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Solar photovoltaic panels produce direct current (DC) power. However, most of the utilities and almost every household use alternating current (AC). Therefore, a solar inverter is usually employed to convert variable DC supply output of the solar panels into AC current of utility frequency.
There are two types of inverters employed in solar installations: central string inverters and small micro-inverters. Micro-inverters are relatively new to the market and their popularity has been growing increasingly during the recent years.
Micro-inverters are rated between 190 and 220 W and are used to convert the output of a single panel. Unlike traditional string inverters, micro-inverters are connected to each solar panel and then in parallel to each other. As a result, the performance of each panel can be managed independently, and the shading of one panel will not affect the performance of the overall system.
Dual micro-inverters were first introduced in 2011. They essentially perform tasks similar to common micro-inverters, except that they are connected to two solar panels instead of one.
Micro-inverters have a number of key benefits:
Unlike central string inverters that optimize the entire solar panel system, micro-inverters optimize every individual solar panel thereby enhancing the performance of each solar panel.
Micro-inverters do not require high voltage DC wiring, which enhances the safety of system owners and solar panel system.
Maximum Power Point Tracking (MPPT)
The performance of the solar panel depends on the voltage load applied from the inverter. MPPT technique can be used to find the required voltage. Micro-inverters employ this technique such that when MPPT is applied to each individual panel, the performance of the system will eventually increase.
No Single Point of Failure
Since each solar panel consists of its own inverter, failure would mean that only one panel is not working.
Long Service Life
As micro-inverters are usually not exposed to heat loads or high power, they tend to last for a long time.
Micro-inverters dissipate heat lesser than that of central inverters. Therefore, they do not require active-cooling, ensuring silent working conditions.
Other significant benefits include high scalability, reliability, easy and quick system expansion, simple design and wide compatibility range.
The solar inverter market is constantly growing, and there have been several technological advancements over the years in this field.
One of the most promising is the micro inverter. Although, this technology has been in existence for quite some years, the present challenge lies in designing a highly reliable product that suits our real world conditions.
Improved reliability and cost trends of the current micro-inverter systems ensure that this technology would be best suited for a wide range of applications including residential roof tops and commercial installations.
Sources and Further Reading