Magnar Hernes
Senior Research Scientist
Magnar Hernes
Senior Research Scientist
Publications and responsibilities
Challenges and Strategies for a Real-Time Implementation of a Rainflow-Counting Algorithm for Fatigue Assessment of Power Modules
The aim of this work is to obtain a reliable estimation of the remaining lifetime of power-electronic modules. Lifetime models provide information on the fatigue durability of power modules under repetitive loading circumstances. However, the thermo-mechanical stresses that a device is exposed to...
Challenges of SiC MOSFET Power Cycling Methodology
This paper investigates the power cycling methodology for reliability testing of SiC metal-oxide-semiconductor field-effect transistors (MOSFETs). Dedicated test benches were designed and built to study this issue. The results indicate that power cycling of SiC MOSFETs is affected by threshold...
Driver stage implementation with improved turn-on and turn-off delay for wide band gap devices
This paper presents a driver topology intended for WBG devices with the goal of improving the switching performance. In particular, the initial delay time of the switching transient was targeted. In high power and high frequency bridge converters, the dead time causes output voltage waveform...
Driver stage implementation with improved turn-on and turn-off delay for wide band gap devices
ReliPE
Analysis of power cycling for semiconductor devices in modular multilevel converters
This paper presents a numerical analysis of the temperature profiles within the semiconductor devices of modular multilevel converters (MMCs). These temperature profiles are essential for assessing the power-cycling lifetime of IGBT modules, which influences the converter reliability. An electro...
Liquid insulation of IGBT modules: Long term chemical compatibility and high voltage endurance testing
To facilitate operation of power electronics for subsea operation at ambient pressure components have to be submerged in a liquid. Equipment and schemes for testing of long term properties have been developed. Several techniques were used to investigate compatibility between a silicone gel and...
Improving the short circuit ruggedness of IGBTs
The demands on reliable and fault tolerant power electronic devices are increasing. One opportunity to increase the IGBT short circuit ruggedness is to modify the thermal capacitance and the thermal resistance close to the chip and hence extend the possible short circuit duration. Therefore...
Possible failure modes in Press-Pack IGBTs
Reliability of Press-Pack IGBTs is a topic with limited published data and information. This paper presents results of a power cycling test with state-of-the-art high power devices. An accelerated lifetime test scheme was defined, and six out of eight devices were tested until failure. A microscopy...