Inter-harmonics Parameter Detection Based on Interpolation FFT and Multiple Signal Classification Algorithm

Abstract

To detect inter-harmonics with low amplitude near to harmonics with high amplitude under white noise condition with short-duration data, a method based on interpolation FFT algorithm and Multiple Signal Classification (MUSIC) algorithm is presented in the paper. Firstly, the primary frequency components of signal are extracted from sampled signal by interpolation FFT Algorithm with Hanning window. Residual signal is derived by subtracting the main frequency components of signal from sampled signal. Secondly, the frequency components of residual signal are detected by MUSIC Algorithm. The primary frequency in the first step and the residual frequency in the second step are considered as the whole frequency components of sampled signal. Lastly, the corresponding amplitude and angle of each frequency is detected by least square method. Simulation result show that the proposed method can detect inter-harmonics near the integer harmonics under noise with short data and the estimated result for parameters of frequency and amplitude can meet the need of measuring accuracy.