光伏离网系统如何设计选型，其实还是和选电脑一样简单。

我们先说离网逆变器。

首先逆变器是啥，电池的电是直流电能，需要转化成定频定压或调频调压的交流电 ，才能供负载使用，尤其是供一般家用负载使用。

这时就需要一个转化器，这个转化器就叫逆变器。如果是反向转化，由交流电变成直流电，则叫整流器。

离网系统基本都是直流变交流，所以逆变器是整套系统的核心中的核心。

逆变器分并网逆变器，离网逆变器，和并离网逆变器三种

1.并网逆变器：是能把光伏发出的电，并进市电，但是离网系统输出是不需要将发出来的电并入市电电网，基本是自产自销供给本地负载使用，所以做离网系统，不考虑选购并网逆变器。

2.离网逆变器则是没有市电电网并入功能，只服务离网发电系统，实现分布式发电的自产自用。

3.并离网逆变器则是两个功能都具备，如果你这边的离网系统，在自产自用之余，未来有并网需求的可能，则可以考虑选这个，为未来并网做预留。这个一般更适用于大型离网发电系统，存在发电过多用不完并到市电的可能。

但是并离网逆变器比较贵，如果你的离网系统完全没有并网需求，完全就是给特定负载使用，那就还是选纯粹的离网逆变器更划算，一般适用于中小型的离网系统。

Off-grid inverter

Let's start with the off-grid inverter.

First of all, what is the inverter, the battery electricity is direct current, need to be converted into constant frequency voltage or frequency modulation voltage alternating current, to be used for the load, especially for the use of general household load.

Then you need a converter, the converter is called the inverter. If it is a reverse conversion, from AC to DC, it is called a rectifier.

Off-grid systems are basically DC alternating current, so the inverter is the core of the whole system core.

Inverters are divided into grid-connected inverters, off-grid inverters, and off-grid inverters

1. Grid-connected inverter: can put the photovoltaic power, and the mains power, but the off-grid system output is not required to send out the electricity into the mains power grid, is basically self-produced and self-sold to local load use, so do not consider the off-grid system, the purchase of grid-connected inverter.

2. The off-grid inverter only serves the off-grid power generation system without the function of integrating the mains power grid, so as to realize self-production and self-use of distributed power generation.

3. And the off-grid inverter is equipped with both functions. If the off-grid system on your side has the possibility of grid connection in the future, besides its own production and use, you can consider choosing this one to reserve for future grid connection. This is generally more suitable for large off-grid power generation systems, there is too much power generation and to the mains may be.

But the off-grid inverter is more expensive, if your off-grid system has no grid-connected needs, is completely used for specific load, it is still more cost-effective to choose pure off-grid inverter, generally suitable for small and medium-sized off-grid system.