LED lighting, solar photovoltaic power generation system composed of solar photovoltaic energy efficient LED lighting systems including solar batteries, DC-DC converters, maximum power tracking MPPT fMaximum power point tracking) control, storage and batteries for power LED lighting control, LED light source and other parts.

Solar photovoltaic lighting system works is: in a time period of sunlight, the solar batteries will be collected solar energy into electricity; under the control of the control system, the use of solar photovoltaic maximum power point tracking (MPPT) mode , the energy stored in the battery; in the LED lighting system requires power supply, LED light source to provide a safe and efficient voltage and current. Energy efficient LED lighting system to work, work and life for the people to provide clean environmentally friendly green lighting.

Solar photovoltaic solar photovoltaic cell power generation is one of the main ways of using solar energy.

Generation of solar photovoltaic cells photovoltaic effect principle is, of crystalline silicon solar cells, the open circuit voltage of the typical value is 0.5 0.6 V, through the light at the interface layer of the electron hole on a more current form the greater. Interface layer to absorb more light energy, the greater the current the same form. The current application and research of solar cells are silicon solar cells, compound semiconductor cells and dye-sensitized solar cells. Silicon solar cell is the mainstream of solar photovoltaic cells, silicon solar cells in monocrystalline silicon solar cells with conversion efficiency up, the laboratory more than 24% conversion efficiency, industrial-scale production of single crystal silicon solar cell efficiency of 18 % or more. Thin film solar cells has been greatly developed in recent years, polycrystalline silicon} silicon / microcrystalline silicon thin film solar cells and other new type of solar cell industry has the scale, the maximum conversion efficiency of 16% or more. In recent years, CIS, CIGS thin film solar cells, GaAs solar cells and other compound semiconductor solar cells have also made practical progress. Dye-sensitized TiO solar cells have also made remarkable achievements.

Since solar cell output voltage and current exists between the nonlinear and variability. In certain circumstances there is a maximum 'power output point and the maximum power point with a corresponding voltage and current. When the environment changes, the solar cell output characteristic curve also changes. Solar cell output voltage and output current characteristic curve shown in Figure 2. In order to get as much solar power, solar cells, raised the maximum power tracking problem. Maximum power point tracking control method commonly used constant voltage tracking, perturbation and observation method, the incremental conductance method, fuzzy logic control method, load current / voltage largest law means the entire LED operating current and constant voltage constant current driver can drive . According to the voltammetric characteristics of LED, in the LE D in the forward area, small voltage fluctuations can cause large changes in current, so the constant current drive should be alternatives.

Specific performance art LED lighting

LED light-emitting principle. Ⅲ LED is a V compounds, such as GaAs (gallium arsenide), GaAsP (gallium arsenic phosphide), A1GaAs (AlGaAs) and other semiconductor processing, its core is PN junction, so it has a general PN junction V an Antwerp, namely the forward and reverse cut-off, breakdown characteristics. When the P-type semiconductor and N type semiconductor combination, due to the presence at the interface carrier concentration difference. Thus electrons and holes are from the area of ​​high concentration to low concentration of regional spread. So, P District, the rest of the side of the hole can not be moved out of negative ions, N area and left side of the loss of electrons can not move in the positive ion. These charged particles can not move is the space charge. Space charge concentration of N in the P zone and near the interface zone, forming a thin space charge region, is the PN junction. When a P-N junction when a forward voltage. Alter the dynamic equilibrium of P-N junction. Injection of minority carriers (minority carriers) and the majority carrier (more children) when combined, they put the excess energy released in the form of light to convert light energy directly into electrical energy. If the reverse voltage to the PN junction, minority carriers (minority carrier) injection is difficult, it is not light.

White LED key implementation. Currently, GaN-based white LED obtained are: blue LED + yellow phosphor, tri-color LED synthetic white, tri-color phosphor purple LED + 3 approach. The most common way to form white light blue LED chip technology and can be effectively excited blue phosphor together to form a radiating white LED.LED peak around 470 nm blue light, and some fluorescent blue excitation peak of 570 issued nm, the yellow green. With another part of the transmission out of the blue and yellow green excitation produced by mixing phosphors produce Y l O: Ce white light. Mostly currently used phosphors activated by rare earth aluminate Y l O: Ce (YAG), when a blue excitation light yellow-green when it is issued, so called the yellow-green phosphor. This method is light, high luminous efficiency, preparation is simple, mature technology. But the color changes with the angle. Optical coherence is poor, and the life of the phosphor and the LED is also inconsistent, with the passage of time when asked, color rendering index and color temperature will change, affecting the quality of the light source of light. Using red, green, blue, or RGB LED RGB LED control chip mixture to achieve white light. The former three-chip model, the latter three LED assembly type. Red, green and blue LED is encapsulated in a tube, the luminous efficiency of up to 20 lm / W, high luminous efficiency, color is good [31. However, this method of synthesis of the inadequacy of white light LED driver circuit is more complex. Three-chip-type primaries Hunhe high cost, and because the red, green and blue LED light 3 decay characteristics are inconsistent with the increasing use of time, three-color mixing ratio will change. Will be a corresponding change in the color index UV or violet excitation LED RGB phosphors to generate white light. More accessible in this way the same white color as the color only by the ratio of phosphor decision, in addition, also get a high color rendering index. But the biggest difficulty is how to get high conversion efficiency of three-color phosphor, in particular, efficient red phosphor. But also to prevent UV leakage is also very important.