Limiting of Negative-Sequence Currents by Varying Clustered Dc Voltages for Cascaded H-bridge STATCOM under Unbalanced Grid Voltages
点击次数：
所属单位：计算机科学与技术学院/人工智能学院/软件学院
发表刊物：PROCEEDINGS OF THE 2017 12TH IEEE CONFERENCE ON INDUSTRIAL ELECTRONICS AND APPLICATIONS (ICIEA)
关键字：STATCOM Negative-sequence currents current THD Unbalanced
摘要：The unbalanced grid voltages can generate negative-sequence currents for the cascaded H-bridge STATCOM. To limit the negative-sequence currents, the negative-sequence currents control loop and negative-sequence grid voltage feedforward are usually employed. However, these methods would result in asymmetric three-phase dc-link ripples and low modulation index, which will deteriorate the current THD. To improve the currents quality, this paper proposes a new negative-sequence current limiting method by varying three clustered de voltages. To counteract the negative sequence grid voltage, the relationship between the negative-sequence voltage and clustered de voltage is established. This relationship reveals that the differences between three clustered dc voltages and their average voltage can generate negative-sequence voltages, which can achieve symmetric modulation waves to balance three-phase dc-link ripples, and limit the third harmonic currents. Moreover, to achieve fixed and high modulation index, a modulation index control is employed by regulating the average voltage of three clustered voltages. The advantages of proposed method are verified in a 380V/7kVar cascaded STATCOM prototype.
ISSN号：2156-2318
是否译文：否
发表时间：2017-01-01
合写作者：wang,sen,Lu, Daorong,Yao, Jianhui,Sun, Yongheng,Wang, Jiangfeng,邢岩,胡海兵
通讯作者：王森章