An Inter-harmonic Detecting Algorithm Based on the Generalized dk-qk Coordinate Transform

This paper proposes a new inter-harmonic detecting algorithm based on the generalized d_k-q_k rotational coordinate transform theory. The proposed algorithm can be used to detect the inter-harmonics of any balanced three-phase system. Firstly, the detected inter-harmonic frequency is transformed to integer; Then the integral harmonic is obtained by applying the dq_k coordinate transform; Finally, the inter-harmonic result is restored by the inverse frequency transform. In addition, the zero-sequence component can be detected by the similar algorithm. The simulation and experimental results prove that the proposed method is valid for detecting any terms of inter-harmonic.