A new multiple-stage converter topology for high power and high precision fast pulsed current sources
A new high current, low rise time and high precision pulse generator is presented. The topology is based on the use of different stages, each one specific for a particular operation range in terms of power and switching frequency. The design and operating principle of the proposed topology are described. Finally, the results obtained from an implemented reduced scale prototype are compared with the simulation ones in order to validate the design.
Investigation of IGBT-devices for pulsed power applications
IGBT-switches from ABB Switzerland have been characterised at ISL with regard to civil and military pulsed power applications. The investigated devices are press-pack IGBT modules with a blocking voltage of 2.5 kV and a continuous current rating of 2 kA. Using capacitive energy storage systems the IGBT was investigated as closing switch with the objective of generating short current pulses with high amplitudes, as they are e. g. required for driving a high power microwave (HPM) source. Inductive energy storage systems have a higher energy density than capacitive systems. The drawback, however, is the need of opening switches in order to commutate the current into the load. For such a system we investigated the turn-off behaviour of the IGBT. The experiments show that the IGBT modules used are capable to generate 12 kA pulses with switching times below one microsecond. Investigating the IGBT as opening switch in an inductive storage circuit has proved its superiority over comparable switching configurations using power MOSFETs. Comparing IGBT and MOSFET configurations with the same total die size and same on-state resistance and therefore same price allows to gain advantage from a much higher commutation voltage in case of the IGBT, which in turn allows for a much shorter commutation time.
Roman Homosexuality: Ideologies of Masculinity in Classical Antiquity
This comprehensive study of Roman sexuality and the ideologies of masculinity discusses a wide range of ancient texts, arguing that native Roman concepts of masculinity did not rely on the distinction between homosexuality and heterosexuality, but were instead structured around such antitheses as free versus slave, dominant versus subordinate, and masculine versus effeminate.