The research on security and stability of PWM technology of high-voltage high-power three-level NPC inverter

The security and stability operation mechanism is the key problem of the high power and voltage three-level neutral point clamp inverter^[1]. As the security and stability of PWM is very important for normal operation of system, the control strategy and algorithm are the basis for the safety operation of the inverter. In the process of starting up the inverter, the optimal settings of minimum pulse width and secure access are the most important problems needed to be solved. In the normal operation process of the inverter, the accuracy algorithm of PWM output region identification and the dead zone insert need to be fully considered. The treatment method during the emergency stop time of the inverter is also one of the key contents of improving security and stability. And the theoretical innovation through the multi-disciplinary overlapping (such as power electronics, intelligent technology) should be adopted. Combined with existing achievements, this paper carries out research in the aspects of improving security and stability of PWM of high-voltage and high-power three-level NPC inverter. The results lay a theoretical and experimental foundation for the following theoretical research.