PV DC output

Hello,

It is hard to tell what might cause that without seeing your file. Here are some possible explanations:

1. Inverter clipping: If the nominal array voltage at maximum power (Vmp) is high compared to the inverter maximum MPPT voltage, the inverter may be clipping the array voltage to the MPPT limit during periods of high POA irradiance. Clipping reduces the power output of the array.

2. Inverter power limiting: If the DC-to-AC ratio (array nameplate DC capacity to inverter nameplate AC capacity) is high, the inverter may be limiting the output of the system to the inverter's rated AC capacity during periods of high POA irradiance.

3. Shading by nearby objects or soiling. If you include shading and soiling in your analysis, these will reduce the system's output.

4. Self-shading for fixed and one-axis tracking: Depending on the ground coverage ratio (GCR) and the shading option you choose, shading of modules in neighboring rows could cause a reduction in the system output.

You can use the diagram on the Losses tab of the Results page to investigate these possible causes.

Best regards,
Paul.

SAM's photovoltaic models assume that the photovoltaic array is connected to an inverter, and that the inverter and load (for Residential and Commercial financial models) are connected to the grid.

The Detailed Photovoltaic model reports "Array DC power (kW)" and PVWatts reports "DC array power (W)" in the time series results that you can use if all you need is the DC power.

Best regards,
Paul.