Induction motor speed control

Discussion in 'The Projects Forum' started by brunounreal, Feb 28, 2012.

  1. brunounreal

    Thread Starter New Member

    Apr 23, 2010
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    Hi,
    i'm researching for a project that i'm begining about a speed control for a induction motor.
    I'm searching for a IC that can do the control of a full Bridge Inverter using pwm with unipolar voltage switching to drive a monophasic induction motor.
    does anyone who have some knowledge in this area could give me a little help? i would be very greatful.
     
  2. crutschow

    Expert

    Mar 14, 2008
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    A good place to start is a PWM controller chip such as one of these from Texas Instruments. They are designed for switching power supplies but can be readily adapted to control a PWM bridge to power your motor.
     
  3. brunounreal

    Thread Starter New Member

    Apr 23, 2010
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    those dont work as i want because the pwm is given by comparing a triangular wave with a dc value and i need to comparate a triangular with a sinus wave to obtain a modulated wave.
     
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    While you could probably do it buy physically modifying the motor, a single phase motor does not lend itself to variable speed. This is assuming that a single phase motor is what your calling "a monophasic induction motor. "

    The reason is that single phase does not produce a "rotating magnetic pulse" on its own. It uses a separate winding controlled usually by a 'centrifugal switch' and a capacitor for starting.
     
  5. crutschow

    Expert

    Mar 14, 2008
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    They can work if you sum the sine wave into the error amp input along with the filtered output voltage. The chip will then compare the output voltage with the sine wave input and adjust the output to match in the input sine wave.

    Or you can run it open loop by just replacing the dc input with the sine wave input in the error amp.
     
  6. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Just delete it.
     
  7. crutschow

    Expert

    Mar 14, 2008
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    And how do you do that? :confused:
     
  8. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    On ur post click edit and there u will see delete button.
    Then u have to high light the delete message option and enter.
     
    shortbus likes this.
  9. crutschow

    Expert

    Mar 14, 2008
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    Got it. Thanks. Guess it's a thread that you can't delete.
     
  10. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Thanks R!f@@ ! Didn't know you could do that.
     
  11. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Welcome guys.

    There is a way to delete a thread. Wanna know ?
     
  12. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Ok, I'll bite.
     
  13. Georacer

    Moderator

    Nov 25, 2009
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    Sure. Go to "Moderating Tools"->"Thread Actions"...

    ...oh wait...

    ;P
     
  14. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Start Politics or Preaching :D
     
    shortbus likes this.
  15. Experimentonomen

    Member

    Feb 16, 2011
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    yuck!! the two subjects i hate.

    Now get this thread back on topic! There are single plase motors that dont use a start/run cap, these can easily be VFD'd, i did it with a shaded pole motor.
     
  16. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Good one R!@ff
     
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