基于电压收敛性预测的MMC低开关频率均压控制策略Reduced Switching Frequency Voltage Balancing Control Strategy Based on Voltage Convergence Prediction for Modular Multilevel Converters
蒲羿;罗永捷;熊小伏;宋勇辉;陈强;
摘要(Abstract):
随着基于模块化多电平换流器(modularmultilevel converter,MMC)的柔性直流输电技术逐渐向高电压等级、高传输容量发展,MMC子模块数量迅速增加,由此带来换流器运行效率低下的问题日益凸显。为实现MMC内部悬浮电容能量均衡,传统均压算法控制下的各桥臂子模块高频投切,会产生大量无效开关损耗。针对这一问题,提出一种低开关损耗的MMC调控方法。首先,基于MMC运行原理,推导了子模块投切、轮换与电容电压暂态增量的数学关系,从而提出对电容电压序列收敛性的预测方法。基于此,提出一种改进的低开关频率均压控制策略。该策略根据对桥臂内子模块电压序列的收敛性的预测结果,在每个离散控制周期初始时刻动态调控子模块轮换数,以消除非必要的子模块轮换。与现有均压策略相比,该策略能在不降低均压效果的前提下,有效降低开关频率,有助于提高系统的运行效率。基于实际柔性直流输电工程参数,在PSCAD/EMTDC上搭建仿真模型,对所提出改进型方法和现有低开关频率控制方法进行了对比验证。
关键词(KeyWords): 模块化多电平换流器;均压控制;开关频率;电压收敛性
基金项目(Foundation): 国家自然科学基金项目(51707027)~~
作者(Author): 蒲羿;罗永捷;熊小伏;宋勇辉;陈强;
Email:
DOI: 10.13335/j.1000-3673.pst.2019.2465
参考文献(References):
- [1]Freytes J,Akkari S,Rault P,et al.Dynamic analysis of MMC-based MTDC grids:use of MMC energy to improve voltage behavior[J].IEEE Transactions on Power Delivery,2019,34(1):137-148.
- [2]魏新伟,何志兴,徐千鸣,等.载波移相调制模块化多电平换流器双均压系数电压平衡方法[J].中国电机工程学报,2018,38(24):7314-7325+7458.Wei Xinwei,He Zhixing,Xu Qianming,et al.Dual voltage-sharing coefficients voltage balance method for modular multilevel converter with carrier phase shifted modulation[J].Proceedings of the CSEE,2018,38(24):7314-7325+7458(in Chinese).
- [3]Wang Q,Liu K,Wang K,et al.Fast capacitor voltage balancing strategy based on system history operation information for MMC[J].IET Generation,Transmission&Distribution,2019,13(7):1104-1109.
- [4]李静怡,齐磊,赵翠宇,等.MMC预充电子模块电容电压均衡特性仿真建模[J].电网技术,2017,41(12):3816-3823.Li Jingyi,Qi Lei,Zhao Cuiyu,et al.Simulation and modeling of pre-charging voltage balancing among MMC sub-modules[J].Power System Technology,2017,41(12):3816-3823(in Chinese).
- [5]Peng H,Xie R,Wang K,et al.A capacitor voltage balancing method with fundamental sorting frequency for modular multilevel converters under staircase modulation[J].IEEE Transactions on Power Electronics,2016,31(11):7809-7822.
- [6]赵聪,李耀华,李子欣,等.适合于柔性高压直流输电系统的模块化多电平变流器的自适应均压方法[J].电网技术,2017,41(5):1510-1518.Zhao Cong,Li Yaohua,Li Zixin,et al.An adaptive voltage balancing method of modular multilevel converter for HVDC transmission systems[J].Power System Technology,2017,41(5):1510-1518(in Chinese).
- [7]罗永捷,李耀华,李子欣,等.适用于高压大容量MMC-HVDC系统的改进低开关频率均压控制策略[J].中国电机工程学报,2017,37(5):1341-1351.Luo Yongjie,Li Yaohua,Li Zixin,et al.An improved reduced switching frequency voltage balancing control strategy for bulk power MMC-HVDC systems[J].Proceedings of the CSEE,2017,37(5):1341-1351(in Chinese).
- [8]夏超英,陈峰,于佳丽.基于固定规则的MMC电容电压均衡策略[J].中国电机工程学报,2018,38(18):5548-5556.Xia Chaoying,Chen Feng,Yu Jiali.Capacitor voltage balancing method for MMC based on fixed rules[J].Proceedings of the CSEE,2018,38(18):5548-5556(in Chinese).
- [9]Hu P,Teodorescu R,Wang S,et al.A currentless sorting and selection-based capacitor-voltage-balancing method for modular multilevel converters[J].IEEE Transactions on Power Electronics,2019,34(2):1022-1025.
- [10]Glinka M,Marquardt R.A new AC/AC multilevel converter family[J].IEEE Transactions on Industrial Electronics,2005,52(3):662-669.
- [11]Gum T S,Hee J L,Tae S N,et al.Design and control of a modular multilevel HVDC converter with redundant power modules for noninterruptible energy transfer[J].IEEE Transactions on Power Delivery,2012,27(3):1611-1619.
- [12]Rohner S,Bernet S,Hiller M,et al.Modulation,losses,and semiconductor requirements of modular multilevel converters[J].IEEE Transactions on Industrial Electronics,2010,57(8):2633-2642.
- [13]王坤,刘开培,胡志鹏,等.适用于含大量子模块的MMC快速电容电压均衡策略[J].电网技术,2017,41(12):3854-3861.Wang Kun,Liu Kaipei,Hu Zhipeng,et al.A fast capacitor voltage balancing strategy for MMC with large number of sub-modules[J].Power System Technology,2017,41(12):3854-3861(in Chinese).
- [14]Luo Y,Li Z,Xu L,et al.An adaptive voltage-balancing method for high-power modular multilevel converters[J].IEEE Transactions on Power Electronics,2018,33(4):2901-2912.
- [15]杜晓舟,梅军,邓凯,等.模块化多电平换流器电容电压均衡控制方法[J].电网技术,2016,40(1):26-31.Du Xiaozhou,Mei Jun,Deng Kai,et al.Voltage balance control method of MMC[J].Power System Technology,2016,40(1):26-31(in Chinese).
- [16]管敏渊,徐政.MMC型VSC-HVDC系统电容电压的优化平衡控制[J].中国电机工程学报,2011,31(12):9-14.Guan Minyuan,Xu Zheng.Optimized capacitor voltage balancing control for modular multilevel converter based VSC-HVDCsystem[J].Proceedings of the CSEE,2011,31(12):9-14(in Chinese).
- [17]何智鹏,许建中,苑宾,等.采用质因子分解法与希尔排序算法的MMC电容均压策略[J].中国电机工程学报,2015,35(12):2980-2988.He Zhipeng,Xu Jianzhong,Yuan Bin,et al.A capacitor voltage balancing strategy adopting prime factorization method and shell sorting algorithm for modular multilevel converter[J].Proceedings of the CSEE,2015,35(12):2980-2988(in Chinese).
- [18]陆翌,王朝亮,彭茂兰,等.一种模块化多电平换流器的子模块优化均压方法[J].电力系统自动化,2014,38(3):52-58.Lu Yi,Wang Chaoliang,Peng Maolan,et al.An optimized method for balanceing sub-module voltages in modular multilevel converters[J].Automation of Electric Power Systems,2014,38(3):52-58(in Chinese).
- [19]屠卿瑞,徐政,郑翔,等.一种优化的模块化多电平换流器电压均衡控制方法[J].电工技术学报,2011,26(5):15-20.Tu Qingrui,Xu Zheng,Zheng Xiang,et al.An optimized voltage balancing method for modular multilevel converter[J].Transactions of China Electrotechnical Society,2011,26(5):15-20(in Chinese).
- [20]赵成勇,熊岩,徐义良,等.具有较低复杂度和开关频率的MMC混合排序均压算法[J].电力系统自动化,2017,41(15):136-142.Zhao Chengyong,Xiong Yan,Xu Yiliang,et al.Hybrid sorting algorithm with low complexity and switching frequency for capacitor voltage balanced control of modular multilevel converter[J].Automation of Electric Power Systems,2017,41(15):136-142(in Chinese).
- [21]许烽,徐政,张哲任,等.基于降损调制技术的全桥MMC电容电压无需排序均衡控制[J].电网技术,2013,37(12):3347-3355.Xu Feng,Xu Zheng,Zhang Zheren,et al.Reduced loss modulation based capacitor voltage non-sorting balancing control for full-bridge MMC[J].Power System Technology,2013,37(12):3347-3355(in Chinese).
- [22]Hassanpoor A,Roostaei A,Norrga S,et al.Optimization-based cell selection method for grid-connected modular multilevel converters[J].IEEE Transactions on Power Electronics,2016,31(4):2780-2790.
- [23]Li Zixin,Gao Fanqiang,Xu Fei,et al.Power module capacitor voltage balancing method for a±350 kV/1000 MW modular multilevel converter[J].IEEE Transactions on Power Electronics,2016,31(6):3977-3984.