The Research Of Traction Inverter Fault Diagnosis Based On The Analysis Of Motor Vibration Signals

At present, in the context of rapid economic development, China's rail transit industry is moving in the direction of high-speed and intelligent development. So how to ensure the safe operation of rail transit vehicles has become a problem which can not be ignored. At the AC drive system, the traction converter power core of the rail transit vehicle power traction. Complete the conversion between the energy is its mainly work. As an important part of the converter, the reliability under the working state of traction inverter affects the normal operation of the vehicle state directly.Therefore, reliable inverter fault diagnosis is an effective way to ensure vehicle safety.Based on the state of the motor vibration during the actual operation of the high-speed EMU, the fault diagnosis of the traction inverter of the standard EMU is studied in this paper. Firstly, the paper analyzes the main circuit structure and working principle of AC drive system in high-speed EMU, and analyzes the topology structure,working principle and control method of traction inverter. At the same time, the common faults and fault characteristics of the traction inverter were briefly introduced when it works in actual conditions. Secondly, this paper takes the power switching element IGBT as the research object, which is one of the traction inverter structure.And uses the Simulink module in the MATLAB software as the simulation platform,establishing the simulation model of the three-level inverter, which is based on the space vector pulse width modulation (SVPWM) strategy, and having a classification discussion about the fault state of the power switching element in the traction inverter structure. On the basis of this, Simulink simulation of each failure mode is carried out.Among them, the voltage and current signals of the AC side of the inverter are selected as the object of fault diagnosis research. Than through the fast Fourier transform (FFT) analysis, the influence of the power switch element on the characteristic signal is obtained. Finally, analyzed and processed the vibration signal of the high-speed EMU motor. The results verify the influence of the power switching element fault on the output voltage and current signal, and verify the fault diagnosis of the traction inverter based on the analytical model.In addition, by analyzing the structure and working principle of the traction motor, the electromagnetic vibration caused by the fault of the input signal is studied.After the harmonics inputted to the traction motor which generated during the process of traction inverter, the motor will make the corresponding harmonic pulse torque,which has an impact on the motor output frequency.At the same time, the 5th and 7th harmonic in the fault current signal is the main reasons causing the motor vibration signal 12 times the frequency, the 11th and 13th harmonic is the reasons causing 24 times the frequency. And this is using as an important basis for the fault diagnosis of traction inverter. Through the analysis of the vibration of the traction motor in the actual operation of the high-speed EMU, the fault diagnosis method is verified.