Solar Micro Inverter
A solar micro-inverter is an electronic device used to convert direct current into alternating current from an
individual solar panel. micro inverters have some benefits over traditional central inverters, notably, they
increase the efficiency of solar panels
by up to 5 percent and 25 percent.
However, micro-inverters do not make much economic sense when compared to central inverters, because they cost
more per watt - $0.52 per watt compared to $0.4 per watt for central inverters, as of October 2010. Recently
developed micro inverters can accept direct current input form two solar panels.
When micro inverters are used, the need for string sizing is done away with. Here, every individual module is
directly linked to a micro-inverter and fitted on a racking below. The AC wiring harnesses on the micro-inverter
are joined to form a continuous alternating current circuit that eventually lead to the AC utility dissemination
Because all the output wiring from the photovoltaic array is AC, system safety is improved. Dangerous DC
voltages are therefore eliminated once the AC power is turned off for emergency or maintenance - typically, only
50-volts or under will flow in the array once the AC array is off.
Why micro-inverters have higher reliability
Generally, micro-inverters are more reliable than conventional inverters, having a Mean Time to Failure of more
than 300 years. Additionally, most micro-inverter manufacturers give generous warranties, typically 15 to 20 years,
compared to 5 to 10 year warranties of string inverters. Durability of a micro-inverter is determined by the
components and design used to make it.
Given the high amounts of heat generated with string inverters, more stress is applied to them, thus, their
shorter life-span. A micro-inverter allows voltage input from a single solar panel, meaning that fewer components
are needed to work with lower voltages. Reliability is also improved by better packaging, a feature of most
micro-inverters, although a couple of string brands have good packaging too.
Some micro-inverters are data enabled, making it possible for them to exchange data over a communication
channel, like the internet, using protocols such as WiFi or Zigbee.
Why should you use micro-inverters over conventional inverters?
Reliability and durability - if a single micro-inverter fails, it will only affect the solar panel it is
connected to, rather than the entire array as is the case with normal solar inverters. Additionally,
micro-inverters have a longer mean life to failure than normal inverters.
More efficient - Micro-inverters have more efficiency than normal inverters, claiming to generate between 5 to
25 percent more power from the solar panels. This is possible as micro-inverters harness the maximum power
production of each panel, as opposed to other inverters that harness for the entire solar array.
A string inverter will only detect an overall change, even if it is a single panel functioning at a different
point, and then adjust the MPPT point to match. A percentage loss of up to 9 percent across the entire system array
can result into a total system power loss of over 50 percent.
Other advantages of micro-inverters include: easy set up, scalability, lower lifecycle expenses, space
maximization and less heat generated.
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