三相APF的切换系统建模与二次最优控制

为提高三相有源电力滤波器(active power filter，APF)的动态控制性能，本文基于PWM原理提出一种三相APF的等效离散切换系统模型(equivalent discrete-time switched linear system，EDSLS)，经平衡流形邻域线性化后得到其线性离散系统模型(linear equivalent discrete-time switched linear system，LEDSLS)，最后针对该模型设计了能够实时跟踪补偿指令电流的二次线性最优控制器。该控制器以PWM占空比为控制量，物理意义明确，易于工程实现，并具有潜在的应用价值。仿真结果证明了该系统模型的正确性，设计的控制器可有效提高三相APF的动态性能。

Modeling and Quadratic Optimal Control of Three-phase APF Based on Switched System

A new equivalent discrete-time switched linear system (EDSLS) model of the three-phase active power filter (APF) based on the pulse-width modulator (PWM) theory is proposed. Then the EDSLS model is further transformed to a linear equivalent discrete-time switched linear system (LEDSLS) by linearization at some neighborhood of the equilibrium manifold. Finally, a quadratic linear optimal controller is designed with on-time tracking property, where the duty cycle is adopted as the control variables. The proposed control scheme has clearer physical significance and can be easily adopted in practice. The simulation results show that the proposed three-phase APF model and the control strategy are correct and effective.