离网型光伏发电系统也被叫做独立光伏发电系统，它能够不依赖电网而独立运行，将光能转化为电能，可以有效解决因缺电、停电等带来的难题。由于离网型光伏发电系统不受地域的限制，所以它的使用很广泛，只要有阳光照射的地方就可以安装使用，能够实现“有光就有电”。离网型光伏发电系统非常适合偏远无电网的地区使用，同时也可以作为经常停电地区的应急发电设备。

 发电原理 

晶体硅n/p型太阳电池的工作原理:当p型半导体与n型半导体紧密结合连成一块时，在两者的交界面处就形成p-n结。当光电池被太阳光照射时，在p-n结两侧形成了正、负电荷的积累，产生了光生电压，形成了内建电场，这就是"光生伏特效应"。从理论上讲，此时，若在内建电场的两侧面引出电极并接上适当负载，就会形成电流，负载上就会得到功率。离网型光伏发电系统的电池组件就是利用半导体材料的电子学特性实现P-V转换的固体装置。

 系统组成 

离网光伏系统一般由太阳电池组件组成的光伏方阵、太阳能充放电控制器、蓄电池组、离网型逆变器、直流负载和交流负载等构成。

（一）太阳电池组件

太阳电池组件是太阳能供电系统中的主要部分， 也是太阳能供电系统中价值最高的部件，其作用是将太阳的辐射能量转换为直流电能；

（二）太阳能充放电控制器（也称“光伏控制器”）

太阳能充放电控制器也称"光伏控制器"，其作用是对太阳能电池组件所发的电能进行调节和控制，最大限度地对蓄电池进行充电，并对蓄电池起到过充电保护、过放电保护的作用。在温差较大的地方，光伏控制器应具备温度补偿的功能。

（三）蓄电池组

储存白天太阳能组件所发电量，以供无光照时使用。

（四）离网型逆变器

离网型逆变器是离网发电系统的核心部件，负责把直流电转换为交流电，供交流负荷使用。为了提高光伏光伏逆变器图发电系统的整体性能，保证电站的长期稳定运行，逆变器的性能指标非常重要。

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.