Can you use a PI filter topology to smooth ripple V for 50 V AC @ 10 A

Discussion in 'The Projects Forum' started by Kyle Tremblay, Dec 22, 2014.

  1. Kyle Tremblay

    Thread Starter New Member

    Dec 22, 2014
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    Hello. I am trying to build a hi current DC supply - was wondering if any LC filters such as CLC could be used to obtain some level of smoothing rectified AC from a transformer (60Hz) without resorting to switch mode topologies or IC voltage regulators. As far as I know that much current isn't possible to regulate, correct? The alternative is simply a large filter cap was wondering if there was any easy way to improve this.
     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
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    yes it is possable. and as far as that being a lot to reguate, we use supplies here atup to 30 volts at 20,000 amps. filtered and regulated.
     
  3. Papabravo

    Expert

    Feb 24, 2006
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    Filtering and regulation are two different things entirely and you should not conflate the two. There is seldom a need to resort to switchmode topologies when going from an AC source to an AC load. Further AC voltages are not typically regulated. Regulation is normally applied to DC voltages.
     
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Look at "ferro-reasonant transformers" and/or "swinging chokes"
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The common CLC Pi filter could be used, the ripple from 60Hz full wave rectified AC will be 120hz.
    Depends if you want regulation or smoothing?
    10 amps is not that high.
    Max.
     
  6. crutschow

    Expert

    Mar 14, 2008
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    It's not clear. :confused: Is the output 10A AC or 10A DC at 50V?
     
  7. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Huh?
     
  8. Kyle Tremblay

    Thread Starter New Member

    Dec 22, 2014
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    By AC I
    Just looking for smoothing. I used the word "regulate" because up till now I've only seen linear voltage regulators + a smoothing cap used for this task. At lower currents and up to 24V, IC's like the 78xx's are used after the smoothing cap for getting pure DC at a fixed voltage. These aren't for anything larger then 1 amp though. As far as I've researched another way of smoothing is using some type of LC filter like the PI setup. How well does this work just from the perspective of smoothing, not regulating/holding a constant output - the values listed above are input values into the full wave rectifier not load requirements. Is there a formula for choosing the correct L and C's? The load btw is a flyback driver so any output DC voltage will do just as long as its flat enough so I can switch it with some clarity using a MOSFET.
     
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