fet controller for dc to dc

Discussion in 'General Electronics Chat' started by stevecoats, Jul 12, 2013.

  1. stevecoats

    Thread Starter New Member

    Feb 5, 2012
    3
    0
    I have an inverter for my solar system that will not operate at a V aboue 55V. My solar panels put out about 65V when they are really cooking and this will shut off my inverter. I cannot reconfigure the solar panels for several reasons. I want to build a dc to dc buck system and I have irf 2011 and IRF 540n fets. I would like to operate the system with an 8 pin picaxe in pwm mode. I notice that all the application notes for the irf2011 show a high and low fet. Can't I just use the high side and a few fets in paralell to handel 600W?
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,156
    3,063
    Wouldn't it be easier to just maintain a load on the inverter and thereby the PV panel, or on the panel directly, to pull the voltage down along the I-V curve? Could be as simple as turning on a light bulb when a panel voltage passes,say, 50V.
     
  3. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    5,003
    745
    Use a comparator op amp circuit,and set it to come on at 55v, putting the fets on with dummy loads or light bulbs.
     
  4. stevecoats

    Thread Starter New Member

    Feb 5, 2012
    3
    0
    Thanks for the quick reply. In fact, I have tried that. I have 1600Wmax out worth of solar cells. I have put a 500+W load and it was still not enough, that's a huge load and I still have problems. I also have an outback solar controller that I attempted to use to control the output voltage and in spite of the massive amount of programmable options, they cannot simply give you a fixed voltage out (and they confirmed it twice). It would work for a while and then turn off.

    So anyone have a suggestion for another simple way to buck about 10V (or answer my original question?)
     
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