Effects Of Inverter Clipping On Solar Power Variability
Abstract
Inverter clipping applies to photovoltaic systems with a solar power capacity greater than the inverter output, mitigating the incoming solar variability while losing a surplus in solar energy production. We study the effects of inverter clipping on solar power generation variability by modeling a PV system with monofacial or bifacial modules, fixed tilt and tracking, using solar data for Boulder, CO, and assessing the resulting solar power generation with a novel dimensionless variability index (DVI). Comparing the output AC to the input DC power, annual averages of daily DVI diminish between 4% and 15%, the greater for bifacial modules. We analyze the direct effect of the inverter-to-load ratio (ILR) for two selected days with little and large variability. Generated power variability decreases after a given ILR value for each configuration, under a systematic behavior: at high ILR, variable days deliver more AC energy with lower variability for fixed tilted configurations. For clear sky days, this occurs for tracking configurations.
Keywords
PV Energy Generation, Solar Variability, Inverter-to-Load ratio, Inverter Clipping