A Detection Approach for Random Harmonic Current in Single-Phase Circuit

Based on the transform relation between stationary coordinate and rotational coordinate, a real-time detection approach for random harmonic current in single-phase circuit is presented. This paper proposes digital Hilbert phase-shifting filter to construct two orthogonal current vectors with same amplitudes in stationary coordinate from single-phase harmonic current, and deduces the characteristics that random selective harmonic current component in rotational coordinate rotating at selective angular frequency is direct current to realize the detection of random single-phase harmonic current. The analyses and simulation prove the correctness of this method.