Conference Agenda

This paper explores the use of spread spectrum clocking (SSC) to reduce electromagnetic emissions in clocked electronic systems by dispersing energy across the frequency spectrum around the clock signal’s central frequency. Unlike the widely adopted conventional frequency modulation (FM) technique, this study focuses on an advanced nested frequency modulation approach, where a second modulation stage is introduced. This secondary modulation helps further distribute the energy into the unoccupied gaps between adjacent sidebands within the Carson bandwidth, thereby reducing peak emissions. A detailed analysis of the relationship between the two modulation frequencies and their impact on overall emission reduction is presented through simulation examples and measured results.

This paper presents experimental tests and comparisons focused on the high-frequency electromagnetic compatibility (HF-EMC) of a high-speed permanent magnet synchronous machine (PMSM). For the same PMSM, two different versions of stators are considered. They differ in the stator-winding design, where the second one incorporates a multidisciplinary optimization (MDO) process, aimed at improving the machine’s EMC performance. A high-speed PMSM usually applied in a Vapor Cycle System (VCS), typically found in aircraft cooling systems, is considered as a case study. Their HF impact and performances in terms of common-mode (CM) and differential-mode (DM) impedances are addressed, as well as in terms of conducted EMI disturbances in a 10-kW powertrain setup. The HF-EMC assessment of the machine may be useful for further optimization designs regarding stator-windings variability design when EMC performance is a priority.

Characterization of battery cells and creation of measurement-based models is a key step in design process of battery packs for electric vehicles (EV). Simulations of such models allow optimization of a battery pack design to minimize safety and functional errors which might otherwise appear late in the design stage and increase development time and cost. This paper demonstrates a method for measuring battery cell impedance with vector network analyzer (VNA) under switch-controlled pulsed charge and discharge bias current,

and presents the resulting impact on inductance of the cell at 108 MHz. The battery cell inductance under bias current at temperature from -20◦C to 40◦C is presented. Finally, the bias current and temperature impact on the battery cell is shown.

In electric vehicles, high-voltage electric drive is the main source of electromagnetic emission (EMI). For best correlation to vehicle, tests shall be performed close to vehicle configuration and load conditions. Results from those tests give a forecast of later vehicle situations regarding legal EMC requirements as well as internal belongings. Limitations are in deeper analysis in case of deviations from a EMC test result. The aim is to provide a measurement method in time domain for a better understanding of mechanism and coupling paths inside and outside of an electric drive system. Additionally, individual correlations such as CM or DM can be evaluated by calculating individual channels. An one-time recording in a specific time frame and load condition gives some kind of a view to all necessary port currents and voltages and can be overlaid and compared. Furthermore it is possible to verify simulation models. This study shows an example of a Time-Domain measurement method for simultaneous evaluation of 16 measurements points on an electric drive and how results can be used for further analysis and better understanding. It can be used starting from DC up to 100MHz, depending on the test setup and used probes.