The high-frequency magnetic linked solid-state transformer (SST) has the tremendous potential to solve the issues related to interfacing the grid with renewable energy sources and the non-linear loads as well as to provide the additional control functionalities. Several H-bridges are usually connected in series for the medium voltage grid integration of the SST. The number of the dual active bridge modules and the number of high-frequency magnetic links (HFMLs) usually increase with the increase of the number of series connected H-bridges. This increases the possibility of parameter mismatches and system instability. Therefore, the multiple-active bridge (MAB) dc-dc converter concept has been proposed for next generation SST, where multiple H-bridges share the same HFML. This configuration reduces the number of HFML and increases the cross-coupling power transfer capability. However, the design process of the MAB converter involves a multi-physics research in the field of power electronics, magnetics, switching, control, and energy management. In this paper, the detailed analytical modelling and the control technique of the silicon carbide (SiC)-based MAB converter are investigated. The small and large signal average models of the converter are developed and a voltage balance controller is designed for the better understanding of the controller characteristics. The effect of connecting several H-bridges to a single HFML is investigated in detail. Moreover, to reduce the switching loss, the converter topology adopts the SiC-based switching devices instead of the traditional silicon (Si)-based devices and the nanocrystalline magnetic material is used for the HFML design due to its low specific core loss. A scaled down laboratory prototype of the MAB converter is implemented in the laboratory and can be utilized as a basic building block for the next generation SST.

中文翻译：

---

用于下一代固态变压器的 SiC 基高频磁链转换器的建模与控制

高频磁链固态变压器 (SST) 具有解决电网与可再生能源和非线性负载接口相关问题以及提供额外控制功能的巨大潜力。几个 H 桥通常串联连接，用于 SST 的中压电网集成。双有源电桥模块的数量和高频磁链（HFML）的数量通常随着串联 H 桥数量的增加而增加。这增加了参数不匹配和系统不稳定的可能性。因此，针对下一代 SST 提出了多有源桥 (MAB) dc-dc 转换器概念，其中多个 H 桥共享相同的 HFML。这种配置减少了 HFML 的数量并增加了交叉耦合功率传输能力。然而，MAB 转换器的设计过程涉及电力电子、磁学、开关、控制和能量管理领域的多物理研究。在本文中，研究了基于碳化硅 (SiC) 的 MAB 转换器的详细分析建模和控制技术。开发了转换器的小信号和大信号平均模型，并设计了电压平衡控制器，以便更好地了解控制器特性。详细研究了将多个 H 桥连接到单个 HFML 的效果。此外，为了降低开关损耗，转换器拓扑采用基于 SiC 的开关器件，而不是传统的基于硅 (Si) 的器件，并且纳米晶磁性材料由于其比磁芯损耗低而被用于 HFML 设计。MAB 转换器的缩小实验室原型在实验室中实施，可用作下一代 SST 的基本构建块。