Horst Gruning

Power supply quality improvement with a dynamic voltage restorer (DVR)

This paper presents the technical aspects of designing a dynamic voltage restorer to meet the stringent requirements of voltage dips mitigation with respect to the magnitude of voltage dip, fault duration, permissible line voltage deviations and response time. An introduction to IGCT technology based on latest transparent anode GTO (T-GTO) and gate technology is given. The performance of the DVR based on digital simulations is discussed. A description of a hardware-based real-time simulator model for the performance assessment of DVR in voltage dips mitigation is presented. The results of the real-time simulator are compared with the digital simulations. Finally, control and protection concepts for the DVR are highlighted.

Snubberless superfast high power module using MOS driven field controlled thyristors

The steady-state and switching behaviour of field-controlled thyristors (FCTh) have been analyzed by 2D simulation and experiment. By means of a low inductive drive, very fast turn-on ( tau /sub on/ approximately=80 ns) and turn-off (t/sub st/<or=100 ns, t/sub R/<or=100 ns) were achieved even with 2.5 kV/200 A devices. Effects improving the current distribution homogeneity during transients led to an extremely wide SOA (1600 V, 190 A/cm/sup 2/), a linear scaling behavior, and an excellent predictability by single cell simulation (better than 5% for a 800 V, 100 A/cm/sup 2/ turn-off). Thus, FCThs perform well for hard-switched and for resonant applications, showing excellent on-state versus switching loss tradeoff, diodelike turn-on and commutation, and pronounced reduction of switching loss at limited dV/sub A//dt. Ease of control is obtained through hybrid technology: a 200 A/2 kV MOS input FCTh module is presented.<<ETX>>