Research On The Feature And Detection Of Broken Rotor Bars In Variable Frequency Speed Regulation Induction Motors

It is necessary to achieve the fault diagnosis on the feature and detection of broken bars with high sensitivity and reliability. However, the use of Variable Frequency Speed Regulation (VFSR) induction motors, not supplied by AC grid but converter-fed, has been spreading for its high efficiency and good performance of speed adjustment. Thus, it is a new challenge for the research on the feature and detection of broken rotor bars in variable frequency speed regulation induction motors. This dissertation just addresses itself to the challenge/trouble.The broken bars fault feature based on current signal is thoroughly analyzed in this dissertation. Firstly, according to the conventional theory on broken bars feature, the influences that the converter extorted on the spectra of stator current (converter output current), power supply current (converter output current), inverter input current, are revealed clearly. Secondly, subdivision FFT, adaptive filtering, MUSIC and other fault detection methods are analyzed. Furthermore, the MATLAB/SIMULINK simulation models of V/F Control VFSR, Vector Control VFSR and Direct Torque Control VFSR induction motor, healthy or faulty with broken bars fault, are established respectively, and the corresponding simulation has been completed combined with Ansoft software. Thirdly, the corresponding experiments are completed. Finally, subdivision FFT, adaptive filtering, MUSIC and other fault detection methods are used to analyze the simulation and experimental results for validating the feature of broken bars fault in VFSR induction motors.