Modular regenerative switching cell with integrated voltage-clamp

Pulsewidth modulated (PWM) inverters with IGCT-Technology become more and more interesting with the ongoing research in this technology due to the advantageously switching behaviour and the low conductive looses. At the time, the maximum blocking voltage of commercially IGCTs does not exceed 6.5 kV. Therefore, the series connection of the semiconductor devices is indispensable in medium-voltage applications. In this context a new modular regenerative switching cell with integrated voltage-clamp is presented. The main aspect of the proposed concept is to avoid utilizing a voltage-clamp in the dc-link to damp the overvoltage of the di/dt-choke.