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.