Microinverter vs String Inverter : What You Need to Know

An electronic device known as a solar inverter serves as the main controller of the solar generator. He seems like the “brain” of the whole team. Imagine this solar photovoltaic (PV) system as a workhorse on your rooftop or other property. They are responsible for converting solar energy into electrical energy by capturing it.

However, it is currently not possible to use direct current (DC) electricity generated by the panel (except in certain off-grid situations). It must be converted to alternating current before it can power the refrigerator or cool the house (AC). Direct current (DC) electricity generated by solar panels is converted to alternating current (AC) electricity using solar inverters used by appliances and HVAC systems in homes.

WHAT IS A MICRO INVERTER?

To control the DC-AC power inversion for a single solar panel, a microinverter is an inverter that is paired with the panels. There is no central inverter in systems that use microinverters, which makes them different from systems that use central inverters. Instead, each panel is connected to a separate microinverter.

Microinverters are Module Level Power Electronics (MLPE) devices that convert DC electricity generated by solar panels into AC electricity that can be used by appliances and HVAC systems. They are considered a high-tech luxury item.

In other words, a microinverter works similar to a small string inverter for a single PV panel located on a particular panel. Before investment, they also perform DC optimization.

HOW IT WORKS?

Each solar panel works independently of the others when connected in parallel. In this arrangement, a microinverter installed behind or nearby converts the solar energy generated by each individual panel of electricity from DC to AC.

Modern solar microinverters optimize the solar output of each panel in your home system using MPPT and other advanced techniques. This results in the best optimization and smoothest conversions.

After the rollback, AC electricity enters your home, where it can be used to power your appliances and heat or cool rooms. Any excess is sent to the electrical grid. (Or, if it’s set to draw amperage, to the battery.)

ADVANTAGES AND DISADVANTAGES OF THE MICROINVERTER

Quick Shutdown Ability – Can be quickly and easily shut down to meet electrical codes in various locations.

Per Panel Inspection – A microinverter’s performance can be monitored one panel at a time, but a standard inverter can only monitor the entire system. This means that even minor issues with the panels can be quickly found and resolved.

Works well even in shaded areas: The microinverter works smoothly and makes the most of sunlight even in partially shaded locations and when all panels are facing different directions, as there is an inverter behind each panel. Compared to optimizers, they even have a slight advantage.

Gaps

Because there are so many inverters, maintenance is difficult.

Compared to string inverters they are not cost effective, especially for typical 5kW home installations.

Not suitable for stormy areas as the microinverter can be used as a mini lightning rod.

WHAT IS A STRING INVERTER?

A central inverter with inputs for a “string” of panels to run on a single unit is called a string inverter. The inverter is connected to the ends of a string of connected panels connected in series. Several inputs are visible on the string inverter.

Depending on the overall size of the solar power system, each home solar installation can consist of a single inverter or up to two string inverters.

A “series string” of solar panels, also known as a 6-12 solar array, is what a string inverter uses to operate in a series circuit.

HOW IT WORKS?

Solar panels form what are called “strings” or groups when connected in series. There may be more than one string, depending on the maximum power output of the generator and the location of the panel. A chain usually consists of 8 to 15 panels.

All modules in a string must be of the same type, have the same power rating, and face the sun at the same angle and in the same direction to generate the most electricity possible.

Each string carries high-voltage DC electricity from the panel to the inverter, which is often located on the ground floor of your home next to the electrical panel. You can place the inverter outdoors, in your garage, or in your basement.

An inverter is attached to each string, usually as a separate input. You may even need multiple string inverters to drive all your multi-strings, depending on the size and design of your solar panel. The inverter converts the direct current and transfers it through the strings to alternating current.

ADVANTAGES AND DISADVANTAGES OF THE CHAIN ​​INVERTER

Very few wiring errors – Since there is only one inverter, system wiring is fairly easy. As a result, the possibility of a wiring error is very low.

Cost effective – In terms of installation costs, string inverters are quite inexpensive.

Easy Troubleshooting – Installation with a string inverter is fairly simple to troubleshoot as there is only one of them to deal with if there is an interruption in power generation.

Gaps

Compliance challenges due to slow closure

It is not effective in the shade.

Due to the prohibitive cost of adding a second string inverter, increasing production capacity became a challenge.

25-year warranty for microinverters compared to a short 8-12 year warranty.

Insufficient monitoring at the panel level

GENERAL REASONS

Residential solar inverters available today fall into one of three categories: microinverters; string inverters and hybrid inverters.

Whether on-grid or off-grid, string inverters and microinverters share the same properties. Both convert DC electricity into usable AC electricity before sending it to your equipment.

They also route any additional AC current to the mains when connected to the mains. With strings or microinverters, there is no demand for on-site battery storage. (However, the battery connection is present at least for most off-grid applications.)

As will be explained below, string inverters differ from micro inverters when it comes to DC-AC conversion.

DIFFERENCE

Both inverters need to switch from DC to AC. This location makes all the difference. String inverters convert DC to AC at the string level, while microinverters do it on the back of each solar panel on the roof. Microinverter vs. the string inverter contains other points-

Production – Due to their optimization at the panel level, microinverters often work best for homes with complex roofs and shading or dirt issues. However, due to their high efficiency, string inverters can work well for homes with simple roofs and proper orientation. The latest string inverters feature dual MPPT technology.

Initial Cost – Compared to string inverters, microinverters typically have a higher initial equipment cost. One of the more popular microinverters has a 25-year warranty and costs around $0.7/W. With a 10-year warranty, string inverters are available for about a third of that price.

Maintenance – Due to the low AC voltage they carry, microinverters are known to have low individual failure rates. However, the failure rate increases with the number of components in the system, and a 5 kW solar system, for example, might contain 23 microinverters. Someone has to climb on the roof, remove the solar panels and install a new microinverter in case of failure. The wall-mounted cable inverter eliminates the need for maintenance personnel to climb onto the roof.

WHICH IS FOR YOU?

While most microinverter manufacturers tout extremely low failure rates, this claim remains skeptical. Inverters, which are the most complex electronic components in solar systems, also fail the most, according to one source: decades of experience in the solar installation industry. Instead of installing one string of inverters, it would be rather hesitant to install 20. Only in extreme cases of significant shading problems is it recommended to do so.

Although microinverter manufacturers market the ability to monitor each panel as a feature (and it is), they do not offer monitoring that allows the user to accomplish this. Unless you agree to purchase a higher level of monitoring as an upgrade, they only allow the installer to view data at the panel level of your system and not you as a customer.

This implies that, as a customer, all tracking data presented to you is information about the system as a whole. A skeptic will say that they do this to protect themselves and their installers from service calls related to a faulty inverter. It’s pretty hard to tell if only 1 or 2 of about 25 UPS’s are out of order using only system-wide monitoring data.

For this reason it is better than microinverters, but from a customer perspective it is better to buy a system with an additional cash payment for a monitoring level that provides panel level analysis. The whole system shuts down when the string inverter fails, so it’s easy to notice.

CONCLUSION

The limits of your project will probably determine the type of inverter you use: micro, string or power optimizer. If you can grow your system in direct sunlight, choose a string inverter. If you need to start small and grow later, use a microinverter. Consult Beny.com to find the perfect solution for your electrical system.