Research On Three-Level IGCT Converter’s Temporary Property

Three-level converters make two switches connected in series, thus can resolve one single switch cannot stand a high DC voltage. The IGCT is a new type of power electronic devices which is developed from a GTO, it behaves high off-state voltage, large turn-off current, high switching frequency, low losses and high reliability. Combining Three-level topology and IGCTs is an effective approach to build high voltage, high power converters.Diodes clamped three-level converters have many control ways, SPWM and SVPWM are general. These two control ways make the converters’performance different. Three-level converters with IGCTs as their switches will have their special issues need to be research, such as the clamping circuit and snubber circuit. Analysing IGCTs’temporary state, fast recovery diodes should not be neglected, and also the clamping circuit and stray parameters. To investigate the application of3-level IGCT converters, some research on3-level inverters, fast recovery diodes, IGCTs has been done. The purpose of these research is to acknowledge their practicability and effects on performance by circuit parameters.The thesis analyses diode clamped3-level topology and two control ways, simulations have been established by computers. According to IGCTs and fast recovery diodes’working theory, their device models have been made. The models were placed in test circuit with clamping circuit, observing the parameters which infect IGCT’s temporary character. Finally, IGCT phase-module running test has been made to find out whether circuit parameter is reasonable or not.