A novel control of a current source active filter for AC power system harmonic compensation

A novel control strategy for an active power filter which consists of a current-source PWM (pulsewidth-modulated) converter and LC filters to eliminate PWM carrier frequency components is proposed in order to obtain good harmonic-compensation characteristics. The PWM converter is controlled by the feedback loops of filter input currents and their derivatives to suppress the transient oscillations in LC filters without inserting damping resistors. Analyzing the control system as a sampled data system, optimum values of feedback gains are investigated, that is, the cutoff frequency of the optimum design is about one-seventh of the PWM carrier frequency, and the compensation delay time is two times as large as the carrier period. The performance of the active power filter with the proposed control strategy is confirmed by experiments.<
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