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Re: LCLR Resonance...
Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
Hi,
At 09:21 PM 9/26/2006, you wrote:
Dear forum members,
Yesterday, I tried to simulating the behavior of a LCLR circuit
using PSPice. I connected a LCLR circuit to an AC source (sine wave
generator). The analysis type was 'AC sweep'.
Using PSpice, I plotted various graphs with Frequency on the x-axis
and the following three parameters in Y-axis:
1. Current through Parallel Inductor (inductor in tank circuit)
2. Current through Parallel Capacitor (capacitor in tank circuit)
3. Current through Series inductor.
My understanding is that at resonance:
1. The current through the tank circuit's L and C will be same.
2. The tank circuit's (either through L or C) will be IN PHASE with
the input sine wave source.
I am not sure of the "exact" circuit you have, but the above is only
true if the circuits are tuned to resonate exactly at the same
frequency as the sine wave.
Question:
I noticed that at resonant frequency the current through the Series
inductor was not IN PHASE with the input AC (sine wave) source. The
phase difference between the AC source and the current through the
series inductor was approximately 90 degrees. Is that true?
Yes, that will always be true.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/phase.html
Also, I have read in some SSTC articles that explains the use of PLL
to auto-tune the coil. Is it possible to use the current through
the series inductor as the feedback signal?
Certainly through the "primary" inductor.
One thing I noticed is that at resonance, the series inductor
current is not in phase with the ac sine wave source.
I can use the current through the Tank circuit's L or C will be in
phase at resonance and it can act as a feedback (either using an
antenna or current transformer). But, I would like to use the series
inductor's current to lock to the resonant frequency. Please let me
know your suggestions.
I am not sure where this "series" inductor is in the circuit.
Cheers,
Terry
Thanks and regards,
Raj.