Dickmann, Stefan

The use of wide-bandgap semiconductors in modern power electronics creates new challenges in EMC. These result, among other things, from high frequencies and steep switching slopes. In addition, parasitic elements of semiconductors, passive components and the printed circuit board can cause resonances, which become noticeable in oscillations. In this work, a possibility is presented to simulate resonances in a power electronic circuit. The circuit used is a series-LC resonant converter with SiC-MOSFETs. An impedance model of the resonant load is generated with consideration of parasitic elements. The accurate simulation is validated by comparison with time domain measurements. EMC measurements of conducted and radiated emissions are done. It is shown that the resonances lead to emissions which can be predicted using the time domain simulation.

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.

In this paper, we present a filter circuit that can be used to prevent sensor disturbances caused by intentional electromagnetic interference (IEMI). Sensors are an increasingly important component in almost all electrical systems, and faulty sensor readings can cause major problems. We show that sensor disturbances can be caused by IEMI and that sensors with Inter-Integrated Circuit (I²C) interfaces are particularly susceptible to this type of interference. We present a filter circuit that can be connected directly to I²C sensors in order to prevent disturbances caused by IEMI. Through both simulation and experimental testing, the effectiveness of the filter in preventing errors in sensor readings without impacting the functionality of the I²C communication is demonstrated.

Standardized radiation measurements can be simulated by various numerical or analytical approaches. In this article, a transfer function method is proposed for a fast and accurate antenna voltage prediction. Assuming that the interference source can be characterized as a linear Norton equivalent current source, its internal admittances and source currents are determined from measurements made with a vector network analyzer and an oscilloscope. The setup of the radiation measurement is described as a transfer function using its scattering parameters. A system of equations is set up with the multiport theory and solved for the antenna voltage, which is fed into a spectrum analyzer model. The result is compared to a measurement in a fully anechoic chamber. The method is extended to interference sources with stochastic signals, and, in the course of this, an approach for the estimation of the radiation measurement is developed. A dc motor is used as an application example.