考虑系统时滞因素,突破传统对有源电力滤波器(APF)分析时所用的近似线性化处理方式,建立了一种基于离散仿射切换理论的三相APF仿射时滞离散切换模型。在此基础上将电网侧谐波电流作为控制输出,前馈预测的指令谐波电流与理想指令谐波电流误差作为干扰项,提出H∞控制器和切换规则的设计方法,进而实现谐波电流跟踪控制。仿真分析表明.该方法在精确反映三相APF动态特性的同时有效补偿了系统时滞,避免了时滞现象对系统补偿效果和稳定性的不良影响。
Instead of the traditional linearization method used in APF(Active Power Filter) analysis,the discrete affine switching theory is applied in the modeling of three-phase APF with time-delay,based on which,its H∞ controller and switching rules are designed. The harmonic current at grid side is regarded as the control output and the error between the instructive harmonic current predicted by feedforward control and the ideal instructive harmonic current is considered as the distracter to follow and control the harmonic current. Simu- lative results show that the proposed method reflects the dynamic characteristics of three-phase APF accurately while compensates the system time-delay effectively,avoiding its adverse influence on system compensation effect and stability.