引用本文: | 陆羿,李继红,裘鹏,等.基于电容电压波动的模块化多电平换流器电容电压均衡策略[J].电力系统保护与控制,2018,46(24):158-164.[点击复制] |
LU Yi,LI Jihong,QIU Peng,et al.Capacitor voltage balancing algorithm for modular multilevel converters based on voltage fluctuation[J].Power System Protection and Control,2018,46(24):158-164[点击复制] |
|
摘要: |
针对模块化多电平换流器(MMC)的子模块电容电压均衡问题,为了在较低的开关频率下抑制电容电压波动,提出了一种标记排序电容电压均衡策略。标记排序均衡策略能够根据设定的电容电压波动率边界与每个子模块的投切状态和电容电压,将同一桥臂内的子模块标记为两种类型,分别进行排序与投切控制。其中电容电压波动率边界可以根据系统运行的不同条件进行调整。提出了用于评价电容电压均衡控制策略性能的两个通用性指标,分别为器件平均开关频率和桥臂的电容电压波动率。在PSCAD/EMTDC中搭建了一个21电平MMC的测试系统,将标记排序均衡策略的控制性能和已有的两种电容电压均衡策略进行了仿真对比,并计算了不同均衡策略下MMC的损耗分布。仿真结果证明了标记排序均衡策略的有效性。最后,对电容电压波动率边界取不同值时的情况进行了仿真测试,给出了电容电压波动率边界的选取建议。 |
关键词: 模块化多电平换流器 电压波动抑制 电容电压均衡 开关频率 损耗计算 |
DOI:10.7667/PSPC171777 |
投稿时间:2017-12-06修订日期:2018-01-30 |
基金项目:国家电网公司科技项目资助(52110417001J) |
|
Capacitor voltage balancing algorithm for modular multilevel converters based on voltage fluctuation |
LU Yi,LI Jihong,QIU Peng,XU Yuzhe,XIAO Huangqing,XU Zheng |
(State Grid Zhejiang Electric Power Co., LTD, Hangzhou 310027, China;College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China) |
Abstract: |
For the capacitor voltage balancing of Modular Multilevel Converters (MMC), in order to suppress the submodule (SM) capacitor voltage fluctuation with lower switching frequency, this paper proposes a mark sorting voltage balancing algorithm. The Mark Sorting Voltage Balancing Algorithm (MSVBA) marks SMs in one arm with two different labels according to the set fluctuation threshold, current state and capacitor voltage of each SM, and then sorts and switches SMs respectively. The fluctuation threshold can be adjusted artificially according to various conditions of the system. Two parameters are proposed to evaluate the performance of capacitor voltage balancing algorithms in this paper, which are the average switching frequency of power devices and the voltage fluctuation rate of arm. A detailed model of 21-level MMC-HVDC test system is built in PSCAD/EMTDC, and the MSVBA is compared with two previous algorithms in the test system. The loss distribution of the MMC under different capacitor voltage balancing algorithms is also calculated. The result proves the validity and the feasibility of the proposed MSVBA. Finally, the performances of the MSVBA with different fluctuation threshold are investigated and some suggestions on parameter selection are given. This work is supported by Science and Technology Project of State Grid Corporation of China (No. 52110417001J). |
Key words: modular multilevel converters voltage fluctuation suppression capacitor voltage balancing switching frequency loss calculation |