Re: An SSTC simulation

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

Original poster: dhmccauley-at-spacecatlighting-dot-com 

Its primarily the extra loss, which adds up especially at higher
frequencies.
Loss is voltage x current across the switch.  Anytime you are switching a
waveform where voltage and current is not zero, there is loss.  With ZVS or
ZCS switching, voltage or current
is zero during the switching transition, minimizing losses.

Dan


 > What part is dangerous about the hard switching? Is it the extra loss, or
 > the voltage spikes? The voltage spikes can be handled with MOVs, and when
 > tuned right, the switching should be reletively soft. The lower coupling
 > the better for this too because there is less frequency splitting. When
 > tuned to the primary frequency, there is no notch.
 >
 > Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "Dan Strother"
 >
 > Ah, very interesting. The circuit and concept look great, but there is one
 > thing bothering me: Won't dynamically tuning to the secondary coil cause
 > the MOSFETs to dangerously hard-switch a lot of current in the primary
circuit?
 >
 >
 > Dan Strother
 >
 >
 >
 >  >Original poster: Kchdlh-at-aol-dot-com
 >  >
 >  >Fundamentally, yes: series-resonant primary, parallel-resonant
secondary.
 >  >But my scheme a) uses resonant storage-capacitor charging while Jimmy's
 >  >does not and b) incorporates "dynamic" control of the tuning. Also, I
 >  >don't believe Jimmy's storage capacitors are necessarily fully
discharged
 >  >every mains cycle. So perhaps they'd last a whole lot longer!
 >  >
 >  >In regard to my amplifying circuit, I'd like to point out something I
just
 >  >realized. There's no! need to have the U1 EX-OR in the circuit:
regardless
 >  >of the phasing between primary and secondary, feedback will be positive
 >  >during one of the two mains half-cycles; doesn't matter which one.
 >  >
 >  >Just slap any old secondary onto it and it will take off!
 >  >
 >  >Ken
 >  >
 >
 >
 >
 > Jimmy
 >
 >
 >
 >
 >
 >