Brandt, Sönke

The conducted electromagnetic interference (EMI) caused by a DC-DC power converter interfacing an automotive electric battery and the 48 V board grid can eventually affect the operation of the battery management system at the battery side of an electric vehicle or could transfer emissions to the board grid, where the conducted and radiated EMI originating from the converters could influence the signal electronics of automotive components. This work takes into account hardware setups of two different converter topologies: a phase-shifted full-bridge (PSFB) and a two-phase interleaved buck (TPIB) converter, both for up to 3 kW power and 400 V to 48 V voltage conversion. An analysis of the conducted and radiated emissions for half-load and full-load conditions is performed in buck operation mode. The results indicate the TPIB-topology having higher radiated emissions, higher differential mode emissions, but lower common mode emissions than the PSFB-topology.

This paper presents the degradation of 1200 V Siliconcarbide (SiC) MOSFETs in regard to the influence of different gamma radiation doses (γ-radiation). The impacts of four distinct γ-radiation doses (300 Gy, 200 Gy, 100 Gy and 50 Gy) were examined. The analysis was conducted using four different MOSFETs from several manufacturers, all of them in the TO263-7 package. They belong to the same voltage class with similar on-state resistance but varying technologies. The primary indicators for degradation analysed in this study are the threshold VGS(th) and the breakdown voltage VDSS(BR).

Hohe Anforderungen an die elektronischen Komponenten von Systemen der medizinischen Bildgebung können im Rahmen derer Energieversorgung nur durch den Einsatz von moderner Leistungselektronik erfüllt werden. Mit der Verwendung von Wide-Bandgap-Leistungshalbleitern, z. B. in Stromrichtern von Röntgensystemen, gehen damit schnellere Schaltvorgänge sowie hohe Schaltfrequenzen einher. Dies macht eine Untersuchung der Auswirkungen auf die Elektromagnetische Verträglichkeit (EMV) erforderlich. Das betrifft sowohl die Einhaltung von normativen EMV-Grenzwerten als auch die Wechselwirkung der parasitären Eigenschaften von Komponenten innerhalb eines Systems. Im Forschungsprojekt DiMoLEK werden messtechnische Untersuchungen durchgeführt und es wird ein Ansatz zur Modellierung der parasitären Eigenschaften von passiven Komponenten entwickelt. Die Simulation von Stromrichtern mit anschließender Analyse der Wechselwirkungen parasitärer Eigenschaften ermöglicht die Optimierung der (elektromagnetischen) Resilienz. Dies kann beispielsweise durch eine Anpassung des Designs der Komponenten und der Modulationsverfahren erreicht werden.

This paper investigates the effect of repeated type I short-circuit (SC) events on device parameters of modern 1200V silicon carbide (SiC) MOSFETs. Therefore, tests have been performed with a constant short-circuit time, DC-link voltage as well as a controlled case temperature of 60° C. Different SiC MOSFETs in TO263-7 package with similar on-state resistance of different manufacturers with both trench and planar structure have been analysed. In order to determine possible degradation, the threshold and the breakdown voltage are particular interesting parameters as well as the behaviour of the components in the first and third quadrant operation.

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.

In this study, the impact of short-circuit (SC) events on 1200 V power SiC-MOSFETs is investigated. Therefore, trench and planar devices in the TO263-7 SMD-package were stressed with different pulse times of SC-type I. In order to understand the resulting failure mechanisms and to detect potential degradation of the MOSFETs, a static characterisation of device parameters were carried out before and in between the SC-events. Particular the gate threshold voltage Vth shows instabilities for SiC-devices under different stress conditions [1], [2]. The short-circuit behaviour as well as the static characterisation are discussed with regard to critical failures and the observation of degradations effects.

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.

The double pulse measurement is a standard test method to analyze the dynamic behavior of power electronic devices like IGBTs, MOSFETs, and diodes. In this work, a double pulse measurement is modeled and simulated with SPICE to investigate the influence of the MOSFETs, the printed circuit board and the inductive load on the switching oscillations. The main parasitic elements are taken into account for an accurate simulation. The simulation results are validated by comparison with measurement results. The SPICE-simulation shows that the lead length from the printed circuit board to the inductive load influences the switching oscillation. The reason is a resonance of the lead's inductance and the parasitic winding capacitance of the inductor. This fact can be used for a reduction of the oscillation.

According to the recent trend, SiC-MOSFETs have been increasingly conquering the sector of high power semiconductors [1]. This also includes the field of discrete devices for high frequency high current applications which has been dominated by Si-IGBTs in the past and the present. Compared to these Si-IGBTs the wide band gap (WBG) devices can perform very fast switching with very high slew rates. In the proposed survey, state of the art discrete SiC-MOSFETs will be analysed in a high quality measurement setup in order to rate and compare the dynamic characteristics.