Translated Abstract
Evolved from GTO, IGCT has combined both the advantages of IGBT’s and GTO’s. It has a spreading usage in high power high voltage applications for its high blocking voltage, high turn-off current, low losses and high reliability. Yet lack of study on it is noticeable. Research in this thesis focuses on the simulation model of IGCT, the choke and clamp circuit for IGCT and the series connection of IGCTs. The purposes lie in the construction of simulation model for IGCT, design of choke and clamp circuit, voltage balance of series connected IGCTs’.
This thesis analyzes the main characteristics of IGCT’s and make comparisons among different simulation models as well as different simulation softwares. A functional model for IGCT has been constructed using PSIM software considering the actual requirements. As the current rising speed during IGCT’s turn-on process is uncontrollable and turn-off process can produce voltage overshoot as a result of stray inductances, a choke and clamp circuit is designed and verified through simulation and experiment to solve these problems. For the voltage unbalance of series connected IGCTs, several circuit structure has been analysed. A feasible circuit has been designed and then verified through simulation and experiment.The short circuit phenomenon has been analyzed and a protection scheme has been raised and verified through simulation.
Both theoretical and experimental results have validated the correctness of IGCT model constructed in this thesis. Besides, choke and clamp circuit design is feasible. Finally, due to less storage time, IGCT can be easilly operated under series connection with a much smaller snubber circuit.
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