You'll need to supply more details to get much help here, including what your own personal skills and capabilities are. 5kW is a lot of juice and therefore carries risk and dangers.
i am graduate from electronics i am familiar from hf induction welder raging from 30kw to 600 kw used in pipe mfg triode type what now need small heater to heat small parts of soft iron tube is so costly so i want to make it solid state