Need help on 3 phase sine generator(phase shifter)

Discussion in 'The Projects Forum' started by munap, Dec 3, 2012.

  1. munap

    Thread Starter Member

    Nov 23, 2012
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    0
    Greeting,

    i just found this awesome website,so i have something to ask about 3 phase sine generator by using phase shifter (LM324). My questions are :

    1) Is the attached circuit below can be used practically(at least output on oscilloscope).
    2) I have used 2 types of simulation software(Proteus and Multisim) and both software couldnt get similar output as shown in the attached circuit.
    3) Could someone suggest some simulation software could indicate 3 phase output such as animated 3 phase motor or could the attached circuit do it(because i couldnt even get sinusoidal waveform).

    Please share your idea, i really appreciate it. Thanks in advance.
     
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,019
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    The LM324 is a op-amp and won't do what you want. At the top of each page of the forum is a E-book with a lot of great information, this page - http://www.allaboutcircuits.com/vol_4/chpt_12/6.html has one on "ring counters". Near the bottom of the page it shows a "Johnson counter" circuit that will do what your asking. Its called a ,"three phase square/sine wave generator".

    You should really use the E-book as a good reference.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The LM324 is a quad single-supply opamp, not a phase shifter. The shift in phase is caused by the RC networks R2/C2, R1/C1, R3/C3. The feedback resistors, R5 thru R7, control the gain of each stage.

    If you look at the time scale on the bottom of the plot, you will note on the left, "665m"; this means 665 ms (milliseconds) has elapsed since the start of the simulation. Also, I only displayed up to 667ms.

    You'll need to either start the simulation at 0v, use the UIC or Startup option, or initialize nodes to specific voltages before running your simulation; otherwise your simulator will probably grind on for awhile before it gives up due to too many possibilities.

    One problem with this circuit is that there is no automatic gain control; the gain is a compromise between allowing the simulation to start within a reasonable amount of time, and waveform clipping. You'll note that the sine waves look pretty good prior to ~668mS, and distorted afterwards.

    I used Circuitmaker Student for that simulation several years ago. Circuitmaker was discontinued approximately 10 years ago; it is a dead product.
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    With apologies to SgtWookie, that is not a good circuit, IMHO. If you simulate it with op amps having different gain-bandwidth products, the frequency changes by the square root of the GBW ratio. For example, with GBW=1MHz, the frequency is 500Hz. With GBW=10MHz, the frequency is 1.58kHz.
    See attachments. Simulation is with LTspice.
     
  5. munap

    Thread Starter Member

    Nov 23, 2012
    33
    0
    Thanks all, really nice to know all these things.

    i got class this morning so,ill see what i can do and still need your suggestions.
     
  6. munap

    Thread Starter Member

    Nov 23, 2012
    33
    0
    Helo all,

    please do response to this..i have found another circuit could generate 3 phase sine, and i have done the simulation and the hardware but i have problem on the simulation. I just couldnt find the proper indicator for the 3 phase output,i want to prove the circuit succeed generate 3 phase sine wave. Any indicator for 3 phase output or anything could be done so the circuit is proven, either on the practically or simulation and its nice if both ways are available. Here i attach together the schematic diagram of the circuit at below. Also, the simulation i have only orcad,isis proteus and multsim.

    Please do not hesitate to suggest me anything, i really will appreciate it and thanks alot.
     
  7. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Why do you need a 3 phase sine wave?
     
  8. munap

    Thread Starter Member

    Nov 23, 2012
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    Thanks for the response, this actually is my mini project for a subject and the scope cover the things i mentioned, for an example generate 3 phase sine waveform using phase shifter method. I have reached almost 50% progress and the left 50% progress are the report + output needed (at least the output could shows any type of indicator on simulation software that i succeed produce 3 phase sine wave, other than oscilloscope in simulation). The report part doesnt matter, i really hope that i could solve the problem i had, for now.

    There are alot of output indicators for the 3 phase in the simulation(Proteus) but
    not coincide the requirement (cant find right animated motor, only dc motor, most available). i just wish that i could shows the right output indicator to my lecturer.

    Really appreciate to your response sir, thanks.
     
  9. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    This sounds like homework. Aren't you supposed to design the 3 phase oscillator? If so, we've seen no evidence of your work.
     
    Last edited: Dec 4, 2012
  10. munap

    Thread Starter Member

    Nov 23, 2012
    33
    0
    Helo,

    Ya i should attach my simulation. Please suggest me for the indicator. The 1st simulation i use multisim and the 2nd one is proteus. The last picture is the hardware i have made on bread board.

    Actually i dont have to design but i need to do research and develop a product based on my research. If my lecturer give homework on designing, ill ask him and refer to the book.

    Thanks in advance
     
    Last edited: Dec 4, 2012
  11. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    What do you mean by "the indicator"? I think something is being lost in the translation.
     
  12. munap

    Thread Starter Member

    Nov 23, 2012
    33
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    Helo,

    Sorry for the confusion, my english so bad. The "indicator" i meant is an output application to indicate the result of output.
     
  13. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    As you have probably discovered, that circuit does not produce sine waves.
    Do you need a specific frequency?
    The best way to prove that a circuit is producing 3 phase sine waves is to display them on an oscilloscope.
     
  14. munap

    Thread Starter Member

    Nov 23, 2012
    33
    0
    Helo,

    The output i have got on both hardware and simulation seem like sine wave but i also cant verify that because i'm not sure about it.
    About the frequency and the frequency range not need to specified, so i thought the RC value doesnt matter, but if you could suggest better RC value, i would really appreciate it.

    Thanks.
     
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