National Semi "Solar Magic"

boBboB Solar Expert Posts: 1,008 ✭✭✭✭
So, what do you think of this new "Solar Magic" from National Semiconductor ? There is also a video or two around.

boB :D


http://www.renewableenergyworld.com/rea/news/article/2009/03/solarmagic-improves-pv-performance-test-shows

http://www.national.com/analog/solarmagic

Comments

  • Solar GuppySolar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: National Semi "Solar Magic"

    I think for large installations it has some merit ... its not cheap

    For our readers the concept is each string has basically a variable power supply at the end of each string. The power supply is centrally controlled and is adjusted to keep the VMP of all the parallel strings the same, maximizing the harvest and greatly reducing the losses to mis-matched panels and shading. There is power required to runs the "equalizers" but its lower than the gains from getting every watt of a string even if its vmp is different than the other strings in parallel.

    For commercial applications when it would be common to have some daily shading, and on systems with literally 10's if not 100's of parallel strings it can have a big impact ... for a typical residential application it would not be a cost savings. They are showing maybe 10-20% improvements, it really depends more on how much shading is occurring at an installation or what the tolerances of the solar panels are to begin with.

    Also for residential and large 200+ watt panels is possible to have single string per inverter or an inverter that has dedicated mppt tracking per string ... so I would never expect this to be in home / residential installation
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: National Semi "Solar Magic"

    Wow !! It's magic !
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: National Semi "Solar Magic"

    so these things are like mppt controllers placed for each designated string that hold the voltage up and not down.:confused: interesting concept, but to call it magic is dumb on their part. i guess i'd have to pay for it with my check magic.:p
  • boBboB Solar Expert Posts: 1,008 ✭✭✭✭
    Re: National Semi "Solar Magic"

    S.G., where did you get this info ? I have met an engineer and read articles, but they never did say how it worked, exactly. They were very illusive. Either that, or they were so dumbed down that they could not explain it 5% as simple as you just did.
    I believe that this method has crossed my mind at one time or another though.

    Thanks for clearing that up !
    boB :D
  • Solar GuppySolar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: National Semi "Solar Magic"

    By reading NI information it seems it's the same or similar to this product boB

    http://www.actsolar.com/products/index.php which has a much better explanation of how the product is intended to work

    In the NI application, looks like they have it on every panel, and in the video they mention they can couple uneven strings, and mention its a "boost" technology.

    IHMO it way over selling what it does ( the 50% better number for example ), one should not be putting solar where its shaded in the high output hours of the day and it would only help with parallel strings, single strings with Mppt controllers would have no advantage, they just adjust as panels drop out and bypass diode conduct.

    With today's panels, one can get > 4Kw in a single string ... its a solution looking a problem. Keeping a one string to inverter or using multi Mppt channel inverters is a much better solution and MUCH lower cost. I really am at a loss how a company like NI could spend so much on this, they would make much more money on selling better power devices.

    SG
  • boBboB Solar Expert Posts: 1,008 ✭✭✭✭
    Re: National Semi "Solar Magic"

    Thanks SG. We don't like to put modules in the shade at high noon, but I suppose there are those places where it's unavoidable. I would hope that one could use just ONE of either of these units on the only string that needs boosting, rather than on the strings that might not need the box. Maybe some could look at it as a problem looking for a solution instead of the other way around.

    Oh well.... Another product idea anyway. Thanks for the link.

    boB :D
  • SheldonSheldon Solar Expert Posts: 51 ✭✭✭✭
    Re: National Semi "Solar Magic"

    disclosure, I work for National, but not in this product area.

    Our former CEO championed this product, its definitely an improvement where you have unavoidable shading or other environmental compromises, the demo with Golf Carts running under 50% shade lattices was impressive.

    Of course you would be best off to not have compromises, but not everyone can keep their array unshaded, and pristine all the time. The obvious use of this is in systems where there are shadows, leaves etc that can't be avoided, and the efficiency improvement would be worth the investment, compared to simply adding more panels.

    The market that would seem to scream for this is "Marine" where you have limited deckspace, rigging shadows, salt, water and other occluding materials as well as continuous roll, pitch and yaw variation of the pointing. And its relatively insensitive to price. So far, have not been successful in persuading them to address it.

    I will look at including these in my PV array which will be installed to complement a Whisper 200 turbine, south of San Jose, since I will be using a 48V system voltage.
  • boBboB Solar Expert Posts: 1,008 ✭✭✭✭
    Re: National Semi "Solar Magic"
    Sheldon wrote: »
    disclosure, I work for National, but not in this product area.

    What do you do there at NS, Sheldon ?? I use many NS components, of course.

    boB
  • SheldonSheldon Solar Expert Posts: 51 ✭✭✭✭
    Re: National Semi "Solar Magic"

    I'm one of the guys who does process development at the silicon level, optimizing devices such as LDMOS vs process costs, so that our design engineers can make products that are competitive. My work shows up on the shelf about 3 yrs down the road generally. http://www.national.com/ds/LM/LM10500.pdf is a part that builds on my most recent work.

    Solar Magic might be though of as similar to breaking up a large displacement 4 cylinder into a V12 engine. It does not so much change the ultimate power, but it gives a flatter torque curve, giving you more useful power at lower rpm. The analogy is not exact, but may help comprehension.

    You get more output from any size array, by extracting the maximum available power in that instant, where loss of a cell/panel becomes less significant, just as in the 4 vs 12 Cyl example above.

    If you had room & budget to put in a larger array, then like a larger engine, you would get more power, even if less efficient. If you are constrained on "displacement" then you pursue tuning options to wring the most power from the smaller size, just as if you have a limited area or budget for panels.

    Since you also size inverters to maximum array power, running at less than optimal means that you not only have extra costs in the array, you have extra costs in underutilized inverter capacity.
Sign In or Register to comment.