Dr Harold Ruiz

Associate Professor in Electrical Machines and Power Systems

School/Department: School of Engineering

Telephone: +44 (0)116 229 7825





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Dr Harold Ruiz is the Programme Director of Electrical and Electronics Engineering and Head of the Energy Systems and Superconducting Materials Research Team at the School of Engineering.

Harold brings together the cryogenics facilities at the Space Park Leicester (the largest space center at the UK) and the extensive computational facilities of the School of Engineering.

Harold got his diploma in Physics in 2004 and since then he has been working on Electrical Machines, Power Systems, Renewables Integration, and a wide variety of projects in Applied Superconductivity. He holds a MSc in Condensed Matter Physics from the National University of Colombia (his home country), a MSc on Physical Technologies, and a PhD in Electrical Machines and Applied Superconductivity from the University of Zaragoza in Spain.

Before joining the University of Leicester in 2016, where he is currently an Associate Professor in Electrical Machines and Energy Systems, he first worked as Visiting Researcher for the Center for Advanced Power Systems of the Florida State University (USA), moving then to the Center for Advanced Photonics and Electronics Systems of the University of Cambridge at the UK in 2014. He has participated in about 10 research funded projects accounting for circa $2.5M (USD) all of them focused on diverse aspects of superconductivity and energy systems in the UK, US, and the EU.


The main areas of activity of the research team led by Harold are oriented to the computational modelling, prototyping, optimization, and physical understanding of energy systems, electrical machines, and innovative superconducting technologies.

In particular, Harold's team specializes in the application of variational methods, optimal control algorithms, and Finite Element Methods, these applied to a large set of problems in Electrical Engineering, Materials Sciences and Applied Superconductivity.

Our problems can include aspects as diverse as power network analysis, machine learning, econophysics, supply chain processes, space image processing, or the use and prognostics of metamaterials for energy systems.

Harold has participated in more than 10 research funded projects accounting for circa $2.5M USD.

His main focus is "energy" within a multidisciplinary approach, with topics ranging from the study of Josephson junctions in the microscopic world, to the optimization and prototyping of superconducting propulsion systems, the thermal, mechanical, and electromagnetic modelling of HV cables and coils for, ultra-high power density motors, generators, transformers, fault current limiters, and energy storage systems.

Harold has also developed novel algorithms for satellite data retrieval aimed to tackle global challenges in developing countries, with successful grants being funded by bodies such as EPSRC and the UKRI Newton Fund Programs.



Harold counts with more than 50 publications in renown Peer Reviewed Journals and International Conferences. He has served as guess editor in multiple journals, is scientific advisor for the major conferences in applied superconductivity, and actively supports the scientific community as peer-reviewer of IoP, AIP, MDPI, T&F, Elsevier, and Nature journals. 

For a full account of publications, please visit

A sample of some of Prof. Ruiz favorite publications is shown below:

  1. M. Kapolka and H. S. Ruiz, Maximum reduction of energy losses in multicore MgB2 wires by metastructured soft-ferromagnetic coatings (2022), Scientific Reports, DOI : 10.1038/s41598-022-10728-5
  2. M. U. Fareed, M. Kapolka, B. C. Robert, M. Clegg, and H. S. Ruiz. 3D FEM Modelling of CORC Commercial Cables with Bean's like magnetization currents and its AC-Losses Behaviour. IEEE Transactions on Applied Superconductivity 32(4), 8200205 (2022)
  3. M. U. Fareed and H. S. Ruiz, Critical State Theory for the Magnetic Coupling between Soft Ferromagnetic Materials and Type-II Superconductors. Materials 14(20), 6204 (2021)
  4. H. S. Ruiz, A. Sunarso, K. Ibrahim-Bathis, S. A. Murti, and I. Budiarto, GIS-AHP Multi-Decision-Criteria-Analysis for the Optimal Location of Solar Energy Plants at Indonesia. Energy Reports 6, 3249-3263 (2020)
  5. B. C. Robert, M. U. Fareed, and H. S. Ruiz, How to Choose the Superconducting Material Law for the Modelling of 2G-HTS coils. Materials, Volume 12(17), 2679 (2019)
  6. B. C. Robert, M. U. Fareed, and H. S. Ruiz, Local Electromagnetic Properties and Hysteresis Losses in Uniformly and Non-Uniformly wound Superconducting Racetrack Coils. Journal of Applied Physics, Volume 126, 123902 (2019)
  7. M. Baghdadi, H. S. Ruiz, and T. A. Coombs, Nature of the low magnetization decay on stacks of second generation superconducting tapes under crossed and rotating magnetic field experiments. Scientific Reports, Volume 8, 1342 (2018)
  8. B. C. Robert and H. S. Ruiz, Magnetic characteristics and AC losses of DC Type-II Superconductors under oscillating magnetic fields. Superconductor Science and Technology, Volume 31, 035006 (2018)
  9. X. Zhang, H. S. Ruiz, J. Geng, and T. A. Coombs, Optimal Location and Minimum Number of Superconducting Fault Current Limiters for the Protection of Power Grids. International Journal of Electrical Power and Energy Systems, Volume 87, Pages 136-143 (2017).
  10. M. Baghdadi, H. S. Ruiz and T. Coombs. Crossed Magnetic Field Experiments on Stacked Second Generation Superconducting Tapes: Reduction of the Demagnetization Effects. Applied Physics Letters 104, 232602 (2014).
  11. H. S. Ruiz, C. Lopez, and A. Badi­a-Majos. Inversion Mechanism for the Transport Current in Type-II Superconductors. Physical Review B 83, 014506 (2011).
  12. A. Badia-Majos, C. Lopez, and H. S. Ruiz. General Critical States in Type-II Superconductors. Physical Review B 80, 144509 (2009).
  13. H. S. Ruiz and A. Badi­a-Majos. Nature of the Nodal kink in Angle-Resolved Photoemission Spectra of Cuprate Superconductors. Physical Review B 79 054528 (2009).


Below you can find a non-exhaustive list of topics of interest within my group, but for any other please do not hesitate to contact me.

  1. Integration and optimization of renewables in large scale energy systems.
  2. GIS analysis and satellite data retrieval for the deployment of renewables in challenging landscapes.
  3. Superconducting cables and related technologies.
  4. Energy Storage Systems.
  5. Bearings and Magnetic levitation technology for the Transport Industry.
  6. Ultra-high power density rotary Machines such as: Superconducting Generators for naval ship and aircraft propulsion.
  7. Ultralight MW wind turbines.
  8. Superconducting Transformers and dielectrics at cryogenic temperatures.
  9. Hybrid Metamaterials for power technologies and high magnetic field applications.
  10. Numerical Optimization Methods and Optimal Control Problems in Science and Engineering.
  11. Optical properties in Low and High Temperature Superconductors (Microscopic descriptions).
  12. Properties of electronic transport in High Critical Temperature Superconductors.


EG7020 MSc Individual project

EG4221-EG7035 MSc Advanced Electronically Controlled Drives

EG3005 BEng/MEng Third Year Project

EG3201 BEng/MEng Power Systems and Electrical Networks

EG2004 BEng/MEng Engineering Experimentation and Analysis 2

EG1006 BEng/MEng Engineering Experimentation and Analysis 1

EG1201 BEng/MEng Electrical and Electronic Engineering

Press and media

Any press or media inquiries related to the following topics are kindly welcome:

  • Applied Superconductivity
  • Superconductors
  • Energy Systems
  • Electrical Machines
  • Power Systems
  • Cryogenics
  • Renewables



  • FHEA. Fellow of the Higher Education Academy UK Recognition reference: PR128012 Date of recognition 21/06/2017
  • EEHEA. External Examiner of the Higher Education Academy Advance HE UK. June 2018
  • PDOC-CAM - Certified and Active Mentor for Early Career Researchers and PostDoctoral Researchers at University of Cambridge UK (Since 2021)
  • UKRI - Future Leader Fellowships Grant Examiner (Since 2021)
  • EPSRC - Standard Grants Examiner (Since 2020)
  • INNOVATE UK - Catapult Grants examiner (Since 2018)
  • EPC - Engineering Professors' Council member. Since 2017
  • NCN - Narodowe Centrum Nauki (Poland National Science Centre) Equivalent to the EPSRC in UK. Grant Examiner (Since 2019)


Selected Merits and Awards:

  • EUCAS 2023 Board Member. Scientific Programme Committee. 16th European Conference on Applied Superconductivity, Bologna, Italy. 3-7 Sept. 2023
  • CEC 2021 Board Nominee: The Cryogenic Society of America Cryogenic Engineering Conference July 19-23 (2021)
  • IOP Trusted Reviewer Award. The Institute of Physics (IOP) Peer-review Excellence Award September 22 (2020)
  • PGCAPP. Postgraduate Certificate in Academic and Professional Practice HEA - PR107970 30/06/2016
  • Cum Laude. Highest Distinction for PhD studies in Spain. (2012).
  • Europeous Doctor. Honour mention. (2012).

Selected Grants as PI:

  • (£303k) EPSRC Grant No. EP/S025707/1 (2020-2023).
  • (£86k) EPSRC-DTP Studentship programme (2020-2023)
  • (£18k) UKRI CoA Fund Grant No. RW13G0003 (2020)
  • (£180k) British Council Institutional Links Grant No. 413871894 (2019-2020)
  • (£70k) Niger Delta Development Commission PhD Studentship offer (2017-2020)
  • (£240k) EPSRC Grant NMZF/064-2014 (Research Associate 2014-2016)
  • (€100k) Research Fellowship (PhD). CSIC-Spain (2008/11-2012/04)
  • (€25k) Research Fellowship (MSc). Santander Bank. Spain (2008/01-/12).
  • ($20k COP) Scholarship of Academic Excellence (MSc). UNAL Colombia (2005-2006).

Other grants as CoI or RA: Approximately £1M with participation in EPSRC HORIZON and CSIC Research projects.



  • PhD on Physics and Applied Superconductivity. University of Zaragoza 2008/11 - 2012/04 1st Class Cum Laude and European Doctor (Highest distinctions in Spain) Department of Condensed Matter Physics and Materials Science Institute of Aragón Spain.
  • MSc. Physical Technologies, University of Zaragoza 2008/01 -/10 1st Class Research Fellowship Department of Condensed Matter Physics and Materials Science Institute of Aragón Spain.
  • MSc. Physics, National University of Colombia 2005/06 - 2007/06 1st Class Research Fellowship Department of Physics Bogotá - Col.
  • BSc Physics, University Francisco José de Caldas 2000/02-2004/04 1st Class Department of Physics Bogotá - Colombia.


  • FHEA (with merit in research). Fellow of the Higher Education Academy UK Recognition reference: PR128012 Date of recognition 21/06/2017
  • PGCAPP (with merit). Postgraduate Certificate in Academic and Professional Practice The Higher Education Academy Recognition reference: PR107970 Date of recognition 30/06/2016
  • EEHEA. External Examiner of the Higher Education Academy Advance HE UK Professional development course for accreditation as external examiner. June 2018
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