Ahmed Lotfy Elrefai

Associate Professor
ahmed.lotfy@ejust.edu.eg

Personal Info

B26.F02.14

Electrical Power Engineering

Ahmed L. Elrefai received his B.Sc. degree in Electrical Power Engineering from Cairo University, Egypt in 2011. He also received his M.Sc. degree in Electrical Engineering from Faculty of Engineering, Cairo University, Egypt in July 2013. In October 2013, Dr. Elrefai was awarded the Japanese government MEXT/Monbukagakusho scholarship to complete his doctorate studies in Electrical Engineering from Kyushu University, where he received his doctorate degree in September 2016.
From 2016 to 2021, he served as a postdoctoral researcher at the magnetic nanoparticle biosensing systems research center, Kyushu University, Japan where he was awarded a two year postdoctoral fellowship (2018-2020) from Japan Scoiety for Promotion of Science (JSPS). In 2021, he joined Cairo University, Egypt, as Assistant Professor at the Electrical Power Engineering Department. Since February 2025, he has held the position of Associate Professor in the Electrical Power Engineering Department at Egypt-Japan University of Science and Technology.
Dr. Elrefai has 14 years of experience in academic research, supervision of postgraduate students and academic teaching of postgrad/undergrad courses. He also has 3 years of experience as technical instructor at Egypt’s National Telecommunications Institute and Information Technology Institute, delivering hands-on training programs on designing production-ready industrial electronic products.

Power Electronic Converters – Smart Grids – IOT Applications in Electric Systems – Grid Forming and Grid Following Inverters – Battery Management Systems – Motor Control and Machine Drives – Wireless Power Transfer –  Embedded Systems Design and Implementation – Magnetic Sensors – Magnetic nanoparticles Biomedical Applications – Magnetic Particle Imaging – Magnetic Hyperthermia – Solar Still Desalination


Awards

-      2022/2021/2020 Cairo University Publication Award

-      2015 Excellent Student Award of IEEE Fukuoka Section, Japan.

-      2011 Outstanding Academic Performance Award, Egyptian Ministry of Electricity and Energy, Egypt.

-      2011 Prof. M. M. Khalifa award for distinguished undergraduate students, Cairo University, Egypt.


Impacted Journal

[1]       K. Enpuku, A. L. Elrefai, J. Gotou, S. Yamamura, T. Sasayama, T. Yoshida, "Difference in AC magnetization between suspended and immobilized magnetic nanoparticles in Néel-relaxation dominant case: Effect of easy axis alignment in suspended nanoparticles," Journal of Applied Physics, Vol. 130, No. 11, 113903, Sep. 2021.

[2]       A. L. Elrefai, K. Enpuku, T. Yoshida, "Effect of easy axis alignment on dynamic magnetization of immobilized and suspended magnetic nanoparticles," Journal of Applied Physics, Vol. 129, No. 9, 093905, Mar. 2021.

[3]       A. L. Elrefai, T. Sasayama, T. Yoshida, K. Enpuku, "AC Magnetization of Immobilized Magnetic Nanoparticles with Different Degrees of Parallel Alignment of Easy Axes," IEEE Transactions on Magnetics, Vol. 57, No. 2, 5200105, Feb. 2021.

[4]       A. L. Elrefai, T. Yoshida, K. Enpuku, "Viscosity Dependent Amplitude and Phase of Harmonic Signals of Magnetic Nanoparticles," Journal of Magnetism and Magnetic Materials, Vol. 507, 166809, Aug. 2020.

[5]       K. Akiyoshi, T. Yoshida, T. Sasayama, A. L. Elrefai, M. Hara, K. Enpuku, " Wash-free detection of biological target using cluster formation of magnetic markers," Journal of Magnetism and Magnetic Materials, Vol. 500, 166356, Apr. 2020.

[6]       K. Enpuku, A. L. Elrefai, T. Yoshida, T. Kahmann, J. Zhong, T. Viereck, "Estimation of the effective magnetic anisotropy constant of multi-core based magnetic nanoparticles from the temperature dependence of the coercive field," Journal of Applied Physics, Vol. 127, No. 13, 133903, Apr. 2020.

[7]       A. L. Elrefai, T. Yoshida, K. Enpuku, "Effect of viscosity on harmonics signals of magnetic nanoparticles for thermometry application," Journal of Magnetism and Magnetic Materials, Vol. 491, 165480, Dec. 2019.

[8]       S. Hamanaga, T. Yoshida, T. Sasayama, A. L. Elrefai, K. Enpuku, "Three-dimensional detection of magnetic nanoparticles using a field-free line with weak field gradient and multiple pickup coils," Japanese Journal of Applied Physics, Vol. 58, No. 6, 061001, May 2019.

[9]       A. L. Elrefai, T. Yoshida, K. Enpuku, "Magnetic parameters evaluation of magnetic nanoparticles for use in biomedical applications," Journal of Magnetism and Magnetic Materials, Vol. 474, pp. 522-527, Mar. 2019.

[10]     A. L. Elrefai, T. Sasayama, T. Yoshida, K. Enpuku, " Empirical expression for DC magnetization curve of immobilized magnetic nanoparticles for use in biomedical applications," AIP Advances, Vol. 8, No. 5, 056803, Dec. 2017.

[11]     A. L. Elrefai, T. Sasayama, T. Yoshida, K. Enpuku, " Magnetic Core-Size Distribution of Magnetic Nanoparticles Estimated From Magnetization, AC Susceptibility, and Relaxation Measurements," IEEE Transactions on Magnetics, Vol. 53, No. 11, 8204605, Nov. 2017.

[12]     A. L. Elrefai, I. Sasada, " Magnetic Particle Detection System Using Fluxgate Gradiometer on a Permalloy Shielding Disk," IEEE Magnetics Letters, Vol. 7, 6507804, Sep. 2016.

[13]     A. L. Elrefai, I. Sasada, and S. Harada, "Gradiometer and Magnetometer Integration by Using a Pair of Fundamental Mode Orthogonal Fluxgate Sensor Heads," IEEE Transactions on Magnetics, Vol. 51, No. 11, Nov. 2015.

[14]     A. L. Elrefai, and I. Sasada, “Magnetic particle detection in unshielded environment using orthogonal fluxgate gradiometer,” Journal of Applied Physics, Vol. 117, 17C114, Mar. 2015.


International Conference

[1]       M. Reda, A. L. Elrefai, and S. M. Abdelkader, " Extended Shift Modulation Control of Dual Active Bridge Converter for Enhanced Solar Powered EV Charger," Oral, , IEEE 23rd Mediterranean Electrotechnical Conference, Feb. 2026, Cairo, Egypt.

[2]       M. Reda, A. L. Elrefai, and S. M. Abdelkader, "Advanced Control and Optimization of PV-Based Boost Converter with MPPT and Dual Active Bridge for EV Charging Applications," Oral, International Middle East Power System Conference, Dec. 2025, Aswan, Egypt

[3]       A. S. Soliman, A. S. Qamr, A. L. Elrefai, and A. H. Mohamed, "SPICE Comparison Between Neutral Point Clamped Inverter and 2-Level Inverter for Electrical Traction Drive System," Oral, International Middle East Power System Conference, Dec. 2024, Cairo, Egypt

[4]       N. A. Abdulhamid, and A. L. Elrefai, "Modeling and Design of Proportional Integral Resonant Controller for Attenuation of Current Ripple in LLC Resonant Converter of Electric Vehicle Onboard Charger," Oral, International Middle East Power System Conference, Dec. 2023, Mansoura, Egypt.

[5]       A. L. Elrefai, T. Yoshida, and K. Enpuku, "Viscosity Dependent Amplitude and Phase of Harmonic Signals of Magnetic Nanoparticles," Poster, Joint European Magnetic Symposia, Aug. 2019, Uppsala, Sweden.

[6]       A. L. Elrefai, T. Yoshida, and K. Enpuku, “Magnetic parameters evaluation of magnetic nanoparticles for use in biomedical applications,” Poster, International Conference on the Scientific and Clinical Applications of Magnetic Carriers, May 2018, Copenhagen, Denmark.

[7]       A. L. Elrefai, T. Sasayama, T. Yoshida, and K. Enpuku, “Empirical expression for DC magnetization curve of immobilized magnetic nanoparticles for use in biomedical applications,” Poster, Magnetism and Magnetic Materials Conference, Nov. 2017, Pittsburgh, USA.

[8]       A. L. Elrefai, T. Sasayama, T. Yoshida, and K. Enpuku, “Magnetic Core-size Distribution of Magnetic Nanoparticles Estimated from Magnetization, AC Susceptibility and Relaxation Measurements,” Poster, International Conference on Magnetics, Apr. 2017, Dublin, Ireland.

[9]       T. M. Abdo, A. L. Elrefai, A. A. Adly, and O. A. Mahgoub, "Performance analysis of coil-gun electromagnetic launcher using a finite element coupled model," Oral, International Middle East Power Systems Conference, Dec. 2016, Cairo, Egypt.

[10]     A. L. Elrefai, I. Sasada, " Magnetic Particle Detection System Using Fluxgate Gradiometer on a Permalloy Shielding Disk," Poster, IEEE Magnetics Summer School, Sep. 2016, Tohoku, Japan.

[11]     A. L. Elrefai, I. Sasada, and T. Yoshida, “Improvement of Fluxgate Gradiometer Detection of Magnetic Nanoparticles using a shielding Permalloy Desk,” Oral, Joint International Magnetics Conference and the Magnetism and Magnetic Materials Conference, Jan. 2016, San Diego, USA.

[12]     A. L. Elrefai, I. Sasada, " Orthogonal Fluxgate Gradiometer Sensor and its Application in Particle Detection," Proceedings of International Exchange and Innovation Conference on Engineering and Sciences, Oct. 2015, Fukuoka, Japan.

[13]     A. L. Elrefai, I. Sasada, and T. Yoshida, “Reduction of fluxgate gradiometer susceptibility to uniform magnetic fields using permalloy shielding disk,” Oral, Annual Conference on Magnetics in Japan, Sep. 2015, Nagoya, Japan.

[14]     A. L. Elrefai, I. Sasada, and S. Harada, "Gradiometer and Magnetometer Integration by Using a Pair of Fundamental Mode Orthogonal Fluxgate Sensor Heads," Oral, International Conference on Magnetics, May 2015, Beijing, China.

[15]     A. L. Elrefai, I. Sasada, and T. Yoshida, “Fluxgate Gradiometer for Magnetic Nanoparticle Magnetorelaxometry in Unshielded Environment,” Poster, International Conference on Magnetics, May 2015, Beijing, China.

[16]     A. L. Elrefai, and I. Sasada, “Magnetic Particle Detection in Unshielded Environment using Orthogonal Fluxgate Gradiometer,” Oral, Magnetism and Magnetic Materials Conference, Nov. 2014, Hawaii, USA.


Funded Research Grants

-      2024 Graduation project funding program, Faculty of Engineering, Cairo University, Egypt.

-      2022 Graduation project funding program, Scientific Research and Technology Academy, Egypt.

-      2018 Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellowship Funding program, Japan.

-      2016 IEEE Magnetics Society Student Travel Grant, Joint MMM/Intermag Conference in San Diego, USA.

-      2015 IGSES-Kyushu University Overseas Scientific Activity Grant, Intermag conference in Beijing, China.

-      2013 MEXT Ph.D. Scholarship, Japanese Ministry of Education, Culture, Sports, Science and Technology, Japan.



Courses Teaching

PostGraduate Courses 

-     Power semiconductor devices.

-     Power Electronic converters modelling and control.

-     Design, Modeling and Control of Power Electronics systems in Electric vehicles.

-     Power Quality in Electric Grids.

UnderGraduate Courses 

-      Power Electronic Converter Circuits

-      Renewable Energy Systems and On-grid/Off-grid Applications

-      Mechatronics/Electric Vehicles Model-based design

-      Isolated and Resonant Converters

-      Electric Machines and Transformers 

-     Operational Amplifiers Circuits and Practical Applications

-     Microcontroller Fundamentals and Applications

-      Electric Circuits and Electronic Devices

-      Fundamentals of Engineering Design Process