Qualified Model Reduction (QMR)

PSS is a leader in the development of software for the calculation of heat generation in cables, cable bundles, fuses, power distribution boards etc. These are used in complex systems, for example in the wiring systems of automobiles. PSS develops calculation methods for this purpose, which are based on the Qualified Model Reduction (QMR). Software tools based on QMR replace the standard methods used up to now (e. g. the Finite Elements Method, in short: FEM).

Instead of completely modelling and solving a problem, PSS deals with concrete questions and the actual relevant parameters. This applies to the description of the problem, the calculation and the presentation of the results. This is the essential simplification that PSS achieves with QMR.

The illustration shows the fundamental difference. Here for comparison a schematic comparison of the procedures of FEM and QMR:

(a) Numerical standard-processes (e.g. FEM)

Image FEM

(b) QMR

Image QMR


There are basically two approaches to creating an object. A synthetic (a) that models a form or information from individual parts and a reductive (b) that removes excess material. The approach (b) corresponds to the PSS-own QMR method, while numeric standard procedures (e. g. FEM) apply the procedure (a).

The main advantage of QMR is the preservation of the structure of the problem. As shown in Figure 1b, QMR con-siders the problem as a whole and thus enables a tailor-made, individual solution.

In summary, QMR can be divided into the following steps:

  • Modelling of the physical problems with suitable conservation laws,
  • Model reduction and development of adapted, faster calculation methods,
  • Validation with measurements.

QMR thus delivers a manageable and cost-effective, fast and flexible method for solving the problems mentioned above, which maintains the accuracy

Our competitors and their products use almost exclusively the approach (a) or rather, complex measurements. Wiring systems, however, are complex systems whose calculation requires an efficient method. QMR fulfils exactly this requirement. The following table shows the advantages of the QMR compared to measurements and numerical standard procedures:

Measurements and FEMQMR
• Load case analysis by measurements and unfocused numerical standard procedures result in high time and cost expenditure.
• Extensive and unfiltered results of measurements and simulations.
• Thermal and electrical simulation of critical components by qualified model reductions to capture worst case scenarios.
• Focused and clear presentation of results through the use of QMR.
Image FEM Image QMR