Four-level medium voltage multilevel converter for high power applications

This work presents a preliminary analysis on a new 4-level medium voltage multilevel converter topology. The topology is able to reach medium-voltage operation for 3.3 kV and 6.6 kV applications with conventional semiconductors such as IGCTs or HV-IGBTs. The switching states and their equivalent circuits are presented, along with an adapted multi-level modulation scheme based on level shifted PWM. As with other multilevel converter topologies a dc-link voltage balance algorithm is required, which is also introduced in this paper. Simulation results feeding an RL load are included to to give a first glance on performance of the converter. The main advantages and disadvantages of the proposed topology are also addressed, including future work.