用于快速充电站的高频高效模块化固态变压器

随着碳化硅器件的发展，基于固态变压器（SST）的充电站供电架构相比传统基于工频变压器的方案在效率、功率密度及扩展性等方面已展现出优势。提出一种基于三电平功率单元输入串联输出并联的模块化SST。其中，隔离DC-DC级采用串联半桥LLC变换器，分析了软开关实现条件和参数设计，比中点箝位型三电平LLC更易实现ZVS，更适合高频高效运行。为实现单元间均压均流，基于后级均压前级均功率的协调控制思想，提出一种基于直流链电压反下垂的分布式控制方法，同时实现了均压、均功率和输出电压二次调节等多个目标。所提方法在一台10 kV级，360 kW SST样机上得到了实验验证。

High-frequency High-efficiency Modular Solid State Transformer for Quick Charging Stations

With the advancements in silicon carbide power devices, the solid state transformer (SST)-based power delivery architecture for quick charging stations shows advantages over traditional line-frequency transformer-based solution in terms of efficiency, power density, and scalability. A modular SST is pro-posed based on input-series output-paralleled three-level power cells. The series-half-bridge (SHB) LLC converter is adopted for the dc-dc stage. Compared to neutral-point-clamped three-level LLC in terms of soft-switching condition and parameter design, the SHB LLC is easier to achieve zero voltage switching (ZVS) and more suitable to high-frequency high-efficiency operation. To achieve voltage balancing and current sharing among cells, the coordinated control strategy is adopted, where the front stage is responsible for power sharing while the back stage is responsible for voltage balancing. A distributed dc-link voltage inverse-droop control method is proposed to realize voltage balancing, power sharing, and output voltage regulation. The proposed method is exper-imentally verified on a 10 kV input, 360 kW SST.