h-bridge circuit and spwm circuit

Discussion in 'Homework Help' started by danny2, Oct 31, 2009.

  1. danny2

    Thread Starter New Member

    Oct 28, 2009
    29
    0
    hi all,
    recently i working on the project,i need to construct the bipolar and unipolar for sinusoidal pulse width modulation generator.i need to construct the h-bridge circuit to see the bipolar and unipolar spwm waveform.
    so i would like to know that how the h-bridge with capacitive load can differential the bipolar and unipolar spwm?
    As i know that the h-bridge circuit is usually use to drive the any motor.
    beside that,is there possible to generate the bipolar and unipolar spwm by using multilevel diode clamp?

    thank you.
     
  2. danny2

    Thread Starter New Member

    Oct 28, 2009
    29
    0
    i have been search on the internet that construct the sine wave generator.
    they are many method such as sine wave shaper,breakpoint method,osciloscope,555timer,and others.
    none of this method suitable for my application,because i want to sine wave generator in the way of analog.other than that,i also need to construct unipolar spwm as well but no source of this circuit can be found.

    anyone can help me?
     
  3. danny2

    Thread Starter New Member

    Oct 28, 2009
    29
    0
    can anyone tell me this circuit can generate bipolar of the spwm?
    the frequency range is from 1hz-1khz.
    the voltage input <12V.
    i want to create sine wave generator.the carrier wave form is triangular waveform and modulating waveform is sinusoidal waveform.after that the sunusoidal waveform feed into h-bridge circuit.the h-bridge circuit here is to testing the sinusoidal voltage.
     
  4. Thav

    Member

    Oct 13, 2009
    82
    0
    I'm not familiar with that you mean by unipolar and bipolar SPWM. The attached schematic would generate the necessary PWM gate signals to drive your inverter.

    As far as how to implement that in real life, you can generate it in the analog realm, but it's much more common with a digital processor. Is this something you'll actually have to build or does it just have to get the right answer on paper?
     
  5. danny2

    Thread Starter New Member

    Oct 28, 2009
    29
    0

    i have to build this sinusoidal waveform generator.
    now my problem is dont know how to adjust the amplitude,frequency and perform the harmonic on the orcad.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    In the schematic you've posted, they are attempting to use SCRs with DC.

    This generally does not work very well, as once you get the current flowing through the SCRs by triggering them, you have to stop the current flow by some other means - the SCR, once triggered, will continue to conduct until the current flow falls to nearly zero, where it resets.

    This is why SCRs are primarily used in AC circuits.
     
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