about SMPS inverter
Hello,
In my opinion you need galvanic (safety) insulation between the 12VDC and the 350V DC bus (for your full bridge). So you need a transformer. A forward converter (push pull or H-bridge) introduces low ripple currrent and has good efficiency. You can even make it zero voltage switching giving realy good efficiency.
Advantage of the full bridge DC to 350Vdc converter topology is that you don't need the center tapped transformer (with limited coupling factor between the two primary windings). A HIP4080A (or similar device) can be used as the full bridge driver at the low voltage side.
I would not recommend 400 kHz operation due to available core materials and parasitic inductance and capacitance, stay below 100kHz, but above audio range. With these lower frequencies, you don't have to drive the switches extremely fast. This reduces EMC related problems.