Are you in the process of installing a Solar PV system?
I think you will agree with me when I say:
Setting up a solar PV system can be overwhelming.
There are a lot of things to consider when choosing a quality Solar PV system.
After Solar panels, one of the important components to consider are the inverters which account for a high cost in a solar project.
Add to that there are a number of inverters in the market. So which one to choose?
In this guide, we help you choose an affordable solar inverter of high quality.
We look at the basics of Inverters, the different types of inverters and factors to consider when choosing a solar inverter.
Let’s get started.
A Solar inverter or PV inverter converts DC(Direct Current) output of Solar panels into usable Alternating current(AC) that can be fed to the grid or supplied to the building that can be used by the appliances.
(Image source: http://www.mysolarprojects.com/solar101.html)
A Solar Inverter is part of the Balance of system(BOS) which comprises of all the solar PV components other than the solar panels. This includes wiring, mounting structures, power conditioners and other components which help manage the AC load and balances the DC(direct current) generation by the solar panels.
Different types of Solar Inverters
- Grid Tied Inverters
- Off-grid Inverters
- Grid interactive or Hybrid Inverters
Grid Tied Inverters
These inverters are used with the Grid-tied PV systems where the Solar PV system is integrally connected to the grid power.
In this system, the inverters convert Direct current generated by the solar panels to Alternating current(AC) equivalent to the voltage of the grid power. The power generated is fed to the building or grid using a bidirectional interface set at the distribution panel.
Here’s the kicker:
This system works really great for Net metering purposes where excess power generated can be supplied back to the grid. And you earn the feed-in tariff/credit from the Distribution companies(DISCOMs)
This system does not have battery backup. In case of the grid failure the inverter stops to function as a safety feature so that there is no grid supplied back from the Solar PV system(Also known as the anti islanding)
(Image source: https://www.ashden.org/solar-grid)
Off grid Inverters
An inverter where you have access to the gird is fine? But what to do when you live in remote places?
Don’t worry. There’s a solution.
We can use the Off-grid inverters.
These inverters are used in the case of Off Grid Solar PV systems where PV systems are completely disconnected from the grid power.
Here the inverters work like the normal power Inverters used at home which convert grid power (AC) to DC(Direct Current) for battery power backup and when there is a grid failure converts DC to usable AC power for power consumption.
(Image source: https://pureenergycentre.com/solar-offgrid/)
This type of system is a combination of grid tied and Off-grid systems which supply power from solar to the grid for feed-in tariff credits and use the battery backup for power storage.
Lavancha offers Hybrid Solar power inverters(XTM SERIES Studer inverter) for all these cases:
Case 1: General Wiring
Grid and Solar power utilized with battery backup for the following cases:
Case 2: No need of Grid Power
Load – 1000 W (Solar availability is 1000W , there is no need of grid power)
The load is fed by Solar power only
Case 3: Solar and Grid power shared
Load – 1000 W
(Solar availability is 600W and Grid power – 400 W)
Case 4: A case for Net Metering purposes
Load – 400W (Solar availability is 1000W)
Excess 600W is supplied back to the grid.
The power is shared by both Solar and grid power and excess solar power is supplied back to the grid for feed-in tariff credit
Case 5: No load and solar power generated supplied to the grid
Load demand is 0 W and Solar availability is 1000W and 1000 W generated by the solar panels is supplied back to the grid for credit.
Case 6: Off Grid Topology
The hybrid inverter can also work in the Off Grid topology where power is not supplied from the Grid and exclusively provided by the Solar.
Other types of Inverters
- String inverters
- Central Inverters
- Micro inverters
- Power optimizers
In this case, the solar panels are stringed together with parallel connections going to a single centralized inverter which converts the Direct current generated from the solar panels to Alternating current(AC). This kind of an inverter costs less but produces electricity as it the least productive solar panel.
When using a central inverter, the DC power produced from each string runs along wires to combiner boxes where they are connected in parallel with other strings. From there, the DC power is then run into the central inverter and converted to AC power.
In this case, the solar panels stringed together run parallel which connects to the Central Inverter which does the conversion.
These can be looked as distributed inverters compared to String or Central inverters. These are installed for individual solar panels which convert DC to AC. Using this kind of a system one can also monitor the performance of individual panels.
These are a mix of Central and micro inverters. They are fitted to the individual solar panels to condition Direct current generated from the solar panel and are directed to a central inverter.
Things to consider when purchasing Solar inverters
The capacity of the inverter is the maximum load that you can be connected to the inverter. For example, if the inverter capacity is 1MW, then it can support a maximum load of 1MW.
Check the battery capacity for how much a solar invert can offload and what loads can be supported when there are power outages.
Surge power and other power considerations
An inverter needs to supply two types of power – peak power and usual power:
Surge Power is the maximum power that the inverter can supply, usually for only a short time
This power is used for certain appliances that require surge power when starting when they require high power after which they start using the typical power.
Typical is what the inverter has to supply on a steady basis. This is the continuous rating.
Metering support: Check whether the inverter supports for net metering facilities with Net Metering / Utility Meter integration
This technology is used by the grid tied inverters to optimize Solar panels to provide maximum power output.
Maximum power point is the optimal condition where Solar panels produce the most power.The power produced from the Solar panels varies based on temperature, Shading, irradiance levels and other factors.
MPPT tracks and optimizes the solar panels for this sweet spot (Maximum power point) to get the maximum power output from the Solar panels.
Programmable controls for regulation and monitoring
The solar panel’s output depends on a number factors like temperature, irradiance, heat, shade, and others. An inverter should be able to regulate the output from the solar panel in spite of the variations to ensure there is a steady power output.
Also, there should be ways to monitor the energy output from the solar panels. Check if there are programmable controls in the form of display panels or there is support for mobile apps for monitoring of power from the solar panels.
With so many solar inverters in the market, it goes without saying you need be aware of the intricacies involved in buying Solar inverters. Make use of the facts, tips and techniques covered in this article to help choose a quality solar inverter.
You now understand what are the different types of solar inverters and what best fits the requirements.
We at Lavancha provide German make solar Hybrid inverters- XTM SERIES studer inverters that serve the purpose for both On and off grid Solar PV systems. Got any questions or thoughts about Solar inverters, please feel free to leave your comments. For any of your requirements, please get in touch with us. We would be happy to help you.