有源电力滤波器系统中含有未知的不确定性问题,在其运行中负载发生变化,影响系统稳定性,致使原有控制效率降低。为提高系统抗干扰能力,增强系统鲁棒性,笔者针对包含不确定干扰的系统数学模型,基于H∞控制理论,采用线性矩阵不等式的鲁棒控制器设计方法,设计了单相并联有源电力滤波器H∞输出反馈控制器。该控制器可在2~3个周波内将电网28.93%的畸变率补偿在3%以内,并且在负载电流发生变化时,仍可实现快速的动态补偿和高精度的稳态补偿。通过仿真实验,证明了该控制器不仅可以保证闭环系统稳定,同时还具有良好的动态补偿效果和较强的鲁棒性。
Time-varying uncertainties and load variation will influence the stabilization of active power filter control system. In order to enhance disturbance suppression capability and robustness, a state-space model which includes outside interference was established for APF based on H∞ control theory. An H∞ output-feedback robust controller was designed for the single phase shunt APF using linear matrix inequality. The controller can compensate the aberration rate of power grid from 28.93% to less than 3% in 2~3 cycle, and when the load current changes, the rapid dynamic compensation and high-precision steady-state compensation still can be achieved. The controller not only ensures the stability of the close-loop system and the stronger interference suppression ability, but also owns an effective dynamic compensation.