标题：Simultaneous Common-Mode Resonance Circulating Current and Leakage Current Suppression for Transformerless Three-Level T-Type PV Inverter System
作者：Li, Xiaoyan; Xing, Xiangyang; Zhang, Chenghui; Chen, Alian; Qin, Changwei; Zhang, Guangxian
作者机构：[Li, Xiaoyan; Xing, Xiangyang; Zhang, Chenghui; Chen, Alian; Qin, Changwei; Zhang, Guangxian] Shandong Univ, Sch Control Sci & Engn, Jinan 250061, Sha 更多
通讯作者：Zhang, CH;Zhang, Chenghui
通讯作者地址：[Zhang, CH]Shandong Univ, Sch Control Sci & Engn, Jinan 250061, Shandong, Peoples R China.
来源：IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
关键词：Common-mode (CM) resonance circulating current (CMRCC) suppression;; hybrid control strategy; improved LCL (ILCL) filter; leakage current; reduction
摘要：The improved LCL filter is used in transformerless three-level photovoltaic inverter system for leakage current suppression. However, the common-mode (CM) resonance circulating current (CMRCC) is generated, which causes inverter-side current oscillation, leakage current increment, and system instability. To overcome these issues, an improved CM circulating current model with detailed analyses of CMRCC is proposed in this paper. Based on above theories, the CMRCC is influenced by filter parameters, zero-sequence duty ratio, and number of switching transitions. To suppress CMRCC, a hybrid control strategy composed of proportional integral (PI) and feedforward control is presented. It is realized by real-time adjusting zero-sequence duty ratio in space vector modulation technique. Compared with the conventional damping resistor techniques, the CMRCC and leakage current are effectively suppressed with the proposed method. Thus, the performance of inverter-side currents and leakage current suppression is greatly improved. Besides, the capacitor-voltage-feedforward control is adopted to eliminate resonance peak in the differential-mode circuit. Simulation and experimental results are given to demonstrate the effectiveness of theoretical analyses and the proposed method.