Multibattery Charger System Based on a Multilevel Dual-Active-Bridge Power Converter

Abstract

This work introduces a novel battery charger implemented with a four-level three-phase neutral-point-clamped converter and a four-level single-phase dual-active-bridge converter, which offers the intrinsic advantages of multilevel conversion, provides galvanic isolation and allows bidirectional power flow. A detailed and extensive modeling of the system is developed, together with the design of appropriate closed-loop control and modulation. The proposed system allows individual charging of each battery pack, ensuring that the full capacity of the battery bank is utilized, even when the battery packs have different state-of-charge levels, differ in nominal capacities, or use different chemistries. Furthermore, the proposed control system manages the overall DC-link voltage and ensures voltage balance across both DC-links in the system. The effectiveness of the proposed system configuration and control has been validated through simulations. The simulation results show good dynamic response in different operating scenarios, confirming the suitability, feasibility, and benefits of the proposed implementation and control approach.