I would like to start by congratulating you for a fantastic piece of software !!
My first attempt to use it is to model an LLC DC/DC with a PID feedback controller as modelled using B-sources.
I am using the idt() and ddt() function in my current SPICE simulator and it does not seem to be available in QSPICE. Any recommendation for a substitute or perhaps I might propose something similar to be implemented?
Keep up the good work