Experiment and simulation of rotor’s torsional vibration based on sensorless detection technology

To settle the problems of high-cost detection and complicated fixture of sensors in fault diagnosis, a sensorless method for the detection of torsional vibration based on the current of the motorpsilas stator is proposed aiming at the mechanical equipment driven by AC induction motors. Computer simulation model is set up using SIMULINK and the analysis of computer simulation is carried out. A test device driven by the induction motor with a DC generator as load is set up for the simulation of torsional vibration of the shafting. With the rapid on-off changes via computer-controlled load circuit simulating torsional vibration of the shafting, the comparison between the information of transverse vibration signals picked up by an eddy current displacement sensor and the information of torsional-vibration characteristic frequency extracted from the current signals using Hilbert conversion envelope spectrum is carried out. Simulation experiments are in coincidence with the simulation results. The results show that the fault information of the mechanical equipment driven by motors is coupled to the stator current in the form of torsional vibration. Compared with traverse vibration detection, sensorless method is more sensitive to the detection of torsional vibration. So it is more suitable for fault detection and diagnosis of some mechanical systems that generate torsional vibration. That lays a firm foundation for the wide application of sensorless detection and diagnosis method.