CN111997823B - Low-frequency and frequency-adjustable float type wave power generation device - Google Patents
Low-frequency and frequency-adjustable float type wave power generation device Download PDFInfo
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- CN111997823B CN111997823B CN202011032149.XA CN202011032149A CN111997823B CN 111997823 B CN111997823 B CN 111997823B CN 202011032149 A CN202011032149 A CN 202011032149A CN 111997823 B CN111997823 B CN 111997823B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
- F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
- F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
- F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
- F03B13/16—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem"
- F03B13/20—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" wherein both members, i.e. wom and rem are movable relative to the sea bed or shore
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
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- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient
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Abstract
The invention relates to the field of renewable energy power generation, and discloses a low-frequency and frequency-adjustable float-type wave power generation device which comprises a double-mass oscillator device and comprises a first mass body, a second mass body, a connecting rod, a rotating shaft, a coupler and a generator, wherein the generator is connected with the rotating shaft through the coupler, the connecting rod perpendicular to the rotating shaft penetrates through the rotating shaft, the two ends of the connecting rod are respectively and movably connected with the first mass body and the second mass body, and the distances between the first mass body, the second mass body and the rotating shaft can be adjusted. The invention adopts a double-mass vibrator form, realizes extremely low frequency self vibration and obviously reduces the required structural space; frequency tuning factors are considered, frequency can be modulated by adjusting the relative positions of the two mass bodies in real time, resonance is realized, and output power is improved; the device has important application prospect in the aspects of maritime system, new energy power supply and the like.
Description
Technical Field
The invention relates to the field of renewable energy power generation, in particular to a low-frequency and frequency-adjustable float type wave power generation device.
Background
Renewable energy sources include, but are not limited to, solar energy, wind energy, and wave energy. Among them, the wave energy is 2-3kW/m due to its high predictability and large energy density 3 Gradually attract the attention of researchers. In recent years, different types of wave energy collectors have been proposed, mainly of the float type. The principle of the float-type wave collecting device is that relative motion of a float and the sea bottom, or a platform, or an immersion-type device drives an energy output system (usually pneumatic transmission, mechanical transmission and high-pressure hydraulic transmission), and then the float motion caused by waves is converted into electric energy.
From the perspective of mechanical design, the float-type energy generating device has the highest energy collecting efficiency only when the self-oscillation frequency of the float or the internal oscillator thereof is consistent with the frequency of waves. Munk (Munk W h. origin and generation of waves [ R ]. script institute of ocean La Jolla Calif,1951) states that ocean wave energy is indeed a renewable energy source of low frequency, with wave frequencies in most sea states between 0.3 and 1Hz, much less than traditional mechanical structure vibrations (<10 Hz). To achieve this low frequency resonance, Shami et Al (Al Shami E, Wang X, Ji X.A student of the effects of influencing the sensitivity of a point-adsorbent wave energy converter on the harnessing performance [ J ]. Mechanical Systems and Signal Processing,2019,133:106281) added an additional number of immersion devices to reduce the float frequency; flocard and Finnigan (Flocard F, Finnigan T D. incorporated power capture of a wave energy device by inertia addition [ J ]. Applied Ocean Research,2012,34:126 addition 134) adding sand and sand mixture within the float increases inertia to reduce float frequency. In addition to these passive methods, active methods such as translation control and reactive control have also been attempted to maintain the resonance of the float (Flocard F, Finnigan T. incorporated power capture of a wave energy device by inertia adjustment [ J ]. Applied Ocean Research,2012,34:126 134; Durand M, Babaret A, Pettiotitti B, et. Experimental adjustment of the performance of the search wave energy converter with a real time translation [ J ]. EWTEC, Porto, 2007; Baitt Bar A, Cl 2006. optical simulation of a wave energy device in regulated regulation [ J ]. 77, Applied wave 2. open-end [ J ]. Applied J ]. 26, 77). It should be noted that the aforementioned methods are directed to frequency tuning of the float itself.
On the other hand, the float can be used as a device with a single degree of freedom spring-damper-mass vibrator inside. The float provides only a frame of floating support for the inner vibrator. In this case, optimizing the vibration state of the internal vibrator is also a way to improve the energy collection efficiency. For the design of the internal vibrator, many structural topologies are proposed in the field of mechanical Energy collection, such as an X-type structure, a staple-clip-type structure, and an eccentric wheel structure (Liu C, J. vibration Energy transforming with an a Nonlinear structure [ J ]. Nonlinear dynamics,2016,84(4):2079 and 2098; Wu Y, Qiu J, Zhou S, et al. A piezoelectric vibration transducer used for multi-directional and ultra-directional vibration Energy transforming [ J ]. application, 2018,231: 600-type; Halim A614, Rantz R, Zhang Q, et al. electromagnetic vibration Energy transforming [ J ]. application, 3566: Applied, Applied by 2018,217). However, the natural frequency of these current design topologies is rarely below 1 hz. As mentioned above, the wave frequency in most sea states is between 0.3 and 1 Hz. Although some literature attempts to convert low frequency vibrations into high frequency vibrations for Energy harvesting have achieved some success, such frequency-boosting techniques can complicate the structural topology, which can lead to reduced Energy efficiency during transmission (Fan K, Cai M, Wang F, et al. A string-suspended and driven rotor for efficient mechanical Energy harvesting [ J ]. Energy Conversion and Management,2019,198: 111820). For this purpose, a vibrator having an extremely low natural frequency, which can be used in a wave power generation device, is worthy of study, and the device needs to have a certain frequency tuning capability in order to cope with the different wave frequencies under different sea conditions.
The invention patent document CN102094746A discloses a simple pendulum type wave power generation system, which utilizes the mechanical energy generated when the weight inside the floating body swings with the wave to generate power. All of its power generation devices are completely sealed and no moving parts are exposed to the sea water. The eagle beak type end floating body can capture wave energy more effectively. It should be noted that the power generation device is internally provided with a simple pendulum type oscillator, and mechanical energy generated by the movement of a single mass body along with waves is converted into electric energy. The invention does not relate to the effects of low frequency and frequency adjustment, and if the single mass body (simple pendulum type) vibrator is required to realize low frequency characteristics, the single mass body (simple pendulum type) vibrator is based on the natural vibration frequency
The pendulum length l needs to be very long, i.e. the required installation space can be very large.
Patent document CN103994017B discloses a pendulum power generation device using hull oscillation. According to the continuous swing of the ship body on the sea surface, a pendulum is designed in the ship body, and the relative motion of the pendulum and the ship body is utilized to generate electricity. The pendulum-type power generation device is not designed with a frequency tuning function, and a single mass body (pendulum-type) also causes an extremely large structural space requirement.
Utility model document CN208396861U discloses a wave power generation device, it can change inside eccentric wheel quality, spring rate and vertical vibration range, and then changes the operating frequency band of inside oscillator, influences wave power generation device's energy output. The utility model meets the requirements of the wave power generation device on frequency tuning to a certain extent, but is completely different from the power generation device provided by the invention in design principle and structural form.
Disclosure of Invention
The invention provides a low-frequency and frequency-adjustable float-type wave power generation device aiming at the problems in the prior art, and aims to solve the problems that a wave power generation system in the prior art occupies a large space and is complex in structure.
The above purpose of the invention is realized by the following technical scheme:
a float-type wave power generation device with low frequency and adjustable frequency comprises a dual-mass oscillator device, wherein the dual-mass oscillator device comprises a first mass body, a second mass body, a connecting rod, a rotating shaft, a coupler and a generator; the generator is connected with the rotating shaft through a coupler, the rotating shaft is provided with a connecting rod which is perpendicular to the rotating shaft in a penetrating mode, two ends of the connecting rod are respectively movably connected with the first mass body and the second mass body, and the distance between the first mass body and the second mass body and the distance between the rotating shafts can be adjusted.
Firstly, the invention is different from the traditional single pendulum and other pendulum type frequency modulation structures, adopts a double-mass oscillator form, can realize real-time frequency tuning only by adjusting the relative positions of two independent mass bodies, and realizes resonance with waves so as to improve the output power; the working distance of the double-mass vibrator only accounts for 1/2 or even 1/3 of the traditional single pendulum type vibrator, the required structural space is obviously reduced while extremely low frequency self vibration is realized, and the size of the float type wave power generation device is favorably reduced;
secondly, the invention adjusts the position of the two mass bodies by an intelligent means, does not need manual field operation in the whole process, saves time and labor, and integrates the modern technology into a field self-running instrument, so that the wave-activated generator can better adapt to the actual working environment of wave power generation.
As a further optimized scheme of the present invention, the connecting rod is in the form of a screw rod, through shaft type stepping motors matched with the connecting rod are respectively arranged in the first mass body and the second mass body, and the through shaft type stepping motors can drive the first mass body and the second mass body to move back and forth along the connecting rod, so as to tune the vibration frequency of the dual-mass oscillator device.
Here, the implementation process of the low-frequency natural vibration and frequency tuning of the dual-mass vibrator device (hereinafter referred to as "vibrator") in the present invention is briefly described in principle, and the structural control equation is as follows:
wherein L is 1 And L 2 The first mass center of mass and the second mass center of mass are the distances from the axis of rotation, respectively. m is m Is a single mass physical mass including the stepper motor physical mass used. And c is oscillator damping, including self mechanical damping and parasitic damping of the generator. θ is a vibration angle of the single-degree-of-freedom vibrator. The points above theta represent the derivatives over time, i.e.
And
respectively, the vibration angular velocity and the vibration angular acceleration. K is em Is the back electromotive force of the generator, in units of Vs/rad. i is the output current of the generator. The control equation can be obtained by a lagrange method, wherein the first term is inertia force torque, the second term is restoring force torque, the third term is damping force torque, and the fourth term is torque provided by the generator.
In the case of small amplitudes sin θ ≈ θ mathematically. According to the basic knowledge of structural dynamics, the natural vibration frequency of the vibrator can be expressed as a corresponding rigidity term m m g(L 2 -L 1 ) Divided by mass item
The root number is then divided by 2, i.e.,
where g is the acceleration of gravity. Obviously, the frequency of the oscillator can pass through the relative position L of the first mass body and the second mass body at this time 1 And L 2 And determining to realize the frequency adjustment effect. The corresponding stepping motors arranged in the first mass body and the second mass body can adjust the positions of the first mass body and the second mass body along the connecting rods. When the two masses are symmetrically distributed about the axis of rotation, i.e. L 1 ＝L 2 The self-oscillation frequency of the double-mass oscillator reaches zero hertz, and the requirement effect of extremely low frequency is realized.
Besides, it should be noted that the actual pendulum length space of the oscillator is only the length of the connecting rod, and the reduction of the frequency is not realized by infinitely increasing the pendulum length, so that the structural space required by the oscillator is far smaller than that of the traditional simple pendulum when the low-frequency effect is realized. When the natural vibration frequency is matched with the wave frequency, the energy output efficiency of the float type wave power generation device is effectively improved.
In this case, according to a classical power calculation formula, the square of the output current i of the electromagnetic motor is multiplied by the impedance value of the connected circuit, namely the output power of the vibrator,
in the formula, Z load The impedance value of the circuit connected with the motor or the external load. t is t 1 And t 2 Two time nodes for energy collection.
It should be understood that the physical mass of the first mass and the second mass is the same during the derivation process, and in the implementation, the mass, shape, material, etc. of the two masses can be different, and the equations (1) to (2) can be changed, but the principle is not changed.
If the physical masses of the first and second masses are not equal, equation (1) is modified to
The corresponding equation (2) is changed to,
in the formula, m m1 Is the physical mass of the first mass, m m2 Is the second mass physical mass. As described earlier, equations (4) and (5) are in principle consistent with equations (1) and (2), but are irreparable in the expression due to the disparity in physical masses of the two masses.
It should be understood that one or more stepping motors are installed inside each mass body, and the number of the stepping motors and the manner of moving the mass body by the stepping motors cannot be used as limitations to the scope of the present invention, depending on the pushing ability of the stepping motors.
In general, the dual-mass oscillator device can be obtained by changing the relative position L of two independent masses 1 And L 2 The extremely low self-oscillation frequency and the frequency adjustment are realized, so that the wave frequency is matched, and the energy output efficiency of the whole power generation device is improved. Based on equation (2), it can be seen that the oscillator device can reach even zero frequency when the masses of the two masses are equal. Compared with the traditional pendulum structure, the vibrator device has smaller structural space required by the vibrator device in the aspect of realizing extremely low frequency, and is beneficial to reducing the volume of the float-type wave power generation device. The generator connected to the rotating shaft can efficiently convert vibrational energy into electrical energy.
It should be understood that the upper limit of the adjustable natural frequency of the vibrator is related to the length of the connecting rod, and is not limited in particular.
As a further optimization scheme of the invention, the system comprises an acceleration sensor for monitoring the frequency of waves and outputting a change signal to the through shaft type stepping motor, and a controller such as a single chip microcomputer is installed or connected in the acceleration sensor. When the sensor monitors that the wave frequency changes greatly, the single chip microcomputer can output control signals according to a pre-input algorithm program to drive the through shaft type stepping motors in the first mass body and the second mass body to rotate, and then the corresponding mass bodies are driven to move, so that frequency modulation is achieved.
As a further optimized solution of the present invention, the first mass body and the second mass body are each composed of one or more mass blocks, the shape and mass of each mass block are not particularly limited, but for the convenience of adjusting the relative position, a driving device such as a through shaft type stepping motor should be installed on each mass block.
As a further optimization scheme of the present invention, the first mass body and the second mass body have equal mass. Of course, as described in the above formulas (4) and (5), in other embodiments, the masses of the two masses are not particularly limited; only as a preferred option, when the masses of the first mass body and the second mass body are equal, as shown in formula (2), the masses of the first mass body and the second mass body can be approximately divided, so that the dependent variable of the self-oscillation frequency in the dual-mass oscillator device is reduced, which is beneficial to realizing the extremely low frequency tuning of the present invention.
As a further optimization scheme of the invention, a first supporting plate and a second supporting plate are oppositely arranged by taking the connecting rod as a symmetry line, and two ends of the rotating shaft are respectively arranged on the first supporting plate and the second supporting plate through bearings.
As a further optimized solution of the present invention, a generator support is fixedly installed outside the generator, and the other end of the generator support is connected to the first support plate or the second support plate. The generator supporting piece unloads the weight for the generator, and avoids the influence of the self gravity of the generator on unnecessary external load of the rotating shaft.
As a further optimized scheme of the present invention, the generator is a permanent magnet generator, an asynchronous generator, a synchronous generator, or a switched reluctance generator, and is configured to convert mechanical energy generated by the first mass and the second mass vibrating around the rotating shaft into electrical energy.
As a further optimization scheme of the invention, the double-mass-oscillator-type sea water proof device comprises a shell used for bearing the double-mass-oscillator device; in addition, the shell is provided with a floating device to ensure that the device continuously floats on the surface layer of the water body, thereby being beneficial to the normal work and the recovery treatment of the device.
As a further optimization scheme of the invention, the periphery and the bottom of the shell are closed, and the top of the shell is provided with a cover plate capable of being opened and closed.
Compared with the prior art, the invention has the beneficial effects that:
compared with the traditional mechanical energy collecting device mainly adopting a single pendulum type, the double-mass vibrator structure has the advantages that the first mass body and the second mass body are arranged at the two ends of the rotating shaft, so that extremely-low-frequency self-oscillation can be realized in a smaller pendulum length space; the invention adopts the stepping motor to control the position of the mass body to carry out frequency tuning, and can adjust the relative position of the mass body in time according to the frequency change of external sea state waves to realize resonance, so that the power generation output power of the invention is more considerable than that of the traditional float power generation device; the invention has simple structure and reasonable design, and realizes extremely low frequency self-oscillation and frequency tuning based on the actual requirements of wave power generation, so that the device has important application prospect in the aspects of maritime systems, new energy power supply and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic view of a float wave power unit of the present invention (see through the housing);
FIG. 2 is a schematic diagram of a dual-mass resonator device according to the present invention;
fig. 3 is an engineering elevation (perspective) view of the float-type wave power unit of the present invention;
FIG. 4 is a left side view (perspective) of the float type wave power generation device of the present invention;
FIG. 5 is an engineering top view of the float-type wave power generation device of the present invention;
FIG. 6 is a right engineering view (perspective) of the float-type wave power unit of the present invention;
FIG. 7 is an engineering section view taken along line A-A of FIG. 3 in accordance with the present invention;
FIG. 8 is a schematic diagram of key mechanical components of the dual mass resonator device of the present invention;
fig. 9 is a schematic structural view of key mechanical components of the dual mass resonator device of the present invention;
FIG. 10 shows the results of the free vibration test in which the natural frequency of the dual-mass oscillator device corresponds to the relative position of the dual masses, which in this embodiment specifically represents the position L of the first mass 1 The position of the second mass body is fixed and unchanged;
fig. 11 shows a relationship between the output voltage of the float-type wave power generation device and the wave period when the first mass body is at different positions in the wave water tank test, where the output voltage is the open-circuit voltage of the generator, and the abscissa corresponding to the peak position of each curve in the reference graph is the reciprocal of the natural frequency of the vibrator at that time in the first mass body position;
in the drawings, 1-housing; 1 a-a cover plate; 2-a first mass; 3-a second mass; 4-a connecting rod; 5-a rotation axis; 6-a first support plate; 7-a second support plate; 8-a first bearing; 9-a second bearing; 10-a coupler; 11-a generator; 12-a generator support; 13-vibrator fixing bottom plate; 14-a first through shaft type stepping motor; 15-second through shaft stepping motor.
Detailed Description
The following further describes embodiments of the present invention with reference to the drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in fig. 1 to 7, the present embodiment provides a low-frequency and frequency-tunable float-type wave power generation device, which includes a housing 1 and a dual-mass vibrator device. As shown in fig. 2, the dual-mass oscillator device includes a first mass body 2, a second mass body 3, a connecting rod 4 for connecting the first mass body 2 and the second mass body 3, a rotating shaft 5, a first supporting plate 6, a second supporting plate 7, a first bearing 8, a second bearing 9, a coupling 10, a generator 11, a generator supporting member 12, and an oscillator fixing base plate 13.
Wherein, as shown in fig. 9, the rotating shaft 5 is horizontally arranged, the connecting rod 4 is perpendicular to the rotating shaft 5 and rigidly connected with the rotating shaft at the middle part thereof, the connecting rod 4 is in a screw rod form, two ends of the connecting rod respectively penetrate through the first mass body 2 and the second mass body 3, the first mass body 2 and the second mass body 3 have the same shape and quality, a first through shaft type stepping motor 14 and a second through shaft type stepping motor 15 are respectively and fixedly arranged in the first mass body and the second mass body, the connecting rod 4 is used as a penetrating shaft of the first penetrating shaft type stepping motor 14 and the second penetrating shaft type stepping motor 15 at the same time, when frequency adjustment is needed, the through shaft type stepping motor 14 or the second through shaft type stepping motor 15 drives the corresponding mass body to rotate along the connecting rod 4, and the rotary motion is converted into linear motion by using the characteristic of the lead screw, so that the linear displacement of the first mass body 2 or the second mass body 3 is realized.
It is supplementary to explain that each through shaft type stepping motor is fixedly arranged inside the corresponding mass body and independently drives the corresponding mass body to rotate, so that the position of the mass body is quickly and accurately adjusted.
Of course, in other embodiments of the present invention, the displacement of the first mass body 2 and the second mass body 3 can be realized by other forms such as a hydraulic push rod, an electric push rod, etc., and the connecting rod 4 can be correspondingly arranged in a form of a polished rod, and all forms can effectively adjust the relative position of the mass bodies, so the present invention does not specifically limit the distance adjusting manner of the mass bodies.
In this embodiment, the generator 11 is specifically a permanent magnet motor, the rotating shaft 5 can rotate back and forth under the vibration of the first mass body 2 and the second mass body 3, one end of the rotating shaft 5 is coaxially connected with the generator 11 through the coupler 10, and then the generator 11 is utilized to convert mechanical energy generated by the mass body through the axial vibration into electric energy.
In this embodiment, this device is still including installing the acceleration sensor (not shown in the figure) of casing 1 inner wall, acceleration sensor internally mounted has the singlechip, electric connection between acceleration sensor, singlechip and each link up shaft type step motor, contain vibration information in the vibration information that acceleration sensor collected. In the actual power generation process, vibration information acquired by the acceleration sensor is input into the single chip microcomputer, the single chip microcomputer performs frequency calculation based on the vibration information containing wave frequency information, if the fact that the change of the wave frequency is large is monitored, the single chip microcomputer sends out a control signal according to a pre-input program, a first through shaft type stepping motor 14 inside the first mass body 2 is driven to rotate so as to drive the first mass body 2 to move along the connecting rod 4, a second through shaft type stepping motor 15 inside the second mass body 3 is driven to rotate so as to drive the second mass body 3 to move along the connecting rod 4, and therefore the self-vibration frequency of the double-mass-vibrator device is changed, the double-mass-vibrator device is matched with the external wave frequency, and the energy collection efficiency is improved.
It should be noted that the installation position of the acceleration sensor is not unique, and when the sensor is located at different positions, the measured signal amplitude of the acceleration sensor is different, but the collection of the frequency information is not so much affected, and therefore the setting point of the acceleration sensor is not specifically limited.
Fig. 8 shows the key mechanical components of the dual mass oscillator device, including the first mass 2, the second mass 3, the connecting rod 4 and the rotating shaft 5.
On the basis, the low-frequency and frequency tuning realization process of the dual-mass oscillator device (hereinafter referred to as the "oscillator") is explained from the structural principle perspective, and the structural control equation is as follows:
wherein L is 1 And L 2 The distances of the first mass body 2 centroid and the second mass body 3 centroid from the rotation axis, respectively. m is a unit of m Is a single mass physical mass. And c is oscillator damping, including oscillator self mechanical damping and generator parasitic damping. K em Is the back electromotive force of the generator 11 in units of Vs/rad. i is the output current of the generator 11. In the case of small amplitudes, mathematically sin θ ≈ θ, the natural frequency of the vibrator can be expressed as,
where g is the acceleration of gravity. It is obvious that the frequency of the vibrator can be determined by the relative position L of the first mass body 2 and the second mass body 3 1 And L 2 And determining to realize the effect of frequency adjustment. The first through-shaft stepping motor 14 inside the first mass body 2 in the present embodiment rotates by itself to move the position of the first mass body 2, and the second through-shaft stepping motor 15 inside the second mass body 3 rotates by itself to move the position of the second mass body 3. When the two masses are symmetrically distributed about the axis of rotation 5, i.e. L 1 ＝L 2 The self-oscillation frequency of the double-mass oscillator reaches zero hertz, and the requirement effect of extremely low frequency is realized. When the natural vibration frequency is matched with the wave frequency, the energy output efficiency of the wave power generation device is effectively improved.
In this case, the output power of the oscillator is
In the formula, Z load The impedance value of the circuit connected with the motor or the external load. t is t 1 And t 2 Two time nodes for energy collection.
In this embodiment, it should be understood that the physical masses of the first mass body 2 and the second mass body 3 are equal, and thus are approximately divided by each other in the derivation process of formula (2); in other embodiments, the mass, shape, material, etc. of the two masses may all be different, and equations (1) to (2) may vary, but the design principle is not changed.
In the application of the present embodiment, in order to reduce the load on the rotating shaft 5, the first bearing 8 and the second bearing 9 are respectively installed at two end portions of the rotating shaft 5, and penetrate through the first support plate 6 through the first bearing 8, and penetrate through the second support plate 7 through the second bearing 9, and the first support plate 6, the second support plate 7, the first bearing 8 and the second bearing 9 are vertically arranged and mirror-symmetrical with respect to the connecting rod 4, so that the effective gravity support can be provided for the rotating shaft 5 with a small friction force, and the kinetic energy output of the rotating shaft 5 is not affected. In order to strengthen the supporting effect, the bottoms of the first supporting plate 6 and the second supporting plate 7 are also connected through the vibrator fixing bottom plate 13 to form a more stable frame structure.
Similarly, in this embodiment, a generator supporting member 12 is disposed outside the generator 11, one end of the generator supporting member 12 is fixedly connected to an outer wall of the generator 11, and the other end of the generator supporting member 12 is connected to the second supporting plate 7, so as to provide a gravity support for the generator 11, avoid the influence of the self-gravity of the generator 11 on the external load of the rotating shaft 5, and ensure the transmission efficiency and the service life of the rotating shaft 5.
It should be understood that the above-mentioned supporting form of the rotating shaft 5 and the generator 11 is only a preferred example, and similar supporting effect can be achieved even if other single-side vibrator supports or the generator is positioned on the supporting plate, and the like, and therefore, the supporting form is not particularly limited.
Supplementary notes are that anticorrosive paint is sprayed on the outer wall of the shell 1, the whole shell is of a cube structure, the bottom and the periphery of the shell are sealed, the top of the shell is provided with an openable cover plate 1a, the inner wall of the shell 1 is connected with the bottom wall of the vibrator fixing bottom plate 13, the shell 1 provides a floating support and a sealed space for the dual-mass vibrator device, and vibrator components in the device are effectively prevented from being corroded by seawater; in addition, the outer side wall of the shell 1 is provided with a circle of waterproof floating plate to ensure that the invention continuously floats on the surface layer of the water body; of course, in other embodiments, the device of the present invention can also achieve the floating effect by controlling its own weight or by improving the structure, and is not limited in particular.
Aiming at the design principle of the device, the free vibration test is carried out in the embodiment so as to test the low-frequency self-vibration and frequency modulation capability of the device under the free vibration working condition; and a wave water tank test is carried out to test the low-frequency self-vibration and frequency modulation capability of the invention under the wave working condition.
In the two experimental examples, the first mass body 2 and the second mass body 3 are both cubic, 50 mm on a side, and each 0.947 kg in mass. The mass of the connecting rod 4 is 0.2 kg and the total length is 300 mm. The distance L between the centroid of the first mass body 2 and the coordinate origin is defined by the intersection point of the rotating shaft 5 and the connecting rod 4 as the coordinate origin 1 Can be adjusted from-75 mm to 125 mm, and the distance L between the centroid of the second mass body 3 and the coordinate origin 2 The thickness was fixed to 125 mm. The specific experimental results are as follows:
experimental example 1 free vibration test
In this test, the second mass body 3 is fixed in position and the first mass body 2 is gradually moved downward from the top, and fig. 10 shows the natural vibration frequency of the dual-mass vibrator device under the free vibration condition when the first mass body 2 is at different adjustment positions. Referring to fig. 10, the frequency of the dual-magnon device can reach very low frequency of 0.2 hz in experiments. When the position of the first mass body 2 continues to move downwards, the natural vibration frequency rises and finally reaches a maximum value of 1.4 Hz, which shows the effectiveness of the dual-mass oscillator device in realizing the extremely low-frequency natural vibration and frequency tuning.
Experimental example 2 wave water tank test
The device is placed in a wave water tank for testing. Fig. 11 shows the output voltage of the float power generation device at different wave periods when the position of the first mass body 2 is different in the case where the position of the second mass body 3 is fixed. In the figure, symbol h represents the wave height. Referring to fig. 11, the natural vibration frequencies of the first mass body 2 are different when the positions thereof are different, and a lower natural vibration frequency of 0.67 hz can be observed in the wave water tank test. And the change of the vibrator frequency enables the floater device to be suitable for different sea conditions, thereby being beneficial to improving the energy output.
In summary, fig. 10 and fig. 11 both show that the float-type wave power generation device using the dual-mass oscillator as the core can better realize the extremely low natural vibration frequency (<1 hz), and can effectively realize the frequency modulation function through the relative position adjustment of the two masses, so as to match the wave frequency and improve the energy collection efficiency.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, and the scope of protection is still within the scope of the invention.
Claims (9)
1. The utility model provides a float formula wave power generation facility of low frequency and frequency adjustable which characterized in that: including two mass oscillator devices, two mass oscillator devices include first mass, second mass, connecting rod, rotation axis, shaft coupling and generator, wherein, the generator passes through the coupling joint the rotation axis, run through on the rotation axis and be equipped with it vertically the connecting rod, the both ends difference swing joint of connecting rod has first mass and second mass, the quality of first mass, second mass equals, first mass, second mass with distance between the rotation axis all can be adjusted.
2. A low frequency and frequency tunable float wave power unit as claimed in claim 1, wherein: the connecting rod adopts the form of lead screw, first mass body, the internal portion of second mass all be equipped with connecting rod complex link up shaft type step motor, link up shaft type step motor can drive first mass body, second mass body along the round trip movement is made to the connecting rod, is used for the frequency of vibration of double-mass oscillator device is harmonious.
3. A low frequency and frequency tunable float wave power unit as claimed in claim 2, wherein: the system comprises an acceleration sensor, a through shaft type stepping motor and a controller, wherein the acceleration sensor is used for monitoring the frequency of waves and outputting a change signal to the through shaft type stepping motor.
4. A low frequency and frequency tunable float wave power unit as claimed in claim 2, wherein: the first mass body and the second mass body are both composed of one or more mass blocks.
5. A low frequency and frequency tunable float wave power unit as claimed in claim 1, wherein: the connecting rod is provided with a first supporting plate and a second supporting plate as symmetrical lines in an opposite mode, and two ends of the rotating shaft are installed on the first supporting plate and the second supporting plate through bearings respectively.
6. A low frequency and frequency tunable float wave power unit as claimed in claim 5, wherein: the outside fixed mounting of generator has generator support piece, generator support piece's the other end with first backup pad or second backup pad are connected.
7. A low frequency and frequency tunable float wave power unit as claimed in claim 6, wherein: the generator is a permanent magnet generator, an asynchronous generator, a synchronous generator or a switched reluctance generator and is used for converting mechanical energy generated by the first mass body and the second mass body through vibration around the rotating shaft into electric energy.
8. A low frequency and frequency tunable float wave power unit as claimed in any one of claims 1 to 7, wherein: the double-mass vibrator device comprises a shell for bearing the double-mass vibrator device, wherein a floating device is arranged on the shell.
9. The apparatus of claim 8, wherein: the casing is airtight all around and bottom, and the top is equipped with the apron that can open and shut.
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