As per my understanding, you are trying to simulate electrical vehical dynamics (both mechanical and electrical) in simulink.
The design of electric vehical may vary. For example, some EVs use PMSM motor, while some may use BLDC or reluctance motors. Also, there may be variations seen in the control system design or drivetrain point of view.
To get started with power train simulation, below given resources may be helpful to get started.
Onramp courses: These are free online courses available on the Mathworks website. I am suggesting few of the courses that may prove usefull to you.
1) Simscape Onramp Course: https://matlabacademy.mathworks.com/details/simscape-onramp/simscape Learn the basics of Simscape® for modeling dynamic systems in various physical domains
2) Stateflow Onramp: https://matlabacademy.mathworks.com/details/stateflow-onramp/stateflow You can learn how to implement stateflow diagram in the control loops for your EV model.
Powertrain documentation: Go through the below MathWorks documentation to know about different models of components available for Power-train modelling. It includes different components such as: inertia, couplers, gears etc. https://www.mathworks.com/help/vdynblks/powertrain.html
As a next step, you can familiarise yourselves with the Powertrain blockset and its products, by referring the website: https://www.mathworks.com/help/autoblks/
After going through the above mentioned resources, you may refer the below given shipped examples to get started with the simulation of Electric vehicle.
1) Shipped example: Build Full Electric Vehicle Model: https://www.mathworks.com/help/autoblks/ug/explore-the-electric-vehicle-reference-application.html
2) Shipped example: Charge an electric vehicle: https://www.mathworks.com/help/autoblks/ug/charge-an-electric-vehicle.html
I hope you find the information useful !
