A disc type solar energy concentrating tracking system with overload protection and flexible buffering

Abstract

The present application relates to a kind of with overload protection and flexible buffer disc type solar light-gathering tracking system, belong to new energy technology field.This mechanism solves the problem that traditional solar tracking system is insufficient in rigidity under dead weight, is prone to deformation, and Stirling engine is damaged by light-gathering energy overload.The technical scheme includes: Stirling engine is connected to net rack by support rod with built-in buffer, and buffer uses double-spring pre-press design to absorb vibration;The deflection angle of the outer layer of non-supporting mirror of rotating parabolic reflector is controlled independently by 3-RPS parallel mechanism, and focal point energy dispersion is realized;The moving platform and fixed platform of the 3-RPS parallel mechanism are distributed in isosceles triangle, and the structural rigidity is optimized to resist dead weight load.The present application can significantly improve the stability of mechanism, reduce the risk of energy overload, and the structure is compact, suitable for large solar power station.The design enables the same set of tracking mechanism to intelligently switch between high-efficiency precise focusing and active safety defocusing two modes, thereby solving the technical contradiction that traditional tracking mechanism lacks built-in overload protection capability, and additional protection sacrifices light-gathering efficiency.

Description

Technical Field

[0001] This invention relates to the field of new energy, and in particular to a dish-type solar concentrating tracking system with overload protection and flexible buffering. Background Technology

[0002] With the rapid development of solar energy technology, solar power generation systems have become an important component of the clean energy sector. However, the energy capture efficiency of solar power generation systems is highly dependent on the angle of sunlight incidence. Therefore, in order to maximize the utilization of solar energy, solar tracking technology has gradually become a key support.

[0003] In the development of tracking mechanisms, two types of systems have emerged: single-axis and dual-axis. While single-axis tracking mechanisms are simple in structure, they can only track the sun's position in a single direction and cannot guarantee that the concentrator axis remains parallel to the sunlight. Therefore, dual-axis tracking mechanisms are currently widely used. However, traditional dual-axis mechanisms are mostly based on a series configuration, generally suffering from low system stiffness and insufficient stability. Especially in harsh environments, they struggle to compensate for external disturbances by actively adjusting the mirror's attitude, ultimately resulting in tracking accuracy failing to meet practical requirements.

[0004] To overcome the low stiffness of serial mechanisms, traditional parallel mechanisms have been introduced into tracking systems. While their multi-branch structure improves overall stiffness to some extent, they still fall short when facing the self-weight load of large concentrators. During long-term operation, they are prone to slight deformation due to continuous load, affecting positioning accuracy. Furthermore, existing mechanisms generally lack effective wind vibration suppression mechanisms. Under strong wind conditions, the branches and moving platform are prone to vibration, which can cause the concentrator mirror to shift, further weakening system stability.

[0005] It is worth noting that current technical solutions generally focus too much on the tracking accuracy of azimuth and elevation angles, while neglecting the fundamental necessity of energy management. This excessive pursuit of precise focusing inherently carries the risk of energy overload: to achieve high thermal efficiency, the system design requires continuously focusing sunlight onto receivers such as Stirling engines. However, under extremely favorable solar conditions, this continuous focusing can easily cause the energy density on the receiver surface to exceed its safety threshold. Furthermore, external factors or instantaneous errors in the tracking system can further exacerbate the volatility and uncontrollability of energy accumulation. However, the design goal of existing tracking mechanisms remains solely focused on how to track the sun more accurately; their structure itself lacks the ability to actively "defocus" under energy overload conditions, and energy overload protection is not a core design consideration.

[0006] These limitations highlight the shortcomings of existing solar tracking mechanisms in terms of structural design: firstly, stiffness enhancement requires asymmetric optimization to address self-weight loads; secondly, passive or active vibration damping mechanisms need to be integrated to cope with wind loads; and thirdly, energy regulation functions need to be introduced to achieve overload protection. Therefore, there is an urgent need in this field for a solar tracking mechanism that integrates active energy regulation and passive flexible buffering functions. It can not only track the sun with high precision but also intelligently address energy overload risks and buffer external vibrations, thereby comprehensively improving the reliability, safety, and service life of dish solar power systems. Summary of the Invention

[0007] The purpose of this invention is to address the problems existing in the prior art by providing a dish-type solar concentrator tracking system with overload protection and flexible buffering, which can track the trajectory of the sun and ensure tracking accuracy under its own weight and a certain amount of wind load.

[0008] The technical solution adopted in this invention is: a dish-type solar concentrating tracking system with overload protection and flexible buffering, including a Stirling engine, a support frame with a flexible buffer device, a parabolic rotating mirror, a 3-RPS parallel tracking mechanism, and a grid frame; the parabolic rotating mirror is divided into inner and outer layers, each layer consisting of multiple mirrors, all obeying the same equation, and the structure and size of any mirror in the inner or outer layer are exactly the same as other mirrors in the same layer; the 3-RPS parallel tracking mechanism includes a moving platform, a fixed platform, and three identical RPS branches. Each mirror is fixed to the moving platform of a separate 3-RPS parallel mechanism, and each RPS branch consists of a spherical joint S connecting the moving platform and the linear telescopic device, a telescopic device P joint, and a revolute joint R connecting the linear telescopic device and the fixed platform. The inner and outer RPS branches have the same structure, and the moving and fixed platforms of all 3-RPS parallel mechanisms are similar isosceles triangles; the grid frame is used to connect the parabolic rotating mirror and the 3-RPS parallel mechanism.

[0009] In the aforementioned dish-type solar concentrator tracking system with overload protection and flexible buffering, the rotating parabolic reflector employs a layered design, consisting of an inner and outer mirror layer. Both the inner and outer mirror layers follow the same parabolic equation of revolution, ensuring consistent optical performance. The inner mirror layer is completely uniform in structure and size; to avoid the shading effect caused by the Stirling engine above, the mirror near the center is specifically cut off. The outer mirror layer also maintains consistent specifications. Each mirror is independently fixed to a corresponding 3-RPS parallel mechanism actuator platform, and together they form a complete rotating parabolic reflector system through coordinated control.

[0010] In the aforementioned parallel dish-type solar tracking mechanism, the support rod has a built-in buffer, consisting of upper and lower support rods, an inner core, two preloaded springs, an end cap, and a housing. One end of the inner core is threaded to the upper support rod, and the other end abuts against the inner wall of the lower support rod. The first spring is located inside the housing, with both ends pressing against the head of the lower support rod and the end cap; the second spring is located on the inner wall of the lower support rod, with both ends pressing against the inner core and the inner wall of the lower support rod. One end of the housing is threaded into the end cap, and the radius of the other end is smaller than the head of the lower support rod to seal it. When the support rod is stretched, the second spring compresses to generate resistance; when compressed, the first spring deforms under pressure through the end cap and the housing, thus achieving buffering.

[0011] In the aforementioned parallel dish-type solar tracking mechanism, the grid frame consists of two layers of connecting frames and trusses. The trusses are distributed to connect the two layers of frames to enhance support and wind load resistance. The connecting frames are provided with bolt holes for connection to the reflectors and the parallel mechanism. The grid frame edges are provided with upper and lower bosses; support rods pass through the upper boss and abut against the upper surface of the lower boss. An outer shell is provided around the bosses, and the outer shell, support rods, and grid frame are fixed together with bolts.

[0012] In the aforementioned parallel dish solar tracking mechanism, the 3-RPS parallel mechanism has the same inner and outer layer structure. The moving platform is an isosceles triangle inscribed in a circle with a radius of 560 mm, and the fixed platform is a similar isosceles triangle. The ratio of the circumcircles of the moving and fixed platforms is 1.15. The RPS branch is connected to the vertex of the isosceles triangle of the fixed platform via a revolute joint, with the perpendicular line from the axis of the revolute joint coinciding with the angle bisector of the fixed platform. The center of the ball joint is located on the angle bisector of the isosceles triangle of the moving platform.

[0013] Based on the practical application requirements of the parabolic sphere of revolution, the parallel tracking mechanism must have a large stroke; therefore, a three-stage hydraulic cylinder is used as the linear telescopic drive device. This hydraulic cylinder has a compact structure and can achieve a longer stroke than a single-stage hydraulic cylinder within a limited installation space. Its cascaded structure is as follows: the hydraulic rod of the first-stage hydraulic cylinder serves as the second-stage hydraulic cylinder, the hydraulic rod of the second-stage hydraulic cylinder serves as the third-stage hydraulic cylinder, and the piston head of the third-stage hydraulic cylinder is set as a spherical part of a spherical pair. During operation, hydraulic oil enters the first, second, and third-stage hydraulic cylinders sequentially, and under pressure, each stage raises the hydraulic rod, achieving the telescopic motion.

[0014] In the aforementioned parallel dish solar tracking mechanism, the support rods used to connect and support the upper Stirling engine are connected to the outer frame of four mirrors distributed 90° apart circumferentially. Each support rod consists of two layers, bolted to the top and middle flanges of the Stirling engine, respectively. For the outer 3-RPS parallel mechanism that does not require support for the Stirling engine, its mirrors can deflect independently. When the energy is within acceptable limits, the mirrors maintain a standard orientation to keep the focus focused; when the energy is overloaded, the mirrors use a preset deflection mechanism to deflect the light spot away from the focus, thus dispersing the energy. This function is achieved through structural design, without the need for complex control.

[0015] The beneficial effects of this invention lie in its effective solution to the shortcomings of traditional solar tracking mechanisms in terms of stiffness, wind load resistance, and energy management through structural innovation. The isosceles triangular 3-RPS parallel mechanism significantly improves structural stiffness, optimizes self-weight load distribution, and reduces the risk of deformation during long-term operation. The flexible buffer with integrated dual-spring preload design absorbs wind load vibration energy, ensuring the reliability of the connection between the Stirling engine and the support rod, and avoiding structural failure caused by impact loads. The outer support mirror is driven by its independent 3-RPS parallel mechanism, enabling deflection within a specific angle range. Compared with existing technologies, the innovation of this invention in overheat protection lies in: embedding overload protection function into the tracking mechanism body through structural design. During most normal operation, all mirrors work together to maintain the complete parabolic shape; only in the event of extreme overload risk does a specific mirror deflection occur, achieving rapid physical protection. Compared to traditional dual-axis mechanisms that can only achieve overload protection by changing the mirror position, this invention can achieve the same highest focusing efficiency as an unprotected mechanism during periods without overload risk. This overcomes the shortcomings of ordinary tracking agencies that lack protection capabilities, and also avoids the drawbacks of sacrificing overall efficiency or increasing system complexity to add protection. Attached Figure Description

[0016] Figure 1 This is a structural diagram of the present invention.

[0017] Figure 2 This is a structural diagram of the outer support receiver's disc surface and moving platform according to the present invention.

[0018] Figure 3 This is a schematic diagram of the space frame structure of the present invention.

[0019] Figure 4 This is a schematic diagram of the internal structure of the support frame buffer of the present invention.

[0020] Figure 5 This is a structural diagram of a single 3-RPS parallel mechanism of the present invention.

[0021] Figure 6 This is a cross-sectional view of the three-stage hydraulic cylinder used in the 3-RPS parallel mechanism of this invention.

[0022] Figure 7 This is a diagram showing the deflection angle of the unsupported disc surface in this invention.

[0023] In the diagram: 1—Stirling engine, 2—Support rod, 3—Support rod buffer, 4—Rotating parabolic reflector, 5—Grid frame, 6—3-RPS parallel mechanism, 31—Lower support rod, 32—Buffer inner core, 33—Second buffer spring, 34—Buffer outer shell, 35—Rod head, 36—First buffer spring, 37—End cap, 38—Upper support rod, 41—Non-supported mirror, 42—Supported mirror, 51—First layer connecting frame, 52—Truss, 53—Upper boss, 54—Outer shell, 55—Lower boss, 56—Second layer connecting frame, 61—Moving platform, 62—Third-stage hydraulic cylinder, 63—Fixed platform, 8—Piston rod, 9—Third-stage hydraulic cylinder, 10—Second-stage hydraulic cylinder, 11—First-stage hydraulic cylinder. Detailed Implementation

[0024] The dish-type solar concentrating tracking system with overload protection and flexible buffering proposed in this invention is described below in conjunction with the accompanying drawings:

[0025] like Figure 1 , 2 As shown in Figure 3, the present invention includes a Stirling engine 1, a support frame 2, a rotating parabolic reflector 4, a grid frame 5, and a 3-RPS parallel tracking mechanism 6. The Stirling engine 1 is suspended near the focal point of the rotating parabolic reflector 4 by four support rods 2 with buffers spaced 90° apart. The other end of the support frame is connected to the grid frame 5. The support rods 2 are divided into two layers, which are bolted to the flanges at the top and middle positions of the Stirling engine 1, respectively. The shape and size of the upper end of the bottom support 7 are completely consistent with the fixed platform of the 3-RPS parallel mechanism 63, which can be fixedly installed on a specific position on the ground by welding or bolting.

[0026] The Stirling engine 1 is fixed to the upper center position of the grid frame 5 by four evenly distributed support rods 2.

[0027] like Figure 2 , 3 As shown, the space frame 5 consists of two layers of connecting frames and trusses. Trusses 52 are distributed between the two layers of connecting frames to enhance the support capacity and wind load resistance of the mechanism. Bolt holes are pre-drilled on the first layer connecting frame 51 and the second layer connecting frame 56 for welding with the rotating parabolic reflector 4 and the 3-RPS parallel mechanism 6. The space frame for connecting the support rods has two additional bosses on the edges of the upper and lower layers. The support rods pass through the upper boss and abut against the upper surface of the lower boss. The two bosses are equipped with outer shells, and the outer shells 54, support rods 2 and space frame 5 are connected together by bolts. One end of the support rod 2 is fixed to the boss of the space frame 5, and the other end is mounted on the Stirling engine 1 through a flange. The flange is used to install the Stirling engine 1 and reduce the vibration generated during its start-up.

[0028] The support rod 2 is a hollow cylindrical rod made of high-strength alloy. A buffer 3 is installed inside it. The specific structure of the buffer 3 is as follows: Figure 4 As shown, the structure mainly includes an inner core 32, a first spring 36, a second spring 33, an end cap 37, and an outer shell 34. The upper end of the inner core 32 is machined with external threads, passing through the central through hole of the end cap 37 and engaging with the internally threaded hole at the bottom of the upper support rod 21 for secure fastening. The lower end face of the inner core 32 abuts against the inner wall protrusion of the lower support rod 31. The first spring 36 is sleeved outside the inner core 32 and housed within the outer shell 34, with its two ends pressing tightly against the upper surface of the lower support rod head 35 and the lower surface of the end cap 37, respectively. The second spring 33 is disposed within the inner cavity of the lower support rod 31, with its two ends pressing tightly against the lower end face of the inner core 32 and the bottom surface of the inner cavity of the lower support rod 31, respectively. The upper end of the outer shell 34 is provided with internal threads, screwing and fixing it to the end cap 37; the inner diameter of its lower end is smaller than the outer diameter of the lower support rod head 35, thereby sealing the rod head 35 within the outer shell 34. When the support rod 2 is subjected to tensile or compressive loads, the first spring 36 and the second spring 33 undergo compressive deformation respectively, thereby absorbing energy and playing a buffering role.

[0029] The parabolic rotating mirror 4 is made of highly reflective silvered glass and has a parabolic focal length of 3.8 meters. The mirror 4 employs a split design, consisting of an inner and an outer layer. The inner layer comprises five identical lenses of the same size and shape, with its central area cut to prevent the Stirling engine 1 from blocking light. The outer layer consists of eight identical lenses of the same size and shape. All lenses in both the inner and outer layers follow the same parabolic equation.

[0030] The 3-RPS parallel mechanism 6 has thirteen parts, each corresponding to one of the thirteen lenses and fixedly connected. For example... Figure 5 As shown, each 3-RPS parallel mechanism 6 includes a moving platform 61, a fixed platform 63, and three RPS branches 62 connecting the moving and fixed platforms. Both the moving platform 61 and the fixed platform 63 are isosceles triangular steel plates. The circumscribed circle radius of the moving platform 61 is 560 mm, and the circumscribed circle radius of the fixed platform 63 is 487 mm, with a ratio of 1.15. Each RPS branch 62 includes a connecting rod connected to the moving platform 61 via a ball joint, a telescopic device serving as a prismatic joint P, and a base connected to the fixed platform 63 via a revolute joint R. In this embodiment, the telescopic device is a three-stage hydraulic cylinder. Its first-stage cylinder is connected to the fixed platform 63 via the revolute joint R, and the end of its final-stage piston rod is a ball of a ball joint connected to the moving platform 61.

[0031] Based on the rotational parabolic surface data selected for the actual application scenario, a large stroke is typically required for the parallel tracking mechanism. Therefore, three three-stage piston cylinders are used as the drive device for the linear telescopic device. The linear drive mechanism of the 3-RPS parallel mechanism, with its three-stage hydraulic cylinders, is as follows: Figure 6 As shown, the hydraulic rod of the first-stage hydraulic cylinder 11 is the hydraulic rod of the second-stage hydraulic cylinder 10, and the hydraulic rod of the second-stage hydraulic cylinder 10 is the hydraulic rod of the third-stage hydraulic cylinder 9. The end of the piston rod 8 is a spherical part of a spherical pair. When hydraulic oil enters the first-stage hydraulic cylinder 11, the second-stage hydraulic cylinder 10 is lifted under the pressure of the hydraulic oil. When the pressure of the hydraulic oil reaches a certain level, the hydraulic oil enters the second-stage hydraulic cylinder 10, lifting the third-stage hydraulic cylinder 9. When the pressure of the hydraulic oil continues to increase to a certain level, the hydraulic oil enters the third-stage hydraulic cylinder 9 and lifts the piston rod 8.

[0032] The working process of this invention is as follows: Under normal operating conditions, all 3-RPS parallel mechanisms 6 move in concert, driving the rotating parabolic reflector 4 to precisely track the sun's position, ensuring that sunlight is continuously focused on the receiver of the Stirling engine 1. When encountering gusts of wind, the buffer 3 inside the support rod 2 absorbs vibration energy through its double-spring preload structure, ensuring the reliability of the connection between the Stirling engine and the support rod. When excessive or abnormal light intensity causes energy overload, the 3-RPS mechanism corresponding to the outer mirror can be driven independently, causing the mirror to structurally deflect, moving part of the light spot out of the focal area of ​​the focusing disk, thus physically dispersing energy to ensure system safety, such as... Figure 7 As shown, this mechanism achieves coordinated operation of tracking, interference immunity, and protection through structural design.

Claims

1. A dish-type solar concentrating tracking system with overload protection and flexible buffering, comprising a Stirling engine, a rotating parabolic reflector, a 3-RPS parallel mechanism, a grid frame, and a bottom support, characterized in that: The Stirling engine is connected to the grid structure via a support rod. The support rod has a built-in buffer, which includes an inner core, a first spring, and a second spring, for absorbing wind loads and vibration loads. The outer mirror of the rotating parabolic reflector contains at least four unsupported mirrors. The 3-RPS parallel mechanism of the unsupported mirrors is equipped with an independent deflection control mechanism, which allows the reflected light spot to deviate from the focal area of ​​the Stirling engine to achieve energy overload protection. The structure of the 3-RPS parallel mechanism is optimized for stiffness.

2. The solar tracking mechanism according to claim 1, characterized in that: The buffer includes an inner core, a first spring, a second spring, an end cap, and a housing; one end of the inner core is threaded to an upper support rod, and the other end abuts against the inner wall of a lower support rod; the first spring is disposed inside the housing, with its two ends pressing against the head of the lower support rod and the end cap, respectively; the second spring is disposed on the inner wall of the lower support rod, with its two ends pressing against the inner core and the inner wall of the lower support rod, respectively.

3. The solar tracking mechanism according to claim 1, characterized in that: The moving platform of the 3-RPS parallel mechanism is an isosceles triangle inscribed in a circle with a radius of 560 mm, with its vertex pointing towards the center of the mechanism. The ratio of the radius of the circumscribed circle of the fixed platform to the radius of the moving platform is 1.

15. The vertex of the moving platform triangle coincides with the center of the spherical joint, and the angle bisector of the isosceles triangle of the fixed platform coincides with the perpendicular line to the axis of the rotary joint.

4. The solar tracking mechanism according to claim 1, characterized in that: The space frame includes a first-layer connecting frame, a second-layer connecting frame, and trusses; the trusses are distributed between the first-layer connecting frame and the second-layer connecting frame; the edge of the second-layer connecting frame is provided with an upper boss and a lower boss, and the support rod passes through the upper boss and abuts against the upper surface of the lower boss.

5. The solar tracking mechanism according to claim 1, characterized in that: The deflection control mechanism includes a three-stage hydraulic cylinder, which is composed of a first-stage hydraulic cylinder, a second-stage hydraulic cylinder, and a third-stage hydraulic cylinder cascaded together. The piston rod of the third-stage hydraulic cylinder is provided with a spherical joint at its end for connecting to the moving platform. The stroke limit block of the third-stage hydraulic cylinder is determined by the maximum deflection angle of the mechanism disc.

6. The solar tracking mechanism according to claim 1, characterized in that: The rotating parabolic reflector consists of an inner supporting mirror and an outer unsupported mirror. The central area of ​​the inner supporting mirror is cut off to avoid the Stirling engine. There are at least four outer unsupported mirrors distributed circumferentially. The 3-RPS parallel mechanism corresponding to each outer unsupported mirror can independently deflect the outer unsupported mirror within a certain range by extending and retracting the sliding joint, so that its reflected light spot deviates from the focal area of ​​the Stirling engine, thereby realizing the active energy regulation of the system.

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