Transient thermal field modelling

The purpose of this paper is to provide a thermal model for apparatus and assemblies, especially electrical drives, capable of predicting the temperature distribution under steady state or transient operational conditions.

Starting from Fourier's partical differential equation, the regions of interest are represented by lumped parameters, i.e. by R, C‐networks, and the heat flow is modelled by a system of non‐linear ordinary differential equations. Thus, the thermal equivalent circuit model is established. Next step is an analytical approach to predict the temperature functions in the considered sub‐regions. The presented analysis is validated by a benchmark example and by measurements.

The usefulness of the model is demonstrated by means of benchmark calculations and comparisons with measurements. It is relevant to the design stage as well as to the performance prediction, particularly with respect to on‐line control techniques.

The accuracy of the model would benefit from further research into the mathematical representation of the heat flow by thermal resistances and capacitances, particularly taking into account the temperature dependency.

The paper presents a valuable tool for engineers involved in temperature problems.

Efficient analytical thermal analysis is presented in this paper, taking into account a large number of potentially non‐linear elements (sub‐regions).