光伏離網系統如何設計選型，其實還是和選電腦一樣簡單。

離網逆變器

我們先說離網逆變器。

首先逆變器是啥，電池的電是直流電能，需要轉化成定頻定壓或調頻調壓的交流電 ，才能供負載使用，尤其是供一般家用負載使用。

這時就需要一個轉化器，這個轉化器就叫逆變器。如果是反向轉化，由交流電變成直流電，則叫整流器。

離網系統基本都是直流變交流，所以逆變器是整套系統的核心中的核心。

逆變器分并網逆變器，離網逆變器，和并離網逆變器三種

1.并網逆變器：是能把光伏發出的電，并進市電，但是離網系統輸出是不需要將發出來的電并入市電電網，基本是自產自銷供給本地負載使用，所以做離網系統，不考慮選購并網逆變器。

2.離網逆變器則是沒有市電電網并入功能，只服務離網發電系統，實現分布式發電的自產自用。

3.并離網逆變器則是兩個功能都具備，如果你這邊的離網系統，在自產自用之余，未來有并網需求的可能，則可以考慮選這個，為未來并網做預留。這個一般更適用于大型離網發電系統，存在發電過多用不完并到市電的可能。

但是并離網逆變器比較貴，如果你的離網系統完全沒有并網需求，完全就是給特定負載使用，那就還是選純粹的離網逆變器更劃算，一般適用于中小型的離網系統。

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.