Modulation and Closed-Loop Control of a 6-Phase 3-Level NPC Integrated Inverter/Charger for EVs

Electrification of mobility is essential to overcome relevant challenges of our society. The powertrain and other power electronics systems constitute the heart of the electric vehicle. This paper proposes to use a six-phase three-level neutral-point-clamped dc-ac converter, interfacing the vehicle battery bank with a symmetrical six-phase open-end winding machine, integrating both the traction inverter and on-board charger functions. Compared to a conventional powertrain design, this system increases efficiency, fault tolerance, modularity, and enables traction and all charging modes with just a single power electronic converter. Furthermore, this paper details suitable modulations and closed-loop controls to operate the system under the different traction and charging modes. Simulation results with the developed switching and average models are presented to validate the proposed modulations and controls.