Not Sure What This Is Called...?

solartechtown.com
solartechtown.com Solar Expert Posts: 29 ✭
in General Solar Power Topics #1
Hey,

My teacher wanted me to find information about a device that allows solar panel arrays to continue to produce efficient power even while one solar panel was covered up or when there are a lot of clouds in the sky. At first he referred to it as a energy management system, but Google did not give me any successful results, and I believe he also called it some kind of linear...energy booster or something similar.

Does anyone here have an idea of what he may be talking about?

Thanks
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: Not Sure What This Is Called...?

    Is your teacher being lazy, or is this a homework assignment ?

    Search for "MPPT" & "Solar Optimizer"

    It's a gadget that plugs into a single PV panel, and does some Dc-Dc conversions to keep the max amps in a series string, optimized.

    But it does not help when you have clouds, all the PV's and optimizers wont solve a lack of "direct sun". this only helps in partial shade conditions, where a small portion of the panel or array is shaded.
    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 ,

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: Not Sure What This Is Called...?

    There are actually many ways to address that question:
    1. Use, for example 5xVmp=17.5 volt panels in series with a MPPT (Maximum Power Point Tracking) Solar Charge Controller charging a 12-24 volt battery bank... Vmp=87.5 volts - 17.5 volts = 60 volts, MPPT "down converts" high voltage/low current to low voltage/high current for the battery bank. The solar panels include "bypass" diodes that allows a "dark panel" (does not generate/pass current) and the rest of the string to produce.
    2. For a Grid Tied system, same deal. Put XX panels in series, bypass diode will pass current through "dark panel" and as along as Vmp-dark of the array is > Vpanel minimum input voltage for the GT inverter, the system will still work.
    3. There are also Grid Tied Inverters that are one per solar panel. 20 panels, 20 GT Inverters. Shade one panel, 19 inverters still generate power.
    4. There is a company called Solar Edge that uses a small DC to DC converter that can take parallel strings (15 series panels * 4 parallel strings for example). And, as I understand, can raise the apparent Vmp of a series string with some shaded panels backup to match the unshaded strings (if you shade >10% of the solar array in a string, it will start to drop out and that parallel string will not provide any power). My guess is the Solar Edge module trades of current for voltage (i.e., drops string current to raise Vmp-string-with-dark-panels).
    Anyway, those are some of the ways that I am aware of... There are pluses and minuses for any of the above (engineering details)--but it is a start.

    Of course, we always recommend that solar PV panels are not ever shaded... And some shading the covers multiple panels (power lines, antenna, etc.)--will just kill output no matter what you do.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
    Re: Not Sure What This Is Called...?
    solartechtown.com wrote: »
    Hey,

    My teacher wanted me to find information about a device that allows solar panel arrays to continue to produce efficient power even while one solar panel was covered up or when there are a lot of clouds in the sky. At first he referred to it as a energy management system, but Google did not give me any successful results, and I believe he also called it some kind of linear...energy booster or something similar.

    Does anyone here have an idea of what he may be talking about?

    Thanks

    sounds like bypass diodes and many pvs have them built in.
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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #5
    Re: Not Sure What This Is Called...?

    I think the Tigo system is what he was talking about. It attaches smart DC-DC converters to single PV panels and trades off voltage to keep the current up so that connected string panels don't get "bottlenecked". The advantage of this product unlike other distributed type solutions is that you only have to put it on panels that have shading concerns. Say you have a chimney that compromises 4 panels out of an array of 24. Just adding on 4 Tigos is pretty cost effective shaded mitigation. I've never actually used them, as I like the Solaredge system in general, but it is a good niche solution.
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  • TheBackRoads
    TheBackRoads Solar Expert Posts: 274 ✭✭
    #6
    Re: Not Sure What This Is Called...?

    The magazine "Home Power" talked about these systems a few issues back in regards to grid tied setups.. I'll dig around and try to find what issue it was..
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