1.College of Electrical Engineering Beijing Jiaotong University Beijing 100044 China 2.Beijing Jingneng Clean Energy Electrical Power Co.Ltd Beijing 100028 China 3.Creat-Poreen Power Electronics Co.Ltd Beijing 100083 China
Abstract:The grid interface inverters of distribution generation should realize low-voltage ride-through property to deliver power to the grid under unbalanced voltage sags.In this paper,a novel multi-objective control strategy is proposed for grid-interface inverters to meet diverse ride-through requirements during gird faults.First,a unified formula for the current reference is established and multiple targets can be controlled by the adjustable parameters k1 and k2.Next,an optimized search path for k1 and k2 is derived to control the oscillating power of the inverter.Moreover,a linear search path which can replace the optimized one is obtained by simplifying the optimized path.Then,according to the monotonous property of the controlling objective,a novel multi-objective control scheme is proposed with adaptive limitation for the current unbalanced factor.Finally,the effectiveness and flexibility of the proposed control strategies are verified by simulation results.
[1] 阳同光,桂卫华.电网不平衡情况下并网逆变器控制策略综述[J].电工技术学报,2015,30(14):241-246. Yang Tongguang,Gui Weihua.An overview on control strategies of grid-connected inverter under unbalanced voltage conditions[J].Transactions of China Electrotechnical Society,2015,30(14):241-246. [2] 章玮,王宏胜,任远,等.不对称电网电压条件下三相并网型逆变器的控制[J].电工技术学报,2010,25(12):104-110. Zhang Wei,Wang Hongsheng,Ren Yuan,et al.Investigation on control of three-phase grid-connected inverters under unbalanced grid voltage conditions[J].Transactions of China Electrotechnical Society,2010,25(12):104-110. [3] 沈永波,年珩.不平衡及谐波电网下基于静止坐标系的并网逆变器直接功率控制[J].电工技术学报,2010,25(12):114-123. Shen Yongbo,Nian Heng.Stationary frame direct power control of grid-connected inverter under unbalanced and harmonic grid voltage[J].Transactions of China Electrotechnical Society,2016,31(4):114-123. [4] 周京华,刘劲东,陈亚爱,等.大功率光伏逆变器的低电压穿越控制[J].电网技术,2013,37(7):1799-1807. Zhou Jinghua,Liu Jindong,Chen Yaai,et al.Low voltage ride-through control of high power inverter for gird-connection of photovoltaic generation[J].Power System Technology,2013,37(7):1799-1807. [5] 陈亚爱,刘劲东,周京华.太阳能并网逆变器故障穿越控制策略[J].中国电机工程学报,2014,34(21):3405-3411. Chen Yaai,Liu Jindong,Zhou Jinghua.Fault ride-through control strategy for solar grid-connected inverters[J].Proceedings of the CSEE,2014,34(21):3405-3411. [6] 叶盛,黄守道,黄科元,等.不对称电压下 PWM 整流器的控制策略[J].电网技术,2010,34(10):94-98. Ye Sheng,Huang Shoudao,Huang Keyuan,et al.Control strategy of pulse width modulation rectifier under asymmetrical input voltages[J].Power System Technology,2010,34(10):94-98. [7] 郭小强,邬伟扬,漆汉宏.大电网电压畸变不平衡情况下三相光伏并网逆变器控制策略[J].电机工程学报,2013,33(3):22-28. Guo Xiaoqiang,Wu Weiyang,Qi Hanhong.Control strategies of three-phase PV grid-connected inverter under distorted and unbalanced voltage conditions[J].Proceedings of the CSEE,2013,33(3):22-28. [8] Ma Ke,Chen W,Liserre M,et al.Power controllability of a three-phase converter with an unbalanced AC source[J].IEEE Transactions on Power Electronics,2015,30(3):1591-1604. [9] Rodriguez P,Timbus A V,Teodorescu R,et al.Flexible active power control of distributed power generation systems during grid faults[J].IEEE Transactions on Industrial Electronics,2007,54(5):2583-2592. [10]Wang Fei,Duarte J L,Hendrix M A M.Pliant active and reactive power control for grid-interactive converters under unbalanced voltage dips[J].IEEE Transactionson Power Electronics,2011,26(5):1511-1521. [11]Wang F,Duarte J L,Hendrix M A M.Design and analysis of active power control strategies for distributed generation inverters under unbalanced grid faults[J].IET Generation,Transmission & Distribution,2010,4(8):905-916. [12]Castilla M,Miret J,Sosa J L,et al.Grid-fault control scheme for three-phase photovoltaic inverters with adjustable power quality characteristics[J].IEEE Transactions on Power Electronics,2010,25(12):2930-2940. [13]Guo Xiaoqiang,Liu Wenzhao,Zhang Xue,et al.Flexible control strategy for grid-connected inverter under unbalanced grid faults without PLL[J].IEEE Transactions on Power Electronics,2015,30(4):1773-1778. [14]王强钢,周念成,颜伟,等.电网电压不平衡下光伏发电系统的改进功率控制[J].中国电机工程学报,2013,33(增刊):30-37. Wang Qianggang,Zhou Niancheng,Yan Wei,et al.Improved power control of photovoltaic generation system under unbalanced grid voltage conditions[J].Proceedings of the CSEE,2013,33(S):30-37. [15]阳同光,桂卫华.电网不平衡情况下并网逆变器多目标协调控制策略研究[J].电工技术学报,2015,30(11):148-157. Yang Tongguang,Gui Weihua.Research of multi-objectivecoordinated control strategies of grid-connected inverter under unbalanced voltage conditions[J].Transactions of China Electrotechnical Society,2015,30(11):148-157. [16]邓哲,周峰武,林辉品,等.电网故障时基于双输入SOGI-FLL的新型电网快速同步方法[J].电工技术学报,2013,28(12):32-43. Deng Zhe,Zhou Fengwu,Lin Huipin,et al.A novel fast grid-synchronization method under grid failure based on dual-input SOGI-FLL[J].Transactions of China Electrotechnical Society,2013,28(12):32-43. [17]Rodriguez P.Advanced grid synchronization system for power converters under unbalanced and distorted operating conditions[C]//32nd Annual Conference on IEEE Industrial Electronics,Paris,France,2006:5057-5062.