电网不对称时抑制负序电流并网逆变器的控制策略  

Control Strategy of Suppressing Negative Sequence Current of Grid-Connected Inverter Base on Asymmetric Grid

作　　者：姜卫东[1] 吴志清[1] 李王敏[1] 佘阳阳[1] 胡杨[1] 

机构地区：[1]合肥工业大学电气与自动化工程学院,合肥230009

出　　处：《电工技术学报》2015年第16期77-84,共8页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51007018;51177037)

摘　　要：当三相电网不平衡时,传统双闭环控制策略下将在直流侧和交流侧分别产生偶数次和奇数次非特征谐波,从而严重影响并网逆变器的输出品质。针对这一问题,本文首先建立了电网不平衡时并网逆变器的数学模型,给出了同步旋转坐标下的电压矢量方程;并根据瞬时功率理论分析了功率波动形式;然后提出了一种瞬时正、负序分离方法,该算法准确度较高,且基本无延时;为了使三相并网电流对称,以抑制负序电流为控制目标,正序电流由控制器的外环给定,在正序和负序同步旋转坐标下实现并网电流的控制。在实验室内搭建了并网实验平台,实验结果表明新的控制策略下并网电流波形对称,有效地抑制了负序电流。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.

关 键 词：电网不对称负序电流正 负序分离瞬时功率遗忘算法 

分 类 号：TM615[电气工程—电力系统及自动化]