Buck Boost Converter analysis

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Percent_Impedance

Joined May 14, 2008
3
Hi,

Well I started my MSEE and my first class is power electronics. We have a buck boost converter which I have to perform steady state analysis and perform a DC design.I have attached it as a Pdf including two more pdf's which have the slope waveform sketched and the calculations. I derived the current slope accross the inductor, ripple current, and the inductor value! The problem is I do not know If my calculations are right or wrong!

If anyone can help me in this I would greatly appreciate it.

My answers on the attached Pdf are for 2.1 (a) (b) (c).

Ill explain real quick the way I see it! when the circuit is in steady state the voltage and current balance to zero. ok, now the current slope accross the inductor is the Vout/RL which is -20/4ohm = 5amps (+-)...

Now my slope equations follow this as you will see. Now since I want to reduce the current ripple to 10% and therfore I need to calculate a value of inductance to conform to this I took 10% of 5 Amps and got 0.5 ...

Ok now, when I put it in my inductance formula i get 500uH


P.S. Im not worried about getting the answers! I rather want explanations on how to look at the circuit and what im doing wrong. If you can also tell me if my values are right or wrong that would be very benefitial. Thank you in advance!!!
 

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Hi,
I was wondering if you have obtained the answer to the problem posted above or if you have any other answers to problems in the same book. I am studying from the same book on my own and could use some extra help.

Thanks!
 
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