Torque Ripple Mitigation Via Optimized Current Profiling in Interior Permanent Magnet Synchronous Motors

Torque pulsation in electrical machines contributes to undesired acoustic noise and structural vibration and has been studied extensively. In the literature, torque ripple mitigation techniques could be generally divided into two categories, namely magnetic design and optimal excitation. In this article, an optimal excitation strategy for mitigation of torque pulsation in interior permanent magnet synchronous motor (IPMSM) drives is proposed. The basic idea is to use optimized stator excitation to counteract the intrinsic pulsation due to cogging and time harmonics in the magneto-motive force. To achieve substantial reduction, the optimal current profiles are to be calculated off-line using interior-point algorithm which demands a large number of iterations. However, iterative computations in this study are accelerated drastically by taking advantage of Extended Field Reconstruction Method (EFRM) and Maxwell Stress Tensor (MST) method. To validate the proposed optimization strategy, the computed current profiles are examined through finite element analysis (FEA) calculation and experiment both of which present successful mitigation of torque pulsation.