Contrary to the half-bridge modules in conventional modular multilevel converters with only serial and bypass operation, emerging topologies bring additional parallel inter-module connectivity, introducing sensorless voltage balancing, load current sharing, and enhanced efficiency. However, matching voltages and characteristics is crucial for the modules to allow for a parallel mode between them, but it is not feasible for mixed-type or heterogeneous battery systems. This paper introduces a reconfigurable battery system designed to solve the challenges of integrating batteries with varying characteristics. Using compact coupled inductors and a novel modulation strategy, the system achieves intermediate states between parallel and series modes when dealing with heterogeneous modules. The coupled inductors, with minimal magnetic material and a small footprint, have a negligible common-mode inductance for the high load current and limit circulating currents through high differential-mode inductance. Furthermore, the proposed modulation strategy introduces inter-module DC–DC conversion functionality and enables an efficient bidirectional energy transfer, fully capable of controlling the power exchange between modules widely independently from the output control. This inter-module DC–DC functionality enables effective charge or load balancing among batteries of varying voltages, types, and age. Importantly, the same transistors perform the DC–DC functionality and the output control so that the topology does not need more silicon. Extensive simulations and experiments demonstrate the performance of the system. The proposed system can notably reduce the inductor’s core size by more than 80% with the circulating current as high as one-fifth of the load current. The solution also reduces the cost of the inductor by more than four times. Moreover, the findings demonstrate > 15 % improvement in conduction and > 50 % in switching losses.

中文翻译：

---

具有异构模块的模块化可重构混合电池系统


与仅具有串行和旁路操作的传统模块化多电平转换器中的半桥模块相反，新兴拓扑带来了额外的并行模块间连接，引入了无传感器电压平衡、负载电流共享和更高的效率。然而，匹配电压和特性对于模块之间实现并联模式至关重要，但这对于混合型或异构电池系统来说是不可行的。本文介绍了一种可重构电池系统，旨在解决集成具有不同特性的电池的挑战。使用紧凑耦合电感器和新颖的调制策略，系统在处理异构模块时实现并联和串联模式之间的中间状态。耦合电感器具有最少的磁性材料和较小的占位面积，对于高负载电流具有可忽略的共模电感，并通过高差模电感限制循环电流。此外，所提出的调制策略引入了模块间DC-DC转换功能，并实现了高效的双向能量传输，完全能够独立于输出控制来控制模块之间的功率交换。这种模块间 DC-DC 功能可在不同电压、类型和寿命的电池之间实现有效的充电或负载平衡。重要的是，相同的晶体管执行 DC-DC 功能和输出控制，因此该拓扑不需要更多的硅。大量的模拟和实验证明了系统的性能。所提出的系统可以将电感器磁芯尺寸显着减小 80% 以上，而环流电流高达负载电流的五分之一。 该解决方案还将电感器的成本降低了四倍以上。此外，研究结果表明，传导性能提高了> 15%，开关损耗提高了> 50%。