Microinverters and Central Inverters: Key Differences

Inverters & Monitoring
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central inverter VS. microinverter

An inverter switches the direct current (DC) generated by the solar panel into an alternating current (AC). The inverter then sends the AC to the house, allowing it to power your lights, fridge, air conditioner, and more.

Power generated from solar doesn’t work without an inverter because the outlets in our homes use AC. The application of DC on its own is far more limited.

When the DC from the panel switches to AC, some power is lost. How much is lost, however, depends on the efficiency of the inverter. Using the appropriate inverter for your solar project can make a difference in the system’s efficiency.

What A Central Inverter Does

Central inverters allow a system to convert power from large solar arrays with fewer inverters. Central inverters typically handle between 50 kW and 1 MW per inverter. 

In the United States, central inverters come in either 600V or 1,000V DC voltage categories. The 600V inverters often get used for commercial rooftop applications, while the 1,000V category central inverters often only get used in utility applications. 

Monolithic central inverters use a single power train and MPP tracker. Modular central inverters use multiple power trains. While modular inverters are more complex, they allow the central inverter to continue to function at reduced power if a couple of solar panels stop working. 

The Difference Between a String Inverter and Central Inverter

The main difference between a string inverter and a central inverter is the power the inverter can handle. Central inverters have longer strings of modules connected to them. They use string combiners and recombiners to feed more current into the inverter. 

Optimized String Inverters

A string inverter ties several strings of solar panels to one inverter. This setup allows the inverter on the ground level to manage everything. However, if shade covers one or two of these modules, it messes with the production of the entire array.

Optimized string inverters use a string inverter to control everything and power optimizers on each solar panel to minimize the impact of shade on the system. This setup also allows for module-level monitoring, which decreases the time it takes to problem solve.

How Microinverters Work

Microinverters essentially are miniaturized inverters placed on the back of each solar module. Each microinverter converts power at the solar panel, allowing monitoring at the modular level and decreasing the impact of shade on the system’s overall production.

Are Microinverters Worth the Extra Money

Solar arrays with microinverters require a microinverter with each solar panel, which can quickly increase the cost of this inverter type. However, if you have a home with shading issues or limited space, microinverters are a better option than a traditional string inverter.

The Best Inverter Choice for Your Circumstance

Which inverter is best depends on the application. While one inverter may work great for business applications, it may not work for residential or utility purposes. The type of solar project you’re working on determines the best inverter for it.

Inverter of Choice for Utility Application

Because utility-scale solar is often massive, central inverters are the best choice for this installation type. Central inverters can power more panels at once, making the system less expensive to install and easier to maintain.

Professionals suggest using a central inverter for utility-scale projects over 10 megawatts. A central inverter not only decreases the cost-per-watt, but if the system is large enough to need multiple central inverters, one inverter going down won’t have as drastic an impact.

The Best Business Solar Inverter

Businesses interested in solar have a range of energy needs. However, they often aren’t large enough to need more than one central inverter.

Depending on financial circumstances and priorities for the installation, the system could use one central inverter, multiple string inverters, or microinverters on each solar panel. If the system is going in an area with minimal shade, optimized string inverters may be the best choice. Optimized string inverters have easier maintenance and are more cost-effective than microinverters.

However, if the goal is to spend the least money, purchasing one central inverter may save upfront costs. Optimized string or central inverters also make monitoring individual modules possible.

The Optimal Residential Solar Inverter

The best solar inverter for residential use depends on the shading and space available for the system. Because residential solar arrays are typically smaller, a string inverter or microinverters work better than central inverters. Optimized string inverters combine the benefits of string and microinverters, making them the ideal option for residential use.

Go Solar Group residential installs use SolarEdge’s HD wave optimized string inverters. These inverters use power optimizers at each solar panel to monitor and increase the production of modules while still allowing for the ease of maintenance that a string inverter provides.

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