Unbalancing voltage of high power series connected IGBT valve

With the fast development and widely application of power electronic technologies, the requirement for high power converters has been constantly increased. The connection of high power insulation gate bipolar transistor (IGBT) in series is a key issue in the high voltage and power self-commuted converter application. The bottleneck for the operation of series connected high power IGBTs is the unbalanced voltage distributed among the IGBTs. But systematic theories and studies in this respect have always been absent. The systematic study must be commenced on the unbalanced voltage to advance the research on high power converter equipment. Based on the static and dynamic processes during operation of the seriesly connected IGBT valve and considering the IGBT characteristics, the corresponding influences of the unbalancing voltage on the series connected IGBT valve were induced; and the grade of unbalancing voltage among the devices was analyzed, which laid a foundation for keeping the voltage balance of the seriesly connected IGBT.