practical, in the case of the device described in the present invention, the upper limit is

It becomes. In the former, the Q value disappears from the expression, whereas in the latter, a figure of merit substantially equivalent to that in the case of monochromatic excitation is obtained. It can be said that this is a significant difference that is important for practical use. There are several reasons why the frequency spectrum index 5 is natural, but the discussion is not particularly important in the present invention.

In addition, according to the present invention, unlike the obvious solution such as simply increasing the damping of the harmonic oscillator in spite of eliminating the frequency selectivity, the amplification effect of the power generation efficiency due to the sharp resonance is sacrificed. There is an effect that it is possible not to.

Furthermore, according to the present invention, there is an effect that relative movement in the environment is not required in order to generate power from the relative movement between the internal mass and the power generation device body, despite maintaining high efficiency. In other words, there is an effect that electric power can be generated if there is an acceleration / deceleration movement with respect to the inertial system.

The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

According to one embodiment of the present invention, the motion state detector time-integrates the sum of the output of the accelerometer and the inverted signal of the speed signal described later by a large time constant and outputs the result as a speed signal. Therefore, the speed signal is held near the zero point in the long term by negative feedback control. With this configuration, it is possible to prevent a situation where acceleration signal errors accumulate due to time integration and impair the reliability of the speed signal.

FIG. 2 is a diagram illustrating the motion state detector. The accelerometer ACC is based on a MEMS element and outputs an acceleration signal. A signal obtained by subtracting the result obtained by dividing the speed signal by a large time constant from this output is time-integrated by the integrator ITG1 to obtain a speed signal output. An adder, an integrator, or the like operates on an analog voltage signal, and includes a low power operational amplifier or FET and passive electronic components.

The functions of the motion state detector in this embodiment are summarized as follows. The only function of this motion state detector is to output the generator speed as an electrical signal. However, in mechanics, all inertial systems are equivalent, so the output velocity can only be obtained by integrating the acceleration, so there is an arbitrary offset. This offset is feedback controlled so that the long-term average of the speed signal is zero. That is, a speed signal for the inertial system is output so that the power generator does not move over the long term. The time constant used to divide the speed signal is one of the factors that can give the reciprocal of the lowest frequency that the generator can handle.

According to this embodiment, the internal mass moves smoothly one-dimensionally on the rail placed horizontally. The internal mass may be supported by a weak spring so that its position on the rail does not deviate too much from the center, but even in that case, the internal mass is not in the vicinity of the natural length of the spring except for the low frequency region that is not handled by the generator. Mass behaves like a free object. The internal mass needs to move on the rail with as little friction as possible. For this purpose, an appropriate one of many known techniques such as bearings, wheels, and magnetic levitation using a diamagnetic material may be selected. When a one-dimensional rail is placed horizontally as described above, the movement of the environment that couples to the movement of the internal mass is parallel translation along the rail, two rails that are not centered about the rail center point. It becomes three of rotational movement.

According to another embodiment of the present invention, the internal mass moves on a vertically placed rail to generate electricity from vertical external environmental motion. In this case, a plurality of stages are hung in series with a spring in order to suppress a vertical size that is too long due to extension of a weak spring under gravity, and each stage is hung from the previous stage at the lower end, and the next stage from the upper end is hung. Since the entire length is suppressed by hanging, a spring having a sufficiently low spring constant and usable in the vertical direction is effectively provided even when the height of the power generator is limited. FIG. 3 shows the case of a single stage.

Returning to the original embodiment of the present invention, the electret material is applied to the surface of the internal mass to be charged, and two metal plates are arranged around it to apply a voltage to control the internal mass. Realize the element. In addition, the energy conversion device is also used as this, or the energy conversion device based on the same principle is configured independently.

More specifically, FIG. 4 is a diagram showing an embodiment of internal mass control based on electrostatic interaction by the control element. The lower surface of the electrically grounded internal mass IM1 is coated with the electret material ELM. The internal mass is supported by a weak spring not shown in the drawing and can move left and right. Electrodes ELR1 and ELR2 are arranged in the lower part, and ELR2 is grounded, while an arbitrary voltage can be applied to ELR1. A force proportional to the voltage is applied to the internal mass. Conversely, in order to use the same configuration as an energy conversion device when the internal mass is moving, mechanical energy can be extracted as current flowing from ELR 1 to the ground electrode. When a capacitor, an inductor, or a resistor is connected between the electrodes ELR1 and ELR2, each effectively acts as a spring, mass, or friction element.

An example of power generation using the internal mass control will be given. Since the internal mass IM1 in FIG. 4 is supported by a weak spring, when the electrodes ELR1 and ELR2 are electrically connected by a conducting wire having a sufficiently low electrical resistance, it behaves like a free mass in the vicinity of the natural length of the spring. First, consider the case where there is no external vibration for simplicity. Suppose that the internal mass is moving at a constant linear velocity from left to right. Next, when the lead wire between the electrodes is opened using a field effect transistor (FET) switch and switched to an uncharged capacitor by a similar FET switch, the internal mass moves further to the right. When the capacitor is charged up, the charged capacitor has a voltage, so it exerts a braking force on the internal mass, and finally the internal mass moves from right to left at the same speed when the capacitor is completely discharged. At this moment, when the capacitor is switched back to the original conductor, the internal mass starts a constant velocity linear motion in the opposite direction. That is, the internal mass moves as if it collided elastically with the wall, and the charged state of the capacitor does not change before and after the entire process, so there is no energy loss. Switching between conductors and capacitors is essentially a process that does not require energy.

When there is vibration in the external environment, the speed of the uniform motion can be gradually increased using the above element process. For this purpose, the generator speed signal obtained from the motion state detector is used. In FIG. 4 again, when the entire power generation apparatus is moving from the left to the right, the internal mass moving from the right to the left is elastically bounced to the right using the element process. Conversely, when the entire power generation apparatus is moving from right to left, the internal mass moving from left to right is elastically rebounded to the left using the above element process. Each time it bounces, the internal mass receives mechanical energy from the external environment and accelerates it.

The amount of energy obtained by increasing the speed of the internal mass using the above process can be recovered by using an energy conversion device so as to keep the speed of the internal mass constant. As another method, the energy of the difference can be taken out as the charging energy of the electric charge remaining in the capacitor by rebounding the internal mass so as not to accelerate in the element process.

In the above description, a method of performing elastic rebound according to the motion state of the power generation device has been described, but the timing at which this operation is performed is not specified. Various methods are conceivable for this, but one method is probabilistic control in which the number of operations in proportion to the speed of the power generation device is executed per unit time. When such control is performed on a large number of internal masses, the same power generation efficiency as that of a harmonic oscillator in resonance can be obtained with respect to external vibrations of any frequency at a frequency within a certain range as a whole. It is done. Even in the case of a single internal mass, it is the same if an average is taken for a long time. The upper limit frequency at which such power generation can be performed is determined by the frequency with which the element process can be performed. The lower limit frequency is determined by the frequency determined by the integration time constant (FIG. 2) of the motion state detector or the length of the path through which the internal mass can move.

According to another embodiment of the present invention, continuous control of the movement of the internal mass is performed by continuously applying a voltage to the electrodes instead of elastic rebound. In particular, the control of exerting a force proportional to the generator speed on the internal mass is more important due to its similarity to the harmonic oscillator in resonance. In this case, a control voltage is applied to the electrode ELR1, but it should be noted that the direction of the current between the control circuit and the electrode depends on the motion state of the internal mass.

Therefore, the control circuit has not only the function of outputting an arbitrary voltage, but also the function of managing the energy transfer associated with the current flowing in and out with a low loss using an internal energy storage device (a natural selection is a capacitor). Must-have. If the energy loss is sufficiently small, the vibrational energy of the outside world gradually moves to the internal energy storage device by performing the motion control. Although a specific method for realizing such a control circuit is not described in detail in the present invention, it is as described in the section 0027 that it is theoretically possible from a physical point of view.

のように３次の項を持たせる。今、外部振動エネルギースペクトルが００３３項で述べたｆ^−５型であると仮走する。さらに外部振動のｒ．ｍ．ｓ．振幅Ｃおよび平均振動数ｆ_ａを用いて（８）式内の非線形性パラメータρ_０を無次元化した量ρ_０Ｃ^２ｆ_ａ ^２をρと定義する。今ρを０から２まで変化させて非線形性の応答を組み入れた装置の数値シミュレーションを行うと実際図５に示すように前記γ値は著しく増大する。但し図６に示すように、内部質量の原点からの平均的に期待されるずれの距離を前記Ｃで規格化した量λも、ρ＝１までは緩やかとは言え、増大するので考慮に入れなければならない。これらのシミュレーションにおいてはμ_０／ｍｆ_ａ＝４であり、また００４０項で述べられたように、無制限な位置ドリフトを防ぐために固有振動数がｆ_ａの０．２５倍の弱いばねによって内部質量が支えられていることを前提とした。In the proportional control described above, the size of a given power generator is not effectively used for high-frequency vibration components. This is because when considering external vibration of a single frequency, the effective Q value expressed by the equation (6) becomes smaller in inverse proportion to the frequency. That is, the amplitude proportional to the Q value is similarly reduced in inverse proportion to the frequency. In order to eliminate this waste, it is necessary to control the movement of the internal mass more sensitively to the high frequency component than to the low frequency component. As one method, instead of performing proportional control to apply force F = μ ₀ v proportional to the output speed signal v to the internal mass as described in the explanation of the equation (6), this expression has a nonlinear term. In other words, it is possible to have a reactivity higher than linear at a high speed. In particular,

A third-order term is given as follows. Now, it is assumed that the external vibration energy spectrum is the f- ⁵ type described in Section 0033. Furthermore, the external vibration r. m. s. An amount ρ ₀ C ² f _a ² obtained by making the nonlinearity parameter ρ ₀ in the equation (8) dimensionless using the amplitude C and the average frequency f _a is defined as ρ. If a numerical simulation of an apparatus incorporating a non-linear response is performed by changing ρ from 0 to 2, the γ value actually increases as shown in FIG. However, as shown in FIG. 6, the amount λ obtained by normalizing the distance of the average expected deviation from the origin of the internal mass by the C increases, although it is moderate until ρ = 1, but is taken into consideration. There must be. In these simulations are μ _{0 /} mf a = _4, and as mentioned in 0040 Section internal mass by 0.25 times the weak spring natural frequency is f _a to prevent unrestricted position drift It was assumed that it was supported.

According to yet another embodiment of the present invention, for example, if the external vibration is known a priori as a sine wave, it can be maximized by momentarily applying a striking force to the internal mass when the speed reaches a maximum value. Realize the power generation efficiency. In other words, if there is knowledge about the external environment, there is generally room for increasing the amount of power generation.

According to still another embodiment of the present invention, the above items are generalized, for example, by installing an appropriate sensor in the power generation device in ocean wave power generation, information on the form and time evolution of ocean waves is obtained and the control circuit is provided. This is used to improve power generation efficiency. In a large-scale application such as this example, the power generation efficiency is further improved by considering the matching of mechanical impedance between the external vibration and the motion of the internal mass of the power generation apparatus.

According to still another embodiment of the present invention, a force is applied to the internal mass by using a ferromagnetic material for the internal mass and arranging two sets of coils in the periphery to apply an electric current. In addition, the energy conversion device is also used as this, or the energy conversion device based on the same principle is configured independently.

According to still another embodiment of the present invention, the output circuit includes a rectifier circuit, a synchronous rectifier circuit, an impedance converter, a smoothing circuit, a flying capacitor booster, a Cockcroft-Walton booster, an energy storage circuit, a secondary battery, and power control. It is configured to include one or more elements of the circuit, and supplies stable continuous power or power suitable for intermittent operation to the outside.

The block diagram of the Example of this invention. The block diagram of the Example of a movement state detector. The block diagram of a perpendicular direction internal mass suspension mechanism. The block diagram of the Example of the electric power generating apparatus based on an electrostatic interaction.

Explanation of symbols

ACC Accelerometer ELM Electret material ELR1, ELR2 Electrode IM1 Internal mass INV Inverting amplifier ITG1 Integrator SPRING1, SPRING2, SPRING3 Spring

Claims (6)

A motion state detector that detects the motion of the power generation device body and outputs the signal;
A control circuit for inputting the signal and outputting an internal mass control signal;
A control element for inputting the control signal and controlling the motion of the internal mass;
One or more internal masses whose movement is controlled by the element;
An energy conversion device that extracts electrical energy as energy output from the movement of the internal mass;
An output circuit for converting the energy output into a form suitable for use, and
A vibration power generation apparatus that generates electric power by converting vibration energy into electric energy. In claim 1,
The vibration power generator, wherein the control element and the energy conversion device are substantially the same device. In claim 1,
The output part of the control circuit connected to the control element includes an energy storage unit, for example, a current flows in both directions in spite of outputting a voltage according to the control signal, and energy entering and exiting at that time is low loss The vibration power generator is realized by a circuit that is supplied or stored from an energy storage unit. In claim 1,
Either or both of the control element and the energy conversion device include an electrostatic interaction by a design using a material containing an electret material, an electromagnetic interaction by a design using a material containing a magnetic material, or a piezoelectric material. A vibration power generator characterized in that it is based on mechanical and electrical energy conversion by design using materials. 5. A method according to claim 1, wherein the force exerted on the internal mass by the control element or the frequency of the constant impact force exerted on the internal mass is proportional to or from the speed signal of the power generator output by the previous motion state detector. A vibration power generator characterized by rapidly increasing non-linearly. The vibration power generator according to claim 1, wherein by combining these power generators, power is generated simultaneously from up to three kinds of translational movements and up to three kinds of rotational movements.

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