新型输入并联输出串联直流变换器研究

Research on a Novel Input-Parallel Output-Series Connected HVDC Converters

针对直流输电的应用要求,提出了一种新的模块化输入并联输出串联高压变换系统,并对系统的主电路拓扑、控制策略进行分析与讨论.该系统中主要功率变换模块采用直流变压器,开环控制,结构简单;功率调节模块为串联谐振移相全桥结构,采用电流闭环控制;两类模块均为恒频控制;模块间的控制简单,具有较高的灵活性和冗余性.仿真和实验结果验证了方案的可行性.

Aiming at the applicational requirements of DC electrical transmission, the paper proposes a modular inputparallel output-series connected converter topology for HVDC transmission system. Main circuit topologies and control methods are analyzed. The proposed structure has the following features： a）power is transferred mainly by DC transform- ers, b）the output power is regulated by series resonant phase-shifted full bridge converters which are based on current closed-loop control, e）both DC transformers and power regulation modules are operating at constant frequency, d）modu- larization structure is flexible. The simulation and experimental results verify the effectiveness of the proposed structure.