Switching system modeling and H_∞ control of three-phase APF with time-delay

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. Simulative 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.