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

Abstract

The invention discloses a sun tracking device and a sun tracking method based on tracking attitude feedback, wherein the device comprises a sensor and a motor, wherein a light receiving panel is electrically connected with a controller; the tracking method comprises the steps of calculating the solar declination and the time difference of the local current day by utilizing the longitude, the latitude and the date time, calculating the solar azimuth angle and the altitude angle in real time according to the longitude, the latitude, the solar declination, the time difference and the time, and realizing real-time tracking by utilizing closed-loop control; the device has simple structure, low cost, no error accumulation of the tracking method and less maintenance, and is suitable for unattended solar energy development in natural environment.

Description

Sun tracking device and tracking method based on tracking attitude feedback

Technical Field The present invention relates to the field of solar energy development automation, in particular to a solar tracking device and tracking method based on tracking attitude feedback.

BACKGROUND OF THE INVENTION With the shortage of energy in the world and the high price of oil, solar energy has been paid more and more attention as an inexhaustible free green energy. In order to improve the utilization efficiency of solar energy, it is necessary to make the sunlight incident as vertically as possible. The scientific and technological community has done a lot of work on sun tracking, and developed two sun tracking methods: active tracking based on sensing the direction of sunlight and passive tracking based on the law of the earth's orbit around the sun.

Active tracking such as "solar radiation tracking control device" (patent number 01217140.9, authorized announcement number CN2472151Y), passive tracking representative such as "micro power consumption timing sun tracking device" (patent number 02222766.0, authorized announcement number CN2562135Y). The former "solar radiation tracking control device" uses a pyramid-shaped photoelectric sensor to receive sunlight. When the sunlight is not perpendicular to the center of the pyramid-shaped photoelectric sensor, the output voltages of the four photovoltaic panels will be unequal. By comparison, the azimuth of the sun can be calculated, and then the stepping motor is controlled to drive the tracking device to align with the sun. The advantages are high precision, but the disadvantages are complex structure, high cost, and large maintenance. Accuracy, using multiple modules such as heating wires, temperature sensors, optical radiation detectors, four-quadrant detectors, and positioning sensors; the latter "micro-power timing sun tracking device" is passive tracking, using the sun's azimuth angle of 15 degrees/hour According to the law, the azimuth angle of the sun panel is driven to rotate synchronously, and the single-axis tracking control is performed from 9:00 to 18:00. The structure is simple, but the disadvantage is that the tracking error is large and the utilization rate of solar energy is low. Dual-axis tracking, without considering longitude and latitude factors, is not suitable for large-scale promotion, has no day and night distinction function, and has low solar energy utilization efficiency. In addition, stepper motors are generally used for driving in the prior art, and photoelectric sensors are generally used for positioning devices, which are expensive and have poor ability to resist environmental interference.

The field of civil solar energy pursues a high level of automation, less maintenance, and lower costs. The current active tracking is expensive because it involves photoelectric sensors, and it is easily affected by dust and light pollution. It requires a lot of maintenance and is not suitable for the field of civil solar energy; Tracking devices are all driven by stepping motors, using high-precision traditional systems, and the cost is high. At the same time, the time difference and the inhomogeneity of the sun's declination change (caused by the eccentricity of the earth's orbit around the sun), and the longitude and latitude are not considered. There is still a big gap from large-scale promotion.

SUMMARY OF THE INVENTION The purpose of this invention is to address the defects of domestic and foreign solar trackers, and propose a new type of passive tracking device, that is, a solar tracking device and a tracking method based on tracking attitude feedback, so as to reduce the cost of the sun tracking device, reduce the amount of maintenance, and meet the Demand in the field of civil solar energy.

The principle of the present invention is: use the single-chip microcomputer to accurately calculate the time difference of the day (the difference between the true solar time and the mean solar time) and the solar declination (the latitude of the direct sun point) according to the date, and then combine the local longitude and latitude to accurately calculate the current altitude of the sun Angle and azimuth, to determine the position of the sun, to distinguish between day and night.

The time difference and solar declination are periodic functions of the date, and the period is one year, which can be looked up in the table. In order to achieve higher calculation accuracy, look-up table interpolation or function fitting methods can be used. The following is a typical function fitting algorithm:

The working day is the day D after counting from January 1. For convenience, let the middle amount X be

$\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 365</span>}}$

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>}}$

The present invention utilizes time difference, longitude and the current moment to calculate the solar hour angle Ω (the angle that turns after the longitude where the sunlight directly shines on the tracking device is called the solar hour angle), and its size 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 the day.

The present invention calculates the solar altitude angle α (the angle between the sun's rays and the ground plane) and the solar azimuth angle β (from the true north direction) through the solar hour angle Ω, the solar declination σ and the latitude  (the north latitude is positive, and the south latitude is negative). start, rotate clockwise to the angle of the sun's rays), then for the vast area from the equator in the south to the Arctic Circle in the north, there is

sinα＝sinsinσ+coscosσcosΩ

The present invention judges day and night by the value of the altitude angle. In order to find the sunrise and sunset times of the local day, let the elevation angle α be equal to zero, there is cos[(CT+CL+δ-12)×15°]=-tan tanσ, CT has two solutions, and the one less than 12 It is the sunrise time, and the solution greater than 12 is the sunset time.

The single-chip microcomputer compares the expected position of the sun with the actual tracking position fed back by the attitude sensor, and obtains the tracking error. According to the control algorithm, the control signal is output to control the operation of the DC motor, and the error is reduced to zero under closed-loop control to realize dual-axis tracking. The single-chip microcomputer recalculates the sun position every once in a while, and performs a new round of tracking, and the length of the interval can be set by the keyboard circuit to the single-chip microcomputer. The attitude sensor is composed of capacitive sensors, in which the altitude angle is obtained by a differential capacitive sensor, and the azimuth is obtained by a three-lobed capacitive angle sensor. Tracking is performed during the day and stopped at night.

The technical solution of the present invention is: a sun tracking device based on tracking attitude feedback, comprising a light-receiving panel, a sensor electrically connected to a controller, and a motor, characterized in that:

The light-receiving panel is connected with the support rod and the height angle adjustment rod through the hinge, the other end of the support rod is connected with the column, and the other end of the height angle adjustment rod is placed in the inner cavity of the column;

The sensor is an altitude sensor and an azimuth sensor, and the altitude sensor is a differential capacitive sensor. The capacitive plate and the fixed plate of the differential capacitive sensor are respectively placed on the other end of the altitude adjustment rod and the inner cavity wall of the column. , the azimuth sensor is a three-lobe capacitive angle sensor, and the capacitive dynamic plate and the fixed plate of the three-lobe capacitive angle sensor are respectively placed on the outer wall and the shell at one end of the column;

The motor is an altitude angle drive motor and an azimuth angle rotation motor. The altitude angle drive motor is fixed on the bracket, and the bracket is fixed on the column. The output shaft of the altitude angle drive motor is decelerated by the reducer and meshed with the worm wheel through the worm, and the worm gear drives the gear coaxially. The gear is connected with the rack on the other end of the height adjustment rod placed in the inner cavity of the column, the azimuth driving motor is fixed on the base, and the output shaft of the azimuth driving motor is decelerated by the reducer and fixed on the column through the pinion The large gear on the coaxial connection;

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

The PC0~PC7 ports of the MCU are electrically connected to the keyboard, the PD2~PD4 ports of the MCU are respectively connected to the RST, SCLK, and I/O pins of the clock chip, and the PD5~PD7 ports of the MCU are respectively connected to the CS, The DATA pin is electrically connected.

As a further improvement to the prior art, the model of the single-chip microcomputer 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 the tracking attitude feedback includes converting the analog signal of the sensor received into a digital signal, and then converting it into an analog value after processing it to push the motor, which is characterized in that:

After the system is initialized, the clock chip starts to count continuously;

According to the date provided by the clock chip, 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 beneficial effect of the present invention relative to prior art is:

One, the sun tracking device in the present invention is mainly made up of single-chip microcomputer, capacitive sensor and DC motor, does not use photoelectric sensor and stepping motor with respect to prior art " micro-power consumption timing sun tracking device ", illustrates the tracking device structure of the present invention Simple, low cost and low maintenance.

Second, the sun tracking device in the present invention belongs to dual-axis tracking, which can track the sun azimuth and altitude angle. Compared with the prior art "micro power consumption timing sun tracking device", the single-axis tracking of the sun azimuth has high precision .

Third, "the sun tracking device of the present invention has an azimuth angle sensor and an altitude angle sensor, adopts a capacitive sensor to realize device tracking attitude feedback, and uses a DC motor to drive. Because there is a feedback link and no error accumulation, the range of motor selection is large.

Its four, the tracking method of the present invention is because the single-chip microcomputer compares the actual tracking position that the expected position of the sun and the sensor feedback come back, draws the tracking error, outputs the control signal according to the control algorithm, controls the operation of the DC motor, and can reduce the error under closed-loop control. Reduced to zero for dual-axis tracking.

Its five, the tracking method of the present invention is a comprehensive horizontal coordinate system follow-up method, because the single-chip microcomputer has accurately calculated all factors necessary for determining the sun position: time difference, solar declination, longitude, latitude, then the present invention has considered time difference, solar declination The inhomogeneity of latitude change throughout the year avoids the calculation error that the sun declination change is approximated as a uniform speed without considering the time difference in the passive tracking technology of the prior art; because the tracking algorithm of the present invention considers longitude and latitude factors, through Set the longitude and latitude values, which can be applied to a wide range of areas compared with the existing technology;

The tracking method of the present invention can also judge the time of sunrise and sunset every day, start tracking at sunrise and stop tracking at sunset, has the ability to distinguish day and night, and can run fully automatically for a long time, avoiding the passive tracking of the prior art, from 9 Single-axis tracking control from 18 o'clock to 18 o'clock has the disadvantages of large tracking error and low solar energy utilization rate. In addition, the differential capacitance ratio is used in the method to resist interference caused by weather changes.

Description of drawings

Fig. 1 is the structural representation of the specific embodiment of device of the present invention;

Fig. 2 is the circuit diagram of the embodiment of the device of the present invention;

Fig. 3 is a structural diagram of the elevation angle adjustment rod lifting mechanism of the specific embodiment of the device of the present invention;

Fig. 4 is the time difference variation curve of the embodiment of the method of the present invention;

Fig. 5 is the solar declination variation curve of the specific embodiment of the method of the present invention;

Fig. 6 is a working principle diagram of a cylindrical capacitive sensor according to a specific embodiment of the device of the present invention;

7 is a structural diagram of a differential cylinder capacitive sensor according to a specific embodiment of the present invention;

Fig. 8 is a structural diagram of a three-lobe capacitive angle sensor according to a specific embodiment of the device of the present invention;

Fig. 9 is a schematic diagram of a circuit of a three-lobe capacitive angle sensor according to a specific embodiment of the device of the present invention;

Fig. 10 is a flow chart of the tracking method of the device of the present invention in a specific embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be further described below in conjunction with the accompanying drawings:

In Figure 1, 1 is the hinge, 2 is the height angle adjustment rod, 3 is the height angle sensor, 4 is the rack, 5 is the worm gear, 6 is the worm, 7 is the gear, 8 is the reducer, 9 is the height angle drive motor, 10 is a bracket, 11 is a controller, 12 is a small gear, 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 large gear, 19 is a column, 20 is a slide block, 21 is a support rod, and 22 is a light receiving panel.

The device is a vertical cylinder structure. The light receiving panel 22 is connected to the height angle adjustment rod 2 and the support rod 21 respectively through two upper and lower hinges 1. The height angle adjustment rod 2 can move up and down in the column 19 to adjust the height of the light receiving panel 22. Angle, the capacitive dynamic pole plate of altitude angle sensor 3 and fixed pole plate are respectively placed on the outer wall of height angle adjusting rod 2 and the inner wall of column 19, and the capacitive dynamic plate of azimuth sensor 17 is placed on the bottom outer wall of column 19. The output shaft of the altitude angle driving motor 9 acts as the worm screw 6 after being decelerated by the reducer 8, and drives the worm gear 5. The worm gear 5 and the gear 7 are coaxially linked, and the gear 7 is engaged with the rack 4 at one end of the altitude angle adjustment rod. The adjustment of the azimuth angle is realized by the pinion gear 12 of the azimuth drive motor 14 decelerated by the speed reducer 13 engaging the bull gear 18 on the column 19 .

In Fig. 2, 30 is the keyboard, 27 is the clock chip HT1380, 29 is the serial communication interface PD0 of the single-chip microcomputer 25, 28 is the serial communication interface PD1 of the single-chip microcomputer 25, 26 is the controller HT1621, 25 is the single-chip microcomputer AT90S4434, and 23 is Altitude angle drive motor control port, 24 is the azimuth angle drive motor control port.

The single-chip microcomputer 25 connects the altitude angle drive motor control port 23 and the azimuth angle drive motor control port 24 through PA0, PA1, the altitude angle sensor 3 is connected with the PA2, PA3 of the single-chip microcomputer 25, and the azimuth angle sensor 17 is connected with the PA4～PA6 of the single-chip microcomputer 25, and the control The device HT162112, the clock chip HT1380, and the keyboard are connected to the single-chip microcomputer 25 through PD5-PD7, PD2-PD4, PC0-PC7.

Figure 3 is a schematic diagram of the lifting structure of the height angle adjustment rod, which is a transmission mode of worm-worm gear-pinion-rack.

Fig. 4 is a graph showing the change of time difference at noon at 120 degrees east longitude. The abscissa in the figure is the number of days, and the ordinate is the time difference. The time difference in a year increases with the number of days.

Figure 5 is a map of solar declination changes. The abscissa in the figure is the number of days, and the ordinate is the declination of the sun. When the number of days in a year changes to 150, the declination rises to the peak with the curve, and then the curve begins to decline. This shows that the variation curve of solar declination is not uniform in a year, and it is approximated as a linear variation in traditional technology, resulting in a large tracking error.

Figure 6 is a schematic diagram of the working principle of the cylindrical capacitive sensor, and the capacitance value is proportional to the relative area of the two plates.

Fig. 7 is a structural diagram of a differential cylindrical capacitive sensor. When the position of the height angle adjustment rod 2 changes, the two capacitors become larger/lower respectively, and the position of the height angle adjustment rod 2 relative to the column 19 can be calculated by using the ratio of the two capacitance values. The interference caused by weather changes can be resisted by using the differential capacitance ratio method.

Figure 8 is a three-lobed capacitive angle sensor. Three fixed plates form a circle in a symmetrical manner, and form three capacitors with the moving plate.

Fig. 9 is a circuit diagram of a three-lobe capacitive angle sensor. When the column 19 rotates, it drives the moving plate to rotate, causing the three capacitances to change. According to the ratio of the three capacitance values, the rotation angle of the column 19 can be calculated, that is, the azimuth angle of the light-receiving panel 22 .

Fig. 10 is a flow chart of the tracking control method.

The specific embodiment Utilizes keyboard 30 to set the required data when the system starts through PC0～PC7 ports of single-chip microcomputer 25: local longitude, latitude, date, dormancy period, RST, SCLK, I/O port of clock chip 27 are electrically connected to single-chip microcomputer 25 PD2～PD4 ports, after acquiring the time from the single-chip microcomputer 25, start uninterrupted timing, and the device starts up and enters into a fully automatic working state. After the device starts, the single-chip microcomputer 25 reads the timing of the clock chip 27, combines the longitude and latitude values stored in the memory, calculates the time difference and solar declination of the day, and then calculates the altitude and azimuth of the sun at that time, and calculates the local sunrise on the same day. Time and sunset time, if the current time is night, the program waits in a loop, if it is daytime, the system will track.

After the tracking starts, the single-chip microcomputer 25 reads the electrical signals of the altitude sensor 3 and the azimuth sensor 17, wherein the altitude sensor 3 utilizes the differential capacitance to perceive the position of the altitude adjustment rod 2 relative to the column 19, and the azimuth sensor 17 passes through the three-lobe The fixed plate perceives the azimuth of the column 19 attached to the moving plate, and the single-chip microcomputer 25 utilizes the A/D conversion function of the PA port to realize the analog/digital conversion of the elevation angle and the azimuth electrical signal; the analog/digital port of the single-chip microcomputer 25 Respectively electrically connected with the altitude sensor 3 and the azimuth sensor 17; the single-chip microcomputer 25 calculates the difference between the sun and the solar panel 22 in the altitude angle and the azimuth angle, respectively utilizes the PID algorithm to calculate the control signal, and passes through the single-chip microcomputer after digital/analog conversion The PA0 and PA1 ports of 25 input the control signal into the signal interface control port 23 of the elevation angle drive motor and the control port 24 of the azimuth drive motor in time division.

The altitude driving motor controls the altitude adjusting rod 2 to move to the corresponding position to realize the height adjustment of the light receiving panel 22; the azimuth driving motor controls the column 19 to rotate to the corresponding position to realize the azimuth adjustment of the light receiving panel 22.

DATA端口，将当前时钟、经度、纬度分时输入控制器26，实现对外显示。The single-chip microcomputer 25 is electrically connected to the HT1621 controller 26 through the PD5-PD7 port

The DATA port is used to input the current clock, longitude and latitude into the controller 26 in time-sharing to realize external display.

Referring to Fig. 10, the tracking method and working process of the sun tracking device based on tracking attitude feedback are as follows: after power-on and starting, the single-chip microcomputer AT90S4434 starts the internal program, waits for the keyboard 30 to input commands, and the operator sets the initial value to the single-chip microcomputer 25 through the keyboard 30, Including the local longitude, latitude, date, time, delay time (step 100); then in step 110, the clock chip HT1380 starts uninterrupted timing after obtaining the initial value from the single-chip microcomputer 25, and the HT1621 controller 26 continuously displays the current clock, Longitude, latitude; In the step 120, the single-chip microcomputer 25 calculates the solar declination and time difference of the day according to the date; In the step 130, the single-chip microcomputer 25 calculates the sun azimuth and the altitude angle in real time according to the longitude, latitude, time difference, solar declination; In the step 140, the single-chip AT90S4434 judges Whether the elevation angle is greater than zero, if it is less than zero, then proceed to step 150, and proceed to step 120 after a specific time delay; if it is judged that the elevation angle is greater than or equal to zero, then proceed to step 160, perform closed-loop control, and realize real-time tracking, then Delay for a specific time (step 170), and turn to step 130 after the delay is completed.

The tracking device is maintained every six months. During maintenance, the operator restarts the system and resets the system clock and local longitude and latitude.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (4)

1. A sun tracking device based on tracking posture feedback comprises a light receiving panel (22), a sensor electrically connected with a controller (26) and a motor, and is characterized in that:

1.1, the light receiving panel (22) is connected with a support rod (21) and a height angle adjusting rod (2) through a hinge (1), the other end of the support rod (21) is connected with an upright post (19), the other end of the height angle adjusting rod (2) is connected with a sliding block (20), and the sliding block (20) is arranged in an inner cavity of the upright post (19);

1.2, the sensors are an altitude angle sensor (3) and an azimuth angle sensor (17), the altitude angle sensor (3) 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 the altitude angle adjusting rod (2) and on the inner cavity wall of the upright post (19), the azimuth angle sensor (17) 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 (19) and on the inner wall of the shell;

1.3, the motors are an elevation angle driving motor (9) and an azimuth angle driving motor (14), the elevation angle driving motor (9) is fixed on a support (10), the support (10) is fixed on an upright post (19), an output shaft of the elevation angle driving motor (9) is decelerated by a reducer (8) and then meshed with a worm gear (5) through a worm (6), the worm gear (5) coaxially drives a gear (7), the gear (7) is connected with a rack (4) arranged at the other end of an elevation angle adjusting rod (2) in an inner cavity of the upright post (19), the azimuth angle driving motor (14) is fixed on a base (15), and an output shaft of the azimuth angle driving motor (14) is decelerated by a reducer (13) and then coaxially connected with a large gear (18) fixed on the upright post (19) through a small gear (12);

1.4, the controller is a singlechip (25), the A/D port of the singlechip (25) is respectively and electrically connected with the altitude angle sensor (3) and the azimuth angle sensor (17), the D/A port of the singlechip (25) is respectively and electrically connected with the altitude angle drive motor control port (23) and the azimuth angle drive motor control port (24):

PC 0-PC 7 ports of the single chip microcomputer (25) are electrically connected with a keyboard (30), PD 2-PD 4 ports of the single chip microcomputer (25) are respectively and electrically connected with RST, SCLK and I/O pins of a clock chip (27), PD 5-PD 7 ports of the single chip microcomputer (25) are respectively and electrically connected with the controller (26)

The DATA pin is electrically connected.

2. The sun tracking device based on tracking attitude feedback according to claim 1, wherein 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, wherein the controller (26) has a model HT1621 and the clock chip (27) has a model HT1380.

4. The tracking method of sun tracking device based on tracking attitude feedback according to claim 1, comprising converting the received analog signal of the sensor into digital signal, processing it and converting it into analog signal to drive the motor, characterized in that:

after the system is initialized, the clock chip (27) starts uninterrupted timing;

calculating the solar declination and the time difference on the same day according to the date provided by the clock chip (27);

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, the judgment is daytime, otherwise, the judgment is night, and the tracking is not carried out at night;

carrying out closed-loop control on the elevation angle and the azimuth angle of the tracking device to eliminate tracking errors; the specific method comprises the following steps:

firstly, solving the time difference of the day and the declination of the sun according to the date, and then calculating the elevation angle and the azimuth angle of the sun at that time by combining the local longitude and latitude to determine the position of the sun and distinguish the day and night;

the time difference and the solar declination adopt a table lookup interpolation or function fitting mode, wherein the function fitting algorithm is as follows:

the time difference delta of the day, the solar declination sigma are respectively:

in the formula, the day of the working day is day D after the time is counted from day 1/month, and the intermediate amount X is set as:

the solar hour angle Ω is: Ω = (CT + CL + δ -12) × 15 °,

in the formula, CT is the current time, CL is longitude correction, 1 degree/4 minutes, and delta is the time difference of the current day;

through the solar hour angle omega, the solar declination sigma and the latitude \58388, the north latitude is positive and the south latitude is negative; calculating the solar altitude angle alpha, the included angle between the solar ray and the ground plane and the solar azimuth angle beta, starting from the north direction, clockwise rotating to the angle of the solar ray projection, and then aiming at the wide areas from the south to the north polar circle, including

sinα＝sinsinσ+coscosσcosΩ

Judging day and night according to the value of the altitude angle, and in order to obtain the sunrise time and the sunset time of the local day, making the altitude angle alpha equal to zero, wherein cos [ (CT + CL + delta-12) × 15 ° ] = -tan \58388andtan σ, the CT has two solutions, the sunrise time is less than 12, the sunset time is greater than 12, and the sun expected position is obtained by the sun altitude angle alpha and the sun azimuth angle beta;

the single chip microcomputer (25) compares the expected position of the sun with the actual tracking position fed back by the altitude sensor (3) and the azimuth sensor (17) to obtain a tracking error so as to output a control signal, and controls the operation of the altitude driving motor (9) and the azimuth driving motor (14) to enable the light receiving panel (22) to be perpendicular to the sunlight.

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