CN109857154B - Method and device for tracking sun by reflector in Fresnel photo-thermal power generation system - Google Patents
Method and device for tracking sun by reflector in Fresnel photo-thermal power generation system Download PDFInfo
- Publication number
- CN109857154B CN109857154B CN201910149754.6A CN201910149754A CN109857154B CN 109857154 B CN109857154 B CN 109857154B CN 201910149754 A CN201910149754 A CN 201910149754A CN 109857154 B CN109857154 B CN 109857154B
- Authority
- CN
- China
- Prior art keywords
- gear
- reflector
- reflectors
- tracking
- sun
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The invention discloses a reflector sun tracking method and a reflector sun tracking device in a Fresnel photo-thermal power generation system.A set of Fresnel focusing system is characterized in that dozens of strip reflectors are connected to a long worm through turbines with the same specification, the initial positions of the reflectors are different, and a driving motor drives a worm shaft to rotate so as to drive all the reflectors to rotate at the same angle; a photoelectric sensor is used for positioning and tracking the sun direction, and a sunlight tracking gear system is used for automatically determining the rotating angle of the reflector; a set of worm and gear system is used for controlling all the reflectors to synchronously rotate; every time the sunlight rotates by an angle theta, all the reflectors synchronously rotate by the same angle theta/2, so that the reflected light beams are always reflected to the collector.
Description
Technical Field
The invention relates to a reflection type sun tracking technology, belonging to the technical field of solar energy application; the method is mainly applied to Fresnel solar thermal power generation systems, and can also be applied to light source tracking in tower type photo-thermal power generation systems and other reflective optical focusing systems.
Background
The solar photo-thermal power generation system is different from the existing common photovoltaic power generation system, and reflects and focuses sunlight into a heat collection system by utilizing a reflector, so that working substances are heated to form steam, and a steam turbine is pushed to generate power. The whole process is similar to thermal power generation, except that the steam generation is performed by collecting and absorbing energy in sunlight instead of burning fossil energy such as coal and natural gas. Compared with photovoltaic power generation, the photo-thermal power generation is not to generate direct current by utilizing a photovoltaic effect and then generate alternating current by inversion, but to drive a steam turbine to generate power by utilizing hot steam, so that the system is compatible with the existing thermal power generation system, the harmonic component of power output is less, the power is stable, the compatibility with a power grid is good, and meanwhile, a thermal energy storage system is arranged, so that 24-hour continuous power generation can be realized. The common forms of the photo-thermal power generation include tower type, groove type, disc type, Fresnel type and the like, and the tower type and the groove type have cost advantage and certain commercial value at present. Fresnel type is similar to trough type but instead of line focusing with parabolic troughs, a number of long surface strip mirrors focus sunlight into a linear collector. The Fresnel type photo-thermal system has the characteristics of small windward side and simple processing of the reflector.
The sun moves from east to west in the morning to night, and for a photovoltaic system, to improve the utilization efficiency of sunlight, the photovoltaic panel is required to be always opposite to the sun and track the movement of the sun. Technically, only a four-quadrant photoelectric sensor is arranged on a photovoltaic cell panel, the sensor is enabled to be always over against the sun through a control system, and the implementation is relatively simple. In the reflective solar photo-thermal system, the sunlight is always reflected to the heat collector, the reflector is not always opposite to the sun, and the included angle between the reflector and the sunlight is always changed.
At present, few documents are available about sun tracking control methods in a photo-thermal system at home and abroad, and related researches are carried out less when a Fresnel type photo-thermal system starts later. The commonly used control means at present is to calculate the sun position at a certain moment by using the local longitude and latitude data, calculate the angle of each reflector according to the relative position, height, distance and other parameters of the reflector and the optical receiver, control signals to the stepping motor, control and adjust the angle of the reflector, and realize the sun tracking. In this process, calculation errors may be caused and errors may be accumulated. And the angle of the reflector is required to be corrected by utilizing closed-loop control formed by photoelectric sensors, and a control system is complex and high in cost.
Disclosure of Invention
In order to solve the problems, the invention discloses a reflector sun tracking method in a Fresnel photo-thermal power generation system, which is simple and convenient, directly tracks the movement of the sun by using a photoelectric sensor, controls the reflector to synchronously rotate by using a mechanical system, realizes reflective tracking, is convenient to control, can improve the tracking efficiency and reduce the cost.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a reflector sun tracking method in a Fresnel photo-thermal power generation system is characterized in that in one set of Fresnel focusing system, dozens of strip reflectors are connected to a long worm through turbines with the same specification, the initial positions of the reflectors are different, and a drive motor drives a worm shaft to rotate so as to drive all the reflectors to rotate at the same angle; every time the sun's sunlight turns through an angle theta, all the mirrors will turn simultaneously through the same angle theta/2, so that the reflected beam is always reflected onto the collector.
A reflector sun tracking device in a Fresnel photo-thermal power generation system comprises a Fresnel focusing system, a sunlight tracking gear system, a photoelectric sensor, a control circuit and a software system, wherein the Fresnel focusing system is arranged on the front side of a reflector;
in the Fresnel focusing system, dozens of strip-shaped reflectors are connected to a long worm through turbines with the same specification, the initial positions of the reflectors are different, a motor drives a worm shaft to rotate, and the sunlight tracking gear system is installed on one reflector;
the sunlight tracking gear system is composed of four gears. The number of teeth of the first gear is 2 times of that of the second gear, the three and the four gears are equal in number, the first gear and the third gear are not coaxial and are synchronous, the second gear and the fourth gear are coaxial and are synchronous, the photoelectric sensor is fixed on the third gear, the first gear is fixed on the rotating shaft of the reflector,
the photoelectric sensor adopts a single-shaft two-quadrant form, is connected with a driving motor through a servo circuit, and is connected with a Fresnel focusing system, a sunlight tracking gear system and the photoelectric sensor through a software system.
The photoelectric sensor adopts a cylindrical, baffle or triangular form, and is used in combination, so that the precision can be improved, and the search angle can be increased.
The driving motor is arranged on the worm shaft, or on the rotating shaft of the reflector, or on the sunlight tracking gear system.
The invention has the beneficial effects that:
the invention relates to a reflector sun tracking method in a Fresnel photo-thermal power generation system, which is characterized in that a photoelectric sensor is used for positioning and tracking the sun direction, and a set of gear system is used for automatically determining the rotation angle of a reflector; a set of worm and gear system is used for controlling all the reflectors to synchronously rotate; the avoided calculation processes reduce calculation errors and accumulated errors, the control system is simple, the tracking efficiency is improved, the cost is low, and the tracking accuracy is ensured by the accuracy of the photoelectric sensor.
Drawings
The reflector of figure 1 rotates the worm gear structure synchronously.
Fig. 2 shows the angular relationship of the reflection of light.
FIG. 3 is a sun tracking gear system.
Fig. 4 is a schematic diagram of a photosensor structure.
Fig. 5 is a control circuit flow diagram.
Detailed Description
The present invention will be further illustrated with reference to the accompanying drawings and specific embodiments, which are to be understood as merely illustrative of the invention and not as limiting the scope of the invention.
As shown in the figure, the reflector sun tracking method in the Fresnel photo-thermal power generation system is characterized in that on the basis of the original Fresnel photo-thermal power generation system, a photoelectric sensor is additionally arranged for positioning and tracking the sun direction, and a set of sunlight tracking gear system is additionally arranged for automatically determining the rotation angle of the reflector; a set of worm and gear system is used for controlling all the reflectors to synchronously rotate; the reflected light beams are always reflected to the collector, so that each calculation process is avoided, calculation errors and accumulated errors are reduced, a control system is simple, and the cost is low.
The working principle is as follows: the sun moves from east to west relative to the morning to night, and for a reflective solar energy utilization system, sunlight is required to be reflected into a heat collection collector all the time, a reflector cannot be over against the sun, an included angle between the reflector and the sun ray is required to be changed all the time, and the sun tracking system of a photovoltaic system cannot be moved. For the reflector, the incident light and the reflected light are symmetrically distributed on two sides of the normal of the reflector. As shown in fig. 2, only when the sun, collector and mirror are in a straight line, the incident light, reflected light, and normal line coincide, and the mirror is facing the sun. When the incident rays of the sun are rotated through an angle theta relative to the moment, only if the mirror and its normal are rotated through an angle theta/2, the reflected rays can still be reflected to the collector, as is the case with mirror 2 in fig. 2. In such a reflective solar energy utilization system, it is necessary to ensure that the angle of rotation of the mirror 2 is half of the angle of rotation of the sun, so that the rays of the sun are always reflected to the collector.
Based on this principle, the present invention relates to a sun tracking gear system 7 as shown in fig. 3, which is composed of four gears. The number of teeth of the first gear is 2 times of the number of teeth of the second gear, the three and four gears are equal in number, the first gear and the third gear are not synchronous, the second gear and the fourth gear are coaxial and synchronous, one circle of rotation of the first gear is achieved, the second gear, the third gear and the fourth gear rotate for 2 circles, and the rotating angles of the second gear, the third gear and the fourth gear are 2 times of the rotating angles of the first gear. Thus, according to the present invention, a photoelectric sensor is fixed on the gear three, the gear one is fixed on the rotating shaft of the reflector, the photoelectric sensor is used for tracking the rotation angle of the sun, when the gear three rotates through the angle theta after rotating through the angle theta, the gear system drives the gear one and the reflector to rotate through the angle theta/2, and the reflected light beam is reflected to the collector by the light reflection principle of fig. 2.
The photoelectric sensor can be directly used in the current photovoltaic system, and in the photovoltaic system, in order to improve the utilization efficiency of sunlight, the photovoltaic cell is required to be always over against the sun. The photoelectric sensor mainly adopts a four-quadrant photoelectric sensor and the like, and has various structural forms. And Fresnel formula light and heat power generation system generally places speculum and linear collector south north to south, and the speculum unipolar is rotatory in one day, and its photoelectric sensor can simplify to unipolar two quadrant forms. As shown in fig. 4 (a), two identical solar cells are separated by a baffle, and fig. 4 (b) is a triangular form, in which two identical solar cells are closely attached to two symmetrical side surfaces based on a triangular prism having an isosceles triangle section. When sunlight obliquely enters, because the baffle forms a shadow or the light flux difference is formed by inclination, the output currents of the two solar cells are different, and only when the photoelectric sensor is opposite to the sun, the outputs of the two solar cells are the same. Fig. 4 (c) is a cylinder type, the lens at the upper opening of the cylinder images the sunlight at the bottom of the cylinder, the sunlight falls on two same solar cells at the bottom surface, and the output of the two solar cells is the same only when the sun is directly incident. In comparison, the cylindrical light receiving angle is small but the accuracy is high, and the baffle type or triangular type light receiving angle is large but the accuracy is low. The two are combined for use, so that the precision can be improved, and the search angle can be increased. Generally, one sensor is used, if the precision requirement is high, a or b can be combined with c, the coarse tracking can be performed by using a or b two sensors, for example, the tracking angle is large, the sun can be searched by using a large angle of a or b, the sun is roughly aligned, and the fine tracking is performed by using the c sensor, so that the tracking precision is improved. By using the photoelectric sensor, the outputs of the two solar cells in the sensor are compared, the driving motor is controlled by a servo circuit, the axial direction of the photoelectric sensor is adjusted until the outputs of the two solar cells are the same, and the photoelectric sensor is just opposite to the sun at the moment, so that the aim of tracking the sun is fulfilled.
According to the foregoing principle, every time the sun's sunlight turns through an angle theta, all mirrors will rotate simultaneously through the same angle theta/2. Dozens of strip reflectors in the Fresnel focusing system only need to be provided with one gear tracking system, can be randomly arranged on one reflector, and can realize synchronous rotation of the reflector by using a synchronous mechanical system. The design of the system is to realize the synchronization of all the reflectors by a worm gear and worm system, as shown in fig. 1, each reflector is connected to a long worm through a worm gear with the same specification, and a motor drives the rotation of a worm shaft to drive all the reflectors to rotate at the same angle. However, since the reflectors are located at different relative positions and have different initial angles, the reflectors need to be set and adjusted according to specific position parameters. The drive motor may be mounted on the worm shaft, or on the mirror rotating shaft, or on the sun-tracking gear system.
Fig. 5 is a flow chart of the operation of the control circuit and software system. The system starts to work, the ambient light intensity needs to be detected firstly, when the ambient brightness is low, the ambient brightness indicates night or cloudy days, only when the weather is good in the daytime, the sun tracking is carried out, and the parameter value of the threshold value 1 is set according to the actual conditions of all places. When the weather is good, the output currents I1 and I2 of two solar cells in the photoelectric sensor are detected, when the two parameters are slightly different, the sensor is considered to be facing the sun, the parameter value of the threshold value 2 is set to be a small value, and the size of the parameter is set according to the circuit parameters and the accuracy of the sensor. If the output currents of the two solar cells are different greatly, the output currents need to be compared, so that the rotation direction of the motor is controlled until the output currents are approximately equal to each other. And returning to perform the next comparison control.
The sunlight tracking gear system adopts single-shaft reflection type tracking, if two sets of gear systems are adopted to respectively control the rotation of the reflector in two axial directions, the double-shaft tracking can be realized, and therefore, the sunlight tracking gear system can be used for tracking control of the reflector in a tower type photo-thermal power generation system.
The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features.
Claims (1)
1. A reflector sun tracking method in a Fresnel photo-thermal power generation system is characterized by comprising the following steps: in one set of Fresnel focusing system, dozens of strip-shaped reflectors are connected to a long worm through turbines with the same specification, the initial positions of the reflectors are different, and a driving motor drives a worm shaft to rotate so as to drive all the reflectors to rotate at the same angle; a photoelectric sensor is used for positioning and tracking the sun direction, and a sunlight tracking gear system is used for automatically determining the rotating angle of the reflector; a set of worm and gear system is used for controlling all the reflectors to synchronously rotate; when the sunlight rotates by an angle theta, all the reflectors synchronously rotate by the same angle theta/2, so that the reflected light beams are always reflected to the collector;
the reflector sun tracking device in the Fresnel photo-thermal power generation system comprises a Fresnel focusing system, a sunlight tracking gear system, a photoelectric sensor, a control circuit and a software system;
in the Fresnel focusing system, dozens of strip-shaped reflectors are connected to a long worm through turbines with the same specification, the initial positions of the reflectors are different, a motor drives a worm shaft to rotate, and the sunlight tracking gear system is installed on one reflector;
the sunlight tracking gear system comprises four gears, the number of teeth of the first gear is 2 times of the number of teeth of the second gear, the number of teeth of the third gear is equal to that of the fourth gear, the first gear and the third gear are not coaxial and are synchronous, the second gear and the fourth gear are coaxial and are synchronous, the photoelectric sensor is fixed on the third gear, the first gear is fixed on the rotating shaft of the reflector,
the photoelectric sensor is in a single-shaft two-quadrant form and is in one or a combination of a cylinder type, a baffle type or a triangular form, the photoelectric sensor is connected with a driving motor through a servo circuit, the driving motor is installed on a worm shaft or a rotating shaft of a reflector or a sunlight tracking gear system, and the software system is connected with a Fresnel focusing system, the sunlight tracking gear system and the photoelectric sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910149754.6A CN109857154B (en) | 2019-02-28 | 2019-02-28 | Method and device for tracking sun by reflector in Fresnel photo-thermal power generation system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910149754.6A CN109857154B (en) | 2019-02-28 | 2019-02-28 | Method and device for tracking sun by reflector in Fresnel photo-thermal power generation system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109857154A CN109857154A (en) | 2019-06-07 |
| CN109857154B true CN109857154B (en) | 2022-03-04 |
Family
ID=66899382
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910149754.6A Active CN109857154B (en) | 2019-02-28 | 2019-02-28 | Method and device for tracking sun by reflector in Fresnel photo-thermal power generation system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109857154B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110513896A (en) * | 2019-09-24 | 2019-11-29 | 华北理工大学 | Trigone formula thermal-arrest comprehensive system for electric generation based on linear Fresnel lens |
| CN112243757A (en) * | 2020-11-05 | 2021-01-22 | 周凤桂 | Complementary modern ecological agricultural device of high-efficient farming light |
| CN114337499B (en) * | 2022-01-10 | 2023-10-31 | 东北大学 | Illumination self-adaptive thermal-patch-prevention greenhouse type photovoltaic power generation device and method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201421203Y (en) * | 2009-02-25 | 2010-03-10 | 林学军 | Ray collecting device following sun |
| CN205245588U (en) * | 2015-12-02 | 2016-05-18 | 北京天瑞星光热技术有限公司 | Transmission and linear fei nieershi solar energy system are followed tracks of to solar energy |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101841268A (en) * | 2009-03-22 | 2010-09-22 | 北京智慧剑科技发展有限责任公司 | Solar multi-directional tracking photovoltaic system |
| CN103064428B (en) * | 2012-12-05 | 2015-08-12 | 苏州市思玛特电力科技有限公司 | A kind of active sun tracking system driven based on liquid level for photovoltaic generation |
| CN106301152A (en) * | 2016-08-24 | 2017-01-04 | 内蒙古科林统德新能源科技发展有限公司 | The solar condensing power generation device of device followed the tracks of by band |
| CN107368101B (en) * | 2017-07-04 | 2020-07-14 | 华北电力大学 | Heliostat device based on sun tracking sensor and working method |
-
2019
- 2019-02-28 CN CN201910149754.6A patent/CN109857154B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201421203Y (en) * | 2009-02-25 | 2010-03-10 | 林学军 | Ray collecting device following sun |
| CN205245588U (en) * | 2015-12-02 | 2016-05-18 | 北京天瑞星光热技术有限公司 | Transmission and linear fei nieershi solar energy system are followed tracks of to solar energy |
Non-Patent Citations (1)
| Title |
|---|
| 自动跟踪太阳光的采光照明系统;任晋芳;《中国优秀硕士学位论文全文数据库•工程科技||辑》;20140715;正文第17-18页以及附图2.6 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109857154A (en) | 2019-06-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109857154B (en) | Method and device for tracking sun by reflector in Fresnel photo-thermal power generation system | |
| US20090314280A1 (en) | Apparatus and A Method for Solar Tracking and Concentration af Incident Solar Radiation for Power Generation | |
| EP2559955A1 (en) | Solar heat collecting system | |
| CN205119523U (en) | Light collecting solar energy high temperature heating device of fresnel transmission | |
| CN103165699B (en) | Tower-type solar energy heliostat bevel gear passive automatic sun-chasing support | |
| CN101737279B (en) | Light-gathering aiming device for tower-type solar thermal power generating system | |
| CN100427846C (en) | Line focusing solar device with fixed reflection surface | |
| Chang | Tracking solar collection technologies for solar heating and cooling systems | |
| CN105275760A (en) | Grid-connected type household disc type Stirling solar thermal power generation system and control method | |
| CN102721195B (en) | Solar condensation and tracking array horizontal directional collection system | |
| CN204610160U (en) | A kind of convergent lens power generation system | |
| CN104620060A (en) | Solar tracking concentrator | |
| CN204593900U (en) | The Fresnel solar reflection unit that focal length is variable, orientation is adjustable | |
| WO2020007292A1 (en) | Single-axis tracking system for enhancing light intensity of component | |
| CN102800731A (en) | Device for increasing solar energy illuminance | |
| CN207865735U (en) | A kind of speculum moves integrally the solar linear beam condensing unit and array of tracking | |
| CN102466329A (en) | Solar energy collection device | |
| JP2004271063A (en) | Solar power generation device | |
| CN103135600A (en) | Control system of heliostat | |
| CN102590983A (en) | Reflector adjusting device | |
| CN106369845A (en) | Transmission light-condensation tracking type solar heat collection device | |
| CN202394121U (en) | Heliostat control system for photo-thermal power generation | |
| CN106679198A (en) | Solar energy condensation device | |
| CN202548423U (en) | Novel reflector adjusting apparatus | |
| KR20170032635A (en) | Concentrating method of light using linear fresnel reflector and device of the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |