Non Linear resistor behavior?

Hello,

I have to use an Non Linear Resistor in my circuit. I thought that I understood how it fucntioned based on the documentation. However, putting in the values that I needed caused errors in the simulation.

=== Simulation (Elapsed: 1 sec) ===

Error:The model contains blocks that require a discrete solver. The powergui Simulation type must be set to Discrete.

=== Simulation (Elapsed: 1 sec) ===

Error:An error occurred while running the simulation and the simulation was terminated

Caused by:

Derivative of state '1' in block 'CircuitNLR/Integrator' at time 0.1 is not finite. The simulation will be stopped. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances)

=== Simulation (Elapsed: 0.817 sec) ===

Error:An error occurred while running the simulation and the simulation was terminated

Caused by:

Derivative of state '1' in block 'CircuitNLR/Integrator' at time 1.0 is not finite. The simulation will be stopped. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances)

Ideally, I would like the resistor to drop from 100M to 1k or less. I am to understand that for 100M the first value of the matrix should be v = 10MV and i = 100mA? And the following for R= 1k, => v = 1v and 1mA = i?

The cirucit will finish normally with the Non linear resistor removed.

Answer 1

[Moksh]

Hi Michael,

I understand that you are trying to model a non-linear resistor in a Simulink model, and you are facing some errors.

Error #1

The model contains a block that requires a discrete solver. You can try the following steps to resolve this error:

• Try switching from a continuous solver to a discrete solver. Some examples are ode1, ode2, etc. You can change the solver under the “Solver” tab in “Model Settings” section.
• If you are using a “powergui” block in your model, try changing its type from “Continuous” to “Discrete”.

Error #2

Derivative of state '1' in block 'CircuitNLR/Integrator' at time 0.1 is not finite. For resolving this error, you can try the following:

• Change your solver type to “Variable-Step” under the Solver tab of the Model Properties.

For more information on this, please refer to the following documentation links:

1. Powergui: Environment block for Simscape Electrical Specialized Power Systems models https://in.mathworks.com/help/sps/powersys/ref/powergui.html
2. Nonlinear Resistor: Time varying variable reisistor block https://in.mathworks.com/help/sps/powersys/ref/nonlinearresistor.html

Hope this information helps!

Best regards,

Moksh Aggarwal