Abstract：When the three-phase grid imbalances, the DC and AC sides are contained with even-numbered and odd-numbered non-characteristic harmonics based on the traditional double-loop control strategy, which can seriously affect the quality of output of the grid-connected inverter. To solve this problem, the mathematical model of unbalanced grid inverter is established in this paper, voltage vector equation is given in the synchronous rotating coordinate; and power fluctuations forms are analyzed according to the instantaneous power theory. Then separation method of the instantaneous positive and negative sequence is proposed, the algorithm accuracy is higher, and almost no delay; In order to acquire symmetrical three-phase grid-connected current, negative-sequence current should be suppressed. Positive sequence current given by the controller of the outer loop, the grid-connected current control is implemented under the positive and negative sequence synchronously rotating coordinate experiment platform was built in the laboratory; experimental results show that the output current of inverter is symmetric under the proposed control strategy at the imbalance three-phase grid voltage.
姜卫东,吴志清,李王敏,佘阳阳,胡杨. 电网不对称时抑制负序电流并网逆变器的控制策略[J]. 电工技术学报, 2015, 30(16): 77-84.
Jiang Weidong,Wu Zhiqing,Li Wangmin,She Yangyang,Hu Yang. Control Strategy of Suppressing Negative Sequence Current of Grid-Connected Inverter Base on Asymmetric Grid. Transactions of China Electrotechnical Society, 2015, 30(16): 77-84.
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