How to create an impedance from R and X time-varying values ?

Hi everyone. I'm a newbie on Matlab and Simulink.

I have two different equations that give me R and L values, but these values change over time. (differential equations)

I'm trying to simulate their behaviour with Simulink but there is a problem: if I want simulate only the resistance component it's easy. I can use a "Controlled Voltage Source".

But I would simulate both in order to create an "impedance (R+jwL)" so I can work with phase shift and phasors. I tried to use a variable inductor from RF blockset but it doesn't work.

I tried also a "Controlled Current Source" to simulate the L value but then I had some Simulink error.

Does anyone have any ideas or suggestions ?

Thanks a lot.

[sloppydisk]

Do you want to simulate the differential equations directly or just pop in the ready-made electrical elements in SimScape? For the latter you could just use the linear inductor , right?

Answer 1

[Nicolo Blini]

I would like to simulate them directly. I already tried to use SimScape and linear inductor but I don't like it. I have to use a lot of Simulink-PS converters to connect other blocks.

[Saeed Rezaee]

If it is a simple RL impedance, you just need to use a controlled current source where the measured current is passed through an integrator and the output is the control input of the source. Next, you just need to integrate a ramp or any varying block in the control loop that generates the current based on the differential equation that rules the RL circuit; alternatively you can use a PI block where the gains are set as external inputs. You should be able to build a generic series or parallel RLC impedances as well.