packageInversion

Information

This package contains examples of model inversion problems, i.e., determining the appropriate value of an input variable X such that a desired output Y is obtained.

• Inversion1 and PseudoInversion1 demonstrate two alternative solution strategies: a full inversion approach, which relies on a nonlinear equation solver to iteratively solve the system equations, and a pseudo-inversion approach, which exploits the time integrator together with a feedback loop to resolve the nonlinear relation. Both approaches are illustrated using a simple mixing problem.
• Inversion2 applies the same methodology as Inversion1, but uses a different iteration variable.
• MediumInversion uses Modelica’s equation-based formulation to determine temperature and pressure from a given specific entropy and specific enthalpy. This results in two nonlinear equation systems of size one, which are solved by Dymola using a nonlinear solver.

The models Inversion1, Inversion2, and PseudoInversion1 all extend the common base model PartialInverse located in the BaseClasses subpackage, which defines the underlying mixing problem.

Contents

Name	Description
Inversion1	Example - Inversion with non-linear equations solver and h as iteration variable
PseudoInversion1	Example - Pseudo-inversion using a feedback control loop
Inversion2	Example - Inversion with temperature as iteration variable
MediumInversion	Calculate (p,T) = f(h,s)
BaseClasses

Revisions

• 2026, by Raphael Gebhart (raphael.gebhart@dlr.de):
  Initial version.