How Helioscope Models Inverters

HelioScope simulates all inverters based on a common set of design & modeling principles: 

Dual-MPPT Stringing

HelioScope assumes that each inverter will model with 2 MPPT's (often with different string lengths in each MPPT zone) unless there is a single string length, in which case it will default to 1 MPPT tracker. There is a maximum power imbalance between the two MPPT zones of 70/30. 

Max Power Point Tracking Efficiency

HelioScope assumes that the inverter will correctly track the MPP of the solar array throughout the day. Said differently, HelioScope assumes 100% MPPT tracking efficiency. 

Operating Voltage Range

Inverter weighted efficiencies are calculated based on performance under MPPT. Because of this, HelioScope simulates the performance of the inverter within the rated MPPT range and will not operate the array outside the inverter's MPPT range. If the MPP point of the array goes outside the inverter's MPPT voltage range, then the power loss will show up as voltage clipping, in the "Constrained DC Output" step of the Annual Production Table. 

Maximum Output Power

The maximum power that HelioScope will simulate is the rated AC output of the inverter. HelioScope will not model a higher instantaneous maximum output based on changes in grid voltage, as all simulation is done based on the inverter's nominal voltage.