模块化串联结构高压电源的两级分组控制系统

基于串联结构的模块化组合变换器在中、高压输入电源中得到广泛采用，但是这类变换器中众多子模块的控制都需要高压电气隔离，这对控制系统的设计提出了较高要求。因此，基于两级式控制系统，设计了一种分组控制系统：将邻近的隔离电压较低的子模块结合成一个模块组，组内采用同一个控制器，通过光耦隔离来控制各子模块，从而减少了控制器和光纤数量，因此简化了控制并降低了成本。进而针对模块组结构，设计了一种冗余供电的辅助电源方案，能够提高供电可靠性。基于分组式控制系统搭建了一台输入10 kV、输出375 V、额定功率40 kW、包含36个子模块的谐振式模块化多电平直流变换器样机，并进行了实验验证。

Two-stage Submodule-grouping Control System for Modular Series-connected High-voltage Power Supplies

The modular series-connected converters are widely adopted in high voltage power supplies. This type of converters has a large number of submodules, and the controllers must be isolated from the submodules, which places high demands on the hardware design of the control system. Based on two-stage control systems, a submodule-grouping control system is proposed. Series-connected submodules are divided into groups. Because of the lower isolation requirement within the group, a single controller is assigned to the group, isolated by optocouplers. This configuration reduces the number of controllers and optical fibers in the system, therefore simplifying the control and reducing the costs. Moreover, a redundant auxiliary power supply for the submodule controllers is introduced to the submodule groups, which improves the reliability of the system. A 40-kW prototype of resonant modular multilevel dc/dc converter is developed, with 10 kV input voltage, 375 V output voltage and 36 submodules. Experiments are carried out to validate the proposed control system.