Thank you very much for this simple PLL implementation. However, I noticed it uses both the real and imaginary parts of the Signal. In a physical implementation we only have access to the real part of the signal, right? So how can this be applied to a real, physical signal?
Be careful ! The varactor is badly modelling.
The transient don't fit with the behaviour of a varactor. To check the problem, please try to charge the cap through a resistor and calculate the energie provided by the source. You don't obtain E=CxV2 (true relationship with varactor). Something wrong.
Now, try to put the integrator block outside the feedback. It works, but limited by the solver (if the order of function is greater than 1).