A Stabilized Circuit-Consistent Foil Conductor Model

TL;DR

This paper identifies an instability in classical foil conductor models used in magnetoquasistatic simulations of power transformers and proposes a modified model to ensure circuit consistency and simulation stability.

Contribution

The paper introduces a stabilized, circuit-consistent foil conductor model that addresses instability issues in existing homogenization techniques for large power converter simulations.

Findings

The classical foil conductor model exhibits time-stepping instability.

A modified conductance matrix improves simulation stability.

Numerical results confirm the effectiveness of the new model.

Abstract

The magnetoquasistatic simulation of large power converters, in particular transformers, requires efficient models for their foils windings by means of homogenization techniques. In this article, the classical foil conductor model is derived and an inconsistency in terms of circuit theory is observed, which may lead to time-stepping instability. This can be related to the differential-algebraic nature of the resulting system of equations. It is shown how the foil conductor model can be adapted to mitigate this problem by a modified definition of the turn-by-turn conductance matrix. Numerical results are presented to demonstrate the instability and to verify the effectiveness of the new adapted foil conductor model.