Composition And Principle Of Solar Power Supply System

1) Photovoltaic panels: the main force of light energy conversion
The photovoltaic panels in the solar power supply system are commonly made of monocrystalline silicon, polycrystalline silicon, amorphous silicon, gallium arsenide, copper indium gallium selenide, etc. For example, monocrystalline silicon is a single crystal of silicon with a basically complete lattice structure. It is a good semiconductor material with a relatively high photoelectric conversion efficiency, which can reach up to about 24%; the manufacturing process of polycrystalline silicon is similar to that of monocrystalline silicon, but the photoelectric conversion efficiency is slightly lower; amorphous silicon belongs to amorphous silicon, which is brown-black or gray-black microcrystals with low purity, but good weak light performance; gallium arsenide is also used in photovoltaic panels as an important semiconductor material; copper indium gallium selenide is mostly used in compound thin-film solar cells such as second-generation solar cells.

At the same time, there is often a special coating on the surface of photovoltaic panels, which is used to reduce sunlight reflection, absorb as much light energy as possible, and improve the utilization efficiency of light energy. When exposed to sunlight, the semiconductor materials in photovoltaic panels play a key role. For example, photovoltaic panels made of silicon materials, when the photon energy in sunlight shines on the semiconductor, it will excite the electrons in the semiconductor, causing it to jump from the valence band to the conduction band, thereby generating electron-hole pairs. Under the action of the internal electric field of the semiconductor, the electrons and holes move to the two ends respectively, thereby forming a photoinduced electromotive force. As long as the external circuit is connected to the two ends of the photovoltaic panel, it can generate current, convert sunlight into electrical energy, and provide a power source for the entire solar power supply system.

2)Battery: "Storage Warehouse" of Electric Energy
Batteries play an extremely important role in the solar power supply system and can be called "storage warehouse" of electric energy. When there is sufficient sunlight, the electricity generated by the photovoltaic panels is not only used for the current load, but also has excess electricity. At this time, the battery begins to play its storage function and stores this excess electricity. When there is insufficient sunlight, such as cloudy days or nights, when the photovoltaic panels cannot generate enough electricity or even cannot generate electricity, the battery will release the previously stored electricity to ensure that the system can continuously and stably supply power to the load, so that the entire solar power supply system will not experience unstable situations such as power outages due to changes in lighting conditions, and maintain stable operation of the system.

3) Controller: "Smart Butler" of System Operation
The controller is the "smart butler" of the solar power supply system. It monitors the voltage and current output of the solar panel at all times. On the one hand, it can intelligently adjust the distribution and storage of electric energy. For example, according to the power status of the battery, it can reasonably control the charging process of the solar panel to the battery. When the battery is almost full, the controller will adjust the charging current and other parameters to avoid overcharging. When the battery needs to discharge to power the load, it will also accurately control the power output according to the actual power demand of the load.

On the other hand, the controller has a variety of protection functions to ensure the safety and stability of the system. Functions like electrical protection can prevent abnormal current and voltage in the circuit from causing damage to the system; reverse connection protection function, whether it is a photovoltaic panel or a battery, if there is a wiring error of reverse polarity, the controller can ensure that it will not be damaged and can continue to work normally after correcting the wiring; short circuit protection function, once a short circuit occurs in the circuit, the controller will cut off the circuit in time to avoid a series of safety hazards caused by the short circuit; there are also overcurrent protection, overcharge protection, over-discharge protection, etc. Overcharging may vaporize the electrolyte in the battery and cause malfunctions, over-discharging of the battery will cause premature failure of the battery, and overcharging and over-discharging may damage the load. Through these protection functions, the controller protects the normal operation of the solar power supply system in all directions, so that it can work stably for a long time.

IV) Inverter and load: power conversion and consumption terminal
The core function of the inverter is to convert DC power into AC power for use by the load. Specifically, solar panels generate DC power, but most of the power used in our daily life and many industrial and commercial scenarios is AC power. The inverter has a complex inverter circuit and other structures. Taking the common fully controlled inverter as an example, its AC element uses IGBT tube, and the conduction or cutoff of the IGBT tube is controlled by PWM pulse width modulation. When the DC power supply is connected, the positive and negative alternating square waves are formed on the primary coil of the transformer through different conduction and cutoff combinations of the IGBT tube. With the help of the LC AC filter, the output end finally forms a sinusoidal AC voltage, thereby completing the conversion from DC to AC.
The load is the user of electric energy and the terminal of electric energy consumption of the entire solar power supply system. It can be a variety of electrical equipment, such as electric lights, televisions, refrigerators and other electrical appliances in the home, motors and production equipment in industry, lighting and display equipment in commercial places, etc. These loads rely on the alternating current converted by the inverter to realize their respective functions, such as electric lights to realize lighting functions, motors to drive machines to operate, etc. Different loads consume electric energy according to actual needs, and together constitute the link of electric energy consumption of the solar power supply system.