Three-Phase Multiple Harmonic Sequence Detection Based on Generalized Delayed Signal Superposition

Grid synchronization has always been an important challenge for three-phase grid-connected converters under unbalanced and distorted grid conditions. Moreover, how to quickly and accurately extract multiple harmonic sequence information is essential for control systems. In this paper, a three-phase multiple harmonic sequence detection method is proposed for estimating both the fundamental and harmonic sequence components under adverse grid conditions. This detection method is denoted as MGDSS-PLL since it contains Multiple Generalized Delayed Signal Superposition operators and a Phase-Locked Loop. The proposed MGDSS-PLL can be flexibly tuned to extracting any harmonic components according to specific applications and it also exhibits great robustness to different grid disturbances. Simulations and experimental results are presented for verifying the performance of the MGDSS-PLL.