Unitrode (now a part of TI) has held seminars for the past 20 years hosted
by some of the most knowledgeable SMPS guys in the field. The books from
these seminars are now available on line at the following address:
http://www.smps.us/Unitrode.html
It is possible to convert the discontinuous operation of the SMPS into a
linear equation using some clever matrix math. Once in this state, one
could verify the gain and phase margin over the expected operating
conditions guaranteeing stability even with large changes in line and load.
High voltage supplies will require some very specialized magnetics that can
both transition the energy of the supply and maintain voltage isolation.
This is all covered in these books.
Steve
KT4FY
-----------------
Manfred
My personal problems with stabilising (I have limited experience in this
design area) are:
adding regulation means putting an inductor in the output and as a
consequence getting the phasing/feedback correct for all possible
conditions: fine for steady no-load up to full load conditions, but for all
the ssb and cw combinations I would need help. I would be interested to
know what the extreme combinations were in your design. Did you just make
the feedback loop longer time constant than the ssb/cw loadings? After all,
how much ripple is tolerable to a power amplifier?
at higher voltages, there "seems" to be less need for good regulation for
fixed mains input voltage, more need for stabilising against mains
variations, eg using a generator or at the end of a long ac distribution
network at a farm for instance.
without switching regulation a smaller output capacitance (smaller size and
weight) is needed as the guard band is very small compared to the triangular
dip when using an inductor
Your experience would be helpful
On the subject of insulating the rf and control stages rather than the mains
voltage stages: I'm very glad to hear someone of your experience suggest
this; I have been greeted with incredulity and disdain (not on this list).
In my work on MW power supplies to the mining and steel industries, it's the
controllers and final output device (motors, furnaces, etc) which are
insulated, I don't see why suitable insulation systems cannot be designed
for rf stages. At the other end of the power scale, this was also an
approach taken in medical monitoring when I was in that field.
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