ZVS in PFC circuit

Status
Not open for further replies.
I

ivan_mateo

Member level 1
Joined
Feb 11, 2019
Messages
40
Helped
1
Reputation
2
Reaction score
2
Trophy points
8
Activity points
385
Hi everyone,

I am plannig to design a constant on time and vary frequency pfc circuit. I found some equations but could not understand how to zvvs is achived in that circuit. ınductor current ramp up at on time, and when the inductor current is decreased at off time. But off time is continue because current is negative and ton is delayed. Can anybody expalin how these theory expain with below equations?
 

Attachments

  • 1613822875871.png
    41.5 KB · Views: 102

Boost PFC in transition mode will not usually zvs. The drain node will ring up and down after the inductor completely discharges. It will ring down to a voltage of vin - (vout-vin). As you know, the drain voltage will not go negative by any more than a diode drop.

And as you know, "Vin" is the bus voltage after the mains rectifier, which changes sinusoidally in a boost pfc.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…