Abstract：In order to improve the power supply security of local load, gird-tied inverter of DG system need to work in both grid-tied and off-grid state, and need seamless switching between two states. This paper proposes a comprehensive seamless transfer control strategy .When unintentional island occur and DG need switch from gird-tied to off-grid state, it is easy to exist out of control area and cause the local load voltage and frequency out-limit. A decoupling P-σ ,Q-v control strategy is adopted to realize direct limit voltage during out of control area. And an improved phase-locked loop (PLL) algorithm is proposed to avoid frequency out of limited by combining the frequency lock loop (FLL) and improved phase locked loop (PLL). Also, an improved pre-synchronization method based on virtual grid-connected is proposed to reduce transient process time when DG transfer form island to grid-connected mode. Hardware-in-the-loop (HIL) simulation based on the RT-LAB is carried out to verify the effectiveness of the proposed strategy.
钟诚, 魏来, 严干贵, 贾祺. 考虑非计划孤岛的分布式电源无缝切换控制策略[J]. 电工技术学报, 2017, 32(9): 129-139.
Zhong Cheng, Wei Lai, Yan Gangui, Jia Qi. A Seamless Transfer Control Strategy of Distributed Generation with Considering Unintentional Islands. Transactions of China Electrotechnical Society, 2017, 32(9): 129-139.
[1] 王成山,武震,李鹏.微电网关键技术研究[J].电工技术学报,2014,29(2):1-12. Wang Chengshan,Wu Zhen,Li Peng.Research on key technologies of microgrid[J].Transactions of China Electrotechnical Society,2014,29(2):1-12. [2] Tirumala R,Mohan N,Henze C.Seamless transfer of grid-connected PWM inverters between utility-interactive and stand-alone modes [C]//Proceedings of the Applied Power Electronics Conference and Exposition,2002:1081-1086. [3] 郭立东,伍春生,王一波,等.一种基于前馈控制的双模式逆变器无缝切换控制方法[J].太阳能学报,2015,36(7):1596-1601. Guo Lidong,Wu Chunsheng,Wang Yibo,et al.A new method based on feed forward control for seamless switching of dual-mode inverter[J].Acta Energiae Solaris Sinica,2015,36(7):1596-1601. [4] Tran T V, Chun T W, Lee H H,et al.PLL-based seamless transfer control between grid-connected and islanding modes in grid-connected inverters[J].IEEE Transactions on Power Electronics, 2014,29(10):5218-5228. [5] 刘红,林明潮.基于新型正序提取器的并网与独立双模式无缝切换策略[J].电工技术学报,2015,30(9):53-60. Liu Hong,Lin Mingchao.A seamless transition strategy between gird-tied and stand-alone modes for inverters based on a new positive component detector[J].Transactions of China Electrotechnical Society,2015,30(9):53-60. [6] 郑文迪,刘丽军,曾静岚.采用改进相位控制方法的微网并网/孤岛平滑切换策略[J].电网技术,2016,40(4):1155-1162. Zheng Wendi,Liu Lijun,Zeng Jinglan.Smooth switching strategy between grid-connected and islanded microgrid using improved phase control method[J].Power System Technology,2016,40(4):1155-1162. [7] 石荣亮,张兴,徐海珍,等.基于虚拟同步发电机的微网运行模式无缝切换控制策略[J].电力系统自动化,2016,40(10):16-23. Shi Rongliang,Zhang Xing,Xu Haizhen,et al.Seamless switching control strategy for microgrid operation modes based on virtual synchronous generator[J].Automation of Electric Power Systems,2016,40(10):16-23. [8] 王晓寰,张纯江.分布式发电系统无缝切换控制策略[J] .电工技术学报,2012,27(2):217-222. Wang Xiaohuan,Zhang Chunjiang.Study of control strategy for seamless transfer of grid-connected distributed generation systems[J].Transactions of China Electrot-echnical Society,2012,27(2):217-222. [9] 蒋冀,段善旭,陈仲伟.三相并网/独立双模式逆变器控制策略研究[J] .电工技术学报,2012,27(2):52-58. Jiang Ji,Duan Shanxu,Chen Zhongwei.Research on control strategy for three-phase double mode inverter[J].Transactions of China Electrotechnical Society,2012,27(2):52-58. [10] Yoon S, Oh H, Choi C.Controller design and implementation of indirect current control based utility-interactive inverter system [J] .IEEE Transactions on Power Electronics,2013,28(1): 26-30. [11] Kwon J, Yoon S, Choi S.Indirect current control for seamless transfer of three-phase utility interactive inverters[J]. IEEE Transactions on Power Electronics,2012,27 (2) :773-781. [12] Liu Zeng, Liu Jinjun.Indirect current control based seamless transfer of three-phase inverter in distributed generation[J].IEEE Transactions on Power Electronics,2014,29(7):3368-3383. [13] 刘增,刘进军.一种可实现分布式发电系统平滑切换的三相逆变器控制方法[J].电工技术学报,2011,26(5):52-61. Liu Zeng,Liu Jinjun.A control method for 3-phase inverters enabling smooth transferring of the operation modes of distributed generation system[J].Transactions of China Electrotechnical Society,2011,26(5):52-61. [14] Vandoorn T L, Meersman B,De Kooning J D M,et al.Transition from islanded to grid-connected mode of microgrids with voltage-based droop control[J].IEEE Transactions on Power Systems,2013,28(3): 2545-2553. [15] 聂志强,梁晖,罗浩,等.基于非线性下垂控制的单模式微网并/离网无缝切换技术[J] .电网技术,2016,40(5):1371-1378. Nie Zhiqiang,Liang Hui, Luo Hao,et al.Single mode grid-connected/islanded micro-grid seamless transition based on nonlinear droop control technology[J].Power System Technology,2016,40(5):1371-1378. [16] 丁明,杨向真,苏建徽. 基于虚拟同步发电机思想的微电网逆变电源控制策略[J]. 电力系统自动化,2009,33(8):89-93. Ding Ming, Yang Xiangzhen, Su Jianhui.Control strategies of inverters based on virtual synchronous generator in a microgrid[J].Automation of Electric Power Systems,2009,33(8):89-93. [17] 孟建辉,王毅,石新春,等.基于虚拟同步发电机的分布式逆变电源控制策略及参数分析[J] . 电工技术学报,2014,29(12):1-10. Meng Jianhui ,Wang Yi ,Shi Xinchun,et al.Control strategy and parameter analysis of distributed inverters based on VSG[J].Transactions of China Electrotec-hnical Society,2014,29(12):1-10. [18] 张玉治,张辉,贺大为,等.具有同步发电机特性的微电网逆变器控制[J] .电工技术学报,2014,29(7):261-268. Zhang Yuzhi,Zhang Hui,He Dawei,et al.Control strategy of micro grid converters with synchronous generator characteristic[J].Transactions of China Electrotechnical Society,2014,29(7):261-268. [19] Rodriguez P,Luna A, Candela I,et al.Multiresonant frequency-locked loop for grid synchronization of power converters under distorted grid conditions [J].IEEE Transactions on Industrial Electronics,2011, 58(1):127-138. [20] 袁志昌,宋强,刘文华.改善动态相位跟踪和不平衡电压检测性能的改进软锁相环算法[J] .电网技术,2010,34(1):31-35. Yuan Zhichang,Song Qiang,Liu Wenhua.A modified soft phase lock loop algorithm improving the performance in dynamic phase tracking and detection of unbalanced voltage[J].Power System Technology,2010,34(1):31-35. [21] Ciobotaru M, Teodorescu R, Rodriguez P, et al.Online grid impedance estimation for single-phase grid-connected systems using PQ variations[C]//2007 IEEE Power Electronics Specialists Conference,Orlando,2007: 2306-2312. [22] Bergen A R. Power systems analysis[M]. Englewood Cliffs, NJ: Prentice-Hall,1986.
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