Cantilever type vibration absorber for heliostat

Abstract

According to the cantilever type vibration absorber for the heliostat, excitation frequency is detected, frequency signals are converted into voltage signals, a piezoelectric stack actuator formed by stacking multiple layers of piezoelectric ceramics is driven by the voltage signals to stretch out and draw back, and piezoelectric crystals can generate micro displacement under the action of an external electric field on the piezoelectric ceramics. Micro displacement generated by the piezoelectric stack actuator is amplified by the displacement amplifier to push the piezoelectric stack actuator and the mass block to move, so that the positions of the piezoelectric stack actuator and the mass block can be changed, the rigidity of the vibration absorber can be adjusted, the natural vibration frequency of the vibration absorber is changed, and variable-frequency vibration absorption is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar energy, more particularly, the present application relates to a cantilever type vibration absorber for heliostat. BACKGROUND

[0002] The heliostat is one of the most important components in the tower type solar thermal power station system, which is a light gathering device for tracking the sun and reflecting and converging the sunlight to the tower top heat absorber. The heliostat belongs to a wind sensitive structure, and the wind-induced vibration control of the heliostat is crucial for improving the mirror light gathering efficiency and increasing the power generation. The traditional passive vibration absorber is designed only for a specific excitation frequency, and the wind-induced vibration frequency of the heliostat has time-varying characteristics, so the passive vibration absorber is not suitable for the heliostat. Therefore, the vibration absorber for the heliostat mainly adopts semi-active control technology. Among them, the intelligent material variable stiffness technology is very suitable for the heliostat structure. At present, the commonly used intelligent materials mainly include piezoelectric ceramics, shape memory alloy and magneto-rheological elastomer.

[0003] Among them, the response speed of the shape memory alloy is controlled by the temperature and the speed of heat dissipation, and the response speed is slow, and it is difficult to accurately control the speed of heat dissipation; the stiffness change of the magneto-rheological elastomer is nonlinear, and the structure tuning stiffness is affected by the vibration frequency, and there is a characteristic of stiffness softening at resonance, which makes the design very difficult. CONTENT OF THE PRESENT INVENTION

[0004] The present application overcomes the deficiencies of the prior art in response time and stiffness softening, and provides a cantilever type vibration absorber for heliostat, so as to solve the above problems.

[0005] To solve the above technical problems, the present application adopts the following technical solutions:

[0006] A cantilever type vibration absorber for heliostat, comprising a piezoelectric stack actuator and a displacement amplifier.

[0007] The piezoelectric stack actuator is controlled to stretch and contract by voltage, and the displacement amplifier is connected with the piezoelectric stack actuator.

[0008] The displacement amplifier comprises a first hydraulic type displacement amplifier and a second flexible hinge type displacement amplifier.

[0009] One end of the piezoelectric stack actuator is connected with the first hydraulic type displacement amplifier.

[0010] The other end of the first hydraulic type displacement amplifier is connected with the second flexible hinge type displacement amplifier.

[0011] The principle of the present application is that the piezoelectric stack actuator is stacked by multiple layers of piezoelectric ceramics, and the piezoelectric crystal generates micro-displacement under the action of an external electric field. The micro-displacement generated by the piezoelectric stack actuator is amplified by the displacement amplifier, which pushes the piezoelectric stack actuator to move, so as to change the position of the piezoelectric stack actuator, adjust the stiffness of the vibration absorber, change the natural frequency of the vibration absorber, and realize variable frequency vibration absorption.

[0012] A further technical solution is that the cantilever type vibration absorber comprises a mass block.

[0013] The mass block is connected with the secondary flexible hinge type displacement amplifier.

[0014] By increasing the mass block and adjusting the position of the mass block together with the piezoelectric stack actuator, better variable frequency vibration absorption effect can be achieved.

[0015] A further technical solution is that the mass block comprises a sealing plate and a counterweight.

[0016] The sealing plate is installed on the outside of the counterweight.

[0017] The primary hydraulic type displacement amplifier is arranged on the side of the mass block by being connected with the sealing plate.

[0018] The piezoelectric stack actuator comprises multiple layers of piezoelectric ceramics and a protective shell, the multiple layers of piezoelectric ceramics are installed in the protective shell, and the protective shell is fixed with the contact end of the primary hydraulic type displacement amplifier.

[0019] A further technical solution is that the primary hydraulic type displacement amplifier comprises an input piston, an output piston and a hydraulic chamber.

[0020] The input piston is connected with the multiple layers of piezoelectric ceramics.

[0021] The number of output pistons is two, and the output pistons are connected with the secondary flexible hinge type displacement amplifier.

[0022] A further technical solution is that the secondary flexible hinge type displacement amplifier comprises multiple hole steel rods and multiple pins.

[0023] Two hole steel rods are connected into an "X" type hinge unit through the pins, multiple hinge units are connected in front and back to form a flexible hinge, one end of the flexible hinge is fixed on one end of the cantilever beam, and the other end is fixed on the output piston of the primary hydraulic type displacement amplifier.

[0024] The moving principle is that the piezoelectric stack actuator moves to press the input piston of the primary hydraulic type displacement amplifier, the input piston moves and makes the output piston of the hydraulic type displacement amplifier move, the output piston is connected with the secondary flexible hinge type displacement amplifier, pushes the secondary flexible hinge type displacement amplifier to move and pushes the entire piezoelectric stack actuator and mass block to move, and vice versa, so as to realize variable frequency vibration absorption.

[0025] Further, the piezoelectric stack actuator, the first hydraulic displacement amplifier, and the second flexible hinge displacement amplifier are two in number.

[0026] Further, the cantilever absorber comprises a cantilever beam and a heliostat mirror surface support beam.

[0027] The cantilever beam is mounted on the heliostat mirror surface support beam, and the mass block is movably mounted on the cantilever beam.

[0028] The piezoelectric stack actuator is controlled to expand and contract by voltage, and the expansion and contraction of the piezoelectric stack actuator is amplified by the displacement amplifier and then acts on the mass block, so that the mass block is controlled to move on the cantilever beam.

[0029] Further, the cantilever absorber further comprises a damping device.

[0030] The damping device is made of elastic damping material, and the damping device is mounted in the middle section of the cantilever beam and can be compressed.

[0031] Further, the cantilever beam comprises a baffle, a steel beam, and a fixed steel plate.

[0032] The baffle is fixed at the cantilever end of the steel beam, the fixed steel plate is fixed at the fixed end of the steel beam, and the damping device replaces a section of the steel beam.

[0033] The fixed steel plate is bolted to the heliostat mirror surface support beam.

[0034] The bolted connection is on the support structure of the heliostat, and compared with the existing absorber for heliostats, which fixes the absorber on the mirror surface, the bolted connection avoids damage to the mirror surface caused by adding the absorber.

[0035] Further, the damping device comprises a rubber damping material and a steel clamp.

[0036] The steel clamp is mounted outside the rubber damping material and fixedly mounted on the steel beam to extrude and fix the rubber damping material.

[0037] The method for adjusting the rubber damping material is to compress the rubber damping material and then tightly fasten it into the buckle on the steel beam from both left and right sides by using steel clamps of different lengths, so as to fix the deformation of the rubber damping material and keep the fixed damping value during the vibration absorption process.

[0038] Compared with the prior art, the power vibration absorber has the following beneficial effects: (1) the power vibration absorber combines a traditional cantilever beam type vibration absorber and intelligent piezoelectric material, can realize stiffness change and frequency shift under semi-active control, meets the characteristics that the frequency of wind-induced vibration of the heliostat has time-varying characteristics, and compared with other stiffness change vibration absorbers using magneto-rheological elastomers or shape memory alloys and other intelligent materials, the stiffness change of the stiffness change vibration absorber is nonlinear and has many influencing factors, and the frequency shift range must be obtained through simulation and test, so the stiffness change curve of the vibration absorber can be calculated through a simple mathematical model, and the frequency shift range of the vibration absorber can be determined in the preliminary design stage, and targeted design is facilitated.

[0039] (2) the rubber damping material is used to replace a section of the cantilever beam on the traditional cantilever beam type vibration absorber, and the cantilever beam is controllably compressed, the damping ratio of the vibration absorber changes with the compression degree, therefore, the vibration absorber damping of the application can be optimal when the mass of the heliostat or the mass of the vibration system changes, so that the vibration system can have optimal vibration absorption effect, and the application can effectively absorb vibration for heliostat structures of different masses.

[0040] (3) the actuator and the displacement amplifier of the application are part of the mass block, so that the mass of the vibration absorber is concentrated on the mass block, the useless mass of the vibration absorber is reduced, the vibration absorption effect is enhanced, and the purpose of light weight and high efficiency is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 the mass block disclosed by the application is shown in the schematic diagram;

[0042] Figure 2 the cross-sectional schematic diagram of the primary hydraulic type displacement amplifier disclosed by the application is shown in the schematic diagram;

[0043] Figure 3 the extension state schematic diagram of the secondary flexible hinge type displacement amplifier disclosed by the application is shown in the schematic diagram;

[0044] Figure 4 the longitudinal sectional view of the semi-active cantilever type power vibration absorber disclosed by the application is shown in the schematic diagram;

[0045] Figure 5 the schematic diagram of the cantilever beam disclosed by the application is shown in the schematic diagram;

[0046] Figure 6 the schematic diagram of the damping device on the cantilever beam in the application is shown in the schematic diagram; Figure 5

[0047] Figure 7 the schematic diagram of the semi-active cantilever type power vibration absorber in different positions disclosed by the application is shown in the schematic diagram;

[0048] ​Figure 8 Fig. 1 is a schematic diagram of the whole structure of the semi-active cantilever dynamic vibration absorber disclosed in the present application;

[0049] In the figure, 1 is a cantilever beam, 2 is a damping device, 3 is a mass block, 4 is a piezoelectric stack actuator, 5 is a first-stage hydraulic displacement amplifier, 6 is a second-stage flexible hinge displacement amplifier, 7 is a heliostat mirror surface support beam, 101 is a baffle, 102 is a steel beam, 103 is a fixed steel plate, 201 is a rubber damping material, 202 is a steel clamp, 301 is a sealing plate, 302 is a counterweight, 401 is a piezoelectric ceramic, 402 is a protective shell, 501 is an input piston, 502 is an output piston, 503 is a hydraulic chamber, 601 is a steel rod with holes, 602 is a bolt, 603 is a hinge unit, 701 is a heliostat mirror surface, and 702 is an array of vibration absorbers. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0051] A cantilever vibration absorber for a heliostat comprises a piezoelectric stack actuator 4, a displacement amplifier, and a mass block 3.

[0052] The piezoelectric stack actuator 4 is controlled to expand and contract by voltage, and the displacement amplifier is connected to the piezoelectric stack actuator 4.

[0053] The displacement amplifier comprises a first-stage hydraulic displacement amplifier 5 and a second-stage flexible hinge displacement amplifier 6.

[0054] One end of the piezoelectric stack actuator 4 is connected to the first-stage hydraulic displacement amplifier 5.

[0055] The other end of the first-stage hydraulic displacement amplifier 5 is connected to the second-stage flexible hinge displacement amplifier 6.

[0056] The mass block 3 is connected to the second-stage flexible hinge displacement amplifier 6.

[0057] The mass block 3 can be any object that can be moved by the second-stage flexible hinge displacement amplifier 6. In a preferred embodiment, the mass block 3 comprises a sealing plate 301 and a counterweight 302.

[0058] The sealing plate 301 is installed on the outside of the counterweight 302.

[0059] The first-stage hydraulic displacement amplifier 5 is arranged on the side of the mass block 3 by being connected to the sealing plate 301.

[0060] The piezoelectric stack actuator 4 comprises a multilayer piezoelectric ceramic 401, a protective shell 402, the multilayer piezoelectric ceramic 401 is installed in the protective shell 402, and the protective shell 402 is fixed with the contact end of the primary hydraulic displacement amplifier 5.

[0061] The primary hydraulic displacement amplifier 5 can adopt any hydraulic device that can realize the displacement amplification of the piezoelectric stack actuator 4, in the embodiment, the primary hydraulic displacement amplifier 5 comprises an input piston 501, an output piston 502, and a hydraulic chamber 503.

[0062] The input piston 501 is connected with the multilayer piezoelectric ceramic 401.

[0063] The output piston 502 is two in number, and the output piston 502 is connected with the secondary flexible hinge type displacement amplifier 6.

[0064] The secondary flexible hinge type displacement amplifier 6 comprises a plurality of hole steel rods 601 and a plurality of pins 602.

[0065] Two hole steel rods 601 are connected into an "X" type hinge unit 603 through the pin 602, a plurality of hinge units 603 are connected in front and back to form a flexible hinge, one end of the flexible hinge is fixed on one end of the cantilever beam 1, and the other end is fixed on the output piston 502 of the primary hydraulic displacement amplifier 5.

[0066] In the embodiment, the piezoelectric stack actuator 4, the primary hydraulic displacement amplifier 5, and the secondary flexible hinge type displacement amplifier 6 are two in number.

[0067] In the preferred embodiment, the cantilever type vibration absorber of the heliostat further comprises the cantilever beam 1, the heliostat mirror surface 701 support beam 7, and the damping device 2.

[0068] The cantilever beam 1 is installed on the heliostat mirror surface 701 support beam 7, and the mass block 3 is movably installed on the cantilever beam 1.

[0069] The piezoelectric stack actuator 4 is controlled to stretch and contract by voltage, and the piezoelectric stack actuator 4 acts on the mass block 3 after being amplified by the displacement amplifier, so that the mass block 3 is controlled to move on the cantilever beam 1.

[0070] The damping device 2 is made of elastic damping material, the damping device 2 is installed in the middle section of the cantilever beam 1, and the damping device 2 can be compressed.

[0071] In the further preferred embodiment, the damping device 2 comprises a rubber damping material 201 and a steel clamp 202.

[0072] The steel clamp 202 is installed outside the rubber damping material 201 and is fixedly installed on the steel beam 102 to extrude and fix the rubber damping material 201.

[0073] The cantilever beam 1 comprises a baffle 101, a steel beam 102, and a fixed steel plate 103;

[0074] The baffle 101 is fixed at the cantilever end of the steel beam 102, the fixed steel plate 103 is fixed at the fixed end of the steel beam 102, and the damping device 2 replaces a section of the steel beam 102.

[0075] The fixed steel plate 103 is bolted to the support beam 7 of the heliostat mirror surface 701.

[0076] The working principle of the cantilever absorber of the heliostat is as follows:

[0077] The sensor detects the vibration excitation frequency of the heliostat, converts the excitation frequency signal into a voltage signal of 0-200V, and transmits it to the piezoelectric stack actuator 4.

[0078] The piezoelectric stack actuator 4 generates an extension amount after receiving the voltage signal, the piezoelectric stack actuator 4 extrudes the input piston 501, the output piston 502 extends and retracts, and drives the secondary flexible hinge displacement amplifier 6 to move.

[0079] The secondary flexible hinge displacement amplifier 6 drives the mass block 3 and the piezoelectric stack actuator 4 to move on the cantilever beam 1, adjusts the stiffness of the absorber, changes the natural frequency of the absorber, and realizes variable frequency vibration absorption.

[0080] Although the present application has been described with reference to the explanatory embodiments thereof, it should be understood that many other modifications and implementations could be devised by those skilled in the art that would fall within the principles disclosed herein. More particularly, many variations and modifications of the subject combination arrangement can be made to the constituent components and / or arrangements of the subject combination arrangement within the scope of the application. Other uses will also become apparent to those skilled in the art, besides those shown and described herein, upon consideration of this disclosure.

Claims

1. A cantilevered vibration absorber for a heliostat, characterized by, This includes piezoelectric stacked actuators and displacement amplifiers; The piezoelectric stacked actuator is extended and retracted under voltage control, and the displacement amplifier is connected to the piezoelectric stacked actuator; The displacement amplifier includes a primary hydraulic displacement amplifier and a secondary flexible hinge displacement amplifier. One end of the piezoelectric stacked actuator is connected to a single-stage hydraulic displacement amplifier; The other end of the first-stage hydraulic displacement amplifier is connected to the second-stage flexible hinge displacement amplifier.

2. A cantilevered vibration absorber for heliostats as defined in claim 1, characterized in that Includes, mass blocks; The mass block is connected to a two-stage flexible hinge displacement amplifier.

3. A cantilevered vibration absorber for heliostats as defined in claim 2, characterized in that The mass block includes a sealing plate and a mass block; The sealing plate is installed on the outside of the mass block; The primary hydraulic displacement amplifier is mounted on the side of the mass block via a connection to the sealing plate. The piezoelectric stacked actuator includes a multilayer piezoelectric ceramic and a protective housing. The multilayer piezoelectric ceramic is installed in the protective housing, and the protective housing is fixed to the contact end of a primary hydraulic displacement amplifier.

4. A cantilevered vibration absorber for heliostats as defined in claim 3, characterized in that The single-stage hydraulic displacement amplifier includes an input piston, an output piston, and a hydraulic chamber; The input piston is connected to a multilayer piezoelectric ceramic. The number of output pistons is two, and the output pistons are connected to a two-stage flexible hinge displacement amplifier.

5. A cantilevered vibration absorber for heliostats as defined in claim 4, characterized in that The secondary flexible hinge displacement amplifier includes multiple perforated steel rods and multiple pins; Two perforated steel rods are connected by pins to form an "X"-shaped hinge unit. Multiple hinge units are connected front to back to form a flexible hinge. One end of the flexible hinge is fixed to one end of the cantilever beam, and the other end is fixed to the output piston of a single-stage hydraulic displacement amplifier.

6. A cantilevered vibration absorber for a heliostat according to claim 5, wherein, The number of the piezoelectric stacked actuator, the first-stage hydraulic displacement amplifier, and the second-stage flexible hinge displacement amplifier is two.

7. A cantilevered vibration absorber for heliostats according to any of claims 2-5, characterized in that, This includes cantilever beams and heliostat mirror support beams; The cantilever beam is mounted on the heliostat mirror support beam, and the mass block is movably mounted on the cantilever beam; The piezoelectric stacked actuator is controlled by voltage to extend and retract. The extension and retraction of the piezoelectric stacked actuator is amplified by a displacement amplifier and then applied to the mass block, causing the mass block to move in a controlled manner on the cantilever beam.

8. The cantilevered vibration absorber for heliostats of claim 7, wherein, It also includes damping devices; The damping device is made of elastic damping material and is installed in the middle section of the cantilever beam. The damping device is compressible.

9. The cantilevered vibration absorber for heliostats according to claim 8, characterized in that, The cantilever beam includes a baffle, a steel beam, and a fixed steel plate; The baffle is fixed to the cantilever end of the steel beam; the fixing steel plate is fixed to the fixed end of the steel beam; the damping device replaces a section of the steel beam. The fixed steel plate is bolted to the heliostat mirror support beam.

10. The cantilevered vibration absorber for heliostats of claim 9, wherein, The damping device includes rubber damping material and steel clamps; The steel clamp is installed on the outside of the rubber damping material and fixed on the steel beam to compress and fix the rubber damping material.

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