Design of 3 phase ac to dc power supply

[usman umar]

i am designing 3 phase power supply. out put from alternator is 28 v , 206.4 A , 100 hz , 0.8 pf..
now i have to use a 3 phase rectifier . DC 28 V is needed at o/p.

what is the output power after rectification . current also? formula??
how to design a capacitor if we want max ripple voltage = 28mv?
how to measure ripples(any cct)?

thanks

 

[mtwieg]

Getting 28mV of ripple at that current level is practically impossible with a rectifier alone, you would need many tens of farads of capacitance. You will likely need a SMPS as after the rectifier to regulate that ripple down to something realistic.

 

[usman umar]

o/p power of alternator= 1.73*28*206*0.8 = 8 Kw

now after 3 phase rectifier
output voltage= 1.35*V = 1.35*28 = 37.8 v
output current of rectifier is I=8Kw/37.8 = 211.6 A

IS above mentioned calculations are true?
also how to design a capacitor for filter? any equation