Co-Simulation Modeling And The Broken Bar Fault Diagnosis Of Squirrel-Cage Motors

While a squirrel-cage motor is working with loads,it may break down due to the common faults,therefore,enterprises have to suffer economic losses for the faults of motors.Under such a circumstance,many scholars set out to research the characteristics of the faults,they take advantage of some signal processing algorithms to highlight the characteristics by the fault stator current data under the condition of three-phase 50 Hz AC power supply.However,enterprises usually adopt the closed-loop control strategy to make the motor speed stable.In order to explore the broken bar fault characteristics under the closed-loop condition,this passage has carried out the following work:(1)The finite element 2D model of squirrel-cage motor Y160M-4 is built with the software Maxwell,which simulates the motor drives constant load under the situation of three-phase 50 Hz AC voltages power supply,thus the healthy and the fault stator current data are acquired.(2)A co-simulation platform of the slip frequency vector control system for squirrel-cage motors is established.It combines Simulink,Maxwell and Simplorer to build the co-simulation platform.The stator current data are acquired by the co-simulation platform in different load cases,which generates respectively from a healthy motor model and a fault one with a broken bar.(3)Based on the stator current data,the fault characteristics under the open-loop and closed-loop conditions are obtained by short time Fourier transform(STFT)and synchrosqueezing wavelet transforms(SWT)time-frequency analysis.The results of time-frequency analysis show that STFT and SWT are suitable to diagnose the broken bar fault,and the fault time-frequency characteristics are quiet different under the two conditions.