Unwanted oscillations in flyback simulation (LTSpice)

[LaMontagne]

Hello,

I am currently working on a simulation for a bidirectional flyback circuit (output diode replaced by a NMOS). When I am using generic components, everything works fine. However when I use
manufacturer supplied spice models for the MOSFETs, I keep getting unwanted oscillations while the mutual inductor is charged (current ramping up).

I assume the oscillations come from the LC tank consisting of the transformer primary inductance and the MOSFET parasitic capacitance. Could this be a simulation problem? I attached the waveform of the transformer primary current showing the oscillations.

Thanks for any help!

 

[FvM]

In contrast to simulation artefacts, the oscillations look smooth and the waveforms plausible at first sight. You must know if the parameters of your simulation have been selected according to real-world circuit parameters. The oscillation during ton looks somehow strange, probably due to unusual or unrealistic circuit parameters. Viewing the LTSpice design could clarify things.

 

[LaMontagne]

Thanks a lot for the response. Here is the circuit I am trying to simulate:


It seems that these oscillations are less of a problem if the on-time is higher. Can I expect to see similar oscillations in the real circuit? (I ask this as I would like to avoid using any RCD clamps etc. if possible)