When investing in a solar panel system, you might come across the term three phase inverter. As you might already know, a solar inverter is responsible for converting Direct Current (DC) into Alternating Current (AC) that can be used by home appliances like refrigerators or TVs.
On the Australian solar market, you will find both single phase and three phase inverters. So, what is the difference between the two, and do you really need a three phase inverter?
Single phase vs. three phase electricity supply
Most Australians live in homes with a single-phase electricity supply. In other words, their home is connected to the grid through one single wire.
In comparison, a three-phase home will be connected to the grid through three wires, which means that the house is able to pull a much larger amount of electricity from the grid.
Three phase electricity supply might be beneficial for homes with energy consuming appliances like electric car chargers, saunas, big A/C systems or pool heaters.
With a three phase electricity supply, you will also be able to send a much greater amount (3 to 6 x) of solar electricity to the grid, than with a single-phased system.
What inverter types can you choose from?
If you live in a home with a three phase electricity supply, you are able to choose between the following inverters when installing a solar panel system:
- Microinverter
- Single phase inverter
- Three phase inverter
Each of these can be good choices. The type you choose does not affect your possibilities of self-consuming solar energy or the exported energy rates.
What is a three phase solar inverter?
This is a device that converts DC energy generated by your panels into AC energy. It then “chops up” and distributes the energy across a three-phase supply.
The inverter will feed the energy evenly across all three phases to your home appliances and/or into the grid.
Why choose a three phase solar inverter?
One of the main reasons for choosing a three phase inverter is to reduce the risk of voltage rise issues. With this type of inverter, the inverter capacity spreads across three different wires, eliminating the need to push all the energy to the grid through one wire.
Because of the spread, you will not increase the voltage of your local grid as much as you would with a normal inverter. Over-voltage issues may lead to tripping and throttling.
What is voltage rise, and why should you avoid it?
Voltage rise is the difference between the voltage of the grid and the inverter voltage (the latter is marginally higher to be able to send surplus energy into the grid).
The grid voltage is normally somewhere between 216 and 253 V (230 V on average), while the inverter voltage is typically 235 V.
If you are located in a suburb or street where many people have solar panel systems, the grid voltage might rise when the panels produce a lot of energy. As the voltage of the grid rises, your solar inverter has to rise above it. If the inverter voltage gets too high, the device might shut off.
With this inverter, you can overcome the issue, as the power is spread across three wires.
Is there any reason not to choose a three phase inverter?
In most cases, the three phase version will be more expensive than a normal inverter, and on average it will cost around $300 and $500 more.
If you are interested in keeping your costs at a minimum, three phase may not be the best or most economical choice.
Do you need a three phase inverter?
No, not necessarily. Remember, if you have a three phase power supply, you can also use a single phase inverter. If you choose a single phase inverter, you will not lose money from lower feed-in tariffs or similar.
But if you ask an electrician for advice, he or she would probably recommend a three phase inverter as it will reduce the risk of voltage rise. Whether a three phase inverter is the best choice for you or not, will depend on your budget.
What is the best three phase inverter on the Australian market?
If you decide to go for a three phase inverter, we recommend you go for a quality product. Here are some of your best choices:
- SolarEdge Three Phase Inverter
- Fronius Symo
- SunGrow 3 Phase Hybrid Inverter
- SMA Sunny TriPower
If you have trouble deciding on which product to choose, you can consult your solar installer for further advice. Find a solar installer today, and find the best three phase inverter for your solar system!