Design, analysis, and fabrication of a direct drive permanent NdFeB magnet synchronous motor for precision position control

Abstract

Direct drive motors have the excellent ability for precision position control due to their direct connection to load and elimination of the gearbox and pulley backlash. Among the direct drive motors, permanent NdFeB magnet synchronous motors (PMSMs) are the best choice for control systems due to their high efficiency, high power density, good dynamic behaviour, and excellent controllability. This study deals with the design, analysis, and fabrication of a direct drive PMSM for precision position control. To reach this aim, the designed motor should have very low cogging torque and torque ripple to avoid the motor deviation at the target point. To achieve these purposes, at first, a suitable combination of slot and pole has been selected for the motor and then the optimum shape of the magnets has been obtained by using the 2D finite element method. For the magnet shape, two important parameters of the magnet are optimised simultaneously. The designed motor has been fabricated and tested. Both simulation and experimental results show that the designed motor has a very good performance as the point of cogging torque and torque ripple views. Also, the experimental results validate the theoretical calculations.