In an analogue PLL, the phase comparator feeds the VCO via a LowPassFilter. It's an L-Pad. It's capacitor has a resistor in series.
You're suppose to calculate the LPF, and there's a fair bit of maths, but you can tune 'by ear' instead with a scope if make the R's variable.
So, what you going to synchronise the VFO to?
And, Is there a block diagram you can post yet? (kinda important!)
edit: I believe you're going to use the instantaneous phase of the output LC as the other input to the PC.
If so I assume the object of the PLL is to null the phase lead/lag between the (VCO) driven IGBT (active) phase and the LC (passive) circuit phase.