Are you fully aware that this is a daunting project, even for
experienced engineers? One requires expertise in magnetics, component
and material parameters, high voltage and a complete grasp of complex
number impedance calculations.
The reasons for the expense are manifold. Relatively small market,
expensive components, specialist design and bulk. The design of such
equipment includes damage limitation -- some very expensive bangs. I
found this though which is quite interesting :-
http://thayer.dartmouth.edu/other/inductor/papers/hfdeice.pdf
However if you really want to electrocute yourself and dump buckets of
components into the junk bin I do have an article for 100 - 500kHz,
several KVA RF genny for induction heating. Siliconix Mospower
Applications published in 1985. Ten pages outlining design procedure
and part circuitry. The data is still valid because the only change in
the last 20 years has been in better, cheaper FETs. Soft magnetic
materials have progressed very little since the 1930s. One would
probably plump for IGBTs now but FETs are still fine.
I checked out Siliconix (Vishay Siliconix now) to see if app sheets
were on-line but they don?t appear to be. Maybe you could find apps
from other major FET and IGBT manufacturers.
I suspect that 500kHz is not ideally high enough for most plastics but
if your energy density is high enough even mica?s tan angle will fry
it. But there?s another problem with the design -- you have to be very
careful and knowledgeable about insulator characteristics and internal
capacitors (mega bucks). Probably, even now, valves (tubes) are used
which hikes up the price too.
Are you aware of the plastic bonding technique of incorporating a
heating wire between the sheets. Might not be suitable for your app of
course.
But my respect to you for you courage (or is it ignorance? ;-) :-)
:-) ) and if you want to examine the sheets I?d be pleased to scan
them. Post your email address, slightly encrypted so web-crawlers
don?t read it.
Best |
