wrong annual energy output in PySAM

Hello,
I am trying to model a simple PV system in PySAM. 
I used Pvwattsv8.default("PVWattsNone") and then set some inputs in the code. For example, I set the system capacity as 4kW, while the default value is 100,000 kW. After executing the model, the result shows the annual energy output for a 100,000 kW system. 
It seems the code executes the model for default values, although I set different values.
I have no idea what's wrong with it.
I copy my code here:

import PySAM.Pvwattsv8 as PV
pv_model = PV.default("PVWattsNone")

pv_model.SolarResource.solar_resource_file = 'path'
pv_model.system_capacity = 4.0  # System capacity in kW
pv_model.SystemDesign.dc_ac_ratio = 1.2  # DC-to-AC ratio
pv_model.SystemDesign.array_type = 0  # Fixed array type
pv_model.SystemDesign.tilt = 30  # Tilt angle in degrees
pv_model.SystemDesign.azimuth = 180  # Azimuth angle in degrees (South-facing)
pv_model.SystemDesign.gcr = 0.4  # Ground coverage ratio
pv_model.Losses = 5

pv_model.execute()

annual_energy = pv_model.Outputs.annual_energy
capacity_factor = pv_model.Outputs.capacity_factor
energy_yield = pv_model.Outputs.kwh_per_kw


 

Hi Niki,

Please see the PySAM documentation for different ways to set a variable's value:

nrel-pysam.readthedocs.io/en/main/variables-pysam.html#set-a-variable-value

For example, you could use

Best regards,
Paul.

Thank you Paul