3 phase rectifier - LTSpice simulation

Discussion in 'General Electronics Chat' started by Skeebopstop, Feb 10, 2009.

  1. Skeebopstop

    Thread Starter Active Member

    Jan 9, 2009
    358
    3
    I have simulated the attached circuit single phase with no issues and expected results, but when I hook up the full 3 phase bridge like this, LTSpice vomits and my capacitors sees kiloAmps of load?!

    Must be something obvious I am missing?
     
  2. ifixit

    Distinguished Member

    Nov 20, 2008
    638
    108
    You need to select a diode model. Right-click on the devices and pick a suitable one from the list... the MUR460 (600V, 4A) will likely work in the simulation, however, in the real world you'll will need doides to handle the 14A load.

    Also... you may need to rt-click on the I-load and check the "This is an active load " option. With this option enabled the load will only supply a current if there is a voltage across it.

    Regards, Ifixit
     
    Last edited: Feb 10, 2009
  3. Alexei Smirnov

    Active Member

    Jan 7, 2009
    43
    1
    You may also try another simulator. Is this what you expected?

    Thank you,
    Alexei.
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    657
    You don't have to select a diode model to make the sim run. I got it to run by adding a 1e12 resistor from the junction of the three sources to GND.
    I don't know if this is relevant, but the SINE voltage needs to be specified as peak, not RMS.
     
  5. Skeebopstop

    Thread Starter Active Member

    Jan 9, 2009
    358
    3
    Thanks guys, setting the diode model seemed to do it.
     
  6. pappano

    New Member

    May 29, 2010
    1
    0
    Hello Ifixit,

    Thank you for your post. I was having the same problem, and your suggestion fixed it.

    Thanks again.

    Vincenzo Pappano
     
  7. NSL22

    New Member

    Dec 20, 2010
    1
    0
    I created the same circuit with different source voltages and a resistor as the load and it's as if my voltage sources are half bridge rectified. Additionally, I don't understand why my peak looks like it is being over ridden by another waveform and why it's peak is so high. I specified an amplitude of 5V and its peak is 8.1V.

    Please help if you can!

    [​IMG]
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    NSL22,
    Take a look at the junction of the negative sides of V1, V2 and V3. You'll see that it looks like a triangle wave. If you right-click and mark that as a reference, you'll then be able to see the three sine wave phases 120° apart, and the DC out will look like a triangle wave.

    The output frequency winds up being six times the input frequency, and the voltages of two of the phases are being added together.

    Try grounding that junction and see what happens to the output waveforms.
     
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