CN204347620U - A kind of single shaft photovoltaic sun tracking system - Google Patents

Abstract

The utility model provides a single-axis photovoltaic solar tracking system, which uses a single-chip microcomputer as the control core, uses a photosensitive resistor to sense the light intensity and then controls the positive and negative rotation of the motor to ensure that the photovoltaic panel is always under the maximum light intensity. The charging efficiency can maximize the power generation efficiency of photovoltaic panels. In addition, parameters such as time, power generation and storage capacity of the battery are displayed in real time on the LCD display, which enhances the stability of the entire system and the ability to adapt to the environment, and prolongs the service life. Therefore, the single-axis photovoltaic solar tracking system of the present invention fully embodies the concept of energy saving and environmental protection, and has good social and economic benefits. As more and more places use solar energy as clean energy, the improvement of solar energy conversion rate and its charging efficiency needs to be improved, and the application prospect of the utility model is very broad.

Description

A single-axis photovoltaic solar tracking system

technical field

The utility model belongs to the field of energy technology, in particular to a single-axis photovoltaic solar tracking system.

Background technique

With the continuous growth of the world's population and the continuous development of the economy, the demand for energy supply is increasing day by day. However, in the current energy consumption structure, fossil fuels such as coal, oil and natural gas are still dominant. According to the latest world energy survey report, fossil fuels can only be used for about 200 years at most, while solar energy is clean energy and is inexhaustible and inexhaustible compared to fossil fuels, which can effectively alleviate the energy crisis. will occupy a dominant position in the world's energy structure. Therefore, photovoltaic power generation technology is an important part of new energy technology. With the improvement of people's awareness of renewable energy, the development and application prospects of solar energy resources will be very broad.

However, in the existing photovoltaic power generation devices, the traditional single-axis system has problems such as low power generation, complex structure, large footprint, difficult maintenance, and low solar energy utilization rate. Moreover, the dual-axis system tracking of the single-axis photovoltaic solar tracking system needs to control two variables at the same time. The complicated control reduces the reliability of the system operation and increases the cost.

Utility model content

In order to solve the above technical problems, the utility model provides a single-axis photovoltaic solar tracking system, which uses a single-chip microcomputer as the control core, uses a photosensitive resistor to sense the light intensity and then controls the positive and negative rotation of the motor to ensure that the photovoltaic panel is always under the maximum light intensity. At the same time, the charging efficiency of the battery is improved through MPPT technology to maximize the power generation efficiency of photovoltaic panels. In addition, parameters such as time, power generation and storage capacity of the battery are displayed in real time on the LCD display, which enhances the stability of the entire system and the ability to adapt to the environment, and prolongs the service life.

The single-axis photovoltaic solar tracking system of the present utility model includes six structures: a single-chip microcomputer control system, a rotating motor, an MPPT controller, a storage battery, an LCD display screen, and a photovoltaic panel;

The single-chip microcomputer control system uses the mathematical model of the sun's altitude and azimuth to calculate the sun's position, and combines the relationship between the light intensity received by the automatic tracking sensor and the specified value of the system to issue commands to control the rotation of the rotating motor;

The rotating motor rotates according to the instructions of the single-chip control system to rotate and adjust the photovoltaic panel, so that the photovoltaic panel is aligned with the sun to track it;

The storage battery is used to store the electric energy generated by the photovoltaic panel. When it needs to be used, the single-chip control system controls the battery to supply the stored electric energy to the user;

Photovoltaic panels, the rotating motor enables the photovoltaic panels to receive sunlight in the best position, and convert solar energy into electrical energy, part of which is supplied to users for direct use, and the other part is stored in the battery;

The MPPT module adopts the combination of the disturbance observation method P&O and the constant voltage control method CVT to improve the system power;

LCD display for displaying date, power generation and storage power.

Further, the automatic tracking sensor is set to work intermittently, and a tracking detection is started every 5 minutes.

Furthermore, the bracket of the single-axis photovoltaic solar tracking system is divided into three parts: the base, the main beam and the photovoltaic system, and the three parts are detachable and connected by bolts.

Further, the north-south angle and the east-west angle of the photovoltaic panel are adjustable, the north-south angle is adjusted according to the season, and the east-west angle is adjusted according to the rotation of the sun.

The effect is better. The east-west rotation system of the photovoltaic panel adopts a thickened steel ball universal turntable, and the universal turntable is the connecting part of the rotating sofa or rotating wardrobe.

Further, the automatic tracking sensor includes: a photosensitive module, a single-chip microcomputer module, a clock chip module, a drive module and a branch motor; the automatic tracking sensor has two modes, one is the mode of automatically judging the external light intensity. When the light is strong, a tracker composed of a photoresistor is used to track in real time, and the other is a timing drive mode, which uses a clock module to drive regularly when the light is weak, and the two modes can be switched in real time.

Furthermore, the single-axis photovoltaic solar tracking system also includes a backup power supply. When the battery cannot meet the power supply demand, the power switch will automatically switch to the backup power supply.

The beneficial effects of the utility model are:

The single-axis photovoltaic solar tracking system of the utility model has the advantages of simple structure, low cost, easy maintenance, strong compatibility and high reliability.

The single-axis photovoltaic solar tracking system of the utility model is a new low-cost MPPT control single-axis linkage solution, which can realize dual-axis effects under single-axis conditions, maximize solar power generation efficiency, and improve battery charging efficiency.

The single-axis photovoltaic solar tracking system of the utility model can promote the continuous improvement and development of photovoltaic power generation devices, and achieve the purposes of protecting the environment, saving resources and reducing pollution.

The single-axis photovoltaic solar tracking system of the utility model fully embodies the concept of energy saving and environmental protection, and has good social and economic benefits. As more and more places use solar energy as clean energy, improving the conversion rate of solar energy and its charging efficiency needs to be improved, and the application prospect of the utility model is very broad.

The utility model achieves stable tracking of the maximum power point, solves the problems of large precision difference and imprecise algorithm, etc., enables the MPPT controller to track the maximum power point more quickly, and conducts accurate measurement through a small disturbance, effectively reducing the The oscillation near the maximum power point of the perturbation method is reduced.

Description of drawings

Fig. 1 is a schematic structural diagram of a single-axis photovoltaic solar tracking system of the present invention;

Figure 2a is a structural schematic diagram of a component of the bracket of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 2b is a structural schematic diagram of part 2 of the bracket of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 2c is a structural schematic diagram of the third part of the bracket of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 2d is a three-dimensional view of the bracket of the single-axis photovoltaic solar tracking system of the present invention;

Figure 2e is a schematic diagram of the bracket of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 3 is a schematic diagram of east-west direction rotation of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 4 is a schematic diagram of rotation in the north-south direction of the single-axis photovoltaic solar tracking system of the present invention;

Figure 5a is a schematic diagram of the celestial coordinate system of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 5b is a schematic diagram of the altitude angle α and the azimuth angle γ position of the sun in the sky in the celestial coordinate system of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 6 is a schematic diagram of the automatic tracking sensor of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 7 is a schematic diagram of the solar tracking process of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 8 is a schematic diagram of the power supply current of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 9 is a schematic diagram of the MPPT module of the single-axis photovoltaic solar tracking system of the present invention;

Fig. 10 is a schematic diagram of the average sunshine duration of four seasons in a day automatically by the single-axis photovoltaic solar tracking system of the present invention.

Detailed ways

The utility model includes six structures including a single-chip microcomputer control system, a rotating motor, an MPPT controller, a storage battery, an LCD display screen, and a photovoltaic panel. The overall design of the utility model is shown in Figure 1. The working mode of the single-axis photovoltaic solar tracking system is as follows:

1) When the sun disappears at night, the light intensity received by the automatic tracking sensor is less than the specified value of the system, and the single-chip microcomputer sends an instruction to control the motor to rotate the photovoltaic panel to the initial position, so as to ensure that the tracking of the photovoltaic panel starts when the sun rises the next day.

2) When the sun appears in the morning, the MCU starts to analyze whether the two sets of photoresistors of the automatic tracking sensor receive the same light. When the photoresistors receive the same light, it means that the photovoltaic panel is facing the sun. If they are different, the single-chip microcomputer system controls the motor to rotate and adjust the photovoltaic panel until it is aligned with the sun. Due to the relatively slow movement of the sun, the system is set to work intermittently and start tracking detection every 5 minutes. It can effectively realize the function of solar photovoltaic panels to automatically track the sun.

3) When the light is weak or covered by dark clouds, the single-chip microcomputer will drive the photovoltaic panel regularly to track the sun according to the information fed back by the photosensitive module. When the external light is restored, it can be switched from timing drive mode to automatic sun tracking mode again.

The storage battery storage system of the utility model is convenient for users. The electricity generated by the photovoltaic panels is directly supplied to the users, and the remaining electricity is stored in the storage batteries.

The bracket system refers to the structure of photovoltaic brackets in previous dynasties, analyzes their structural ideas, sums up the experience, then discards the rough and extracts the essence, introduces the old and brings forth the new, and proposes a detachable design scheme, which realizes the detachability between the base and the main beam, and the detachment between the main beam and the upper photovoltaic system. Removable between brackets. Past generations of photovoltaic power generation systems are composed of many scattered parts. After the goods arrive at the destination, installers need to assemble a large number of parts on site, resulting in long installation periods, high difficulty, high cost, and waste of manpower and material resources. Due to the detachability of the utility model, there are only three parts in the factory. After the actual product arrives at the destination, the installation and debugging can be completed by connecting the three parts with bolts, and the installation efficiency has been greatly improved. On the basis of ensuring stability, wind resistance, and flexibility, it also improves portability and installation efficiency. The scaffold structure is shown in Figure 2a to Figure 2e below.

As shown in Figure 3 and Figure 4, the design of the single-axis rotation system is divided into two parts, one is the angle adjustment in the north-south direction, and the other is the angle adjustment in the east-west direction. Realized the function of adjusting the north-south direction angle according to the season, and tracking the sun rotation in real-time in the east-west direction. The adjustment effect that can only be achieved by using a two-axis rotation system is achieved, the cost is effectively reduced, the circuit is simplified, and the economic benefit is greatly improved.

The east-west rotating structure of any photovoltaic solar tracking system is the core part of the bracket. The certification technical specifications of the China Quality Certification Center have put forward technical requirements in terms of wind resistance, earthquake resistance, and compression resistance for utility models. According to this requirement, the load requirement of the single-axis tracking device is 20kg/m ² , the tracking angle is 110°, and the maximum safe instantaneous wind speed is 140km/h. The east-west rotation system of the utility model adopts a thickened steel ball universal turntable, and the universal turntable is often used for large and heavy connecting parts such as rotating sofas and rotating wardrobes. Using this component, the load-bearing capacity can reach 200kg/m ² , which meets the technical requirements of wind resistance and earthquake resistance in the photovoltaic industry, and the rotation is smooth and stable, and the tracking angle is as high as 360°, and can be finely adjusted. Fig. 5a is a schematic diagram of the celestial coordinate system, and Fig. 5b is a schematic diagram of the altitude angle α and the azimuth angle γ position of the sun in the sky in the celestial coordinate system.

Assume that the distance between the location of the observation point and the center of the earth is r, and the length of AB is L. Point A is located at latitude φ, at 12:00 noon, AB is parallel to the Z axis, and is on the Z=0 plane. In the coordinate system, the coordinates of point A and point B are:

X(A1)=rcos(φ+δ), Y(A1)=0, Z(A1)=rsin(φ+δ)

X(B1)=rcos(φ+δ), Y(B1)=0, Z(B1)=rsin(φ+δ)+L

In the second coordinate system, the coordinates of point A and point B are respectively:

X(A2)=rcosφ, Y(A2)=0, Z(B2)=rsinφ

X(B2)=rcosφ+Lsin23.5°, Y(B2)=0, Z(B2)=rsinφ+Lcos23.5

According to the above calculation formula, the east-west rotation demand range of the utility model is locked at 135.5°, and the utility model design rotation range is 360°. It can be seen that the rotation system in the east-west direction can not only meet the rotation required for daily solar tracking power generation It can also intelligently adjust to an angle parallel to the wind direction when strong wind is detected, so as to achieve the purpose of wind resistance, stability and safety.

During the process of the earth revolving around the sun, by analyzing its orbit, the applicant found that from the perspective of earth observation, the latitude corresponding to the sun is different throughout the year. In order to increase the light receiving capacity of the photovoltaic panel, the north-south direction angle of the photovoltaic panel must be adjustable. This application has carried out theoretical calculations, assuming that there is a celestial sphere, which is an imaginary infinite rotating sphere centered on the earth, and other celestial bodies are imagined to be on the celestial sphere. The structure of the automatic tracking sensor is shown in Figure 6.

The north and south poles of the celestial sphere are aligned with those of the earth, and the celestial equator is on the same plane as the earth's equator. The right ascension line connects the north and south poles of the celestial sphere, and the right ascension angle (χ) at the spring equinox is defined as 0°. At this time, the sun is directly above the earth's equator. The right ascension angle is from the vernal equinox along the celestial equator from west to east from 0 hours to 24 hours, and its units are hours, minutes, and seconds. After dividing the 360° of a week into 24 parts on average, we can know that 15° of them is equal to 1 hour. The declination angle (δ) on the celestial sphere is similar to the concept of the earth's latitude. It is the projection of latitude on the celestial sphere. Its unit is degree, and the range is between -90° and +90°. The declination angle of the celestial equator is 0 degrees, the degree of declination in the northern hemisphere is a positive number, and the degree of declination in the southern hemisphere is a negative number. The earth has always been revolving around the sun. From the perspective of the celestial coordinate system, it is like the sun revolving around the earth on the ecliptic plane, and its trajectory plane forms an inclination angle of 23.45° with the celestial equator plane. Its declination ranges from -23.45°<δ<23.45°. On the winter solstice, δ=-23.45°, on the summer solstice, δ=23.45°, on the spring and autumn equinoxes, δ=0° ^[4] .

According to the previous research and analysis, it can be concluded that the best installation angle of photovoltaic panels in various domestic cities is between 20° and 50°. In our utility model, the inclination angle in the north-south direction can be adjusted between 15° and 55°, as shown in Fig. 5 . It can be seen that our utility model meets the needs of all cities and regions in China.

The structural block diagram of the automatic tracking sensor is shown in Figure 6, which is mainly composed of a photosensitive module, a single-chip microcomputer module, a clock chip module and a drive module. Its working method is mainly to judge the light intensity through the photosensitive module, then transmit the signal to the single-chip microcomputer for processing, and drive the motor after processing by the single-chip microcomputer, so as to realize the function of tracking the sun and make the solar energy absorbed by the photovoltaic panel reach the maximum value. When the light signal comes in, there will be a period of delay, and the photosensitive module will make a second judgment. If the next signal is the same, the program will be executed, and if it is different, it will not be executed, effectively avoiding the problem of accidental short-term light drive system.

When the four photoresistors are affected by the natural light of the environment at the same time, if the light intensity is different, the resistance will change, so the voltage between the left and right photosensitive elements will also change accordingly, and at the same time, the voltage value between the left and right photosensitive resistors will be given to the positive phase input terminal. A 100k series resistor voltage is given to the inverting input terminal, and the high and low levels are compared by the LM358 comparator to drive the motor through the processing of the single-chip microcomputer, so as to realize the automatic light-aligning function of the photovoltaic panel. The solar tracking process of the utility model is shown in Figure 7 below.

The block diagram of the overall circuit structure of the system power supply is shown in Figure 8, which is mainly composed of photovoltaic panels and batteries. It can effectively guarantee the power supply of the tracking rotation mechanism, motor drive mechanism and MPPT controller. In order to ensure the stability of the power supply, a backup power supply with a specification of 200V/50HZ AC is added to the power supply. It uses the LS01-15B12S power module to rectify the mains and output 12V DC. When the battery cannot meet the power supply demand, the power switch will Automatically switch to the backup power supply to ensure the stability of the system and the reliability of the power supply.

The design of each module circuit of the hardware circuit has been completed, and the overall circuit board is welded after the test.

In order to improve the efficiency of solar energy absorption and utilization, we introduce maximum power point tracking technology (MPPT), which can effectively improve the output efficiency of solar panels. Based on this original basis, we designed a comprehensive maximum power point tracking circuit: using a combination of disturbance and observation method (P&O) and constant voltage control method (CVT) ^[7] to further increase the power, Make the final efficiency increase by 20%-30%. The MPPT module process is shown in Figure 9.

In the circuit design, the disturbance observation method and the constant voltage control method are used to achieve stable tracking of the maximum power point, which solves the problems of large accuracy difference and imprecise algorithm, so that the MPPT controller can track the maximum power point faster, and through A small amount of disturbance is used for accurate measurement, which effectively reduces the oscillation near the maximum power point of the disturbance method.

Taking the existing fixed type and the existing single-axis tracking as a reference, and based on the geographical solar movement azimuth ^[8] , the utility model single-axis automatic one-day average sunshine duration in four seasons is analyzed, as shown in Figure 10.

As can be seen from the analysis in Figure 10, since the photovoltaic panels are fixed for fixed tracking, the sunshine time is determined by the natural geographical climate, the utilization rate of solar sunshine is very small, the solar energy absorbed by the photovoltaic panels is small, and the power generation is small; although the single axis can be tracked, it can only The east-west direction is controlled, and the angle cannot be adjusted, so the utilization rate of solar sunlight is still very low, and the power generation efficiency is low. Our utility model can achieve all-round tracking, maximize the angle of sunlight irradiation, and have high power generation efficiency. And in the process of charging the accumulator, the utility model provides an additional power utilization rate of about 30% compared with the common "three-stage" charging method.

Take a 75kW photovoltaic solar power generation system as an example. We compare the economic benefits of different tracking methods with our utility model, as shown in Table 1.

Table 1

Note: The annual saving of electricity costs refers to the electricity charging standard for ordinary residents in Wuhan: 0.87/kwh. Assuming that a 2 MW system uses our utility model in its entirety, the benefits are as follows:

1) Power saving: Using our utility model can produce 2.7733 million kilowatt-hours of electricity every year, resulting in greater economic benefits, saving resources and protecting the environment.

2) Coal saving: According to the use of the utility model, 2.7733 million kilowatt-hours of electricity can be generated every year, and 1.1204 million tons of coal can be saved. 2773300kw h × 0.404kg/kw h = 1.1204 million tons.

3) Emission reduction: Using our utility model, 1.1204 million tons of coal can be saved every year, which can reduce carbon dioxide emissions by 1.1204 million tons*2.66=2.9802 million tons, and sulfur dioxide emissions by 1.1204 million tons*8.46%=94,800 tons.

It can be calculated that if our power generation device is used, it can generate the greatest economic benefits, save resources and protect the environment.

In summary, the innovations of the utility model are as follows:

1) The utility model adopts a single-axis device. Compared with the existing single-axis and fixed axis, it can track sunlight at a larger angle to maximize solar radiation and high power generation efficiency; compared with double-axis, it does not need to have two An independent power actuator, simple control system, low design cost, long service life, good maintainability and high economic benefits.

2) The angle can be adjusted in real time. In different places, the angle of direct sunlight is different. We use the mathematical model of the sun's altitude angle and azimuth angle to calculate the sun's orientation under this condition, so that the photovoltaic system is oriented to the best sunlight. The position is effectively tracked, so that the solar photovoltaic panels can always absorb the maximum sunlight intensity, greatly increasing the photovoltaic power generation capacity and improving the power generation efficiency of the system.

3) The maximum power tracking method (MPPT). Due to the high cost and low conversion efficiency of photovoltaic cells, and its output power is easily affected by factors such as light intensity and battery temperature, in order to improve the efficiency of photovoltaic systems, we designed The utility model system tracks the maximum power point of the photovoltaic cell in real time, so that the output power of the photovoltaic cell is always at the maximum.

But the above-mentioned person is only the preferred embodiment of the present utility model, and all the professionals who are familiar with this skill. After understanding technical means of the utility model, can change under the teaching of the utility model according to actual needs naturally. Therefore all equivalent changes and modifications made according to the patent scope of the utility model should still belong to the scope covered by the utility model patent.

Claims (7)

1. A single-axis photovoltaic solar tracking system, characterized in that it includes: a single-chip microcomputer control system, a rotating motor, an MPPT controller, a battery, an LCD display screen, and six structures of photovoltaic panels; The single-chip microcomputer control system uses the mathematical model of the sun's altitude and azimuth to calculate the sun's position, and combines the relationship between the light intensity received by the automatic tracking sensor and the specified value of the system to issue commands to control the rotation of the rotating motor; The rotating motor rotates according to the instructions of the single-chip control system to rotate and adjust the photovoltaic panel, so that the photovoltaic panel is aligned with the sun to track it; The storage battery is used to store the electric energy generated by the photovoltaic panel. When it needs to be used, the single-chip control system controls the battery to supply the stored electric energy to the user; Photovoltaic panels, the rotating motor enables the photovoltaic panels to receive sunlight in the best position, and convert solar energy into electrical energy, part of which is supplied to users for direct use, and the other part is stored in the battery; The MPPT module adopts the combination of the disturbance observation method P&O and the constant voltage control method CVT to improve the system power; LCD display for displaying date, power generation and storage power. 2. The single-axis photovoltaic solar tracking system according to claim 1, characterized in that, The automatic tracking sensor is set to work intermittently, and a tracking detection is started every 5 minutes. 3. The single-axis photovoltaic solar tracking system according to claim 1, characterized in that, The support of the single-axis photovoltaic solar tracking system is divided into three parts: the base, the main beam and the photovoltaic system. The three parts are detachable and connected by bolts. 4. The single-axis photovoltaic solar tracking system according to claim 1, characterized in that, The north-south angle and the east-west angle of the photovoltaic panel are adjustable, and the north-south angle is adjusted according to the season, and the east-west angle is adjusted according to the sun's rotation. 5. The single-axis photovoltaic solar tracking system according to claim 4, characterized in that, The east-west rotation system of the photovoltaic panel adopts a thickened steel ball universal turntable, which is the connecting part of the rotating sofa or rotating wardrobe. 6. The single-axis photovoltaic solar tracking system according to claim 1, characterized in that, The automatic tracking sensor includes: photosensitive module, single-chip microcomputer module, clock chip module, drive module and branch motor; Further, the automatic tracking sensor has two modes, one is the mode of automatically judging the external light intensity, this mode uses a tracker composed of a photoresistor to track in real time when the light is strong, and the other is a timing drive mode, this mode When the light is weak, the clock module is used to drive regularly, and the two modes can be switched in real time. 7. The single-axis photovoltaic solar tracking system according to claim 1, characterized in that, The single-axis photovoltaic solar tracking system also includes a backup power supply. When the battery cannot meet the power supply demand, the power switch will automatically switch to the backup power supply.