I am currently thinking of designing a planar transformer for my SMPS application. The input voltage will be somewhere in the region of 150V, the output voltage in the region of 1.5kV.
First of all, I have noticed a severe lack of information on the internet that discussed the design process for planar transformers. Typing "Planar transformer design guide" tends to just get me companies trying to sell me their planar transformers. I wish to design my own. Does anyone know of any good material that discussed the actual design of a planar transformer - such as the selection of primary turns, secondary turns - winding configurations, etc.
Furthermore, my transformer must be insulated above 10kV for safety reasons - 1.5kV is not my final output voltage. I am looking online and have noticed that the insulation is typically achieved by placing thin sheets of insulators between the primary and secondary PCB boards stack-up. I have attached such an example for illustrative purposes.
My question is - does each layer of insulation between the primary, secondary PCB boards need to be the entire 10kV? Or does the total isolation between the top board, and the bottom board, need to be 10kV?
To me, it only makes sense that the insulation should be 10kV/insulating layer, since there will be high voltages between each of the secondary PCB stacks.
Additionally - what materials would be recommended to insulate a transformer at such voltages? I have seen Teflon, "FR4" and the like which are used for HV insulation applications
How can we tell which insulators would be good at High frequency? It is to my understanding that insulators lose their properties at high frequency. This info doesn't tend to be held in data sheets for these insulating materials!