Microinverters vs String Inverters

Microinverters vs String Inverters

The main purpose of a solar power system is to convert the Direct Current (DC) solar panels generate into an Alternating Current (AC), which is the type of electricity that can be used to power your home. Solar power is the conversion of renewable energy derived from the sun into usable electricity to power your home or business. Inverter technology has been steadily evolving over the past several decades to better enable homeowners to maximise the use of power from their solar PV systems. Both string inverters and microinverters do this job for you as a solar homeowner, but have unique technical functioning.

A string inverter is also known as a “central inverter” and is a standalone box that is typically installed close to your main service panel and electricity meter. There is typically only one single inverter for each residential solar installation. A string inverter functions in a series circuit, with there usually being 6 to 12 individual solar panels in what is known as a "series string." SMA and Fronius are some examples of leading manufacturers of string inverters in the Australian market.

Microinverters perform the same basic function as string inverters. The installation of microinverters is different from string inverters. Microinverters are installed underneath each solar panel on a rooftop solar installation. The size of each of these microinverters is about the same as that of an internet router.

The big difference between microinverters and string inverters is that a solar panel installation with microinverters will typically have the same number of microinverters as the total number of solar panels. However, there are certain microinverters that accept two or four solar panels too.

Enphase is an example of a leading manufacturer of microinverters in Australia. Enphase microinverters have been on the market since 2009 and have become an integral part of their booming business. Enphase has been consistently working towards developing their technology and their researchers have been studying how to best apply principles of maximum power point tracking (mppt) into their components for enhanced solar PV production to ensure an efficient system.

While standard string inverters will cap the electricity production of each solar panel by the lowest producing panel on your roof, microinverters don’t have this problem, since they function in a parallel circuit. A microinverter is considered to have higher efficiency as it takes full advantage of the production of each individual panel. It will convert the power generated by each panel to the grid voltage. Each solar panel and microinverter combination can “do their best” and contribute as much power as they can.

Power optimizers are an option for standard string inverters, as well. They function very similarly to microinverters, though electricity is not converted into AC behind each panel. That work still gets done at the string inverter.

Optimizers are able to smooth voltage and combat production differences, leading to enhanced solar power output, even in challenging, partially-shaded solar installations. Solaredge is a leading manufacturer of power optimizers.

In the run-off between micro-inverters and string inverters, which performs better depends on the shading conditions. It is as simple as this, if you have shade on your roof due to trees or tall buildings next to your roof, you need micro-inverters or optimisers as string inverters don’t work in shade.

The core advantage of using microinverters is that with the installation of microinverters, you can yield more solar electricity. The reason for this is that there are slight differences in currents between solar panels. When solar panels are in a string, the current is reduced to that of the least-producing panel in the string. Other reasons why a microinverter would be preferred over a string inverters is if a solar system is facing multiple angles, meaning some panels are facing south, some east, and some west, then microinverters are the way to go. One of the most common situations when microinverters come in handy is when the roof where solar installation needs to take place has shading issues from trees or a large chimney. In these situations, the solar panels will be producing different amounts of electricity at different times of the day, but microinverters will ensure you harvest all of the energy, while with a standard string inverter you will lose some of this production.

Contact SunMate Solar today for a free quote and advice on which inverter type best suits your roof to provide maximum production.

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