HELP : How to use triggers and rate limiters with ode15s in Simulink?

Hi,

My model contains various Simulink blocks and one Simscape/SimPower block interfaced with Simulink-PS and PS-Simulink converters.

I found that one of the rare solvers to work with that model is ode15s.

Everything was running fine until the moment I needed to add a Simulink block containing triggered subsystems and rate limiters.

I get a number of signal type errors with the rate limiters. When I force my signal to discrete or continous to get rid of those, I get a "not converging" error and a series of algebraic loop warnings.

The algebraic loops are said to be around my Simulink-PS converters but none of that happens when I take out the block with triggers and rate limiters which is no way near the converters...

I might add that the block with triggered subsystems and rate limiters works fine when integrated in a simpler model with a fixed-step solver. So my guess is that those elements behave strangely with ode15s.

Can someone please help?

Unfortunately I can't upload my model so here are a few screenshots:

Errors

Triggers

Rate limiters

Solver pane

[Jonathan]

Any idea, please?

Answer 1

[Joel Van Sickel]

Hello Jonathan,

you would need to use continuous time transfer functions (as low pass filters) or unit delays in order to break the loop. It is likely that those systems still impact the operation of the simscape system and can be included in the algebraic loop.

Regards,

Joel