1
\$\begingroup\$

I would like to create average model of Cuk converter but not getting any reference. Can anyone give any reference or some idea to start with?

"Generally Cuk converter is 4th order but if we use current mode control with coupled inductor then it becomes second order."

Is this correct?

\$\endgroup\$
1

1 Answer 1

Reset to default
1
\$\begingroup\$

The control-to-output transfer function of the Cuk converter can be described by a 4th-order polynomial expression. It can be analyzed using state-space averaging (SSA) but I feel the PWM switch model derived by Vatché Vorpérian in 1986 is unbeatable in terms of simplicity and efficiency for analyzing switching cells. Dr. Vorpérian did apply his technique to the Cuk converter and studied the effects of the magnetizing inductance on the ac response in a paper he published in 1996.

I looked at this transfer function in my last book on small-modeling of switching converter and the below drawing is an excerpt:

enter image description here

By replacing the nonlinear PWM switch model by its linearized version, you can determine the transfer function. This is a long and tedious exercise and resorting to the fast analytical circuits techniques or FACTs is one way to go. Another approach is to use a SIMPLIS model such as the ones you can freely download from my webpage. The ac response is obtained in a fraction of seconds and you can compare it with your symbolic expression:

enter image description here

This Cuk converter can be extended to a coupled-inductor or an isolated version but it seriously complicates the analysis. However, the FACTs are, in my opinion, the best possible tool to extract the transfer functions you need.

\$\endgroup\$
3
  • \$\begingroup\$ sir is it right if we use current model control and coupled inductor then order reduces to second? actually I am using some current mode controller and coupled inductor ...due to board space constraint I have to use coupled inductor. \$\endgroup\$
    – Power Path
    Commented Feb 22 at 5:11
  • \$\begingroup\$ Yes, CM will improve the transfer function but still, the Cuk converter does not bring a well-behaved control-to-output transfer function. I have updated my series of templates and the ZIP now includes Cuk examples in VM, CM, coupled, uncoupled and isolated. If you like my answer, I thank you to validate it. \$\endgroup\$
    – Verbal Kint
    Commented Feb 22 at 7:27
  • \$\begingroup\$ Many Thanks sir ...As I am new user stack exchange not allowing me to upvote or validate the answer . \$\endgroup\$
    – Power Path
    Commented Feb 22 at 10:00

Not the answer you're looking for? Browse other questions tagged or ask your own question.