The time-frequency analysis of the harmonics with wavelet transform for the power electronics systems

The time frequency analysis technique using wavelet transform is proposed to overcome EMC (electromagnetic compatibility) problems. The proposed technique takes into consideration the change in amplitude of the harmonics during the observation. By applying it to harmonics analysis, we can analyze the harmonics from not only the frequency but also the time point of view. Therefore, it enables us to obtain the effective solution for harmonics problems. In this paper, a wavelet transform is carried out against the actual measured data. Based on obtained results, it is shown that the features and high validity of the proposed technique for the power electronics field by comparing with the previous approach using FFT (fast Fourier transform)