Railway train main power converter: Model predictive current control of a modular multilevel converter

Abstract

In electric railway trains two main power systems can be distin-guished: the system of the power propulsion and the system of the auxiliary power services. Consequently, since the train is supplied from the catenary in AC, the use of an AC to DC power converter is indispensable. This paper pro-poses the application of a modular multilevel converter (MMC) as main power converter (i.e., interfacing the AC catenary and the DC link inside the train). The operation of the MMC is ensured by a model predictive current controller, which controls its input AC current according to specific power requirements. The MMC and the model predictive current control are validated recurring to com-puter simulations. Based on the developed simulation models, the presented re-sults permit to verify the advantages associated with the modularity of the con-verter and with the performance of the model predictive current control.