Experimental Verification of Design Techniques of Permanent-Magnet Synchronous Motors for Low-Torque-Ripple Applications

High-performance motor drive applications require smooth operation with minimum torque ripple. This paper is focused on identifying various design parameters in the stator and rotor that can be utilized to reduce the torque ripple of sinusoidally excited permanent-magnet synchronous motors. This paper investigates the sensitivity of various design parameters on torque ripple and torque linearity that must be considered at the design stage for low-torque-ripple applications. Only the torque ripple and torque nonlinearity due to electromagnetic origin are considered in this paper. Finite-element analysis along with experimental data is provided to validate the findings. Design techniques have been provided to minimize the overall torque ripple and increase the torque linearity. Tradeoff between magnetic flux per pole and electrical loading of the machine is needed for low-torque-ripple performance. This also provides superior torque linearity.