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Author ：Iflowpower – Portable Power Station Supplier
1. Foreword accompanied by increasingly serious energy crises, the development and utilization of renewable resources becomes a key object of people's research. Solar energy is stood out in its universal, long-term, safe and other advantages.
At present, solar energy has been used in a number of fields, such as battery sectors, but there is a problem that is not high in utilization. There are many cases, and the panel is either installed into a fixed angle, or only according to the fixed angle, no The sun light is fully illuminated on the battery board and reduces the utilization of solar energy. 2.
The design principle design is designed to track the sun source. The whole machine includes: solar panel, power management circuit, optical tube, single chip, motor drive circuit, stepper motor, and mechanical rotation platform. The system structure is shown in Figure 1.
According to Figure 2, the system working principle is installed on the intermediate position of the solar cell edge, and the angle of the two photoelectric tubes is irradiated to the side of the battery panel according to the sunlight (as shown in the figure.α,βNot equal, so that the light intensity of the photoelectric tube 1, 2 differs from the optical current of the size, the optical current is converted into a voltage signal, and the step motor is rotated in the direction of the voltage to the voltage. 3.
System hardware design 3.1 Optical intensity acquisition circuitry uses a 3DU33 photoelectric tube having a high sensitivity as a light intensity detecting device, and its photocurrent is greater than 2 mA, and the emitter can be collected by a small electric resistance to obtain a voltage. Moreover, its response time "1 ms, the reaction speed is fast.
It should be noted that under strong light, the photocurrent is large. At this time, the photoelectric tube emitter resistance should not be too large [2], otherwise the respective photoelectronic output voltages tend to 5V, the system cannot detect two optical tubes of the opposite side. The output voltage is poor.
In this design, R1 uses 330ωUnder the winter irradiation in winter, the output voltage has reached 3.6V.3.
2 Stepper motor design using the 5-line four-phase slowing step motor 28Byj-48, the deceleration ratio is 1: 64, the bellral angle is 5.625°/ 64=0.08789°It is far less than a stepper motor without a deceleration ratio, which is a good choice to improve tracking accuracy.
Regarding the four-phase step into the motor, its mode of work can be divided into single 4 shots, double 4 shots, 8 shots three work methods. Single 4 shots are equal to the step angle of the double 4 shots, but the rotational momentum of single 4 is small. 8 Take a walking angle of the work mode is half a single 4 shot and double 4 shots, so 8 shots can maintain high rotational moments and improve control accuracy.
The design uses 8 shots working, then 1 shot has a turn angle is 0.08789°/2=0.043945°Further improve tracking accuracy.
3.3 Power Management Circuits In order to enable the system to operate normally in the outdoor, the power supply is designed to power the system. When the output power of the solar panel is not enough, power is powered by the lithium ion battery; when the lithium ion battery voltage is below 3.
5V, the solar panel charges the lithium ion battery; otherwise power by the solar panel. Test, the system is running normal time input power close to 2.5W (5V / 480mA).
Considering the weather and seasonal factors, it is generally required that the maximum output power of the panel is 3W. Therefore, it is designed to be in series with 8 solar cells (0.5V / 1.
2A) to obtain 4V / 1.2A (maximum output 4.8W) output, Power supply to the system via DC-DC boost circuit.
4. System software design software flow chart As shown in Figure 3, the system is powered by coarse adjustment first to determine the approximate location of the sun source. The idea is: divide the horizontal plane into 12 regions, and sample the light intensity 8 times in each area, and accumulate preservation.
Enter the next area, sample 8 times and accumulate, compare the size of the adjacent area accumulated value, and turn the motor in the direction of the cumulative value, until the largest area of the accumulated value is found, indicating that the sun position is in this area Inside. After the coarse adjustment is completed, the system power supply is managed, and the solar panel voltage and lithium-ion battery voltage sampling are analyzed, and the correct pair of switches will be reasonably equipped with electrical energy. Micromondension Thoughts: Adjust the X direction, after completion, adjust the Y direction.
In order to obtain a smoother sampling data, the phototube is sampled for 64 times, and then the average of the average, the average value of the side photo pipe is compared, and the direction of rotation of the stepping machine is determined. The adjustment is completed until the two photoelectric tube sampling values in the x direction and the Y direction are equal, and the adjustment is completed. At this time, the source is at the center of the battery board.
5. Run the test test conditions: The light source is 105cm from the laser, the laser pen is installed in the center of the battery board, and the laser pen is deviated from the light source.±30°In the range.
The test results are shown in Table 1. 6. Conclusion Test results show that the light source is deviated from the light source±45°In the range, the system can locate the source within 9S, and the deviation is not more than 4cm.
When the actual application, the system keeps with the sun in real time, and there is no large angle of the sun suddenly deflecting the battery board, so the laser pen deviates from the light source distance. The deviation distance measured by this design does not exceed 4cm, and the design requirements are met.
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