Seyedali Mousavi

Differential Approach of Scalar Hysteresis Modeling Based on the Preisach Theory

This paper introduces a differential approach to model scalar hysteresis based on the Preisach theory. This model can generate hysteresis trajectories for both symmetrical and asymmetrical minor loops and keep the memory of a material in a proper manner. It can easily be inverted, it has a simple algorithm with suitable computational speed, and is not memory consuming. Also, the obtained results of the model are in very good agreement with measurements.

Study of very fast transient overvoltages in air‐cored pulsed transformers

Purpose – The purpose of this paper is to study very fast transient overvoltages (VFTOs) in the secondary winding of air‐cored Tesla transformers and also study the resulting electric field stresses.Design/methodology/approach – An exhaustive model based on Multi‐conductor Transmission Lines (MTLs) theory has been used. The governing telegraphists equations have been solved by Finite Difference Time Domain (FDTD) method.Findings – The results demonstrated that there are some overvoltages at the end and middle turns that should be considered in insulation design. The magnitudes of these overvoltages are several times more than the steady state value of the corresponding turn which cause very high electric field stresses.Originality/value – The paper describes results obtained from an original and innovative implementation of FDTD method in transmission line modelling and is applied properly to air‐cored pulse transformers.