I want to know what are the best topologies for building a high power ( range 1kW). Input / output voltage range is 48V.
Usually you will find an input bridge rectifier followed by an H bridge followed by an output transformer with slightly more turns on the secondary than the primary to boost voltage enough to allow a regulated output even when the input is at low line. Rectified output for DC of course and filter. Current feedback protection is recommended also, sometimes in the form of measuring the current in the lower section of the H bridge.