Talk:Maximum power point tracking
|This is the talk page for discussing improvements to the Maximum power point tracking article.|
|WikiProject Energy||(Rated Start-class)|
Suggest merging the articles Constant voltage method, Incremental conductance method, Perturb and observe method to this article. The reader gets very little extra information from these stubs and it would seem to be more rational to be comparing the algorithms here. --Wtshymanski (talk) 15:34, 27 February 2012 (UTC)
- Oppose The individual articles have enough info in them to have articles on their own. Suraj T 03:54, 16 March 2012 (UTC)
I - V term usage?
I know this term applied as I/V for for the curves may look confusing but isn't this the proper terminology for a current over voltage charted curve? This format appears t be used in many other places in the article for other terms. There must be a way to make the format for these terms match the format used elsewhere for the rest of the terms. Will it look like a Mho formula and isthere a way to identify it as not a Mho formula with proper wording? 22.214.171.124 (talk) 02:30, 28 October 2012 (UTC)
The page says "A photovoltaic cell has an approximately exponential relationship between current and voltage".
Eh? That would imply the current increased as the voltage increased. The curve looks nothing like an exponential. I suggest rewriting to say whatever was meant in a clearer way that will be understood by readers. — Preceding unsigned comment added by 126.96.36.199 (talk) 11:51, 1 November 2012 (UTC)
- I choked on that statement, also. It's pure mathematical BS. The current is not related to the voltage for most of the curve. The curve is a well defined, and an almost perfect constant current source. The current is basically constant (depending on energy source parameters, of course) and never varies much up to the voltage saturation point, regardless of load resistance. This is why many different panel ratings and breeds can be parallelled so easily regardless of size and current rating. This is a classic constant current source description. Refeences would be good. 188.8.131.52 (talk) 17:47, 1 November 2012 (UTC)
MPPT as a motor starter
What is this section even doing here? What's being described isn't an MPPT, it's just a power converter. I'm going to change this to just mention that MPPT is usually integrated into the power system. If you can justify why it should be here, please do and show references. Tarchon (talk) 23:37, 3 November 2012 (UTC)
- This sounds like the same circuitry and the same function performed but for a different purpose. I think if it is not finding the MPP then you're correct to remove it. Mention could be made but... naah. 184.108.40.206 (talk) 23:13, 7 November 2012 (UTC)
mgshightech: You can't have mppt without dc-dc conversion because the battery only accepts a narrow range of voltage, and your panels are trying to deliver a different voltage at maximum power, once you are dc-dc converting, you get mppt simply by choosing the proper duty cycle on your pulse width modulated transistors.
This is what I really don't like about this article
top right, the I-V curves shown are supposedly for a solar cell. This is not a family of curves easily predicted by the quantum mechanical nature of solar panels. Nor does it correspond well with curves shown for market panels. Look at these curves for example: http://www.wholesalesolar.com/products.folder/module-folder/Eopply/EP125M72-190.html These curves show what I expect from the underlying quantum mechanical system. The engineers tune the panels junction gap and the gap performs close to that tuned voltage. Photons that can jump electrons across the gap produce electrons at or near the gap voltage. Photons that can't don't produce any current. The more photons, the more current, but the same tuned gap voltage. The maximum power voltage of solar panels changes little with quantity of incident solar energy and this is where mppt people go wrong. They assume that mppt is required because the maximum power voltage has a huge variance, but it doesn't have that huge variance, look at the real curves. And careful examination of other market panels will show the same thing. MPPT is important for things like wind power because the maximum power voltage changes a lot in that case. For solar power, well, if you are clueless enough not to use the right panels for your batteries, then you need it. You will also want it if transferring power over long distances because the distance cause IR losses and we want to minimise those by running power at higher voltages. Higher voltages require dc-dc conversion at the charging station, and it's the mppt controllers that deliver that requirement. Those IR losses would also tend to have an interesting reversal effect on the panels output voltage. They will cause the panels voltage to fall with higher current.
OK, so the important thing to get here is that the I-V curves shown on this article are not good examples of solar panel I-V curves, see the link I provided (hope it is still good). And the value of MPPT charge control is therefore restricted to only a subset of solar power applications where the panels output is not correct compared to the battery/system voltage require it. You can do your own homework if you like but for example, a 60-62 volt panel will do a great job charging a 48 volt system without any special dc-dc conversion. However, panels above and below that voltage are going to require help matching their output to a 48 volt charging system. 70-72 volt panels for example will require dc-dc converting down, and a 56 volt panel needs to be boosted up using an additional panel in series circuit and then dc-dc converted ala mppt down to system voltage. The reason is because after subtracting I-R losses, blocking diode losses, transistor voltage losses, low-shine/high temperature voltage drop, etc. the 56 volt panel can't provide the 56.2 volts required to charge the 48 volt system very close to maximum power. MPPT controllers don't generally do any boosting, so you have to do something about it, and the only option is to add more voltage in series and mppt down to system voltage. — Preceding unsigned comment added by Mgshightech (talk • contribs) 00:48, 11 January 2013 (UTC)
- Your criticism overall would hold if this were an article about "MPPTs for solar panels," but it's an article about MPPTs in general. Sometimes you need them, sometimes you don't. If you don't need one, the article's not particularly relevant to what you're doing. If you want, change it to say "photovoltaic" (which is certainly my preference), but you should note that it says "solar cell", not "solar panel" - it's not the same thing and that has a lot to do with why the IV curve isn't what you're used to. Tarchon (talk) 07:39, 5 February 2013 (UTC)