LCL滤波并网逆变器的零点配置策略

采用LCL滤波器的并网逆变系统中,由于高阶滤波器的存在,并网电流易产生无阻尼谐振,系统闭环设计困难,带宽受限,难以实现很好的系统响应。LCL滤波器中通过二个电流量的加权组合可获得具有一阶积分特性的反馈量,将高阶并网逆变系统的闭环设计降阶处理,简化了系统闭环设计,且易于实现较好的系统响应。目的是全面分析LCL滤波并网系统中可行的加权组合方式。提出一种系统性分析方法,采用比例、积分、微分的加权形式从零点配置角度全面的分析了可行的组合反馈方式。仿真与实验验证了分析的有效性。

Zero-Placement Strategy for Grid-Connected Inverters with LCL Filters

For grid-connected systems with LCL filters, the grid injection current is easy to be resonated. The design of the control is difficult. The bandwidth of system is limited, which results in a poor performance. By the weighted combination of two currents, the high order LCL system is degraded to a low order one. It is easy to obtain good system performance through a simple design procedure. The objective of this paper is to discuss all the feasible combinations for LCL systems. A systematic analysis based on zero-placement is presented for the study of the available weighted combinations using proportional, integral or derivative weighted factor. Simulations and experiments validate the analysis.