Analysis of Torsional Vibrations on the Resolver Under Eccentricity in PMSM Drive System

Since any error in the rotor angle caused by the resolver affects the entire permanent magnet synchronous motor (PMSM) control drive system, it is necessary to investigate its effect on mechanical vibrations. Torsional vibration is accordingly considered in the following study. Thereby, first, the effect of resolver errors on the harmonic content of motor current and, subsequently, torque ripple (TR) was investigated. Then, dynamical modeling is done for the generator–motor–resolver set to get the mechanical frequency response (FR) resulting from the resolver errors. Based on the above modeling, the dynamic equations (DEQs) of the system were derived, and the mechanical characteristics of the set, including natural frequency values and mode shapes, were extracted. Thereafter, TR was employed in the DEQs, and the mechanical FR caused by the resolver error was obtained. Eventually, comparing mechanical FR with electrical FR was done according to diagnosis superiority. All analyses were done using experimentally verified models.