改进型LCL并网逆变器电容电流正反馈控制策略  

An Improved LCL Grid-connected Inverter Capacitor Current Positive Feedback Control Strategy

作　　者：董晓冬 乔建华[1] DONG Xiao-dong;QIAO Jian-hua(School of Electronic Information Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China)

机构地区：[1]太原科技大学电子信息工程学院,太原030024

出　　处：《太原科技大学学报》2024年第3期278-284,291,共8页Journal of Taiyuan University of Science and Technology

基　　金：太原科技大学博士启动基金(20182053)。

摘　　要：弱电网下LCL滤波并网逆变器采用传统电容电流比例有源阻尼进行入网控制时,阻尼环等效为并联在电容两端的虚拟阻抗Z_(eq)(s),而Z_(eq)(s)的负阻特性易导致控制系统无法适应较宽范围内变化的电网阻抗,鲁棒性较差甚至失稳。鉴于此,提出一种改进型电容电流有源阻尼正反馈控制策略,通过在阻尼环路中引入二阶谐振环节,利用频域分析法给出了相关参数的设计过程,可有效扩大Z_(eq)(s)的正阻特性范围,并网逆变器在弱电网下的鲁棒性得到增强。最后,通过仿真验证了改进型方法的合理性和有效性。When the LCL filter grid-connected inverter uses traditional capacitor-current proportional active damping for grid access control under weak power grids,the damping loop is equivalent to the virtual impedance Z_(eq)(s)connected in parallel at both ends of the capacitor,and the negative resistance characteristic of Z_(eq)(s)is easy.As a result,the control system cannot adapt to the grid impedance that changes in a wide range,and the robustness is poor or even unstable.In view of this,an improved capacitive current active damping positive feedback control strategy is proposed.By introducing a second-order resonance link into the damping loop,the design process of the relevant parameters is given by the frequency domain analysis method,which can effectively expand the Z_(eq)(s),the robustness of the grid-connected inverter under weak grid conditions is enhanced.Finally,the rationality and effectiveness of the proposed method are verified by simulation.

关 键 词：电容电流比例有源阻尼 数字控制延时 虚拟电阻 二阶谐振环节 

分 类 号：TM464[电气工程—电器]