pvl_singleaxis error at low sun angles
cwhanse opened this issue · 0 comments
cwhanse commented
Describe the bug:
Low sun angles with a tilted tracking axis cause an error in the backtracking calculation. Code attempts arcos() of a value outside [-1, 1]
pvlib-python #656
To Reproduce
SunZen=80;
SunAz=338;
Latitude=nan;
AxisTilt=30;
AxisAzimuth=180;
MaxAngle=60;
GCR=0.35;
Backtrack=0;
[~,~,mod_thetam, mod_azm]= pvl_singleaxis_v2(SunZen, SunAz, Latitude, AxisTilt, AxisAzimuth, MaxAngle, Backtrack, GCR)
Backtrack=1;
[~,~,mod_thetam, mod_azm]= pvl_singleaxis_v2(SunZen, SunAz, Latitude, AxisTilt, AxisAzimuth, MaxAngle, Backtrack, GCR)