reverse diode voltage (full bridge forward converter)

Jun 02, 2008 0 Replies

Hi all,



I have found a formula that I would like to understand the derivation of.



I am trying to work out the peak reverse voltage on a secondary side full bridge forward converter rectifier diode. The secondary is centre tapped with two diodes, top diode D1 and bottom diode D2, an output choke and capacitor.



I understand the operation of the circuit and would assume the reverse voltage is the primary voltage referred to the secondary during the time that say D1 turns off. But I have found this formula that states



Vrrm >=3D [((Vout +Vf).Vinmax)/(duty max . Vinmax)] + leakage inductance spike



Vrrm =3D diode repeat reverse voltage Vout=3D dc output voltage of converter Vf =3D it doesn=92t state which diode voltage drop this is, maybe it=92s the=



other secondary diode (when d1=3Doff d2=3Don) Vinmax =3D max dc bus voltage =3D input voltage to converter



I have found a link that has the waveforms which I understand but not how to work out the magnitude of the Vd1s reverse voltage. it=92s the waveform titled: These are typical waveforms in a full-bridge PWM topology



formatting link
e-MAYINT1-MAY2002.aspx



Please can someone explain this formula or explain how they would work out the Vrrm on a secondary rectifying diode for a full bridge forward converter.



reggie


Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required