Simulink State space linear LTI system with complex valued matrices B and C

Hello!

I have a problem for which I cannot find a solution.

I have a MIMO-LTI-system x' = A*x + Bu y = C*x with p = q = 2. The input and output matrices B and C have complex values in their entries. For example B = [1+i,1-i; 4+2*i, 4-2*i;....] My state space is therefore C^n not R^n.

How can I simulate such a system in Simulink? Or if not possible, are there solutions to get the response of such a system to arbitrary input?

Thanks a lot for your help!

M.L.

Answer 1

[Rajiv Singh]

Have you looked at LTITR?

Answer 2

[Marcel]

Hi Rajiv!

Thanks for your help. Worked! I could simulate my system answer with LTITR, while transforming my continuous model to discrete type. Thanks a lot! I hope you won't mind if I ask one more question:

Since the LTITR function seems to be a kernel function of lsim, why does lsim not except complex valued systems from the beginning? And why does Simulink not have such a possibility included?

Thanks, Marcel

Answer 3

[Marcel]

To implement such a system in Simulink one can just set up by hand a system of the form x[k+1] = A_dx[k] + B_du[k] y[k] = Cx[k]

where A_d and B_d are the discrete forms of A and B. Since A and B are complex valued matrices, A_d and B_d are so. Simulink is then performing all simulations with complex signals.

[Rajiv Singh]

Great! You ought to "document" this separately with an example.

[Gina]

Have you documented what you have done in simulink?, I am having the same problem and need some help with it.

Thanks.