Abstract：Input-series-output-parallel (ISOP) inverter combined system is generally used in the occasions of high DC voltage at the input terminal and high AC power at the output side. If the topology of the ISOP inverter is applied to the grid-connected system, multiple small-capacity standardized inverter modules can constitute a bulky-capacity grid-connected inverter system, which will effectively improve system reliability and facilitate system design. In this paper, based on ISOP LCL grid-connected inverter combination system, its topology is optimized to reduce the volume and weight of the system. Then the control variables are carefully chosen, and a novel distributed control strategy is put forward to achieve multiple control objectives of grid-connected combined system, including power balance, suppression of resonance spikes, and high power factor of grid current. After that, based on the distributed control, the paper proposes a redundant operation plan to ensure the smooth exit of the faulty module and the successful throwing into the system of the back-up module. Finally, the prototypes are tested, which verifies the proposed scheme.
[1] 王奎, 郑泽东, 许烈, 等. 混合钳位型四电平和五电平逆变器拓扑结构和控制策略[J]. 电工技术学报, 2018, 33(2): 353-360. Wang Kui, Zheng Zedong, Xu Lie, et al.The topologies and control of hybrid-clamped four-level and five-level inverters[J]. Transactions of China Electrotechnical Society, 2018, 33(2): 353-360. [2] 郭小强, 朱铁影. 新型非隔离型三相三电平光伏并网逆变器及其漏电流抑制研究[J]. 电工技术学报, 2018, 33(1): 26-37. Guo Xiaoqiang, Zhu Tieying.Research on leakage current suppression of novel three-phase three-level non-isolated PV inverter[J]. Transactions of China Electrotechnical Society, 2018, 33(1): 26-37. [3] 沈虹, 郭忠南, 关红磊, 等. 单相四开关多电平光伏逆变器研究[J]. 电工技术学报, 2018, 33(8): 1-8. Shen Hong, Guo Zhongnan, Guan Honglei, et al.Research on single-phase four-switch multilevel pv inverter[J]. Transactions of China Electrotechnical Society, 2018, 33(8): 1-8. [4] 方天治, 阮新波. 两类串并联逆变器组合系统的控制策略[J]. 电工技术学报, 2010, 25(8): 72-78. Fang Tianzhi, Ruan Xinbo.Control strategy for two categories of series/parallel connection inverters system[J]. Transactions of China Electrotechnical Society, 2010, 25(8): 72-78. [5] 方天治, 王健, 阮新波. 分布式输入串联输出并联逆变器系统的复合式控制策略[J]. 电工技术学报, 2015, 30(22): 108-115. Fang Tianzhi, Wang Jian, Ruan Xinbo.Compound control strategy for distributed input-series-output- parallel inverter system[J]. Transactions of China Electrotechnical Society, 2015, 30(22): 108-115. [6] Chen Wu, Zhuang Kai, Ruan Xinbo.Input-series and output-paralle connected inverter system for high input voltage applications[J]. IEEE Transactions on Power Electronics, 2009, 24(9): 2127-2137. [7] 陈武, 阮新波, 庄凯. 输入串联输出并联DC/AC逆变器系统的控制策略[J]. 中国电机工程学报, 2010, 30(15): 16-23. Chen Wu, Ruan Xinbo, Zhuang Kai.Control strategy for input-series and output-parallel connected inverter system[J]. Proceedings of the CSEE, 2010, 30(15): 16-23. [8] Sha Deshang, Deng Kai, Guo Zhiqiang, et al.Control strategy for input-series-output-parallel high frequency AC link inverters[J]. IEEE Transactions on Industrial Electronics, 2012, 59(11): 4101-4111. [9] 方天治, 沈乐, 何玮, 等. 多逆变器模块输入串联输出并联组合系统的分布式控制及其冗余技术研究[J]. 中国电机工程学报, 2016, 36(8): 2223-2232. Fang Tianzhi, Shen Le, He Wei, et al.A novel strategy to achieve distributed control and redundancy for multi-module input-series-output-parallel con- nected inverter systems[J]. Proceedings of the CSEE, 2016, 36(8): 2223-2232. [10] Liserre M, Blaabjerg F, Hansen S.Design and control of an LCL-filter-based three-phase active rectifier[J]. IEEE Transactions on Industry Applications, 2005, 41(5): 1281-1291. [11] Dannehl J, Liserre M, Fuchs F.Filter-based active damping of voltage converters with LCL-filter[J]. IEEE Transactions on Industrial Electronics, 2011, 58(8): 3623-3633. [12] Gabe I, Montagner V, Pinheiro H.Design and implementation of a robust current controller for VSI connected to the grid through an LCL filter[J]. IEEE Transactions on Power Electronics, 2009, 24(6): 1444-1452. [13] Ahmed K, Massoud A, Finney S, et al.A modified stationary reference frame-based predictive current control with zero steady-state error for LCL coupled inverter-based distributed generation systems[J]. IEEE Transactions on Industrial Electronics, 2011, 58(4): 1359-1370. [14] 周乐明, 罗安, 陈燕东, 等. 单相LCL型并网逆变器功率控制及有源阻尼优化方法[J]. 电工技术学报, 2016, 31(6): 144-154. Zhou Leming, Luo An, Chen Yandong.et al.A single-phase grid-connected power control and active damping optimization strategy with LCL filter[J]. Transactions of China Electrotechnical Society, 2016, 31(6): 144-154. [15] 鲍陈磊. LCL型并网逆变器的并网电流调节器和电容电流反馈有源阻尼设计[D]. 武汉: 华中科技大学, 2013. [16] 杨东升. 弱电网下LCL型并网逆变器的电流和功率控制技术[D]. 南京: 南京航空航天大学, 2016. [17] 刘尚伟. 单相LCL逆变器并网技术研究[D]. 武汉: 华中科技大学, 2011. [18] 杨树德, 同向前, 尹军, 等. 增强并网逆变器对电网阻抗鲁棒稳定性的改进前馈控制方法[J]. 电工技术学报, 2017, 32(10): 222-230. Yang Shude, Tong Xiangqian, Yin Jun, et al.An improved grid voltage feedforward strategy for grid- connected inverter to achieve high robust stability against grid-impedance variation[J]. Transactions of China Electrotechnical Society, 2017, 32(10): 222-230. 19 通信作者:方天治男,1977年生,博士,副教授,研究方向为逆变器及电力电子系统集成.E-mail: fangtianzhi@126.com
2019, Vol. 34 
