Design, simulation and realization of high power NPC converters equipped with IGCTs

The paper presents the design, simulation and realization of a 6 MVA neutral-point-clamped (NPC) converter equipped with so called integrated gate commutated thyristors (IGCT). The main design target specifications are: reliability, price, efficiency and dynamic behavior. The present topology incorporates special designed power semiconductors capable to hard switch-off snubberless 3.3 kA against a DC link of 2.8 kV at 800 Hz carrier switching frequency. The present converter was simulated by means of two different simulation tools: Saber-circuit simulator and SIMSEN-system simulator. Precise thermal models of the semiconductors were incorporated into the two simulators. Measurements of the switching behavior of the different power semiconductors are also shown.