Kampert, Erik

A dynamical impedance analysis of complex electrical aerospace systems during operation can provide detailed information for efforts to further enhance system stability and reliability. As conventional single-tone impedance measurements are relatively slow compared to possible system state changes, a pulsed method using a synthesised stochastic multitone signal is proposed. This method is validated for a passive permanent magnet synchronous motor through a result comparison with an RF I-V impedance measurement. Then it is applied to an active DC- DC converter to highlight the detection of impedance changes due to the switching of the involved transistors, impossible to detect with conventional impedance measurement methods. It will be discussed how this method can be further adapted to overcome currently existing practical limitations and how it can be optimised for other electrical systems of interest.

Maintaining compliance to electromagnetic compatibility (EMC) standards becomes an increasing challenge for the automotive industry in the course of the ongoing automation of vehicles. Novel extended design procedures and test standards are required to ensure safety of automated driving functions, particularly in an adverse electromagnetic (EM) environment. In order to keep the number of tests within a reasonable and practical limit, an evaluation framework based on virtual design methods and information drawn from legacy experiments and simulations can support the automotive industry. With this digital framework appropriate technological solutions can be identified during the pre-compliance phase and efficient experimental designs can be generated to ensure EMC compliance. Furthermore, such a framework paves the way for digital EMC twins of automated vehicles (AVs) considering the complex interrelations of AV’s (sub-)systems to accurately predict the behaviour of new AV functions in various EM environments. To this purpose, a cross-domain platform is being developed in this work as the backbone of such a virtual framework. It supports the handling, storage and processing of various datasets from EMC test campaigns, including (intentional) electromagnetic interference ((I)EMI) tests, as well as simulations of automotive devices-under-test (DUTs). The platform allows for the establishment of interconnections between various data sources and deeper analyses based on artificial intelligence (AI) methods to deduce EMC information for new developments, whilst maintaining traceability.

Wide band gap semiconductors such as siliconcarbide (SiC)-based devices are favored in the power electronic industry for their reduced switching losses. However, their utilization leads to high d𝑉₍DS₎/d𝑡, causing high-frequency emissions that can affect the operation of connected devices and systems on the board net. This study investigates conducted emissions originating from the output lines of a laboratory adaptation of an automotive interleaved buck converter, interfacing the traction battery of an electric vehicle with 48 V board net, along with monitoring the chip temperature of the SiC MOSFET. Across various combinations of input and output characteristics and operation modes, differences in common and differential mode emission spectra and their comparison with CISPR-25 standard limits, are observed. A study is further done to analyze these experimental results.

Gallium Nitride (GaN)-based converters have emerged as a promising technology to increase the efficiency and power density of power electronic systems in electric vehicles (EVs). However, the integration of GaN semiconductor devices introduces challenges regarding electromagnetic interference (EMI). This work focusses on EMI measurements and on exploring the relationship between defined parameters such as output current or switching frequency and conducted emissions (CE) in converters with GaN switches. Moreover, the relationship between the switching transients of the GaN-FETs and the interference frequency range is examined and the challenges of using GaN-based converters in EVs related to EMI are discussed.

In a modern vehicle, the automotive wire harness forms a crucial part of the sensor signal and power distribution system. It is thus important to understand the impact of electromagnetic interference on such harness, in particular its dependence on layout with respect to an incoming electromagnetic wave. The research presented here investigates the induced common-mode and differential-mode currents in various wire harness layouts, as well as the dependence on both grounding and on the harness design involving an unshielded twisted or untwisted pair. The results indicate that for harness layouts with a substantial component along the electric field directions, such current levels can reach up to those that disrupt automotive sensor communication.