MMC预充电子模块电容电压均衡特性仿真建模  

Simulation and Modeling of Pre-Charging Voltage Balancing Among MMC Sub-Modules

作　　者：李静怡 齐磊 赵翠宇 易荣 赵艇 

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206 [2]荣信汇科电气技术有限责任公司,辽宁省鞍山市114000

出　　处：《电网技术》2017年第12期3816-3823,共8页Power System Technology

基　　金：国家重点研发计划项目(2016YFB0900904)~~

摘　　要：模块化多电平换流器在预充电阶段会出现子模块电压分布不均的现象,严重时会导致子模块旁路,进而影响系统的正常运行。基于MMC预充电过程子模块电容电压的均衡特性,提出了MMC预充电模型搭建方法。该模型充分考虑实际阀塔各导体结构之间的寄生电容参数,以及子模块取能电源等效电阻参数对子模块电压均衡特性的影响。针对超大规模子模块数量下存在的计算效率低的问题,提出了预充电过程MMC单桥臂等效方法,以及换流阀寄生电容集成降阶方法。结合实际工程参数,通过仿真结果与实测数据的对比,验证了所提模型的正确性和有效性。在此基础上,进一步仿真分析了阀塔寄生电容、取能电源等效电阻、子模块均压电阻等参数对子模块电压均衡特性的影响规律,可为工程设计提供参考依据。Phenomenon of uneven distribution of capacitance voltage exists in MMC pre-charging process.This will lead to sub-module bypass,affecting safe and stable operation of the system.Based on voltage unbalance characteristics,a method building MMC mechanism model in pre-charge process was proposed.The model included influence of parasitic capacitance between conductors of actual valve tower and equivalent resistance of energy source on voltage distribution uniformity.In view of low computational efficiency due to presence of large number of modules,this paper proposed an equivalent method of single bridge arm for the pre-charge process,and a method for reducing parasitic capacitance of converter valve.Finally,correctness and validity of the model were verified by comparing simulation results with measured data.On this basis,influence of parasitic capacitance,energy gain,equivalent resistance and grading resistors on unbalanced voltage characteristics were simulated and analyzed,providing a reference for engineering design.1

关 键 词：模块化多电平换流器 子模块电容均衡特性 寄生电容 有限元法 

分 类 号：TM72[电气工程—电力系统及自动化]