Thursday, July 18, 2013

Sine Wave Generation and Implementation using dsPIC33FJ





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22 comments:

  1. Dear Tahmid
    You r really amazing thank you for sharing

    Regards
    Veera...!

    ReplyDelete
  2. u r awesome Tahmid... Well job Keep it up ....

    ReplyDelete
  3. Hi Tahmid,

    Are we make a live call on skype? Do you speak and understand urdu?
    sorry, I am Khalid Rajpoot from Karachi, Pakistan
    I need some help on Spwm Inverter for dsPic33fj16
    Pleaseeeeeeeeeeeeeeeeeeeeeeeeeeeeee inkar nahi krna.
    My Email ID is ( kmr4uall@gmail.com ), I wait your reply email

    ReplyDelete
    Replies
    1. You can ask your questions on a forum like www.edaboard.com

      You can give me the link so that I can take a look at it.

      I'm sorry but I can't give enough time now to Skype. Work load at university is quite high.

      Regards,
      Tahmid.

      Delete
  4. Hi Tahmid,

    You have done the great work.
    i am also trying to make off line UPS using DSPIC33FJ12MC202.
    I have done most of the work in it.
    I am using PWM module for it with full bridge.
    My inverter is giving 220V AC without load.
    But when I connect load at O/P, volts goes down to 60V from 220V.
    I think with load volts should not be get down with any load.
    My transformer rating is 12V to 220v.
    Please help me how to solve this problem.

    Regards
    Dhaval

    ReplyDelete
    Replies
    1. hi Dhaval
      can you upload your ups files

      Delete
    2. We need to see the circuit diagram at least to try and guess where the problem may be.

      I think the problem is in the MOSFET drive section. However, without more details (schematic, code, etc), I can't really tell what's wrong here.

      Without feedback, the output voltage will drop with load, but not this much.

      Regards,
      Tahmid.

      Delete
    3. Hi,
      Thanks for the reply.
      Can you pls give me ur Email ID??
      So that I can send you the schematic of MOSFET driving circuit as well as some other important files.

      Regards
      Dhaval

      Delete
    4. I prefer you upload it online somewhere so that others can see it and benefit from it and the discussions here.

      However, if you feel uncomfortable making your files public, you can email them to me at inferno-rage@hotmail.com

      Regards,
      Tahmid.

      Delete
  5. hi tahmid
    i have question how can we produce 50 hz sine wave in pic

    ReplyDelete
    Replies
    1. Go to this page: http://tahmidmc.blogspot.com/p/blog-page.html

      Look under the section "SPWM and sine wave generation and inverter"

      There are articles/tutorials there covering sine wave generation using PIC

      Delete
  6. This is a nice tutorial on dspic SPWM. Question is, if it is possible to create in a simple 16F series why DSPIC? On 16F Sires we take average amplitude and Correct with PI feedback control, which works fine for most domestic use. If dspic is there, it needs Point by Point sampling and compensate the duty with respect to volt and current ( Microchip App note AN1279) . This is a nice approach using Pwm module in dspic33f and would be fruitful if we get something practical :). Thanks for sharing ur hard work on Public.

    ReplyDelete
    Replies
    1. DSPIC is faster and more powerful than PIC16. So, if you generate sine wave with dsPIC, you can do more things than you can with a PIC16. For example, you can create a cleaner sine wave. You can do more control with the dsPIC, such as having it as a central controller controlling everything to greater precision. You can have quicker and smoother feedback. You can implement PID. You can change amplitude and frequency on the fly. If you were going for a 2-stage (DC link) inverter, the dsPIC could handle both sides (DC-DC and DC-AC) as well as other control/monitoring circuits. You can see the benefits of using the dsPIC. Now it's up to the designer to decide if that is required. If so, then the dsPIC can be used. If not, then the designer can stick with PIC16 or PIC 18.

      Moreover, with prices dropping, the dsPIC is not that much more expensive, but offers greater flexibility and processing power.

      Regards,
      Tahmid.

      Delete
    2. Dear Tahmid
      Thanks for ur kind replay. i was wondering about feedback control with PID. Did u try it with Dspic? It would be very helpful if u attach a code sample for that. Thanks

      Delete
  7. As'salam o Alaikum!

    Syed Tahmid Mahbub,

    I am Muhammad Javed.

    I sure that you have test this inverter, on load its output voltage is stable or not?


    And Please give me the complete drive circuit?


    Regard,

    Muhammad Javed

    ReplyDelete
  8. dear tahmid,
    Its really a great work and very helpful. Actually i am new in microcontroller. i want to generate code using dspic33ep. I already modify the code and got 50hz signal. But there is a problem with 20khz signal. I am not sure why its not working. Can you please help me regarding this problem. I am really trying to fix but i couldn't. If you want i can post the code. It will be great help for me if you have some time. thank you

    ReplyDelete
  9. Hi
    I have a doubt in the calculation. Please help me understand!

    PWM_Freq = 25KHz
    Tpwm = 40us

    Tpwm * No of Values in the sine table = 10ms (Half cycle of 50Hz sine wave)

    Thus I got the number of values to be 250

    But how could a table value of 256 be afforded?

    I don't get this. According to the calculation the frequency gets 48.8Hz. Is this precision okay or my calculation is wrong?

    ReplyDelete
  10. Hi Tahmid,

    Great work.
    Wondering if there is any dead-time in this code!

    ReplyDelete
  11. Hi Tahmid,
    Great work.
    I have doubt in indexing of array (in the the code) sin_table[Result].
    when value of Phase goes beyond 16-bit then it will become 0. when Value of Phase reaches 65500 then value of result variable is 500.
    In next increment Phase value will overflow and Result value will be 0.

    So with this condition it will index 511 location.

    Please clear this doubt.

    ReplyDelete
  12. Hi Tahmid,
    I am not able to view this file. Could you upload it again

    ReplyDelete
  13. Page is not displaying the implementation method. It is only displaying comments. Please fix it.

    ReplyDelete