There are common, and intertwined, misconceptions in the PV industry about string inverters today. The first is that they are subject to the ‘Christmas light effect’, meaning, if one module can’t produce power, the whole string will stop working. The second is that in the presence of shade, inverters will be forced to work at the point of the ‘weakest module in the string’, sacrificing large amounts of power that only module level power electronics (MLPE) can regain. SMA America is here to help put the record straight.
The above theories are incorrect for a couple reasons. Firstly, inverters are not the component of a PV array that prevents the ‘Christmas light effect.’ Additionally, current technologies in PV modules and inverters have solved the problem of the ‘weakest module in the string’ and provide optimized performance without the continuous power loss and complexity of MLPE.
