Mains voltage 220v is RMS value. When rectfied dc voltage on filter capacitor is 1.4 times ie around 315v dc. Power factor boost converter shoud at least provide this much voltage.
i m happy with ur reply,
After the 315 v we are stepping up the voltage to only 400v why ? why cant we go fro 500 or 600v.
is there any specification or reason for selecting the 400v.
to retain control the boost voltage must be just higher than the worst case expected peak mains voltage (230ac=325pk, 275ac = 389Vpk), going to higher voltages at the output makes it difficult for the booster to keep the sine current shape near the zero crossings (+/-30V say) as the step up ratio is so high - also the efficiency is lessened as the higher o/p volts give higher switching losses in the boost diode and therefore mosfet - Regards, Orson Cart.