The importance of fault diagnosis for AC-AC frequency conversion drivers is discussed

based on the study state at home and abroad. The methods of fault diagnosis for frequency conversion drivers based on DSP and the wavelet analysis are presented.The fault diagnosis system is built.The electromechanical equipment state detection based on the wavelet energy is used.The system makes full use of the power date disposing capability of DSP and the characteristics of wavelet analysis.The wavelet analysis is effect on the analysis and the processing of unsteady signals and its multi-resolution analysis technique.The mathematical mold of AC-AC frequency conversion drivers is established.The simulation results prove that the proposed method is feasible.