I'm currently modelling a motor for a vehicle, for which I have a built multibody system, however, when I implemented the electrical system to the physical system, the time to simulate increases to an unreasonable level

I've recently been modelling a crane in using Simulink, and as part of that, I am modelling the electronics of the crane's hoist motor. Howevever, when I brought the motor; modelled using a field oriented control induction motor drive, into my multibody model, the time to simulate increased to the point where it takes over ten minuted to simulate a tenth of a second. Without the motor, it takes just a few minutes to simulate a 22 second simulation. I believe this is a consequence of the Powergui timestep, affecting the time steps in which the multibody systems are actuated. For context I use a discrete Powergui, and the ODE23T solvers, respectively.

Any advice on how to reduce time to simulate would be greatly appreciated.

Answer 1

[Vasco Lenzi]

Hi Harry, a couple of question and suggestion

• how do you interface the Motor with Multibody system? There are best practice available but usually this works best from Simscape Electrical - Simscape Component then Simscape Specialized Power System (which uses the powergui block). See this free library on file exchange on how to couple 1D with 3D simulations: https://www.mathworks.com/matlabcentral/fileexchange/37636-simscape-multibody-multiphysics-library

Basically the best way is to create a kinematic relationship between torque and load of the 1D model applied to frame of a revolute joint:

And here the concept you can reuse with your FOC Induction drive modeled preferably in Simscape Electical Simscape Component. The screenshot are from the documentation of the file exchange entry above.

• We have found that for some models, limiting the level of perturbation used to compute the solver Jacobian can improve performance. Please see this answer and the attached scripts: https://www.mathworks.com/matlabcentral/answers/535318-why-is-my-model-made-of-simscape-and-simscape-multibody-simulating-very-slowly