How do I increase simscape simulation accuracy?

I'm simulating a semi-simple circuit with switches, resistors and caps and a voltage source. I need accuracy on the order of 10e-9 volts, when my voltage source drops below 10e-6, in another section that is slightly attenuated from the voltage source I should see something on the order of 100e-9 and all I see is zero. I have played with the solver settings in simulink and the solver configuration block settings but I haven't been able to get better accuracy. In fact, when I started changing the solver parameters to fixed step or changing the tolerance in the simulink solver configuation, the simulation would not run and stayed on a time step of ~10e-4. So my question is How can I get better accuracy. In spice simulators you can force the tolerances on voltage or solver tolerances.

Answer 1

[Sebastian Castro]

The first thing I would do is make sure the local solver is turned off in your Solver Configuration block. If you want the most accuracy, you want to make sure the Simscape network is treated as a continuous system rather than a discretized one.

Secondly, I'd go to the Solver Pane of the model's configuration parameters and reduce the absolute and relative tolerance parameters until your results are as you expect. You could also try other solver options, including the type of solver used. For example, ode15s is the stiff solver that can generally give the most accurate results, according to the documentation.

- Sebastian