Numerical Modeling of PMSM Noise Reduction by Harmonic Current Injection

In this paper, harmonic components are injected into the phase current of a Permanent Magnet Synchronous Motor (PMSM) used in automotive applications to improve the Noise Vibration and Harshness (NVH) performance. The study proposes and validates a numerical method for modeling this phenomenon. The strategy was first applied experimentally. Subsequently, the experimental currents were measured and used as input for the numerical models developed in Flux2D® and Abaqus®. The harmonic contributions of the experimental currents, obtained from the inverter control strategy, are analysed and adopted as inputs to the electromagnetic model to calculate the forces. These are applied to the Finite Element Model (FEM), which returns the values of vibration and acoustic emission of the motor as the injection strategy is varied. The numerical results are then compared and validated with the experimental data. The strategy is applied as an NVH countermeasure to a specific time order that is particularly noisy for the analyzed PMSM. This order turns out to be dominated by a spatial 0 mode also referred to as the breathing mode. The phase of the injected current harmonic is varied between 0 and 2π. For a specific phase angle, a minimum of the acoustic emission level is reached. The application of the strategy experimentally shows a maximum reduction of 29 dB and 27 dB from the vibration and acoustic levels respectively. Numerical models are able to capture the physics of the system, reproducing the variation in acoustic emission as a function of the phase angle of the injected current. Numerical results are close to the experimental data, with a maximum difference of 3dB on the optimal vibration reduction condition.