Research on rectifier system in high power IGCT three-level PWM converters

The Integrated Gate Commutated Thyristor (IGCT) is mostly applied in medium and high voltage high power converter systems due to its outstanding performance. And IGCT-based high power three-level converters are widely used in motor-driving field. In this paper, based on the high power three-level IGCT back-to-back system, the rectifier system is analyzed. Four phase locking methods are proposed, and the last two methods are used for the case of unbalanced power grid. Improvements are made for the problems of midpoint voltage balance and harmonics in the traditional space vector PWM (SVPWM).