A novel structure of multi-level high voltage source inverter

This paper deals with a new multi-level high voltage source inverter with GTO thyristors. A multi-level approach seems to be best suited for implementing a high voltage conversion system because it leads to harmonic reduction and safely deals with a high power conversion system independent of the dynamic switching characteristics of each power semiconductor device. However, a conventional multi-level inverter has some problems; voltage unbalance between DC-link capacitors, and overvoltages across the inner switching devices. Therefore, the authors propose a novel structure of a multi-level inverter for improving these problems. They discuss the topology, operating modes and the PWM method.<>