Single-phase active power filter based on rotating reference frame method

This paper presents a new control method of the single-phase active power filter (APF) for the compensation of harmonic current components in nonlinear loads. In order to use a new transformation theory, the two-phase system by constructing a imaginary second-phase is formed. In the conventional method, an imaginary-phase lagged to the load current TA(here T is the fundamental cycle) is made. But in this proposed method, the new signal as the second phase is the delayed through the filter. As this control method is applied to the system of single-phase, an instantaneous calculation was developed rather by using the rotating reference frames synchronized with source-frequency than by applying instantaneous reactive power theory that uses the conventional fixed reference frames. The control scheme of single-phase APF is analyzed with the experimental results in a laboratory prototype to verify the validities of the proposed control methods.