Solar inverter is the brain of the solar system, although its basic role is to convert DC electricity comes from solar panels to usable AC electricity, now it takes the responsibility to monitor and control the whole solar system and provides important technical info required for solar system operation and maintenance crews to fix system errors, in addition to that it takes responsibility to manage batteries system incase of its presence in the solar system.
There are 3 different types of solar inverters in the market, as following:
1. Central solar inverter
It’s a large power capacity solar inverter that can handle more than one string. A number of solar strings will be connected together via a combiner box, and then the DC output of the combiner box will be connected to the inverter. With solar central inverters industry development, there is no need for the combiner box as the inverter becomes having more than one input terminals with the capability to handle different strings output voltages.
2. String solar inverter
This inverter power capacity is lower than central solar inverter, it works on string scale. For example, if we have 30 solar panel in the array, it can be divided to 5 strings, which means 6 solar panel per string. For each string, there will be a solar inverter, hence the solar system will have multiple string inverters.
This system will be more efficient with higher AC energy harvest than central solar inverter, for 2 reasons:
- The shaded solar panel will affect the energy harvest only for one string, and the other strings will work efficiently.
- We can make different orientation for each string “tilt angle and azimuth”, so can harvest more energy.
So, string inverter solar system will be more efficient, higher energy yield but more expensive than central inverter solar system which require one inverter only. Also, the reliability in case of using more than inverter “string inverter system case” will be higher.
3. Solar micro inverter
This inverter power capacity will be lower than string inverter, it works in module scale. For each solar panel, there will be micro inverter attached to it and converts DC to AC. Of course, this system will be more efficient than string inverter system as shaded panel will not affect other panels, also we can make different orientation for each panel “tilt angle and azimuth”, so can harvest more energy.
At the end, now it’s clear that solar microinverter system will be more efficient and higher AC energy harvest than solar string inverter system and solar central inverter system, but it will be more expensive.