A robust control scheme for grid-connected voltage source inverters
A robust control scheme for grid-connected voltage source inverters
复制标题
DOI：
10.1109/apec.2010.5433380
复制
发表时间：
2010-03
期刊：
影响因子：
--
通讯作者：
Shuitao Yang;Qin Lei;F. Peng;Z. Qian
中科院分区：
文献类型：
--
作者：
Shuitao Yang;Qin Lei;F. Peng;Z. Qian
分析了带LC滤波器的电压源逆变器（VSI）并网系统的稳定性问题，指出采用传统的比例积分器（PI）控制器进行电网电流控制时，电网阻抗可能发生的变化会对系统的稳定性产生显著影响。随着电网电感性阻抗的增大，PI控制器的低频增益和带宽必须减小以保持系统稳定，从而降低了系统的跟踪性能和抗干扰能力。为了解决这一问题，提出了一种H∞控制器，该控制器具有对电网阻抗变化的显式鲁棒性，同时兼顾了期望的跟踪性能和稳定裕度。通过适当选择加权函数，该H∞控制器在工频附近具有与传统比例谐振（PR）控制器相似的高增益，同时具有足够的高频衰减以保持控制回路稳定。为了提高逆变器的抗干扰能力，还设计了一个高带宽的逆变器输出电流内环。文中详细讨论了加权函数的选取、逆变器输出电流内环的设计以及系统的抗干扰能力。给出了H∞控制器和传统PI控制器的仿真和实验结果，并进行了比较，验证了所提出的控制方案的性能。
This paper analyzes the stability problem of the grid-connected voltage source inverter (VSI) with LC filters, which demonstrates that the possible grid-impedance variations have a significant influence on the system stability when conventional proportional-integrator (PI) controller is used for grid current control. As the grid inductive impedance increasing, the low-frequency gain and bandwidth of the PI controller have to be decreased to keep the system stable, thus degrading the tracking performance and disturbance rejection capability. To deal with this stability problem, an H∞ controller with the explicit robustness in terms of grid-impedance variations is proposed to incorporate the desired tracking performance and the stability margin. By properly selecting the weighting functions, the synthesized H∞ controller exhibits high gains at the vicinity of the line frequency, similar to the traditional proportional-resonant (PR) controller, meanwhile it has enough high frequency attenuation to keep the control loop stable. An inner inverter-output-current loop with high bandwidth is also designed to get better disturbance rejection capability. The selection of weighting functions, inner inverter-output-current loop design, and system disturbance rejection capability are discussed in detail in this paper. Both simulation and experimental results of the proposed H∞ controller as well as the conventional PI controller are given and compared, which validates the performance of the proposed control scheme.