太阳能电池板室外特性的研究（Study on outdoor characteristics of solar panels）

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1、太阳能电池板室外特性的研究（Study on outdoor characteristics of solar panels）Study on outdoor characteristics of solar panels in design experimentAfter the second industrial revolution, fossil fuels such as coal, oil and natural gas became the main energy in production and life. However, with the development of s

2、ociety and economy, these limited reserves of primary energy can not meet the needs of human being. These fossil fuels have also polluted the human environment, and the ecology has been destroyed. Therefore, it is an urgent problem to find and develop a large, clean and pollution-free energy. Solar

3、energy is one of the energy sources. Solar energy is rich in resources, wide distribution, clean, pollution-free and other advantages. Therefore, the research and development of solar energy for human production and life after an important significance, has become the fastest growing energy developm

4、ent industry.There are two ways to use solar power. One is the use of solar energy to boil water, the steam generated by the generator drives electricity, and the other two is solar cells. The solar cell (solar cell) also known as photovoltaic cell or photovoltaic cell, is a kind of based on semicon

5、ductor photovoltaic effect (photovoltaic effect) to convert sunlight directly into electrical devices, there are solar cell silicon, selenium cadmium sulfide, semiconductor materials such as gallium arsenide. Among them, silicon solar cells are now the most mature and dominant in applications. The s

6、olar panel used in this experiment is a silicon solar cell, and with other devices, the basic characteristics of the electrical and optical aspects of solar cells are investigated.First, the purpose of the experiment1. Understanding the basic principles and applications of solar panel work.2. measur

7、e the outdoor characteristics of solar panels.3. use solar panels to design a specific application.Two 、 experimental instruments and appliances3W solar cell board 1, inserted 1 boards, a small DC motor 1, 1W LED 1 220W light tube, multi circle adjustable potentiometer 1 digital multimeter, 1, 1. Sh

8、ort connection block 2.Three 、 experimental principleFormation of 1.PN junctionsTaking silicon as an example, a trivalent element (such as boron) is added to a pure silicon crystal, and a boron atom and a silicon atom form covalent bonds. When doped, the crystal structure remains the same, but the s

9、ilicon atoms in some positions are replaced by boron atoms. Boron is a trivalent element, the outermost layer of only three valence electrons, so when it and the surrounding silicon atoms form covalent bond, silicon atoms outermost electrons on the lack of an electron to form a covalent bond, so fro

10、m the silicon atoms in adjacent to a valence electron to form covalent bond, electrons are taken to leave a vacancy, forming a hole. As long as the boron atom gets little energy, it can release the hole and form a free hole. Thus, every boron atom doped can provide a hole, thus greatly increasing th

11、e number of holes in the silicon crystal. This is a free electron in a semiconductor (minority carrier), the hole is the most (the majority carrier), mainly depends on the hole conduction hole, positively charged, so called hole semiconductor, P type semiconductor, as shown in figure 1.The incorpora

12、tion of pentavalent elements in silicon crystals in the pure (such as phosphorus, arsenic, antimony, etc.) to replace silicon lattice atoms, the outermost layer of the phosphorus atom when doped with four valence electrons and the surrounding silicon atom to form covalent bonds, more than one electr

13、on, as long as the phosphorus atoms have little energy. You can release the excess electrons to form free electrons, in this case, on the formation of N type semiconductor, as shown in figure 1. In N type semiconductors, holes are minority carriers and free electrons are majority carriers, mainly by

14、 free electrons. Free electrons are provided mainly by atoms doped with elements such as phosphorus. The more elements are added, the higher the concentration of free electrons, the stronger the electrical conductivity.Figure 1 N type semiconductor and P type semiconductorWhen the P type semiconduct

15、or and N type semiconductor combination together, due to a P type semiconductor high hole concentration, the concentration of free electrons is low; and the free electron concentration of N type semiconductor high hole concentration is low, so the interface formed on both sides of the carrier concen

16、tration difference, produce diffusion of majority carriers at the interface near the will. That is, the holes in the P region diffuse to the N region, while the electrons in the N region diffuse into the P region. As the diffusion motion occurs, a negatively charged particle region appears on the si

17、de of the P region at the junction of the P region and the N region, while a positively charged particle region appears at the side of the N region at the junction. Thus, at the interface, a internal electric field is formed by N pointing to P, thus preventing diffusion. To achieve balance, no diffu

18、sion at the interface, the formation of a special potential, this is a p-n junction, as shown in figure 2.Figure 2 job carrier diffusion concentration movement2. photovoltaic effectWhen the sun shines on the PN junction, the electrons and holes produced by the light are gathered to the N region and

19、the P region respectively, so that both ends of the PN junction form a light generating electromotive force. This phenomenon is called photovoltaic effect, also known as photovoltaic effect.Solar cells use photovoltaic effect to convert light energy into electric energy. It is a photodiode in itself

20、, and the core part of the photodiode is a PN junction. When sunlight hits the photodiode, the photodiode converts the light energy into electrical energy to produce an electric current. The power of a single solar cell is very low, and it can not meet the needs of production and life. When a series

21、 of batteries are connected in series or in parallel, they can form a solar cell square with a larger output power, that is, a solar panel. Solar panels are the core of solar power generation systems and the most valuable part of solar power generation systems. Its function is to convert solar energ

22、y into electricity, or to the storage battery, storage, or to promote the work load.3. outdoor characteristics of solar panelsNormally, if the light changes the voltage, current, and resistance of a device, such a device is called a photoelectric device. Photoelectric devices have the following four

23、 attributes: time response, spectral response, light characteristics, temperature characteristics. Because the content of this experiment is the study of the outdoor characteristics of solar panels, we only focus on its light characteristics, while other features are less important. The illumination

24、 characteristics of solar panels mainly include the following aspects:(1) open circuit voltage VmaxThe open circuit voltage is the voltage at the two ends of the circuit board in the open circuit, that is, the maximum voltage Vmax can be supplied by the solar panel, and the open circuit voltage is r

25、elated to the illumination intensity E.(2) short circuit ImaxThe short-circuit current short-circuit state outside the current zero resistance in the circuit, it is the maximum current of Imax solar panels can provide, the short-circuit current is equal to the general solar panel photocurrent, and p

26、hotocurrent and incident light intensity is proportional, therefore the short-circuit current and light intensity on E. Figure 3 shows the illumination characteristics of a solar cell.Fig. 3 light characteristic curve of solar cell.(3) load characteristicsSolar panels convert light energy into elect

27、rical energy, output out to the load (such as resistors, motors, light bulbs, etc.), or store electrical energy before feeding it to the load. The resistance of the load changes, and the output current may change. The load characteristic is the relation between the output current and the load resist

28、ance when the load is connected to the circuit with solar panel as the power supply.Four, the experiment content and main instruments are introducedThis experiment uses JDNL solar panel, which is made of polycrystalline silicon. The reason why polysilicon is used to make solar cells is because of it

29、s low cost and high efficiency. At the same time, we use the circuit board to connect the circuit, it has been laying a good line, simply insert the components according to the requirements. The experiment also provides a 200 European multi ring adjustable potentiometer potentiometer knob on each tu

30、rn resistance increase (decrease) 20, 10 laps to reach the maximum (minimum) value of 200 (0.). The experiment was done under outdoor conditions, so record the weather conditions outside. The main contents are as follows:1. measure the open circuit voltage of solar panels Vmax. Adjust the battery bo

31、ard roughly to the sun, turn the meter to the volt 20V, adjust the battery board left and right, and make the voltage value the maximum. The battery plate surface and the vertical direction angle and defined as theta = 0 DEG protractor with quantity. Along the pitch direction adjusting light receivi

32、ng angle theta, delta theta =10 degree angle change, write down the voltage value corresponding to V theta (see attached), images V - cos theta theta. And use text to explain how the open circuit voltage of solar panels varies with light intensity.2. measure short circuit current of solar panel Imax

33、. Adjust the battery board to the sun, adjust the multimeter to the current gear 10A, adjust the battery board left and right, and make the current value the biggest. The battery plate surface and the vertical direction angle and defined as theta = 0 DEG protractor with quantity. Along the pitch dir

34、ection adjusting light receiving angle, the amount of delta theta =10 DEG angle change, write down the voltage value corresponding to I theta (see table two), make the image I theta theta - cos. And use text to explain how the short-circuit current of solar panels varies with light intensity.3. meas

35、ure the relationship between the output current of battery board I and the change of load resistance R. The solar panel is used as the power supply, and the multi ring adjustable potentiometer and multimeter are connected into the circuit (the circuit diagram is designed by itself). Change the resis

36、tance of the potentiometer and observe the change of the current. Variation of R=20 values Omega resistance of the recorded data (see table three), the I - R images.4. Please design a circuit by using the instrument provided by the experiment, and then use the solar panel to drive the motor to work

37、normally, and measure the output power of the solar panel. Change the pitch angle of the battery board, observe the speed of the motor turntable, and explain the reason. (Note: the design of the circuit diagram should be completed before class. The class can be tested only after the teacher has chec

38、ked itFive, thinkingOneIf the north in the winter and summer sun angle between about 40 DEG change, through the experiment, do you think the solar panel receives the light direction, at least once a long time (such as adjustment can be increased 10% of the output power)?2. adjust the solar panel ill

39、umination to accept the angle so that the short-circuit current is maximum. Cover the area of about 1/3 panels along the horizontal and vertical sides, observe whether the short-circuit current changes, record the data, and explain the reasons.Table 1Theta 0 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degreesCos 6V 6Schedule twoTheta 0 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degreesCos 6I 6Schedule threeR, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200I