Advanced iteration for a magnetic equivalent circuit and modeling a 3-phase transformer

Abstract

Considering the nonlinearities of magnetic circuits such as a 3-phase transformer results in an iterative approach. A model of the magnetic circuit for the 3-phase transformer is built up with a magnetic equivalent circuit (MEC); the electric circuit is described by an electric equivalent circuit (EEC). The requests on the iteration procedure are low number of iteration steps and low complexity in order to prevent high computational effort. Newton-Raphson is one possible iteration method, which is useful for high magnetic saturation. Normally, Newton-Raphson requires high computational effort. Hence, it is often easier to use other methods such as direct iteration. Here we show a straightforward setup for Newton-Raphson based on the network analysis of the MEC. This results in a lower number of iteration steps especially for high saturation while requiring a minimum of additional computation operations. A comparison between measurement and simulation for the transformer points out a time efficient solver, and shows the benefit of the application of a MEC.