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Feb 2nd 2015

Differences between a Micro Inverter vs. Central Inverter in Photovoltaic Systems

Determining to use micro inverters versus central inverters can be a common solar question that arises when choosing the optimal photovoltaic design concept. First it’s important to understand the solar engineering differences between a micro inverter and a central inverter. Solar micro inverters have been on the US market since the 1990s. A single small “micro” weatherproof inverter is installed behind each individual solar module. A solar micro inverter converts the DC power generated by the solar panel into AC power right on the back of each and every solar panel. Central inverters have dominated the solar industry since its inception about 40 years ago. One central inverter normally serves an entire solar array. All the modules in the array are connected together into strings and then wired to a large inverter in a central location. The DC to AC power conversion for all the modules occurs at this one central location.

Since solar panels generate DC (direct current), it is essential to have some sort of device to convert DC into AC (alternating current) in order to power up buildings. This is where a solar inverter comes in. Inverters also enable electrical currents to be switched off in the case of a blackout or if repairs are necessary.

The choice to use micro inverters versus central inverters depends on certain situations and both should be given serious consideration. Below is an overview of a few conditions to think through when making your decision; however, to obtain a better direction on your business’s needs, contact the engineers at KMB Design Group. We are a leading consulting firm in the renewable energy field providing photovoltaic design and engineering services in 49 states.

Efficiency

Micro inverters optimize the power output of each individual panel resulting in more power per panel than central inverters. Because solar micro inverter technology has an inverter associated with each individual PV panel, they may provide greater energy per panel compared to central inverters, due to reduced loss from partial array shading. Some studies suggest that the micro inverter system produced on average 20 percent additional power compared to the central inverter system in no shade conditions. And Renewable Energy World states that shading of as little as 9 percent of a solar array connected to a central inverter can lead to a system-wide decline in power output with as much as 54 percent. With a central inverter, the whole energy output is only as strong as the weakest link.

Flexibility

Expanding on your solar panel system with additional solar panels in the future is easier to do if you’re using micro inverters. Central inverters also come in limited sizes which makes expanding a more difficult task. If a single solar panel malfunctions in a micro inverter system, it will not affect the rest of the system.

Longevity

Central inverters have the reputation to be efficient since they have proven results. But since solar micro inverters are not exposed to as high of power and heat loads as central inverters are, they usually last longer. So, micro inverters often come with a 20-25 year warranty; about 10-15 years longer than a central inverter warranty would come with.

Although performances may be more predictable with central inverters, the future definitely looks promising for micro inverters.

 

KMB Design Group is at the forefront of the escalating solar industry, and is considered a leading consulting firm in the renewable energy field providing photovoltaic design and engineering services. Our Solar engineers will give you full analysis and let you know how much energy can be drawn with considerations such as location, obstructions and orientations. We will also provide you with the best designs that will give you maximum output. Licensed in 49 states, we have the ability to work nationally without limitations.