High Frequency Circuit Model of Transformer Windings Based on Frequency Responses for VFTO Studies

摘要

In order to study the effects of VFTO to transformers , the high frequency model for transformer windings must be set up. In this paper, a systematic methodology is presented for establishing the high frequency two-port circuit model of transformer windings under VFTO based on its frequency responses. The p -equivalent circuit is constructed based on the Y-pa-rameters transformed from the measuring S-parameters. A correction to the rational function of Y approximated by Vector Fitting (VF) is calculated, which enforces the real part of Y is positive definite. This enforcement can assure the passivity of the whole model, which could bring a stable simulation. The values of the synthesized RLCG elements can be easily calculated form the rational functions. This kind of p -equivalent circuit model could do stable and exact simulation compared with the experiment results , which shows the validity of the method.