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  1. #1
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    spwm technique pdf

    Hey guys, i need to control the speed (frequency) using SPWM technique. I am using a micro of the 8051 family. I know that there r better pics to do this and even if i am using any 8051, there may be better ways to control the frequency, but i have to do it this way.
    First of all, i have to compare a sinewave with a triangular to create the pulses that will control the frequency. I've seen that all the look up tables for sinewave start with 80H 83H 86H 89H and so on. The thing is that i dont want to send the sinewave to a pin of a port, but just compare its different points with the triangular. So, i am not sure how to do this. The other things is, how can i create sinewaves with different frequencies using the same look up table?
    Thanks a lot!!

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    ac motor speed

    Iam also interested in this project.

    I feel AVR is best suited for this project. ATMEGA 8 is the best of my choice.

    some one come up to help us

    Regards
    Nandhu



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  3. #3
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    spwm atmel

    This is just my suggestion, but if you want to control AC motor using inverter with digital domain, space-vector will give you great benefit rather than SPWM.
    Maybe this link will useful for you
    http://www.atmel.com/dyn/resources/p...ts/doc7546.pdf



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    atmega48 spwm code

    Hi

    See zilog site for AC motor application note - nice with code in C language portable allmost to any micro

    All the best


    Bobi



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    spwm look up table

    It should be noted, that single phase VFD may operate rather badly. It depends on the motor type. A capacitor motor will achieve nearly zero torque at low frequencies, possibly not starting at all. Also a split pole motor isn't very well suited for VF operation. Using a two phase inverter for capacitor motors as in this Microchip application achieves much better performance. http://ww1.microchip.com/downloads/e...tes/00967A.pdf



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