SMA commonly refer to their inverters as being the ‘brain’ of a solar PV system, this may seem like a tag line attempting to sell their products but it is fair to say that any inverter would be the most important component in a grid tied PV system. Commonly the focus is put upon modules when in fact more attention should be paid to the inverter technology employed.
The inverter is responsible for converting the electricity generated by the PV array (DC) to electricity that is usable within the buildings served and by the National Grid. Further to this the unit also monitors the status of the National Grid and controls the PV system in reference to this, shutting down the power output from the PV when required for safety reasons.
The inverter is also required to do this while being as efficient as possible. In a recent “Photon” magazine test of 94 inverters from the top manufacturers the SMA sunny Tripower 20000TLHE-10 topped the chart being the only one to gain an A+ rating.
As well as the commonly string inverter approach (a single inverter for each array), we promote another inverter formation type. The module or micro-inverter uses a single inverter for each module. This allows the modules to act independently from one another meaning a drop in output (through shading or otherwise) from one module will not affect the output of the others. We tend to specify for these inverters where there is more than one source of shading acting on a PV array, maximising output.
We also offer the Nedap Power Router as an option this is an intelligent system which employs a battery store. In essence it measures the output of the PV array and the consumption of the building that it serves and if the PV output exceeds the consumption then the excess is stored within the battery stack for use at a later time. This maximises the financial benefit of the UK Feed-in tariff scheme by ensuring as much energy as possible is used on-site.