Given a desired output power and voltage range how can I determine suitable capacitor and inductor values for DC-DC Converters in general? The topology I'm interested in at the moment (High Step-Up Converter with Coupled Inductors) is obscure and papers related to it do not contain the necessary formulas.
Any help would be greatly appreciated, thanks!
Dear Elijah,
The Inductor (L) at the input side in High Step-Up converters is used to (i) store energy and contribute to voltage gain and (ii) reduce input current ripple. Capacitor (C) at output side is used to obtain and maintain ripple free voltage at the output. The design equation of these elements (L&C) would therefore involve the ripple current(L) or ripple voltage (C), switching frequency and power.
You may refer Rashid textbook wherein the basic design equation for L will be given in terms of input voltage (Vin), duty ratio (D), ripple current (delta iL) and frequency (f).
L=Vin *D / (f * delta iL).
Once you understand the basic inductor design equation for boost converter, you shall definitely be able to extend and apply the same for your coupled inductor based high step-up converters.
Good Luck !
Hi Elijah,
The entire design procedure is described in a useful application note by Fairchild Semiconductors:
https://www.fairchildsemi.com/application-notes/AN/AN-5081.pdf
I think it can answer most of your queries.
-Sanjay
The best way to select Step-Up converter elements is by study this converter with the LTspice. There are innumerable examples with Linear Technology power chips.
Here is fragment from my book
DOI: 10.13140/RG.2.2.10729.08801
http://www.linear.com/designtools/software/
Please refer to this publication :
Proposal and implementation of a novel perturb and observe algorithm using embedded software
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