摘要
针对非隔离型并网变换器因缺少隔离环节导致的共模电压与泄漏电流固有问题,文中通过将滤波电容中点与并网变换器下桥臂公共点短接,来衰减户内供用电装置对地寄生电容耦合到电网侧的漏电流.首先,以并网变换器结构模型为基础建立其动态数学模型,结合漏电流产生原因及抑制机理,实现对共模电压的零序控制;其次,为限制LCL型滤波器的谐振峰引发的电压振荡,采用滤波电容电流反馈回占空比的有源阻尼控制方案;然后,针对零序控制与有源阻尼控制间的交互影响,借助LCL型滤波器控制等效电路分析其产生原因,对比不同控制策略配置下共模电压波形与电网中谐波含量,确立高稳定精度与低谐波含量的控制方案;最后,通过仿真验证降低漏电流与平抑谐振峰的协同控制策略的有效性.
Aiming at the inherent problems of common mode voltage and leakage current caused by the lack of isolation link of grid-connected converters,this paper reduces the leakage current by short-circuiting the midpoint of the filter capacitor and the common point of the lower bridge arm of the grid-connected converter.First,the dynamic mathematical model of the grid-connected converter is established based on its the structural mode,and the zero sequence control of the common-mode voltage is realized by combining the causes of leakage current and the suppression mechanism;Secondly,in order to limit the voltage oscillation caused by the resonant peak of the LCL filter,an active damping control scheme in which the filter capacitor current is fed back to the duty cycle is adopted;Then,according to the interaction between zero sequence control and active damping control,the LCL filter control equivalent circuit is used to analyze its causes,and the common-mode voltage waveform and the harmonic content in the power grid under different control strategy configurations are compared to establish control scheme for precision of high stability and low harmonic content;Finally,the effectiveness of the cooperative control strategy of reducing leakage current and suppressing resonance peak is verified by simulation.
作者
王秀云
王建
刘闯
裴忠晨
林琳
刘道鸿
WANG Xiuyun;WANG Jian;LIU Chuang;PEI Zhongchen;LIN Lin;LIU Daohong(School of Electrical Engineering,Northeast Electrical Power University,Jilin Jilin 132012;Zhejiang Huayun Clean Energy Co.,Ltd.,Hangzhou Zhejiang 310000)
出处
《东北电力大学学报》
2022年第5期44-54,共11页
Journal of Northeast Electric Power University
基金
国家自然科学基金项目(51877035)。
关键词
并网变换器
共模电压
漏电流
零序控制
有源阻尼控制
Grid-connected converter
Common-mode voltage
Leakage current
Zero sequence control
Active damping control
