The basic principle of harmonic detection method based on FBD (Fryze-Buchholz-Dpenbrock) was analyzed, in view of traditional FBD method applied to three-phase four-wire system with complicate calculation and the limitation of the filter link to the low-pass filter, an improved harmonic current detection method was proposed. Firstly, a harmonic current detection method combining FBD and ip-iq method was designed, which not only improves system flexibility but also ensure stability. Secondly, sliding-window iterative of discrete fourier transform filter module was used to replace the low-pass filter, and the total harmonic component was further optimized by wavelet transform, which improves the accuracy and real-time of the filtering process. Finally, the feasibility and superiority of this method are verified by simulation experiments.
