A Novel Oil-immersed Medium Frequency Transformer for Offshore HVDC Wind Farms
Licentiate thesis, 2020

In this project, a design of an oil type medium frequency transformer for offshore wind farm applications is proposed. The design is intended for applications when series coupling of the output of the DC/DC converters of the wind turbine on their secondary side is done to achieve a cost-effective high voltage solution for collecting energy from offshore wind parks. The focus of the work is on the insulation design of the high voltage side of a medium frequency transformer where the magnetic design constraints should also be satisfied.

Above all, a proof of concept is made demonstrating a possible solution for the design of the transformer for such a DC/DC converter unit. The transformer suggested is using oil/paper as insulation medium. Furthermore, characterisation of an eco-friendly biodegradable transformer oil for this type of HVDC transformer application is made. Moreover, an introduction of reliable high frequency characterisation test methods to medium frequency transformer designers is made. In addition, the Non-Linear Maxwell Wagner (NLMW) relations are further developed to form a method for the development of an HVDC MFT transformer. All in all, the DC series concept has been further developed one step closer to pre-commercialization, i.e. from TRL 1 to about 2.

prototype design methodology

HVDC insulation design

Wind energy

DC-DC power converters

finite element analysis

medium frequency transformer

Online - please e-mail PhdAdm.e2@chalmers.se in advance to get the password
Opponent: Dr.-Ing. Karsten Backhaus, Technical University of Dresden, Germany

Author

Mohammad Kharezy

Chalmers, Electrical Engineering, Electric Power Engineering, Electrical Machines and Power Electronics

Calculation of the leakage inductance of medium frequency transformers having rectangular-shaped windings using an accurate analytical method

2019 21st European Conference on Power Electronics and Applications (EPE '19 ECCE Europe),; (2019)

Paper in proceeding

Optimization and experimental validation of medium-frequency high power transformers in solid-state transformer applications

31st Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2016; Long Beach Convention and Entertainment CenterLong Beach; United States; 20 March 2016 through 24 March 2016,; (2016)p. 3043 - 3050

Paper in proceeding

Design Methodology and Optimization of a Medium-Frequency Transformer for High-Power DC–DC Applications

IEEE Transactions on Industry Applications,; Vol. 52(2016)p. 4225-4233

Journal article

Design methodology and optimization of a medium frequency transformer for high power DC-DC applications

2015 Thirtieth Annual IEEE Applied Power Electronics Conference and Exposition (APEC 2015), 30th Annual IEEE Applied Power Electronics Conference and Exposition (APEC), Charlotte, NC MAR 15-19, 2015,; (2015)p. 2532-2539

Paper in proceeding

M. Kharezy, H. R. Mirzaei, M. Eslamian, T. Thiringer and Y. Serdyuk, “A Prototype Medium Frequency Transformer for a Sea-based Wind Farm Series HVDC Collection Network, Insulation Design”

M. Kharezy, H. R. Mirzaei, J. Rastamo, M. Svensson, Y. Serdyuk and T. Thiringer, “Performance of Insulation of DC/DC Converter Transformer for Offshore Wind Power Applications”

M. Kharezy, M. Eslamian, and T. Thiringer, "Estimation of the winding losses of Medium Frequency Transformers with litz wires using an equivalent permeability and conductivity method"

M. Eslamian, M. Kharezy and T. Thiringer, An accurate analytical method for leakage inductance calculation of high-power shell type medium frequency transformer with circular windings"

Driving Forces

Sustainable development

Innovation and entrepreneurship

Areas of Advance

Energy

Subject Categories

Other Electrical Engineering, Electronic Engineering, Information Engineering

Publisher

Chalmers University of Technology

Online - please e-mail PhdAdm.e2@chalmers.se in advance to get the password

Online

Opponent: Dr.-Ing. Karsten Backhaus, Technical University of Dresden, Germany

More information

Latest update

11/26/2021