Improved DC-Charging for Traction Drives with Hybrid Powered Dual Two-Level Inverter

This contribution aims to present a new concept for power sharing of traction drives supplied by local DC grids such as partly or full equipped trolley wire nets. Therefore, a dual two-level inverter with two separate energy storages and an open-end winding machine is used. New control algorithms allow the charging of the energy sources whether two batteries, a combination of a battery and a fuel cell or a combination of battery and a flying capacitor is used. Within the scope of battery performance, this application is able to absorb or deliver the required power from a DC grid and still feed the electrical machine to enable a driving movement of the electric vehicle. As the presented concepts enable voltage balancing due to different battery loads and the use of only one dynamic energy storage in the charging operation, the shown application aims to achieve the high utilization of an electric vehicle powered by a (partly equipped) DC-grid.