A stator current vector orientation based multi-objective integrative suppressions of flexible load vibration and torque ripple for PMSM considering electrical loss

To store energy from the grid into spiral torsion spring (STS) smoothly and efficiently via PMSM, a multi-objective control problem of flexible load's vibration, PMSM's torque ripple, and electrical loss is raised, where the current studies on vibration and torque ripple are mostly addressed separately, not to mention electrical loss. This research attempts to propose a multi-objective integrative control scenario that can simultaneously solve these problems satisfactorily in a unitary nonlinear control framework. Firstly, a dynamic mathematical model of PMSM is built under stator current vector orientation, and then the model of PMSM is combined with the vibration model of STS to establish the overall system model of STS driven by PMSM with considering motor's electrical loss. Then, a backstepping control principle-based multi-objective integrative control approach is proposed to realize the suppression of flexible load's vibration and the reduction of PMSM's torque ripple and electrical loss concurrently. Meanwhile, this research also designs a wide range speed identification method based on the least square algorithm with a forgetting factor. Simulation and experimental results have verified that the proposed integrative control method enables the state variables to track their respective references quickly and accurately, both torque ripple and load vibration are effectively suppressed, and the operating efficiency of the whole system is improved.