Integrated Battery Modular Multilevel Converter based Drive for Electrically Excited and Hybrid Excited Synchronous Machines

This paper proposes a sustainable solution for high-voltage and high-capacity battery-powered traction systems that addresses the dependency on Rare Earth materials for the machine’s Permanent Magnets (PMs), aiming at eliminating or significantly reducing their usage. To achieve this goal, the paper advocates for the adoption of Electrically Excited Synchronous Machines (EESM) and Hybrid Excited Synchronous Machines (HESM) as ideal candidates, eliminating the need for permanent magnets while maintaining high-performance capabilities. Furthermore, integration of the On-Board Charger (OBC) and Battery Management System (BMS) functionality with the traction converter itself offers an opportunity to simplify the design of the overall system and limit the total part count, which can be a challenge for transportation applications with high-power demand and space constraints. Moreover, the battery pack’s voltage levels are observed to be increasing, requiring a modular approach to accommodate evolving voltage requirements effectively. The proposed drive is based on an Integrated Battery Modular Multilevel Converter (IB-MMC) in conjunction with an Electrically Excited Synchronous Machine, which completely avoids the use of Permanent Magnets for traction. The simulation results are provided to demonstrate the effectiveness of the proposal.