Simulation and Experimental Investigation of Dual Three-Phase BLDC Motor Operation at Imbalanced Modular Loading

Abstract

Electric machines built according to the modular principle – with several three-phase windings on a stator – are a new direction of modern electromechanics, because they have a number of advantages compared to traditional single-winding machines. Among these benefits, the most important are increased efficiency and fault tolerance, which is especially important for self-powered electric vehicles. However, the presence of a mutual magnetic coupling between the modules, as well as their unequal electrical load, amplify the electromagnetic torque ripple inherent in one or another electric drive system. In this work, the electromagnetic torque ripples in a dual three-phase (DTP) brushless DC motor (BLDCM) under different loads of its modules were investigated for the cases of absence and presence of mutual magnetic coupling between armature winding sets and in the cases of the drive operation in open and closed control systems. The research was carried out by means of simulation in the Matlab/Simulink environment on a circular model of real mock-up sample of DTP permanent magnet machine developed based on the results of its magnetic field simulation using the finite element method. Adequacy of simulation results is confirmed by experimental investigation. The results of the DTP BLDCM simulation studies showed an increase in the relative electromagnetic torque ripples of individual modules due to both the presence of magnetic coupling between winding sets and the deviation from their equal loading. However, at the level of the whole DTP BLDCM, a significant mutual compensation the electromagnetic torque ripples of the modules is shown, especially if they are magnetically coupled. The presence of closed-loop control systems of individual modules significantly reduces the electromagnetic torque ripples caused by different loading of the modules, especially in the case of magnetically uncoupled modules. References 26, figures 7, tables 3.