The Harmonic Detection Method for APF based on Wavelet Transform

Aiming at the issues of low precision and slow speed of traditional harmonic detection methods, the harmonic detection method for Active Power Filter (APF) based on wavelet transform is put forward. The wavelet threshold function is improved to perform smoothing and denoising operations on the current signal, the sliding window iterative Discrete Fourier Transform (DFT) is employed to decompose and reconstruct the current signals, and the current signal is decomposed and reconstructed by wavelet transform. As a result, the dynamic performance and detection accuracy of APF system is greatly improved. The simulation results show that compared with the traditional instantaneous reactive power detection method, the proposed method reduces THD by 47.52% and improves the system's dynamic response speed by 12.5%.