離網(wǎng)型逆變器是離網(wǎng)發(fā)電系統(tǒng)的核心部件，負(fù)責(zé)把直流電轉(zhuǎn)換為交流電，供交流負(fù)荷使用。為了提高光伏光伏逆變器圖發(fā)電系統(tǒng)的整體性能，保證電站的長期穩(wěn)定運行，逆變器的性能指標(biāo)非常重要。

Off-grid photovoltaic power generation system is also called independent photovoltaic power generation system, which can operate independently without relying on the power grid and convert light energy into electricity, which can effectively solve the problems caused by power shortage and power failure. Because off-grid photovoltaic power generation system is not restricted by the region, it is widely used. As long as there is sunlight, it can be installed and used, and it can realize "there is light, there is electricity". Off-grid photovoltaic power generation system is very suitable for remote areas without power grid use, but also can be used as an emergency power generation equipment in areas with frequent power outages.

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Principle of power generation

The working principle of crystalline silicon n/p solar cells: when the P-type semiconductor and the N-type semiconductor are closely combined into a piece, at the interface of the two forms a P-N junction. When the photocell is irradiated by the sunlight, the accumulation of positive and negative charges is formed on both sides of the p-n junction, generating the photogenerated voltage and forming the built in electric field, which is the "photogenerated volt effect". Theoretically, at this point, if the leading electrodes on the two sides of the built in field are connected to an appropriate load, a current will be formed, and power will be generated on the load. The battery module of off-grid photovoltaic power generation system is a solid device that realizes P-V conversion by utilizing the electronic properties of semiconductor materials.

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Composition of system

The off-grid photovoltaic system is generally composed of photovoltaic array composed of solar cell modules, solar charge and discharge controller, battery pack, off-grid inverter, DC load and AC load.

(1) Solar cell assembly

Solar cell module is the main part of the solar power supply system, is also the most valuable component of the solar power supply system, its role is to convert the solar radiation energy into direct current energy;

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(2) Solar charge and discharge controller (also known as "photovoltaic controller")

Solar charging and discharging controller is also known as "photovoltaic controller", its role is to regulate and control the electric energy generated by the solar cell module, charge the battery to the maximum extent, and play the role of over-charge protection and over-discharge protection of the battery. Where the temperature difference is large, the photovoltaic controller should have the function of temperature compensation.

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(3) Storage battery sets

Store the energy generated by solar panels during the day for use when there is no light.

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(4) Off-grid inverter

Off-grid inverter is the core component of off-grid power generation system, which is responsible for converting DC to AC for AC load. In order to improve the overall performance of the photovoltaic inverter power generation system and ensure the long-term stable operation of the power station, the performance index of the inverter is very important.