Distinguished Lecturer

About Dr. Charles Jullien

Senior EMC Expert, Safran Electrical & Power
Blagnac, France
charles.jullien@safrangroup.com

Charles Jullien is a Senior Electromagnetic Compatibility (EMC) Expert at Safran Electrical & Power, where he has been contributing since 2012 to the design, analysis, and qualification of complex aeronautical electrical systems. He has worked on more than 40 industrial programs, providing technical expertise, audits, and training in EMC. He is an active member of Safran’s Electromagnetism expert network and currently chairs the Safran Group roadmap on Tools and Modelling for Electrical Systems, supporting the development of advanced EMC methodologies for aerospace applications.

Dr. Jullien received his PhD in Electronics and Telecommunications with honors from INSA Rennes through a CIFRE program with Safran and ONERA. His doctoral research focused on the modeling and analysis of electromagnetic coupling in complex cable bundles, applied to aeronautical harnesses. He also holds a Master’s degree in Computational Physics and a Bachelor’s degree in Theoretical Physics from Université Montpellier 2. His technical interests include cable and harness EMC, shielding effectiveness, modeling and simulation, and high-voltage challenges in aerospace systems.

Dr. Jullien has delivered over 60+ presentations at major international EMC conferences and forums, authored numerus journal publications and contributed to many patents at Safran Electrical & Power. An active member of the IEEE Electromagnetic Compatibility Society for over 16 years, he serves as Secretary of the IEEE EMC French Chapter, Secretary of EMC TC4, Officer-at-Large of EMC TC8 (Chair of the High-Voltage Challenges for Aerospace subcommittee), and Secretary of IEEE SA Working Group P2855. He is also regularly involved in graduate-level EMC education in France and internationally.

Topics   & Abstracts

Topic 1: Aeronautical power chain (aircraft power systems)
The presentation will begin with an introduction retracing the evolution towards increased electrification in aircraft, from the concept of the “more electric aircraft” to future prospects for all-electric airplanes. We will review the development of on-board power needs, highlighting iconic examples such as the Concorde and next-generation aircraft like the A350 and B787. An overview of the future of electric protection devices up to 2050 will be presented, along with a discussion of the challenges linked to increasing power and the introduction of high-voltage systems, including HVDC, HVAC, and PWM. The main elements of the power chain will also be briefly introduced.

The section dedicated to generation will highlight power system architecture, the diversity of generation sources, and an introduction to power electronics, with a focus on the associated electromagnetic compatibility (EMC) challenges. The harness segment will explore issues related to high-voltage power transport, crosstalk, shielding, and will include a focus on harness simulation. The engine section will present the transition towards “Smart Engines,” with an introduction to their specific challenges, particularly regarding filtering.

Finally, the presentation will conclude with a recap of the solutions proposed to meet the challenges identified in generation, harness, and engine systems, followed by a brief bibliography.

Topic 2:  Transfer impedance measurement: from simple to complex setup
The electrical wiring interconnection system (EWIS) can be protected either by shielding, i.e. by placing a conductive screen that protects and limits the electromagnetic radiation and coupling, either by separating the links from the others with a certain distance to create a segregation between the signals and powers transmitted. In the first case, we must be able to characterize the effectiveness of the shielding. For many applications, the frequency band used rarely exceeds a few GHz. So, we can divide the problem of a shielded cable into two sub-problems that we link with a transfer function: the transfer impedance. These internal (core VS shielding) and external (shielding VS environment) domains are linked by the transfer impedance which determines the interaction of one domain on the other and vice versa.

The demonstration shows the evolution in complexity of the transfer impedance (Zt) characterization methods. Starting from a sample of a coaxial cable and a setup requiring only a few materials, we will carry out several assemblies allowing the Zt to be measured: triaxial bench, triaxial bench with shielding discontinuity, line injection and localized injection.

This latter method will highlight the future of transfer impedance measurement by localized injections and its potential for extending the characterization of high frequency shields.

Topic 3: Modeling transmission lines based on electromagnetic topology
This presentation focuses on the analysis of transmission lines using the Electromagnetic Topology (EMT) method introduced by Carl Baum. After a review of the fundamental principles of the Topological Line Method (TLM), the talk will demonstrate how this approach allows the decomposition of a complex system into topological networks, thereby facilitating the analysis of electromagnetic interactions. We will outline the main steps involved in the resolution of these topological networks, highlighting the tools available for their modeling and parameterization.

Concrete examples will illustrate the application of this method: the impact of shielding connections on EMC performance, crosstalk within a complex harness, and the interactions between a high-voltage (HV) system and a data transmission harness. Finally, the presentation will explore more advanced applications of electromagnetic topology, such as health monitoring and the modeling of electrical arcs, demonstrating the versatility and relevance of this approach in addressing today’s industrial challenges.