# power electronics homework

Discussion in 'Homework Help' started by kenny-one, Feb 16, 2011.

1. ### kenny-one Thread Starter Member

Apr 21, 2010
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hi guys, im having difficulties in solving these questions, pls if u guys can help id really appreciate, thx in advance. I have attached the questions.

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2. ### Jony130 AAC Fanatic!

Feb 17, 2009
3,993
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For the first question you need to find peak current.
For example for I_mean = 138A and fi=30
Ipeak = 360/30 * 138A = 1656A
So the rms current is equal:
Irms = √t/T *Ipeak = √30/360 * 1656A = 478.046023A

And for the second question.
You need to find Von vs I (straight line equation).
So for Icont = 23A ----> Von = 1.42167V
So the power
P = U * I = 23A * 1.42167V = 32.69841W

3. ### blueroomelectronics AAC Fanatic!

Jul 22, 2007
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Show us what you've done so far.

4. ### kenny-one Thread Starter Member

Apr 21, 2010
37
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thanks alot, now im trying to do it, i will report back soon.

5. ### kenny-one Thread Starter Member

Apr 21, 2010
37
0
okay, for what i understood here,for Q1 we had to derive the equation so that we can find Ipeak (see attachment1).

then with the value of Ipeak known we had now to solve for Irms (see attachment2).
thanks for the help, i wouldnt have figured this out if it wasn't for you.

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6. ### Jony130 AAC Fanatic!

Feb 17, 2009
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You can treat this waveform from question 1 as a square wave.