three-phase inverter bridge-sine table-pic18f4431

[jhon90ortiz]

hello. anyone knows how to generate a sine table with 8 bits (0-255) for the three phases, I can not obtner the correct waveform

 

[ronsimpson]

You can use a spread sheet program like Excell to make a table.
Getting the correct wave form from a good table is a problem.

 

[misterT]

Getting the correct wave form from a good table is a problem.

Why? What is the problem?

 

[ronsimpson]

I can not obtner the correct waveform

This can be a problem with filtering after the table. RC filter or LC filters or delay in amplifiers or phase shift or.........
I don't know if he can't make a table or if he can't make a wave form.

 

[be80be]

This is not that hard you can figure it out with this

.

 

[Mr RB]

You don't need a "table of three phases" you just need a table of 1 phase, and then read data from 3 different points in the table.

It helps if the number of samples in the table can be evenly divided by 3.

 

[ronsimpson]

I think I used 1/4 of a sign table and used math to get the other 3/4 of the table. AND did this with 3 pointers to get 3 outputs at the same time.

 

[jhon90ortiz]

hello, thanks for the replies. I have advanced, I could build the sine table, with 19 points, generating a PWM duty cycle center-aligned with the values ​​obtained from the table but has some distortion, are supposed to be completely symmetrical waves and actually towards the beginning and end of each half cycle (whose values ​​should be equal) have slight differences. Is this common?

 

[ronsimpson]

Can you sent a picture?