Three-phase phase-locked loop algorithms for the detection of positive-sequence and negative-sequence components

Abstract

This work presents a follow-up investigation of two phase-locked loop (PLL) algorithms that were previously proposed for applications involving grid-connected power converters. The first one provides the detection of positive-sequence components in scenarios with high harmonic distortion, resulting in good overall performance. The second one comprises the addition of an adaptive filter (AF) to the latter structure in order to enhance its filtering capability in the presence of subharmonics and interharmonics. Both of them are modified so that they are capable of detecting both positive-sequence and negative-sequence components. The former strategies can be adapted so that it is possible to detect not only the fundamental component, but also any specific harmonic in the input signal if necessary. Experimental results are obtained using dSPACE platform and electronic control unit (ECU) ControlDesk, comprising a thorough comparison among the proposed synchronization algorithms and other well-known approaches in distinct scenarios.