Level-Shifted PWM for a multilevel traction converter using a state composer

A new approach for implementing Level-Shifted Pulse Width Modulation in cascaded multilevel converters while achieving even power distribution is presented. The target is to modulate a multilevel traction converter, however the modulator can be applied to any topology where a series connection of H-Bridges is present. The proposed modulator does not only achieve equal power utilization of the converter's cells, but also enables the improvement of common mode voltages and easy reconfiguration after failures. Simulations are used to verify the modulator's behavior.