China has a vast territory, uneven population distribution and sparse East Michigan. Due to the relative backwardness of geographical environment and economy, some areas are relatively short of electricity. The state power grid can not cover and supply electricity centrally, or the quality of power grid is unstable, which causes certain obstacles to the local economic development and the improvement of people's life. Especially in the north and northwest of China, the problem is particularly prominent, there is an urgent need for a stable and reliable power system suitable for local use. At present, the commonly used separate power supply systems are generator set, solar system, wind power generation system and wind solar complementary system.
The generator set uses the primary energy as the power source to drive the internal combustion engine. The internal combustion engine drives the generator, and the generator performs the magnetic line of force cutting motion to generate electric energy. The primary energy resources are more and more scarce, the price is higher and higher, and seriously affect the natural environment.
Solar energy system, wind power generation system and wind solar complementary system take the inexhaustible light energy and wind energy as the energy source, and convert them into usable electric energy through certain installation and replacement devices. This energy is natural and environmentally friendly, which fully embodies the concept of energy saving, environmental protection and earth loving. At present, the main energy storage devices are nickel cadmium battery and VRLA battery. However, due to the cost, lack of raw materials and other reasons, Ni Cd battery is gradually replaced by VRLA battery. Next, take the photovoltaic system as an example to introduce the application of VRLA battery in the photovoltaic system.
Introduction of photovoltaic system
1、 Working principle of photovoltaic system:
In the case of good lighting conditions, the solar cell module generates a certain electromotive force, and the solar cell array is formed through the series and parallel connection of the modules, so that the array voltage can meet the requirements of the system input voltage. Some of them are supplied to the power system, and some of them are charged by the charge discharge controller to store the electric energy converted from the light energy. When the lighting conditions can not meet the requirements, the battery pack will provide the power required by the power system through the inverter.
2、 Composition of photovoltaic system:
Photovoltaic system is composed of solar cell array, storage battery, charge and discharge controller, inverter and other equipment. The functions of each part of the equipment are as follows:
(1) Solar cell array: in the case of light, the cell absorbs light energy, and there is the accumulation of different sign charges at both ends of the cell, which produces "photovoltage", which is called "photovoltaic effect". Under the action of photovoltaic effect, the two ends of the solar cell generate electromotive force to convert light energy into electric energy, which is the device of energy conversion. Solar cells are generally silicon cells, which are divided into monocrystalline silicon solar cells, polycrystalline silicon solar cells and amorphous silicon solar cells.
(2) Battery pack: its function is to store the electric energy generated by the solar array when it is illuminated and supply power to the load at any time.
(3) Controller: automatic control of the choice of electricity, in the city electricity, solar power, battery power between the choice of battery charging.
(4) Inverter: it is a device that converts direct current into alternating current.