how to 3 phase 120 degree difference?

[avr_micro]

Dear Friends

I want to make a circuit to simulate 3 phase 120 degree difference by avr.I want to connect these signals to transformers and make 3 phase 380 v AC.
How is possible to make this phase difference by AVR?
Is there any complete project in net?


regards,

 

[Faizan Jawaid]

U`ll have to first understand how DC-AC converters work...Creating Phase difference is not the prob...U`ll have to generate 3 PWM signals for 3 phase...Each PWM will control its respective phase... U`ll also need 3 H-Bridges to make AC...Try to search Flyback, Boost converters for converter small DC voltages to high DC voltages...Then these High DC voltages are converter in High AC voltages...

 

[avr_micro]

Ok.but how can i make 120 degree phase different between these three signal.
Is there any capability in AVR for making these signals by pwm?

regards,

 

[Faizan Jawaid]

U have to understand how PWM creates signals....120 Degrees phase difference is no big deal....First use google to find out DC-AC conversion using PWM....U`ll need 3 PWM channels from AVR MCU... One PWM signal should be started with some calculated delay after the start of first PWM signal...Then the third should be started at the same delay after the second PWM signal is started...If u dont get my point clearly pls refer to search engines for DC-AC converters....U`ll understand easily from there + diagrams speaks alot....

 

[FvM]

Most microprocessor VFD projects are using 3 phase pwm, there also several for AVR, at atmel.com and elsewhere. Some projects have been mentioned in related EDAboard threads.