Swen Gediga

Comparison of Si- and SiC-powerdiodes in 100A-modules

This paper presents the comparison of transient behaviour of 6.5 kV Si- and SiC-power diodes in 100 A-modules. The switching behaviour at a current level of 100 A is shown at DC link voltages up to 3.5 kV and at a junction temperature up to 125degC using 25 A-6.5 kV-Si-IGBTs as switching devices. Different switching conditions in chopper circuits realize different rates of current decay up to 1000 A/mus. Furthermore the switching behavior in a series connection of two SiC diodes is shown at DC link voltages up to 10.2 kV in a 3-level npc inverter phase and at a junction temperature up to 90degC. Experimental results are discussed in terms of reverse recovery currents and snappiness.

A new 7.2kV medium voltage 3-Level-NPC inverter using 6.5kV-IGBTs

The SINAMICS GM150 IGBT, a new 3-level-neutral-point-clamped (3L-NPC) Voltage-Source- Converter (VSC) with series-connected 6.5 kV-IGBTs for industrial Medium Voltage Drives is presented. It covers the output voltage range from 6 kV up to 7.2 kV without the need for a step-up output transformer. The SINAMICS GM150 IGBT is based on the proven basic design of its predecessor SIMOVERT MV while the output voltage and current ratings have been extended. The maximum available output power of the water cooled version with a parallel connection of two inverters is 8.7 MVA at an output voltage of 7.2 kV. For the power section state of the art IGBT modules with AlSiC base plates are used. The dynamic voltage sharing for the IGBTs is done by the gate drive units without any additional passive snubber circuits. For the NPC-diodes small passive snubber circuits are used to ensure the dynamic voltage balancing. The mechanical design, the semiconductor ratings and the available converter performance of the SINAMICS GM150 (IGBT) is described. An additional focus is put on the semiconductor switching characteristics in series-connection as well as on the design and the performance of the sinusoidal output filter which is required in retrofit applications with conventional line motors.

Bipolar SiC-Diodes – Challenges Arising from Physical and Technological Aspects

In this contribution we summarize measurements on bipolar high voltage SiC-diodes which were fabricated on 4H-SiC wafers preferentially cut 4° off the [0001] basal plane, whereas the p-emitter thickness was varied in predetermined ratios to the n-base thickness. The switching behaviour of optimized 6.5 kV-Diodes at a current level of 25 A is shown at DC link voltages up to 4 kV and at a junction temperature of 125°C. Experimental results are discussed in terms of snappiness.

SiC-Powerdiodes: Design and performance

In this work we discuss static measurements on bipolar 6.5 kV-SiC-diodes which were fabricated on 4H-SiC wafers preferentially cut 4deg off the (0001) basal plane in order to prove design rules developed for Si-devices. To suppress emitter recombination currents, the p-emitter thickness has to be increased. The switching behaviour of optimized 6.5 kV-diodes with a 3 mum thick p-emitter at different current levels at DC link voltages of 4 kV and at junction temperatures up to 125degC is shown. For these diodes first results on forward stability are also presented.