Re: Pspice model of Tesla Coil

Hello all,
Richard said:
>I am trying to model a Tesla coil using Pspice.
        I have been doing a number of simulations here myself, using both
lumped circuit and helical resonator theory.  I have not worked with pspice
much, but am somewhat familiar with it.  Your estimate of an operating Q of
about 10 for the primary is probably close, and the secondary is probably
close to this when discharging, but higher otherwise.  I suggest taking the
power supply out of the circuit.  Then, assume you have a fully charged
primary capacitor with some voltage Vc on it, and close the switch (spark
gap) to observe the primary/secondary interactions.  Ideally, you should
open the switch (spark gap) later, at the time that the current is a maximum
in the secondary (to model ideal quenching), at which time the current is a
minimum in the primary.  
        A lumped circuit model will not demonstrate the voltage rise due to
the quarter wave transmission line properties of the secondary.  However, a
lumped circuit model is useful to examine how to maximize the current in the
secondary, and how important short quench times are when coupling is high
(as in a magnifier).
        A good model of the how the transformer interacts with the primary,
and the effectiveness of the protection circuitry would be most welcomed.
Based on some measurements I have been taking, I suspect it is not a simple
model.  There are probably several modes of oscillation, and there appears
to be some transformer core saturation (at least with my transformer) when
the spark gap fires (the gap is across the transformer in my system).  In
addition, the power factor correction capacitance values do not appear to be
optimal in a firing coil.  I am investigating this further at the moment.
Mark S. Rzeszotarski, Ph.D.