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
    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


    Sep 9, 2010
    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

    Distinguished Member

    Jun 22, 2012
    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
    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?)