please give me the solution how can i make my ups without 50hz bulky transformer by using only small high frequency transformer
I hope it's not just me who thinks this is an extremely rude and inappropriate thing to say.
You're asking someone here to "give you" the "solution" to your final year project.
You have not provided any evidence that you've made ANY effort or progress yourself. You haven't shown us the part(s) of the inverter that you have already designed, if there are any.
I simply cannot understand how you can make this request, apparently with a clear conscience and no comprehension of why it is outrageously demanding and inappropriate.
(In the event that you actually just need a suggestion for how this can be done, and intend to do the design work yourself, I would suggest you can convert a high-voltage DC supply into a 230VAC or 115VAC sine wave output using two Class D amplifiers in bridge configuration running from a DC supply equal to the peak output voltage required.)