CN100368741C - Sun tracking device and tracking method based on tracking attitude feedback - Google Patents

Abstract

The invention discloses a solar tracking device and a tracking method based on tracking attitude feedback. The device comprises a sensor and a motor electrically connected to a light receiving panel and a controller. The light receiving panel is connected to a support rod and an altitude angle adjustment rod via a hinge, and the other end of the support rod is connected to a column. The controller is a single-chip microcomputer whose analog/digital port is electrically connected to an altitude angle sensor and an azimuth angle sensor respectively, and whose digital/analog port is electrically connected to an altitude angle driving motor control port and an azimuth angle driving motor control port respectively. The tracking method comprises calculating the local solar declination and time difference on the same day by using longitude, latitude and date and time, calculating the solar azimuth and altitude angle in real time according to the longitude, latitude, solar declination, time difference and time, and realizing real-time tracking by using closed-loop control. The device has a simple structure, low cost, no error accumulation in the tracking method, and low maintenance, and is suitable for unattended solar energy development in a natural environment.

Description

Sun tracking device and method based on tracking posture feedback

The invention relates to the technical field of solar energy development automation, in particular to a sun tracking device and a sun tracking method based on tracking posture feedback.

Background art with the shortage of world energy and the rising of oil price, solar energy is increasingly regarded as inexhaustible free green energy. In order to improve the solar energy utilization efficiency, it is necessary to make the sunlight incident as vertical as possible. The scientific and technological community has performed a lot of work on sun tracking, and two sun tracking methods are developed: the method comprises active tracking based on the direction of sensed sunlight and passive tracking based on the earth orbit around the day.

Active tracking such as "solar radiation tracking control device" (patent No. 01217140.9, publication No. CN 2472151Y), passive tracking represents such as "micro-power consumption timing sun tracking device" (patent No. 02222766.0, publication No. CN 2562135Y). The former 'solar radiation tracking control device' receives sunlight by using a pyramid type photoelectric sensor, when the sunlight is not perpendicular to the center of the pyramid type photoelectric sensor, the output voltages of four photoelectric plates are unequal, the sun position can be calculated by comparing the voltages output by the four photoelectric plates, and then a stepping motor is controlled to drive a tracking device to aim at the sun; the latter 'micro-power consumption timing sun tracking device' belongs to passive tracking, utilizes the rule that the azimuth angle of the sun is 15 degrees/hour to drive the azimuth angle of a solar panel to synchronously rotate, and carries out single-axis tracking control from 9 o 'clock to 18 o' clock, has the advantages of simple structure, large tracking error and low solar energy utilization rate, and is not suitable for large-area popularization because the double-axis tracking of the sun can not be realized because the double-axis tracking of the sun is not carried out because the tracking error is large, and longitude and latitude factors are not considered, and the day and night distinguishing function is not provided, so that the solar energy utilization efficiency is low. In addition, a stepping motor is generally adopted for driving in the prior art, a photoelectric sensor is generally adopted for a positioning device, the manufacturing cost is high, and the environmental interference resistance is poor.

The civil solar energy field pursues high automation level, less maintenance and lower cost. The existing active tracking relates to a photoelectric sensor, so that the price is high, the active tracking is easily influenced by dust and light pollution, the maintenance amount is large, and the active tracking is not suitable for the civil solar energy field; the passive control becomes the direction of the civil solar tracking device due to the reliability, but the traditional passive tracking device is driven by a stepping motor, a high-precision traditional system is used, the manufacturing cost is high, meanwhile, the time difference and the nonuniformity of solar declination change (caused by the eccentricity of the earth around the sun orbit) are not considered, the longitude and the latitude are not considered, and the wide difference is still formed from the large-scale popularization.

The invention aims to provide a novel passive tracking device, namely a tracking attitude feedback-based sun tracking device and a tracking method aiming at the defects of a sun tracker at home and abroad, so as to reduce the cost of the sun tracking device, reduce the maintenance amount and meet the requirements of the civil solar energy field.

The principle of the invention is as follows: the singlechip is used for accurately calculating the time difference of the current day (difference between real solar time and flat solar time) and the declination of the sun (latitude of a direct solar point) according to the date, and then accurately calculating the altitude and the azimuth of the sun at the time by combining the local longitude and latitude to determine the position of the sun and distinguish day and night.

The time difference and solar declination are periodic functions of the date, the period is one year, and the table can be looked up. To achieve higher computational accuracy, a look-up table interpolation or function fitting approach may be used, and the following is a typical function fitting algorithm:

the working day is day D after the time is counted from 1 month and 1 day, and the intermediate quantity X is set as

The time difference delta and solar declination sigma of the day are respectively

The invention utilizes the time difference, the longitude and the current time to calculate the solar time angle omega (the angle rotated after the longitude of the sunlight direct-radiation tracking device is called the solar time angle), and the magnitude of the angle is

Ω = (CT + CL + δ -12) × 15 °, where CT is the current time, CL is the longitude correction, 1 degree/4 minutes, and δ is the time difference of day.

The invention calculates the solar altitude angle alpha (the included angle between the solar ray and the ground plane) and the solar azimuth angle beta (the angle from the positive north direction to the sun ray shadow) through the solar time angle omega, the solar declination sigma and the latitude 58388 (the north latitude is positive and the south latitude is negative), and has the advantages of wide area from the south to the north circle and the area from the north to the south

sinα＝sinsinσ+coscosσcosΩ

The invention judges day and night according to the value of the altitude angle. In order to determine the sunrise time and the sunset time of the local day, the altitude angle α is made equal to zero, cos [ (CT + CL + δ -12) × 15 ° ] = -tan \58388andtan σ, CT has two solutions, the sunrise time is a solution smaller than 12, and the sunset time is a solution larger than 12.

The single chip microcomputer compares the expected position of the sun with the actual tracking position fed back by the attitude sensor to obtain a tracking error, outputs a control signal according to a control algorithm to control the direct current motor to operate, reduces the error to zero under closed-loop control, and realizes double-shaft tracking. The singlechip calculates the sun position again at intervals to track a new round, and the interval time can be set by the keyboard circuit. The attitude sensor is composed of a capacitance sensor, wherein the altitude angle is obtained by using a differential capacitance sensor, the azimuth angle is obtained by using a three-petal capacitance angle sensor, the tracking is carried out in the daytime, and the tracking is stopped at night.

The technical scheme of the invention is as follows: the utility model provides a sun tracking device based on track gesture feedback, includes photic panel, the sensor of being connected with the controller electricity, motor, its characterized in that:

the light receiving panel is connected with the supporting rod and the elevation angle adjusting rod through a hinge, the other end of the supporting rod is connected with the upright post, and the other end of the elevation angle adjusting rod is arranged in the inner cavity of the upright post;

the sensors are a height angle sensor and an azimuth angle sensor, the height angle sensor is a differential capacitance type sensor, a capacitance movable polar plate and a fixed polar plate of the differential capacitance type sensor are respectively arranged at the other end of a height angle adjusting rod and on the inner cavity wall of the upright post, the azimuth angle sensor is a three-petal capacitance angle sensor, and the capacitance movable polar plate and the fixed polar plate of the three-petal capacitance angle sensor are respectively arranged on the outer wall of one end of the upright post and the shell;

the motor is an altitude angle driving motor and an azimuth angle rotating motor, the altitude angle driving motor is fixed on a support, the support is fixed on an upright post, an output shaft of the altitude angle driving motor is meshed with a worm gear through a worm after being decelerated by a reducer, the worm gear coaxially drives a gear, the gear is connected with a rack on the other end of an altitude angle adjusting rod arranged in an inner cavity of the upright post, the azimuth angle driving motor is fixed on a base, and the output shaft of the azimuth angle driving motor is coaxially connected with a big gear fixed on the upright post through a small gear after being decelerated by the reducer;

the controller is a single chip microcomputer, an analog/digital port of the single chip microcomputer is electrically connected with the altitude angle sensor and the azimuth angle sensor respectively, and a digital/analog port of the single chip microcomputer is electrically connected with a control port of the altitude angle driving motor and a control port of the azimuth angle driving motor respectively;

PC 0-PC 7 ports of the single chip are electrically connected with the keyboard, PD 2-PD 4 ports of the single chip are respectively electrically connected with RST, SCLK and I/O pins of the clock chip, PD 5-PD 7 ports of the single chip are respectively connected with CS and I/O pins of the controller,The DATA pin is electrically connected.

As a further improvement to the prior art, the model of a single chip in the sun tracking device based on tracking attitude feedback is AT90S4434, the model of the controller (26) is HT1621, and the model of the clock chip (27) is HT1380.

The tracking method of the sun tracking device based on tracking attitude feedback comprises the steps of converting received analog quantity signals of a sensor into digital signals, processing the digital signals, and converting the digital signals into analog quantity signals to drive a motor, and is characterized in that:

after the system is initialized, the clock chip starts to count time uninterruptedly;

calculating the solar declination and the time difference on the same day according to the date provided by the clock chip;

calculating a real-time solar azimuth angle and altitude angle according to the geographic longitude, latitude, time difference and solar declination;

if the altitude angle is larger than zero, judging the vehicle to be daytime, otherwise, judging the vehicle to be night, and not tracking at night;

and carrying out closed-loop control on the altitude angle and the azimuth angle of the tracking device to eliminate tracking errors.

Compared with the prior art, the invention has the beneficial effects that:

first, the sun tracking device in the invention mainly comprises a singlechip, a capacitance sensor and a direct current motor, and compared with the prior art that the micro-power consumption timing sun tracking device does not use a photoelectric sensor and a stepping motor, the sun tracking device has the advantages of simple structure, low cost and small maintenance.

Secondly, the sun tracking device belongs to double-axis tracking, can track the azimuth angle and the altitude angle of the sun, and has high precision when the sun azimuth angle is subjected to single-axis tracking compared with the micro-power-consumption timing sun tracking device in the prior art.

Thirdly, the sun tracking device of the invention is provided with an azimuth angle sensor and a height angle sensor, the tracking attitude feedback of the device is realized by adopting a capacitance sensor, the device is driven by a direct current motor, and the motor selection range is large because of the feedback link and no error accumulation.

And fourthly, the tracking method of the invention compares the expected position of the sun with the actual tracking position fed back by the sensor by the singlechip to obtain a tracking error, outputs a control signal according to a control algorithm to control the operation of the direct current motor, can reduce the error to zero under closed-loop control, and realizes double-shaft tracking.

The tracking method is a comprehensive horizontal coordinate system tracking method, and all factors necessary for determining the position of the sun are accurately calculated by the single chip microcomputer: the time difference, the solar declination, the longitude and the latitude are considered, so that the non-uniformity of the time difference and the annual change of the solar declination is considered, and the calculation error caused by approximating the solar declination change to a uniform speed without considering the time difference in the passive tracking technology in the prior art is avoided; as the tracking algorithm takes longitude and latitude factors into consideration, the tracking algorithm can be applied to a wide area compared with the prior art by setting longitude and latitude values;

the tracking method can also judge the sunrise and sunset time every day, realize that the sunrise starts to track immediately and the sunset stops tracking immediately, has day and night discrimination capability, can run automatically for a long time, avoids the defects of large tracking error and low solar energy utilization rate of the prior passive tracking that single-axis tracking control is carried out from 9 o 'clock to 18 o' clock, and can resist the interference caused by weather change by utilizing the differential capacitance ratio in the method.

Drawings

FIG. 1 is a schematic diagram of the structure of an embodiment of the apparatus of the present invention;

FIG. 2 is a circuit diagram of an embodiment of the apparatus of the present invention;

FIG. 3 is a view of the elevation angle adjustment lever lifting mechanism of the embodiment of the present invention;

FIG. 4 is a time difference plot for an embodiment of the method of the present invention;

FIG. 5 is a solar declination variation curve according to an embodiment of the method of the present invention;

FIG. 6 is a schematic diagram of the operation of a cylindrical capacitive sensor in accordance with an embodiment of the present invention;

FIG. 7 is a block diagram of a differential cylinder capacitive sensor in accordance with an embodiment of the present invention;

FIG. 8 is a block diagram of a three-lobed capacitive angle sensor in accordance with an embodiment of the present invention;

FIG. 9 is a schematic circuit diagram of a three-lobed capacitive angle sensor according to an embodiment of the present invention;

FIG. 10 is a flow chart of a tracking method of the apparatus of the present invention in an embodiment.

Detailed description embodiments of the invention are further described below with reference to the accompanying drawings:

in fig. 1, 1 is a hinge, 2 is an altitude adjustment lever, 3 is an altitude sensor, 4 is a rack, 5 is a worm wheel, 6 is a worm, 7 is a gear, 8 is a reducer, 9 is an altitude driving motor, 10 is a bracket, 11 is a controller, 12 is a pinion, 13 is a reducer, 14 is an azimuth driving motor, 15 is a base, 16 is a bearing, 17 is an azimuth sensor, 18 is a bull gear, 19 is a column, 20 is a slider, 21 is a support rod, and 22 is a light receiving panel.

The device is for standing the cylinder structure, receives on light panel 22 is connected to altitude angle adjusting lever 2 and bracing piece 21 respectively through two upper and lower hinges 1, altitude angle adjusting lever 2 can reciprocate in stand 19, adjusts the altitude angle of receiving light panel 22, and altitude sensor 3's electric capacity moves the polar plate and decides the polar plate and arranges respectively in on altitude angle adjusting lever 2's outer wall and stand 19's inner wall, and azimuth sensor 17's electric capacity moves the polar plate and arranges in on stand 19's bottom outer wall. The output shaft of the altitude angle driving motor 9 is decelerated by the speed reducer 8 and then serves as a worm 6 to drive the worm wheel 5, the worm wheel 5 and the gear 7 are coaxially linked, and the gear 7 is meshed with the rack 4 at one end of the altitude angle adjusting rod. The adjustment of the azimuth angle is realized by means of the engagement of a pinion 12 on a column 19 with a bull gear 18 after the reduction of the azimuth driving motor 14 by a reducer 13.

In fig. 2, 30 is a keyboard, 27 is a clock chip HT1380, 29 is a serial communication interface PD0 of the single chip microcomputer 25, 28 is a serial communication interface PD1 of the single chip microcomputer 25, 26 is a controller HT1621, 25 is a single chip microcomputer AT90S4434, 23 is an elevation angle driving motor control port, and 24 is an azimuth angle driving motor control port.

The single chip microcomputer 25 is connected with an elevation angle driving motor control port 23 and an azimuth angle driving motor control port 24 through PA0 and PA1, the elevation angle sensor 3 is connected with PA2 and PA3 of the single chip microcomputer 25, the azimuth angle sensor 17 is connected with PA 4-PA 6 of the single chip microcomputer 25, the controller HT162112, the clock chip HT1380 and the keyboard are connected with the single chip microcomputer 25 through PD 5-PD 7, PD 2-PD 4 and PC 0-PC 7.

Fig. 3 is a schematic diagram of a lifting structure of a height angle adjusting rod, which is a transmission mode of a worm, a worm wheel, a gear and a rack.

Fig. 4 is a time difference graph of 120-degree noon of east longitude. In the figure, the abscissa is the number of days and the ordinate is the time difference, which rises with the number of days during a year.

Fig. 5 is a diagram of solar declination variation. The abscissa of the graph is the number of days, the ordinate is the declination of the sun, and the declination rises as a peak with the curve when the number of days in the year reaches 150, and then the curve starts to fall again. This means that the solar declination variation curve is not uniform in one year, and the solar declination variation curve is approximately linearly changed in the traditional technology, so that a large tracking error is caused.

Fig. 6 is a schematic diagram of the operation of the cylindrical capacitive sensor, in which the capacitance is proportional to the relative area of the two plates.

Fig. 7 is a structural view of the differential cylinder capacitance sensor. When the position of the altitude angle adjusting rod 2 changes, the two capacitors become larger/smaller, and the position of the altitude angle adjusting rod 2 relative to the column 19 can be calculated by using the ratio of the two capacitors. The method of utilizing the differential capacitance ratio can resist interference caused by weather change.

Fig. 8 is a three-petal capacitance angle sensor, three fixed plates are symmetrically surrounded to form a circle, and form 3 capacitors with a movable plate.

Fig. 9 is a circuit diagram of a three-lobe capacitive angle sensor. When the column 19 rotates, the movable plate is driven to rotate, so as to cause three capacitance changes, and according to the ratio of the three capacitance values, the rotation angle of the column 19, that is, the azimuth angle of the light receiving panel 22, can be calculated.

Fig. 10 is a flowchart of a tracking control method.

The specific embodiment utilizes the keyboard 30 to set the data required by the system starting through the PC 0-PC 7 ports of the singlechip 25: the RST, SCLK and I/O ports of the clock chip 27 are electrically connected with the PD 2-PD 4 ports of the single chip 25 in local longitude, latitude, date and dormancy period, and the device is started and enters a full-automatic working state after the single chip 25 obtains time and starts to count time uninterruptedly. After the device is started, the singlechip 25 reads the timing of the clock chip 27, calculates the time difference of the day and the declination of the sun by combining the longitude and latitude values stored in the memory, further calculates the altitude angle and the azimuth angle of the sun at that time, and calculates the sunrise time and the sunset time of the local day.

After the tracking is started, the single chip microcomputer 25 reads electric signals of the altitude sensor 3 and the azimuth sensor 17, wherein the altitude sensor 3 senses the position of the altitude adjusting rod 2 relative to the upright column 19 by using a differential capacitor, the azimuth sensor 17 senses the azimuth of the upright column 19 attached with the movable polar plate by using a three-petal fixed polar plate, and the single chip microcomputer 25 realizes analog/digital conversion of the electric signals of the altitude and the azimuth by using an A/D conversion function of a PA port; the A/D port of the singlechip 25 is respectively and electrically connected with the altitude sensor 3 and the azimuth sensor 17; the difference between the elevation angle and the azimuth angle of the sun and the solar panel 22 is calculated by the single chip microcomputer 25, the control signals are respectively calculated by the PID algorithm, and the control signals are input into the elevation angle driving motor control port 23 and the azimuth angle driving motor control port 24 in a time-sharing mode through the PA0 port and the PA1 port of the single chip microcomputer 25 after digital-to-analog conversion.

The elevation angle driving motor controls the elevation angle adjusting rod 2 to move to a corresponding position, and the elevation angle of the light receiving panel 22 is adjusted; the azimuth driving motor controls the upright post 19 to rotate to a corresponding position, so as to realize the azimuth adjustment of the light receiving panel 22.

The singlechip 25 is electrically connected with the HT1621 controller 26 through the PD 5-PD 7 ports

And the DATA port inputs the current clock, longitude and latitude into the controller 26 in a time-sharing manner to realize external display.

Referring to fig. 10, the tracking method and the workflow of the sun tracking apparatus based on tracking attitude feedback are as follows: after the power-on is started, the single chip microcomputer AT90S4434 starts an internal resident program, waits for the keyboard 30 to input a command, and an operator sets initial values including local longitude, latitude, date, time and delay time to the single chip microcomputer 25 through the keyboard 30 (step 100); then in step 110, the clock chip HT1380 starts to count time uninterruptedly after obtaining the initial value from the single chip 25, and the HT1621 controller 26 displays the current clock, longitude and latitude uninterruptedly to the outside; in step 120, the singlechip 25 calculates the solar declination and the time difference of the current day according to the date; in step 130, the singlechip 25 calculates the solar azimuth angle and the solar altitude angle in real time according to the longitude, the latitude, the time difference and the solar declination; the singlechip AT90S4434 judges whether the elevation angle is larger than zero in the step 140, if the elevation angle is smaller than zero, the step 150 is carried out, and the step 120 is carried out after the time delay is carried out for a specific time; if the height angle is greater than or equal to zero, the process proceeds to step 160, where closed-loop control is performed to realize real-time tracking, and then a specific time is delayed (step 170), and the process proceeds to step 130 after the delay is completed.

The tracking device is maintained once every half year, and during maintenance, an operator restarts the system and resets the system clock and the local longitude and latitude.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (4)

1. A sun tracking device based on tracking attitude feedback, comprising a light-receiving panel (22), a sensor and a motor electrically connected with a controller (26), characterized in that: 1.1. The light-receiving panel (22) is connected with the support rod (21) and the height angle adjustment rod (2) through the hinge (1), and the other end of the support rod (21) is connected with the column (19). The other end of angle adjusting rod (2) links to each other with slide block (20), and slide block (20) is placed in the inner chamber of said column (19); 1.2, said sensor is an altitude sensor (3) and an azimuth sensor (17), said altitude sensor (3) is a differential capacitive sensor, and the capacitive pole plate and fixed pole of said differential capacitive sensor The plate is respectively placed on the other end of the elevation angle adjustment rod (2) and the inner cavity wall of the column (19), and the azimuth sensor (17) is a three-lobe capacitance angle sensor, and the capacitance of the three-lobe capacitance angle sensor is The movable pole plate and the fixed pole plate are respectively placed on the outer wall of one end of the column (19) and the inner wall of the shell; 1.3. The motors are the altitude angle drive motor (9) and the azimuth angle drive motor (14). The altitude angle drive motor (9) is fixed on the bracket (10), and the bracket (10) is fixed on the column (19) , the output shaft of the said elevation angle drive motor (9) is meshed with the worm wheel (5) through the worm (6) after being decelerated by the reducer (8), and the worm wheel (5) coaxially drives the gear (7), and the gear (7) and the set It is connected with the rack (4) on the other end of the altitude adjustment rod (2) in the inner cavity of the column (19), and the azimuth driving motor (14) is fixed on the base (15), and the azimuth driving motor ( The output shaft of 14) is coaxially connected with the bull gear (18) fixed on the column (19) through the pinion gear (12) after being decelerated by the reducer (13); 1.4, said controller is a single-chip microcomputer (25), and the analog/digital port of the single-chip microcomputer (25) is electrically connected with the altitude sensor (3) and the azimuth sensor (17) respectively, and the digital/analog port of the said single-chip microcomputer (25) They are electrically connected to the control port (23) of the elevation angle drive motor and the control port (24) of the azimuth drive motor respectively: PC0～PC7 ports of said single-chip microcomputer (25) are electrically connected with keyboard (30), and PD2～PD4 ports of said single-chip microcomputer (25) are respectively connected with RST, SCLK, I/O pins of clock chip (27) electrically, so Said PD5～PD7 port of single-chip microcomputer (25) and said controller (26) respectively

The DATA pin is electrically connected. 2. The sun tracking device based on tracking attitude feedback according to claim 1, characterized in that the single-chip microcomputer (25) is an AT90S4434 type single-chip microcomputer. 3. The sun tracking device based on tracking attitude feedback according to claim 1, characterized in that the model of said controller (26) is HT1621, and the model of said clock chip (27) is HT1380. 4. the tracking method of the sun tracking device based on tracking attitude feedback according to claim 1, comprising converting the analog signal of the sensor received into a digital signal, and converting it to analog after processing to push the motor, its features in: After system initialization, the clock chip (27) starts timing continuously; According to the date provided by the clock chip (27), calculate the solar declination and time difference of the day; Calculate real-time solar azimuth and altitude angles based on geographic longitude, latitude, time difference, and solar declination; If the altitude angle is greater than zero, it is judged as day, otherwise it is judged as night, and no tracking at night; Perform closed-loop control on the altitude angle and azimuth angle of the tracking device to eliminate tracking errors; the specific method is: First calculate the time difference and solar declination according to the date, and then calculate the altitude and azimuth angle of the sun at that time by combining the local longitude and latitude, so as to determine the position of the sun and distinguish between day and night; Time difference and solar declination adopt look-up table interpolation or function fitting method, where the function fitting algorithm is: Then the day's time difference δ and solar declination σ are respectively: $\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 229.18</span>}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 75</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 186.8</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 32077</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 14615</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 40890</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}{\mathrm{<span\; class="notranslate">\; 1000000</span>}}$ $\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 180</span>}<span\; class="notranslate">\; [</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6918</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 399912</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 70257</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 6758</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 907</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2697</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1480</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}{\mathrm{<span\; class="notranslate">\; 10000000</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}}$ In the formula, the working day is the D-th day after counting from January 1, and the intermediate amount X is set as: $\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 365</span>}}$ The solar hour angle Ω is: Ω=(CT+CL+δ-12)×15°, In the formula, CT is the current time, CL is the longitude correction, 1 degree/4 minutes, and δ is the time difference of the day; According to the solar hour angle Ω, solar declination σ and latitude , the north latitude is positive and the south latitude is negative; calculate the solar altitude angle α, the angle between the sun’s rays and the ground plane, and the solar azimuth β, starting from the true north direction and going along When the hour hand rotates to the angle of the sun's rays, it has a certain effect on the vast area from the equator in the south to the Arctic Circle in the north. sinα＝sinsinσ+coscosσcosΩ

Judging day and night by the value of the altitude angle, in order to find the sunrise time and sunset time of the local day, let the altitude angle α be equal to zero, there is cos[(CT+CL+δ-12)×15°]=-tantanσ, CT There are two solutions, the one less than 12 is the sunrise time, and the one greater than 12 is the sunset time, so the expected position of the sun can be obtained from the sun altitude angle α and the sun azimuth angle β; The single-chip microcomputer (25) compares the actual tracking position fed back by the sun's expected position with the altitude sensor (3) and the azimuth sensor (17), and draws the tracking error to output a control signal to control the altitude angle drive motor (9) and the azimuth Angle drive motor (14) runs, and light-receiving panel (22) is perpendicular to sunlight.

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