Advances in computational electromagnetics: Selected extended papers from the International Conference on Computational Electromagnetics (CEM) 2023

It is my great pleasure to be editing this special section of the IET Science, Measurement and Technology (SMT) to include some representative papers from the recent CEM Conference which took place in Cannes, France on 11–14 April 2023. The International Conference on Computation in Electromagnetics (CEM) has been the flagship bi-annual event of the Electromagnetics TPN since 1992, but this is the first time it has been run independently from the IET (although we are pleased that they continued to co-sponsored the event). This was the 11th Conference in the series, and as with previous events, it provided a forum for the presentation and discussion of research into computational techniques for solving problems in electromagnetics, with a focus on aspects and applications of numerical modelling based on these techniques. The technical scope of the conference series includes Techniques of Computational Electromagnetics, Numerical Methods, plus Applications of Computational Electromagnetics. Both low and high-frequency fields were covered, as well as electromagnetic hazards and EMC, and the use of CEM in Education. “The hybrid algorithms in constrained optimization of the permanent magnet motors”, Łukasz KNYPIŃSKI et al.: The authors use different hybrid optimisation algorithms in the optimisation of line-start permanent motors, with a view to test various hybrid approaches and discuss the advantages and disadvantages of the algorithms developed. “Reduced Order Modelling Method for Electromagnetic Analysis of Electrical Machines”, B. Mohamodhosen et al.: The authors create a reduced order model (ROM) for the electromagnetic analysis of an electrical machine so that the stator forces can be exported for mechanical analysis. A Response Surface Model Approximation method is used to generate the reduced order model, which is then validated by comparing it with results from finite element analyses. “Electromagnetic Time Reversal for Online Partial Discharge Location in Power Cables: Influence of Interfering Reflections from Grid Components”, Antonella Ragusa et al.: This paper analyses the performance of an online single-sided partial discharge location method based on electromagnetic time reversal (EMTR) theory. The method is applied to a case study when interfering reflections contribute to the transient signals emitted by the PD event, such that classical location techniques tend to fail. The numerical investigation shows that the accuracy of the EMTR-based location method is robust against these effects, achieving a PD localisation with an error of less than 0.1%. “Gradient-Based Eigenvalue Optimization for Electromagnetic Cavities with Built-in Mode Matching”, A. Ziegler et al.: The authors propose a gradient-based optimization scheme, enhanced with closed form shape derivatives of the system matrices. This provides accurate derivatives of eigenvalues, eigenmodes and the cost function with respect to the geometry, thus significantly reducing the computational effort of the optimizer. To avoid the crossing of eigenvalues during the optimisation process, a new algorithm based on eigenvalue matching is proposed. “Spatiotemporal Energy-Density Distribution of Time-Reversed Electromagnetic Fields”, Elias Le Boudec et al.: This paper analyses the spatial energy-density distribution of time-reversed electromagnetic fields by introducing a convergence metric based on the spatial average and variance of the energy density. They analytically prove that the proposed metric identifies the focusing time and the source location, with direct links to the source frequency content. “Experimental Verification of Temperature Effects on Functional Parameters in a Line Start Permanent Magnet Synchronous Motor”, M. Baranski et al.: The paper deals with the finite element (FE) analysis of the temperature influence on functional parameters of the line start permanent magnet synchronous motor (LSPMSM). The non-linearity of the magnetic circuit and the influence of temperature on the magnetic properties of permanent magnets, as well as on the electric and thermal properties of the materials are considered. Simulation results are validated by measurements of a prototype motor on a specially designed and constructed measuring test stand. More information is available on the Conference web site: www.cem2025.com and we look forward to seeing you in Bruges in 2025. Dr. Cris Emson studied electronic engineering at Hull University, and received his Bachelor's degree with Honours in 1977. Since then he has obtained a Master's degree in Microwave and Communications Engineering from Leeds University, and a Ph.D. from the University of Wales Swansea on special finite element techniques for unbounded electromagnetic propagation problems. In 1982 he joined the Rutherford Appleton Laboratory to develop numerical methods for modelling three-dimensional eddy current problems, and after its formation he joined Vector Fields Ltd, developing software packages for 3D eddy current and high-frequency analyses. In 2004 he moved to the USA to take over as Vice-President of Vector Fields Inc. On returning to the UK in 2007 he joined Infolytica Europe. Following the acquisition of the Infolytica software by Mentor (a Siemens Business) in 2017, he took the European arm of the company and changed its name to Infologic Design Ltd, to continue with the sales and support of the electromagnetic software and related services. He has published over 90 technical papers and reports, mainly in the areas of eddy current modelling and special techniques for computational modelling. He has also been actively involved with the IET (formerly IEE) for many years and is a past Chairman of the Science and Engineering Technology Board. He has been a member of the organising committee of each IEE CEM Conference since the second, held in 1994. Data will shared upon contact by the corresponding author.