Sine PWM generation using PIC16F877

[kvrajasekar]

Hi,

I have requirement of sinosuidal PWM
that uses a sine wave to be compared with triangular signal to produce the
PWM wave required .
I am using pic 16F877 .can anyone please post some projects or related links.

I dont know how to do this.


Regards,
Raja.

 

[Faizan Jawaid]

pwm sine

Hello.

The sine wave must be uni-polar because the MCU won`t read negative cycle. Use a full bridge to make it uni-polar and same goes for the triangular wave. Then you can use the Compare function (CCP) of the MCU to compare both waves.

Why don`t you generate PWM signal directly through MCU?

 

[kvrajasekar]

pwm sine

Hi,
Thanks for the response.

Sine and triangle are compared internally thru software.triangle is generated using counters,and sine by LUT.This is my requirement.

Can u give me the steps to generate sine pwm.Here i am also using PID for feedback loop.



Regards,
Raja.

 

[blueroomelectronics]

pwm lut

Are you not expected to do you own homework assignments?

 

[sketerpot]

triangular pwm

This sounds way too complicated. The PIC you're using has built-in support for PWM generation, and it's pretty easy to use. Just look it up in the datasheet.

Is there a reason why you can't use the PIC's built-in PWM hardware?

 

[Siniša]

sine to pwm

It seems you already know what and how you are suposed to do this, but dont want to do it. Don't waste time searching for finished solution on internet, seems your profs are smart. All projects will use hardware pwm generation as is more efficient and your project is using software routines deliberately to force you to learn something.

 

[Davood Amerion]

sine pwm

I think you can use sine wave formula in start of your program to generating LUT, somthing like this:


float teta;
unsigned char sample[180];

for (i=0; i<180; i++)
{
teta = ( (float) i / 180 ) * 3.14159;
sample = (int) (255 * sin ( teta ));
}