Buck converter - couple of questions about capacitors

[kunalbarot]

Buck converter

Input is 3 Phase 415V phase to phase
Secondary voltage across tx is 225 V phase to phase
Dc voltage 326V
output current is 150A max and output voltage is 200V
ripple in output current is 1%

My question is
1) Whst the use of capacitors across diode in Bride rectifier. What happen if we not connect capacitor acorss the diode.

2) A resistor parallel to the input bulk capacitor , what is the use of this and whaat will be the value

3) How to calculate bulk capacitor value

4) how to calculate inductor value.

 

[hamed_sotoudi]

search DC to DC converter in internet you will find a pdf in 6 page that displays converters and role of capacitor and resistor and search for atmel battery charger in 48 page in pdf format. in this file it displays calculation and role of components in simple way. if you want detail information look for it in dc to dc converters book. if you want I can send a book for you. (and this files too )