Unified Active Power Filter Compensating For Source Voltage Unbalance/Current Harmonics and Power Factor Simultaneously

전원 전압의 불평형과 고조파 전류 및 역률을 동시에 보상하는 통합형 능동 전력필터

In this paper, a novel control scheme compensating for source voltage unbalance and current harmonics and power factor simultaneously in unified active power filter systems combined with shunt passive filters is proposed, where no low/high-pass filter are used in deriving the reference voltage for compensation. Using digital all-pass filters, the phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage. The amplitude of d-axis current in a series filter is controlled as zero for power factor correction. The validity of the proposed control scheme has been verified by experimental results.