I. Overview 1. The composition of the solar power supply system The solar power supply system is composed of a solar cell module, a solar controller, an inverter, and a battery (group). (1) Solar cell module: The solar cell module is the core part of the solar power supply system and the most valuable part of the solar power supply system. Its role is to convert the radiant energy of the sun into electrical energy, or send it to a battery for storage, or to drive the load. The quality and cost of solar modules will directly determine the quality and cost of the entire system.
(2) Solar controller: The function of the solar controller is to control the working state of the whole system and to protect the battery from over-charge protection and over-discharge protection. In places with large temperature differences, qualified controllers should also have temperature compensation. Other additional functions such as light control switches and time control switches should be optional for the controller. (3) Battery: Generally, it is a lead-acid battery. In a small and micro system, a nickel-hydrogen battery, a nickel-cadmium battery or a lithium battery can also be used. Its function is to store the electrical energy supplied by the solar cell module when there is light, and then release it when necessary.
(4) Inverter: An inverter is a device that converts direct current (DC) into alternating current (AC). It consists of an inverter bridge, control logic and filter circuits. The inverter also has an automatic voltage regulation function to improve the power quality of the photovoltaic system.
2, off-grid and grid Solar photovoltaic power supply systems are divided into off-grid, grid-connected power generation and a combination of the two. (1) A power generation system that converts solar radiation energy into electrical energy through a solar photovoltaic module is called a photovoltaic power generation system, and a relational system connected with a public power grid is called a grid-connected photovoltaic power generation system. (2) The use of off-grid PV systems is independent of the grid, as it is currently used for low-power, low-power applications, such as. Solar beacon lights and solar street lights. The household solar power system is an off-grid photovoltaic system. (3) The combination of off-grid and grid-connected power generation has strong adaptability. For example, the power generation strategy of the grid can be adjusted according to the peak-to-valley price of the grid, but its cost and operating cost are higher than the above two schemes. 3. Application method of solar power supply system The household solar power supply system can be used alone, and is separated from municipal electricity, and the cost is high. It can also be used in conjunction with municipal electricity, as a supplement to municipal electricity, using solar power in power outages or low-power appliances. Second, the advantages of solar power 1. Solar energy resources are inexhaustible and inexhaustible. Solar energy that hits the Earth is 6000 times greater than the energy currently consumed by humans. In addition, according to the nuclear energy generated by the sun, the sun will shine on the earth for more than 60 billion years. 2. Green and environmental protection. Photovoltaic power generation itself does not require fuel, no carbon dioxide emissions, no air pollution, no noise. 3. Wide application range. Photovoltaic systems can be used wherever there is light. 4. Long service life, simple maintenance and high reliability. The life of crystalline silicon solar cells is as long as 20-35 years. Because there are no mechanical rotating parts, the operation and maintenance are simple, the reliability is high, and now the automatic control technology is adopted, and no manual operation is required. 5. The solar cell module has a simple structure, small volume and light weight, is convenient for transportation and installation, and has a short construction period of the photovoltaic power generation system. 6, the system combination is easy. Several solar cell modules and battery cells are combined into a solar cell array and battery pack of the system; the inverter and the controller can also be integrated. Therefore, the photovoltaic power generation system can be large or small, and it is easy to combine and expand. Third, the status of home solar power supply 1. Current status of solar power supply in China Due to insufficient understanding of solar photovoltaic power generation, high cost and lack of policy support, China is still very backward in household solar power generation. More than 95% of China's photovoltaic products rely on export markets, and the domestic market is too small. About 1 million households in China rely mainly on photovoltaic power generation systems to solve basic living lighting. However, most of them are pastoralists in pastoral areas. These households are still relatively low in power supply and generally only meet basic lighting needs. In addition, there are farmers and beekeepers in forest areas and agricultural areas, as well as small units such as schools and shops without electricity. Household solar photovoltaic power generation systems are already in use, and some urban residents in areas with power shortages have become household solar energy. Users of photovoltaic power generation systems. 2, the status of foreign household solar power supply Europe, the United States, and Japan are among the world's leaders in solar power generation. On home solar energy, the government subsidizes (50% of the cost of installing subsidized equipment in Japan) and encourages households to use solar power. At the same time, the surplus electricity is sold to the power company. At the same time, the power company is also actively acquiring, and the income is used to offset part of the electricity bill. V. Factors to be considered in the design of solar power system 1. Is it suitable for solar power generation? The location of solar power system use, solar radiation, and climatic conditions. 2, the choice of solar cell components - the specific load, quantity and power of the system, the time each type of load needs to work every day. (This is the most critical issue) 3, the choice of inverter - the system's output voltage, DC, AC, or DC communication are all needed. 5, the choice of battery - in the case of rainy weather without sunlight, how many days the system needs to be continuously powered. 6, the choice of controller - the load situation, pure resistance, capacitive or inductive, the starting current is large.
Seven, home solar power system costs 1, hardware costs The overall electricity consumption of domestic households in China generally requires an output of 3000-5000 watts, and a few need to be higher. At present, domestic domestic solar power supply costs about 30 yuan / watt (solar panel power), if a villa needs 10,000 watts of system, the overall hardware cost is about 300,000, some manufacturers offer 50-700,000. The solar cell module is a group of components of the system. The solar cell module is composed of a plurality of solar panels, each of which is 100 watts-200 watts, and the price is 13-18 yuan/watt. The 10,000-watt solar power system has a solar module price of 13-18 million yuan. According to the manufacturer, the price of the whole system is different due to the different materials and brands. 2, installation and maintenance costs The solar cell module has a long service life, and the manufacturer promises to use it for more than 10 years, generally for about 25 years. The battery life is 3-5 years, the inverter life is 3-5 years, and the controller life is 3-5 years. The total cost of battery, inverter and controller replacement is about RMB 20,000. Installation of solar power systems requires professional installers, and ordinary small electricians cannot install them. Therefore, manufacturers need to send people to guide and install. The solar panels are mostly installed on the roof and partially installed in the courtyard. If the bracket is required to be installed in the courtyard, the price of a bracket is about 3,000 yuan. The 100 watt/block solar panel area is about 1-1.2 square meters, and the 10,000 watt power needs 100 pieces, and the total required area is 100-120 square meters. The 150 watt/block solar panel area is about 1.6 square meters, and the 10,000 watts require 67 blocks. The total required area is about 107 square meters. After-sales service is a big problem. If the system is used normally, it is usually 3-5 years or even longer to replace the equipment. However, it does not rule out abnormal use or man-made damage. There are no professional technicians, equipment and accessories. Maintenance is more troublesome and costly. Eight, suggestions 1. The solar cell module is the core of the system and the most expensive part. Foreign countries must provide the name, quantity, power and daily use time of the villa's electrical appliances. Without these data, the manufacturer can't make a product plan and can't make a quote. According to the data in the "Off-grid Power System Survey Form" provided by foreign countries, manufacturers can't do programs at all. At least the name, quantity and usage time of the appliances are needed. The approximate power can be estimated in China. If detailed product plans are required, detailed survey data is required. 2, villa solar power supply system can not be completely separated from municipal electricity, can only be used as a supplement to municipal electricity. There are two main reasons: (1) High cost. Solar power supply meets the overall needs of the villa and requires a system of more than 10,000 watts of power. The most powerful of the household appliances is the air conditioner, and the power of the air conditioner can be calculated according to 12 square meters (1P = 735W). If a villa has a living room and bedroom area of 400 square meters, it needs 24,500 watts of power, which does not include elevators, refrigerators and other electrical equipment. (2) Weather restrictions. The solar power system can only generate electricity on sunny days, and the power generation will be seriously affected in rainy days, so it can only be powered by batteries in rainy days. However, the overall power of the villa is so large that the battery can only meet the power supply for a certain period of time, and there will be a power outage in the case of continuous rainy weather.