A new harmonic detection strategy based on improved series repetitive controller

The d-q detection method based on instantaneous reactive power theory (IRPT) is one of the commonly used time-domain analysis methods for harmonic detection. Due to the poor dynamic performance of the algorithm caused by the low pass filter (LPF) in the d-q detection method, an improved series repetitive control (ISRC) structure is proposed in this paper. Using attenuation factor and correction factor to improve the series repetitive controller, the ISRC contains a negative resonance peak with a peak value of 150 dB at the 6 k harmonic frequency, and the amplitude gain is 0 dB at frequencies outside the 6 k harmonic frequency. Therefore, ISRC can achieve good attenuation effect on 6 k harmonics while maintaining the same gain at other frequencies. ISRC is used instead of LPF in the traditional d-q detection and this strategy improves the dynamic response of the system while guaranteeing its steady state performance. Finally, simulations and experiments verify the feasibility of the strategy. In this paper, an improved series repetitive control (ISRC) structure is proposed, which replaces the low pass filter in the traditional d-q detection method, and the ISRC-dq detection method improves the dynamic response of the system while ensuring the steady-state performance of the dq detection method. image