基于准方波调制策略的谐振型模块化多电平直流变压器  

Resonant Modular Multilevel DC Transformer Based on Quasi-square-wave Modulation Strategy

作　　者：冯起辉 谈竹奎 李继凯 徐玉韬 王少波 FENG Qihui;TAN Zhukui;LI Jikai;XU Yutao;WANG Shaobo(Electric Power Research Institute,Guizhou Power Grid Co.,Ltd,Guiyang 550002,China;XJ Electric Co.,Ltd,Xuchang 461000,China)

机构地区：[1]贵州电网有限责任公司电力科学研究院,贵阳550002 [2]许继电气股份有限公司,许昌461000

出　　处：《电力系统及其自动化学报》2025年第1期131-138,共8页Proceedings of the CSU-EPSA

基　　金：中国南方电网公司重点科技项目(GZKJXM20220041);国家重点研发计划资助项目(2022YFE0205300)。

摘　　要：直流电网是实现可再生能源高效汇集和直流负荷柔性接入的重要方案,直流变压器是互联不同电压等级直流系统的核心装备。本文提出一种谐振型模块化多电平直流变压器,在中压侧采用半桥模块阀组串联,在低压侧采用全桥并联,能够显著降低器件电压、电流应力并减少功率器件和变压器数量。直流变压器拓扑采用准方波调制和移相控制,提高交流链路频率并实现定频输出电压控制。采用基波近似方法,分析其传输功率特性,并建立关键参数设计方法和输出电压控制策略。最后,通过4 kW/600 V/100 V实验样机验证了所提拓扑和控制方法的可行性。DC grid is an essential solution to achieving efficient integration of renewable energy and flexible access of DC loads,and the DC transformer is a piece of key equipment that can interconnect DC systems with different voltage levels.In this paper,a resonant modular multilevel DC transformer is proposed,in which half-bridge submodule strings are series connected on the medium-voltage side and full-bridges are parallel connected on the low-voltage side.As a re-sult,the voltage and current stress are significantly reduced,and the number of power devices and transformers also de-ceases.Quasi-square-wave modulation and phase-shifted control are employed to increase the AC link frequency and achieve the fixed frequency output voltage control.Based on the fundamental harmonic approximation method,the transmission power characteristics are analyzed,and the key parameter design procedure and output voltage control strategy are formulated accordingly.Finally,the feasibility of the proposed topology and control method was validated by a 4 kW/600 V/100 V prototype.

关 键 词：直流电网 直流变压器 模块化多电平变换器 谐振变换器 准方波调制 

分 类 号：TM721[电气工程—电力系统及自动化]