Integrator delivers Wrong output

Hi everybody!

This is my fist poste here ;)

I have a problem in a part of my Simulink Modell with a Integrator that doesnt compute the correct output value.

To explain this i have added a Scope inwich you can see the value before the Integrator (x_punkt1), after (x1) and the derivative of x1.

Actually the Derivative of x1 should be pretty much the same (excapt a time delay) to the value before the integrator.

For further Context I have added a screenshot of the part othe the model in question.

The Simulation is run by a Bypass with the programm "SILVER" wich delivers the refenece value "M_MOT_IST" wich is used to adapt the model to the referenc System. The Integrator is initialized with a start Value.

The Simulation is run at a fixed Time-Step 0.01.

I would greatly apreciate ich someone could help me.

Thanks

Tobi

Answer 1

[Yash]

Hi Tobi,

Ideally, the derivative of the integration should match with the original signal. There could be a variety of reasons why the value is not the same. It is not possible to determine the exact reason without actually examining your model. Kindly share the ".slx" file with us for better analysis.

From your provided screenshots, I can identify a few possible sources of the discrepancy:

1. External Reset: The screenshot shows that a rising external reset is configured to the integrator block. This will reset the integrated value to zero whenever there is a rising edge in the signal. This may alter the behaviour of the model.
2. Initial Conditions: Generally, initial conditions don't impact the derivative since they represent a constant offset. However, it's worth experimenting with different initial conditions to observe any effects.
3. Other Parameters: Review other parameters, such as the value of "c" in the "Derivative" block or any options within the "Integrator" block, to ensure they're set correctly.
4. Sample time: There might be a possibility that the Integrator and the derivative block are properly configured but the sample time or the step size is causing the issue.

For troubleshooting, consider implementing the integrator and differentiator manually using a "MATLAB Function" block. Comparing these manual implementations to the existing block outputs can help isolate the problem and determine which block might be at fault.

Hope this helps in resolving the issue.