Ahmad Vosoughi Hamzekhanlo

Simulations and Experimental Study of Core Eddy Losses

Stray and eddy-current losses in laminated transformer cores: Investigation of additional losses caused by incident/normal magnetic flux in laminated core packets, with particular focus on eddy current loss distribution its contribution to local heating and local hot-spot formation.

Experimental characterization of normal-flux effects: Design and construction of dedicated test objects and measurement setups to investigate magnetic-flux distribution and local eddy-current losses under controlled excitation, different flux directions, and varying operating conditions.

Thermal and electromagnetic measurements: Investigation of infrared thermography and other measurement techniques for identifying spatial distributions of electromagnetic losses and localized heating, complementing conventional measurements of total power loss.

FEM modeling of laminated cores: Development of detailed electromagnetic models to capture the influence of three-dimensional geometry, anisotropic material properties, lamination structure, and local field concentrations on eddy-current and stray losses.

Core saturation and material nonlinearity: Investigation of the influence of magnetic saturation, nonlinear B–H characteristics, and permeability variations on flux penetration and loss generation in laminated core structures.

Higher harmonics and non-sinusoidal excitation: Analysis of the effect of higher-frequency harmonic components.

Equivalent-circuit model for eddy loss calculation: Development of computationally efficient equivalent-circuit for predicting eddy-current losses while accounting for nonlinear material behavior, saturation, frequency-dependent effects, and harmonic excitation.

Model validation and correlation: Systematic validation of numerical and analytical models against experimentally measured total losses, local loss distributions, magnetic-flux distributions, and thermal measurements.

Application to power transformers: Ultimately, the research aims to provide improved methods for predicting stray losses and local hot spots in transformer core structures, supporting more reliable thermal design, loss estimation, and transformer lifetime assessment.

Journal paper

A. Vosoughi and MH Samimi, “Transformer fault type discrimination based on window calculation method and frequency response analysis,” Measurement, vol. 202, 111889, 2022. DOI: 10.1016/j.measurement.2022.111889.

Conference Papers

A. Vosoughi Hamzekhanlo and S. Kornhuber, “Assessment of Aging Related Changes in Transformer Oil Properties for Enhanced Thermal and Aging Model Integration,” ICD 2026 – International Conference on Dielectric Liquids, Southampton, United Kingdom, 2026.

A. Vosoughi, S. Kornhuber, S. Kleyboldt, and M. Moh'd, “Insights in Condition Assessment of Power Transformers Using SOT and DGA Data for End-of-Life Estimation,” CIGRE 2025 International Symposium, Montreal, Canada, September 2025, Paper No. 10366.

A. Vosoughi and MH Samimi, “Evaluation of Mechanical Fault's Severity in Power Transformers by using Maximum Points of FRA Window Curves,” 2023 3rd International Conference on Electrical Machines and Drives (ICEMD), Tehran, Iran, 2023, pp. 1–6. DOI: 10.1109/ICEMD60816.2023.10429613.

A. Vosoughi and MH Samimi, “Evaluation of the Image Processing Technique in Interpretation of Polar Plot Characteristics of Transformer Frequency Response,” 2022 International Conference on Machine Vision and Image Processing (MVIP), 2022, pp. 1–6. DOI: 10.1109/MVIP53647.2022.9738771.