Other Parts Discussed in Thread: UCC2817
Hi team,
Is it possible to use UCC28070 for three-phase full-wave rectification?
If yes, should I input a fixed voltage for VINAC?
Sincerely.
Kengo.
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Hello Kengo,
This can be done using three isolated UCC28970 controllers, one for each phase. Each phase will require it's own full-wave rectifier.
Regards,
Ray
Hi Kengo,
This is not three isolated rectifiers, so it will not work. You'd need a bridge between R and S to go to one UCC28070 boost state, a second bridge between S and T to go to a second UCC28070 and a third for T and S.
Ray
Hi Ray,
Thank you for your reply.
Could you pls tell me what kind of problem will occur?
And, my customer just wants to boost the rectified voltage.
In this case, can they use UCC28070 for three isolated rectifiers? and what can it input for VINAC?
Sincerely.
Kengo.
Hello Kengo-san,
I believe having the three phases hooked up in the way you showed using the UCC28070 would result in a large DC offset. Unfortunately, we don't have any reference designs of the UCC28070 being used in a three-phase application.
It is my understanding that products such as the UCC2817 and UCC2854 family of PFC controllers have been used in solutions that rectify the three phase supply (6 diode rectifier) and use the PFC controller on the DC side of the bridge, similar to what you have shown. This is an uncommon use for our PFC controllers so I don't have any examples to share with you.
Hello Kengo-san,
I'm sorry that I can't give you a definitive answer as we have no reference designs or experience regarding our PFCs designed for single-phase operation, adapted for three-phase systems. I know customers have experimented with this but I have no evidence of a working solution and we have not developed a solution ourselves, so I can't state with absolute certainty how to approach this issue.
I will reference you to an older E2E thread that addresses one customer's approach which appears feasible due to the SYNC function of the UCC28070. This is the best I can offer at this time.
Best Regards,
Ray