Determining a Transfer Function of 3-phase Induction Motor

I am completely out of my field on this topic and appreciate any good references or knowledge. I am tasked with determining an transfer function of a three-phase induction motor with pulse-width modulation using experimental data obtained. I want the transfer function to provide the velocity out of the system given the velocity in. I have various experimental data such as sine sweeps at various amplitudes (input voltages) and log sweeps at various amplitudes. I am not sure how to go from the experimental data to get the transfer function.

Also, are there any generic models of a three-phase indcution motor with pulse-width modulation? I especially need help with how to model pulse-width modulation (3-phase)?

Email: bwill040 @ odu. edu