[TCML] Re: Secondary feedback via current transformer in PLL controlled SSTCs -Overcoming the phase-shift problem

[vatercox@xxxxxxx]

Dear List,
 
With special regard to constructors of  Solid State Tesla Coils using PLL control with positive feedback derived from a current transformer in the secondary ground lead -where problems have reportedly been encountered due to the fact that the current in the TC secondary is 90degrees out of phase with the voltage- (although I'm not to sure whether or not this applies to a "quadrature" PLL), may I ask a question?

  Would it not be possible to solve the problem by using a four-phase output divider eg. a couple of 4013 cmos bistable ic wired as a ring or "Johnson" counter to derive rock-solid 90 degree phase shift irrespective of frequency?

Then, with the VCO operating at twice the resonant frequency,the primary could be fed from "0 degree" output of ring counter with the PLL reference input being provided by the "90 degree" output. This would provide a matching signal to the phase-shifted feedback from the current transformer.

Is this approach at all feasible?

JF Cox
 


Dear List,
 
With special regard to constructors of  Solid State Tesla Coils using PLL control with positive feedback derived from a current transformer in the secondary ground lead -where problems have reportedly been encountered due to the fact that the current in the TC secondary is 90degrees out of phase with the voltage- (although I'm not to sure whether or not this applies to a "quadrature" PLL), may I ask a question?

  Would it not be possible to solve the problem by using a four-phase output divider eg. a couple of 4013 cmos bistable ic wired as a ring or "Johnson" counter to derive rock-solid 90 degree phase shift irrespective of frequency?

Then, with the VCO operating at twice the resonant frequency,the primary could be fed from "0 degree" output of ring counter with the PLL reference input being provided by the "90 degree" output. This would provide a matching signal to the phase-shifted feedback from the current transformer.

Is this approach at all feasible?

JF Cox
 
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