The input of the converter is a rectified voltage. Its peak value varies between 280 V and 340 V. The load of the converter requires a fixed dc voltage of 120 V and require currents between 2 A and 10 A.
Design requirements (given):
switching frequency=50kHz
efficiency=90%
output ripple voltage= 2.4v peak to peak
current ripple= 0.5A peak to peak
1- determine the duty cycle ratios for the extreme operating points.
2-Calculate the required filter component values to guarantee the ripples stated.
3-Calculate the voltage and current stresses for the switch and the diode and choose proper devices from the products of IXYS or Semikron. List the important parameters of the device you chose.
4-Design a turn-off snubber for this converter. Calculate the new efficiency of the system for 310 V input, 10 A output.

 

First you should know such circuit can cause fires and a lot of EMI, if its not properly designed, and the components are not right, and the designer doesnt have experience.

OP doesnt spell question
OP presents a 1:1 copy from an assignment

We shouldnt help untalented individuals become bad engineer or consultant.

There is a roole here. The forum doesnt do homework or assignment processing for you. Not at all.

The teacher is to blame too. First teach fundamentals and problem solving skills.

OP

You should ask qualified question, tell what you understand and what not.
Not even asking question, you wont get much traction here.