Lookup table problem in Simulink

Dear Community,

I’m a newbie in Simscape simulation. As a first learning attempt, I would like to simulate a small 2D RC network of 4 rows and 10 columns. Nodes in this network are RC subsystems connected to each other with electrical lines. I placed a Controlled Current Source into the (3 row , 2 column) node, which I would like to feed with a 1D lookup table. I also placed 5 voltage sensors into nodes (2,2, blue), (2,3, green), (2,4,cyan), (3,2, red) and (1,10,magenta) to measure how voltage evolves in the different locations of the network during the simulation. The 1D lookup table should get data from an external Excel file called RateSchedule.xlsx. Simulation time is 400s. I wired everything together and tried to run the model, but Simulink has a problem in the lookup table, although I provided the interpolation vectors. Could you pls. have a short look to the model what do I do wrong, what I miss here? I’ve attached the model also (TwoDRCNetwork.slx), the current schedule (RateSchedule.xlsx) and the results figure (VoltageResults.fig), which was calculated by a different method. This is how the system response should look like.

Tx for the kind help in advance,

Best regards

Andras

Answer 1

[Sabin]

This seems to be a physical unit mismatch. In the attached model the input to the PS Lookup Table (1D) is not connected to anything. The table grid unit is defined as seconds and the table values unit as Amperes. Because the input is not connected to anything it assumes a unitless 0 as input. The solution is to provide a input in seconds to the unit table.