Finding duty cycle ratios in full-bridge DC-DC converter

Thread Starter

bwc

Joined Feb 19, 2015
3
I am asked to find the duty cycle ratios, D1 and D2, and their ripple frequency in the following circuit:


Vo is controlled to provide an average output voltage of 200 V.

What i've tried doing is setting up this equation:

V0 = Va - Vb = D1 * Vd - D2 * Vd

Resulting in:

200 = D1 * 250 - D2 * 250

From the looks of it, I need another equation so I can find D1 and D2. Where do I go from here ?

Thank you.
 

Thread Starter

bwc

Joined Feb 19, 2015
3
Ok, so looking more closely at these equations, assuming Vtri = 250:
D1 = 0.5 (1+200/250) = 0.9 ; D2 = 0.1

Is this correct ? how do i find the ripple frequency for this setup ? i'm trying to look for equations, but can't seem to find something for a dc-dc converter.
 
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