Re: audio modulated SSTC

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Finn Hammer <f-h-at-c.dk> 



Tesla list wrote:

>Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz>
>Hi Finn,

snip

>  > I think this could be done by varying the supply voltage to the
>  > H-bridge: Oscillate with the bridge, audio modulate a big industrial
>  > IGBT in the supply rail. It will have to burn up at least 50% of the
>  > delivered power, so Therefore a big industrial type is needed, one
>  > that is good for dissipating those 1-2 kW`s loss. In this case, a self
>  > tuning oscillator would be ideal. (I think) I`l try it out some time,
>  > unless someone else does it first, and maby even then.
>Sounds like a good case for a modulated SMPS supply on the face of
>it. But what happens to the plasma if you drop the output voltage?
>Why not just modulate the H-bridge? Am I missing something?
>Cheers,
>Malcolm

Malcolm, all.

A unique property of driving a resonant load with a stepped voltage at It`s 
resonant frequency is, that it automatically aligns to zero current switching.
I may very well be wrong, but it seems to me, that when pulse modulating 
the H-Bridge itself, it is only doing so (ZCS), when the modulation is 
100%, (or 0%, I`m not a radio engineer) and there is no dead time.
I like zero current switching, that`s one reason.

Another reason is that keeping the audio modulation analog would be nice.

And I like single ended, class A amplifiers, so....

These are my opinions.

Cheers, Finn Hammer