基于改进PCI控制器的光伏并网逆变器的直流分量抑制策略

针对非隔离型光伏并网逆变器存在直流分量注入问题,提出一种基于改进比例复数积分（PCI）控制器的直流分量抑制策略。将直流分量当作系统的扰动,设计相应的扰动观测器（DOB）,利用DOB对系统中的直流分量进行实时观测,并基于直流分量的观测值设计补偿环节,实现对直流分量的抑制。此外,针对系统在传统PCI控制器控制下存在系统相位裕度不足的问题,将传统PCI控制器的实数形式的谐振系数替换为复数形式,在复数域下设计改进型PCI控制器,提高系统的相位裕度。最后通过仿真与实验验证所提控制策略的可行性与有效性。

DC COMPONENT SUPPRESSION OF PV GRID-CONNECTED INVERTER WITH IMPROVED PCI CONTROLLER

The DC component injection issues exist in the non-isolated PV grid-connected inverter application. In this paper, an novel DC component suppression strategy was proposed based on an improved PCI controller. Firstly, considering the DC component as system disturbance,a disturbance observer（DOB） was designed to observe the system’s DC component in real-time,then a compensation method was designed for suppressing DC component based on the observed value of DC component. Secondly,a resonance complex coefficient PCI controller was substitute for the traditional PCI controller to obtain more phase margin. Finally,the feasibility and validity of the proposed strategy were verified by the simulation and experimental results.