Solar tracking System for solar cells - Electronic Circuits Projects Diagrams Free

bogdanfirst · 15th February 2004, 10:18 AM

some people requested to post this circuit for the solar tracking system
the circuit is simple. the circuit is a window comparator wich controls the motor until the same light falls on the 2 LDR's

Johnson777717 · 16th February 2004, 02:34 AM

SWEET. Thanks a bunch. My next project!

bogdanfirst · 29th February 2004, 11:04 AM

there can be used 2 circuits to provide a 2 axis rotation. but it think that if the pannel is placed well, only one axis is necessary.

Johnson777717, can you post some pictures after you finish it?

Russlk · 29th February 2004, 12:22 PM

What happens in the morning, when the system has been left pointing West and the sun comes up in the east? It does not appear that either LDR will have light on it.
BTW, nice drawing!

crust · 29th February 2004, 03:57 PM

That is an interesting way to do it. I've always seen the control system use dithering. It moves the panel slightly and then measures the power output. If it increased then it moves a little more. If not, it goes the opposite direction.

Johnson777717 · 1st March 2004, 12:54 PM

Yeah, i'll post some pictures once finished. It may take me a while to semi-engineer the mechanics here, but we'll get 'er done!

Klaus · 2nd March 2004, 02:01 AM

Quote:

Originally Posted by Johnson777717

Yeah, i'll post some pictures once finished. It may take me a while to semi-engineer the mechanics here, but we'll get 'er done!

Yes, that would be the hardest part, to make it track reliably year in, year out, in all kinds of weather, high winds, snow, ice...
Perhaps a worm drive might be a good idea, the big reduction ratio lets you use a small motor and it is not free wheeling.
Angle the panel to your latitude in degrees plus about 10 degrees, to make up for the lower winter sun orbit.
So it just needs to track east to west. You can put in some logic that always returns the panel to fully east after a prolonged no output period (night time). The sun isn't going to rise anywhere else :wink:

crust · 2nd March 2004, 02:17 AM

The university that I went to had a few panels on the roof of the electrical engineering building (Central Texas). It is a pain to add an active positioning system, so they just adjust them 2x per year to match approximate position of the sun.

Johnson777717 · 2nd March 2004, 02:25 AM

Good point Klaus.

I did some brainstorming on the circuit, to see what kind of challenges might be faced. Here are some challenges that I forsee with the system, aside from the mechanics (PS.: The worm gear idea is great!):

1. Figuring the proper diameter and length of the tubes which house the LDR's. Too little diameter, or too much length, and the circuit may spend it's time adjusting to a light amount that cannot be reached by the resolution of the LDR's.

2.Figuring the angle(Pitch) of the support block which is used to support the tubes. Again, too much pitch may produce a resolution point that is too fine for the circuit to "zero" in on.

3. What is the "A" point marked on the left side of the schematic?

4. Figuring the resolution, or output ohm range for the LDR's. LDR's are sold in different models, which output different ranges of ohms for a given light amount. Choosing which one is right is a challenge. I think I may set the circuit up on a breadboard, and use POTS in place of the LDR's to see what kind of ohms output best suits the circuit.

5. Figuring which type of motor is necessary for the axis rotation. Would a stepper motor be well suited here? Too many RPMS with the improper gearing could result in a system that is not capable of finding the best fixed point, and thus not be able to reach the resolution that the LDR's provide (Overcompensation).

6. Figuring the logic to account for the opposing axis operating simultaneously. For instance, axis A may be in the midst of finding the best light point, while axis B is in the midst of finding the best light point. Thus, will the simultaneous operations send the logic of the device to a point where no real zero point is found, and the system sends itself into a perpetual adjusting cycle? I think there needs to be some sort of switch which allows only one of the axis to find the best zero point. Once this is found, or the switch times out, the other axis is allowed to find the best point. So on and so forth until each axis is satisfied.

Any thoughts?

3.

Klaus · 3rd March 2004, 12:25 AM

Quote:

Originally Posted by Johnson777717

Good point Klaus.

I did some brainstorming on the circuit, to see what kind of challenges might be faced. Here are some challenges that I forsee with the system, aside from the mechanics (PS.: The worm gear idea is great!):

1. Figuring the proper diameter and length of the tubes which house the LDR's. Too little diameter, or too much length, and the circuit may spend it's time adjusting to a light amount that cannot be reached by the resolution of the LDR's.

I do not think it is that critical, just enough to create a different output from each unless their combined centreline points towards the sun.

2.Figuring the angle(Pitch) of the support block which is used to support the tubes. Again, too much pitch may produce a resolution point that is too fine for the circuit to "zero" in on.

Again, I doubt its too critical, perhaps 30 degrees to start with? What's more importantis that there is nothing reflective nearby to upset the system;-)

3. What is the "A" point marked on the left side of the schematic?

Just some reference for circuit measurement I guess. It should be exactly half the supply voltage for 'on track' condition.

4. Figuring the resolution, or output ohm range for the LDR's. LDR's are sold in different models, which output different ranges of ohms for a given light amount. Choosing which one is right is a challenge. I think I may set the circuit up on a breadboard, and use POTS in place of the LDR's to see what kind of ohms output best suits the circuit.

Idare say that it is not at all critical what range they are, as long as they are reasonably sensitive. The circuit is like a comparator, comparing a fixed input to the op amps to a variable one and wether the variable one is more pos or neg than the fixed input.

5. Figuring which type of motor is necessary for the axis rotation. Would a stepper motor be well suited here? Too many RPMS with the improper gearing could result in a system that is not capable of finding the best fixed point, and thus not be able to reach the resolution that the LDR's provide (Overcompensation).

I think a stepper motor is way overkill, it needs a dedicated drive board, not the 'H' bridge drive shown. Try an old windscreen wiper motor, they usually have a worm drive ( at least some old ones did). It will also run both ways if you disable the parking switch inside it.

6. Figuring the logic to account for the opposing axis operating simultaneously. For instance, axis A may be in the midst of finding the best light point, while axis B is in the midst of finding the best light point. Thus, will the simultaneous operations send the logic of the device to a point where no real zero point is found, and the system sends itself into a perpetual adjusting cycle? I think there needs to be some sort of switch which allows only one of the axis to find the best zero point. Once this is found, or the switch times out, the other axis is allowed to find the best point. So on and so forth until each axis is satisfied.

I frankly would not bother to try this with two axis resolution. The mechanical effort is very unlikely paid back in an sufficient increase of output unless you plan to do this on a very large solar panel.

Any thoughts?

Have fun.
Klaus

3.

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KyotoDragon · 3rd March 2004, 06:55 PM

According to NREL website data most location will achieve a 20% boost in single axis tracking and 40->50% with dual axis tracking.

My pet project requires dual access tracking, its a solar concentrator for hot water. Check out the fun at www.pluggedin.ca/heater.html (if you're bored).

Old satellite dish actuators make great tracking motors.

Glenn

29th February 2004, 12:22 PM	(permalink)
Russlk Experienced Member	What happens in the morning, when the system has been left pointing West and the sun comes up in the east? It does not appear that either LDR will have light on it. BTW, nice drawing! __________________ see my website: www.geocities.com/russlk

3rd March 2004, 06:55 PM	(permalink)
KyotoDragon New Member	Dual axis rules ! According to NREL website data most location will achieve a 20% boost in single axis tracking and 40->50% with dual axis tracking. My pet project requires dual access tracking, its a solar concentrator for hot water. Check out the fun at www.pluggedin.ca/heater.html (if you're bored). Old satellite dish actuators make great tracking motors. Glenn

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16th February 2004, 02:34 AM	(permalink)
Johnson777717 Experienced Member	SWEET. Thanks a bunch. My next project!

29th February 2004, 11:04 AM	(permalink)
bogdanfirst Experienced Member	there can be used 2 circuits to provide a 2 axis rotation. but it think that if the pannel is placed well, only one axis is necessary. Johnson777717, can you post some pictures after you finish it?

29th February 2004, 03:57 PM	(permalink)
crust Experienced Member	That is an interesting way to do it. I've always seen the control system use dithering. It moves the panel slightly and then measures the power output. If it increased then it moves a little more. If not, it goes the opposite direction.

1st March 2004, 12:54 PM	(permalink)
Johnson777717 Experienced Member	Yeah, i'll post some pictures once finished. It may take me a while to semi-engineer the mechanics here, but we'll get 'er done!

2nd March 2004, 02:17 AM	(permalink)
crust Experienced Member	The university that I went to had a few panels on the roof of the electrical engineering building (Central Texas). It is a pain to add an active positioning system, so they just adjust them 2x per year to match approximate position of the sun.

2nd March 2004, 02:25 AM	(permalink)
Johnson777717 Experienced Member	Good point Klaus. I did some brainstorming on the circuit, to see what kind of challenges might be faced. Here are some challenges that I forsee with the system, aside from the mechanics (PS.: The worm gear idea is great!): 1. Figuring the proper diameter and length of the tubes which house the LDR's. Too little diameter, or too much length, and the circuit may spend it's time adjusting to a light amount that cannot be reached by the resolution of the LDR's. 2.Figuring the angle(Pitch) of the support block which is used to support the tubes. Again, too much pitch may produce a resolution point that is too fine for the circuit to "zero" in on. 3. What is the "A" point marked on the left side of the schematic? 4. Figuring the resolution, or output ohm range for the LDR's. LDR's are sold in different models, which output different ranges of ohms for a given light amount. Choosing which one is right is a challenge. I think I may set the circuit up on a breadboard, and use POTS in place of the LDR's to see what kind of ohms output best suits the circuit. 5. Figuring which type of motor is necessary for the axis rotation. Would a stepper motor be well suited here? Too many RPMS with the improper gearing could result in a system that is not capable of finding the best fixed point, and thus not be able to reach the resolution that the LDR's provide (Overcompensation). 6. Figuring the logic to account for the opposing axis operating simultaneously. For instance, axis A may be in the midst of finding the best light point, while axis B is in the midst of finding the best light point. Thus, will the simultaneous operations send the logic of the device to a point where no real zero point is found, and the system sends itself into a perpetual adjusting cycle? I think there needs to be some sort of switch which allows only one of the axis to find the best zero point. Once this is found, or the switch times out, the other axis is allowed to find the best point. So on and so forth until each axis is satisfied. Any thoughts? 3.