Consider pulse density modulation with external filtering.



"bg" <byju.ganga@gmail.com> wrote in message
news:1114764082.955203.57510@l41g2000cwc.googlegroups.com...
> hi all,
> i have a dspic30f6010.i would like to generate a sine wave with this
> for an ac induction motor.i would like to know whether there is any
> method for controlling the amplitude of sine wave. and also details abt
> the c code for generation of sine wave using dspic30f6010.
>

bg wrote:
> 
> i have a dspic30f6010.i would like to generate a sine wave with this
> for an ac induction motor.i would like to know whether there is any
> method for controlling the amplitude of sine wave. and also details
> abt the c code for generation of sine wave using dspic30f6010.

Consider:

    ______------______------

    --__----------__--------

    ________--__________--__

Mix these signals together with the appropriate amplitudes (3
resistors) and you have a sinewave with no harmonics below the 5th,
I believe.  It takes very little analog filtering to get a clean
sine from it.  You get the waveforms from anything running at 3
times the desired frequency.  The result, before filtering, is
about:

          __--__      __--__
    --__--      --__--

The filter and final output involves 4 resistors, one capacitor,
and an op-amp.  You can generate all the phases you want, in steps
of 1/6 cycle.

-- 
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"bg" <byju.ganga@gmail.com> wrote in message 
news:1114764082.955203.57510@l41g2000cwc.googlegroups.com...
> hi all,
> i have a dspic30f6010.i would like to generate a sine wave with this
> for an ac induction motor.i would like to know whether there is any
> method for controlling the amplitude of sine wave. and also details abt
> the c code for generation of sine wave using dspic30f6010.

Try posting to the Microchip dsPIC forum. That's where most dsPIC experts 
tend to lurk.

Leon
-- 
Leon Heller, G1HSM
http://www.geocities.com/leon_heller 

hi all,
i have a dspic30f6010.i would like to generate a sine wave with this
for an ac induction motor.i would like to know whether there is any
method for controlling the amplitude of sine wave. and also details abt
the c code for generation of sine wave using dspic30f6010.