PVDF based vibration measurements and their correlation with torque estimation in a FOC induction motor drive

This paper presents a study concerning the vibrations generated by an induction motor drive controlled by Field Oriented Control algorithm (FOC). The aim of the study is to identify suitable measurement points and analysis techniques in order to achieve information about vibration generated by an electric drive. Vibrations take origin both by the torque generated by the motor and the motor supply through an inverter, then they are transmitted to neighbouring structures. Torque is estimated on the basis of the estimated flux linkage; vibrations have been both measured and analysed numerically by FEM at two points of the cradle. The numerical and experimental analysis have been carried out for different values of speed and torque. Results have shown that there is an appreciable correlation between measured vibration signal and the harmonics of estimated torque. Therefore in prospective it can be used as a reference for a feedback action to lessen overall ripple effects.