Hello everyone,
I'm trying to realize the buck converter depicted in the first picture, with the desired switching order.
The converter has two outputs, each connected to identical loads. In order to have the converter operate in DCM, K should be smaller that 0.25.
K=(2*L*Fs)/R
K< 0.25
But I can't get the converter switch it's loads in DCM mode. I have attached the SIMULINK model. Please take a look at it, and let me know what the nature of the problem is.
Thank you.
Hello Behzad.
For this to be a buck converter, there is a mistake on your circuit diagram. S' should be a diode - perhaps that solves the problem.
Have fun !
Dear Mr. Johnson,
Thank you for your answer. In the SIMULINK model attached to the question, I realized S' using a diode; also, S, S1, and S2 using MOSFETs.
My problem lies in switching order of S1 and S2.
S' does not need to be a díode. A MOSFET is better to reduce losses and avoid ringing, but it has to be on all the off time, although the intrinsinc díode of a MOSFET will act as a díode.
I do not understand why you have put S1 and S2 it seems an unnecessary compllication.
But I can't get the converter switch it's loads in DCM mode.-HOW DID YOU REALIZE THAT? I need to know this answer before i can comment on your question. Thank you.
Your equation is correct but what is the value you have taken for R?
The value of R has to be R = R1 // R2 (resistors in parallel). Because S1 and S2 have 50% of duty cycle, their current is twice the current of each output. So R is the same as if S1 and S2 were on all the time.
I do not know if this was the problem.
And I insist, for S' better a mosfet than a diode (S' being on while S is off): losses will be lower. This is a kind of buck that is more and more used for high currents.
If you give us the values of L, R1 and R2, perhaps we could help better.
Perhaps you have problem of synchronisation between the two of pulse generators !
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Composites