Modeling and Torque Ripple Control in Faulty SPMSM


Abstract – This paper presents a model of a Surface Permanent Magnet Synchronous Motor which can be used in a faulty case and a torque ripple control approach developed to be applied if the faulty case is detected. Two faulty cases are considered for study, the first consider an asymmetry between the stator phases of the motor created by unbalanced number of turns and the second a short circuit between the stator windings of the motor. Proposed torque ripple control use a phasor approach to provides the current reference for stator asymmetry and an injection of an inverse current for stator short circuit fault in order to decrease the motor torque ripple. The torque control has been implemented using a model of surface permanent magnet synchronous motor based on the dynamic equations. Simulation and experimental results highlight the link between the faulty and the torque ripple and show the possibility to decrease in this case the torque ripples by changing a balanced sinusoidal current reference by unbalanced one. In practical tests the impact of the unbalanced system of currents in the torque variation is studied using an analysis of vibratory harmonic measured at twice of the supply frequency. images