rectifiers Parallel input

Discussion in 'General Electronics Chat' started by Ele, Mar 6, 2010.

  1. Ele

    Thread Starter New Member

    Mar 6, 2010
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    1
    Hey,

    When you take two rectifiers put the inputs in parallel with the same 24V AC source, Single phase.
    To have a full wave passive rectifier (first), that feeds a load. I wan't the second rectifier to recieve it.

    So the output would go from the first + to the second negative.

    Or how can I access the elektron stream of the AC to direct the negative back to the AC, without using the negative of the first bridge.

    Can it be done, and can you explain how. thx.
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    I guess you are thinking of a single phase converter - inverter configuration. Unfortunately this can't be done with simple uncontrolled bridge rectifiers. It is possible to achieve the inversion [DC to AC] part using a phase controlled bridge on the inverter side, provided the firing control phase angle delay is adjustable over the required range. It would also be necessary to have suitable DC smoothing on the converter side prior to feeding the DC to the inverter side.
     
    Ele likes this.
  3. Ele

    Thread Starter New Member

    Mar 6, 2010
    9
    1
    [​IMG]
    Something like this, so instead of going to negative on the first bridge, use the negative of the second. Inbetween is just a simple resistor. So it's an unbalanced DC Supply feeding a resistor but, instead of passing to the negative, pas it to the AC Supply. Using a bridge, Diodes or whatever it takes to do this.
     
    Last edited: Mar 6, 2010
  4. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    It's not clear what you are attempting to do.

    Do you want convert the AC to DC and then pass the power back into the AC supply? That is - going from AC to DC and then back to AC with a net power flow in that direction?
     
  5. Ele

    Thread Starter New Member

    Mar 6, 2010
    9
    1
    There is a AC->DC converter, feeding a resistor, but you can see it as the negative of that bridge isn't accessible, and u need to recreate the negative of the rectifier to pas the return back to the net. So that the current going from the AC -> through the unbalanced DC supply -> to the AC, flows, like it would when you just use the AC->DC converter.
     
    Last edited: Mar 6, 2010
  6. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    Your circuit wont work as you envisage it. The inverting [DC->AC] stage requires a configuration of actively controlled devices - switches IGBT's, SCR's, etc.

    Do a search for (say) the topic "single phase line-commutated inverter" - a relatively simple inverter scheme. This "sub-system" would return energy back to the AC supply.

    This idea is used extensively in AC->DC->AC power transmission systems.

    One wouldn't include an energy wasting resistor in the scheme - typically there is a series inductance which forms a constant current DC link between the converter and inverter sub-systems.
     
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