Sun tracking algorithm

[ajitnayak]

View attachment NREL data.zip

Dear all,
I am trying to achieve single axis tracker using Below algorithm.Here i have attached relevant document and Links.
Now problematic term:

My single axis tracker going to placed in North south direction . Axis of rotation is east to west. I have sensor which can measure angle from 90degree to -90 degree. From below link for my location Bangalore India. Azimuth angle will be 90 degree i.e @ east point. 180 degree at south point 12:15 PM,270 at 6:30 PM again start at 0 in morning.Now i wanted to determine sun position using these angle in +90degree to -90 degree format.

In morning it must be -90 degree
in noon it must around 0 degree
In evening almost 90degree.

Question here how to convert these angle to +90 to -90 degree format.

1. https://pveducation.org/pvcdrom/properties-of-sunlight/elevation-angle
2. https://www.nrel.gov/midc/solpos/solpos.html
3. https://www.sunearthtools.com/dp/tools/pos_sun.php

 

[BradtheRad]

I suppose you want to convert between celestial coordinates and alt-azimuth coordinates? This involves calculations using sines and cosines.

You will need to get familiar with the celestial coordinate system. You will need to observe how the sun occupies the north part of the sky during summer, and the south part of the sky in winter.

Your axis of rotation will point to the celestial north pole (near Polaris the 'North Star').

Your tracker will be angled up or down to the sun's declination for that day of the year. The sun is north of the celestial equator during spring and summer. It is south of the celestial equator during autumn and winter.

Every day at noon the sun is within a few minutes of your meridian (defined as a line overhead going N-S). Your motor will run at an unchanging rate. Therefore if you start each day (at 6 am) pointing your tracker at a location 6 hours prior to your meridian, it will always be within a few minutes of the sun. This method may be simpler than continual calculations.