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
董晓冬 1乔建华1
作者信息
- 1. 太原科技大学 电子信息工程学院,太原 030024
- 折叠
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Zeq(s),而Zeq(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Zeq(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.
Abstract
When the LCL filter grid-connected inverter uses traditional capacitor-current proportional active damp-ing for grid access control under weak power grids,the damping loop is equivalent to the virtual impedance Zeq(s)connected in parallel at both ends of the capacitor,and the negative resistance characteristic of Zeq(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 Zeq(s),the robustness of the grid-connected inverter under weak grid conditions is enhanced.Finally,the rationality and effec-tiveness 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Key words
capacitor-current proportional active damping/digital control delay/virtual resistance/second-order resonance link引用本文复制引用
基金项目
太原科技大学博士启动基金(20182053)
出版年
2024
NETL
NSTL
万方数据