Conversion of An Existing 3 – Phase BLDC Hub motor to A 6 – Phase BLDC Hub Motor and their Performance Analysis for EV Application

In this research work a six–phase BLDC Hub motor designed, developed by using an existing 3–phase BLDC Hub motor material. This conversion orients towards design modifications in the stator winding layout, the number of phases, the number of hall-sensors, placement of hall-sensors and stator winding commutation. Also, a new controller is designed to commutate the six-phase stator winding. The rotor is kept the same without any modification in geometry and number of magnets. The existing 3–phase BLDC Hub motor, which is used in two – wheel EV application, has 48 slots and 52 magnets and a concentrated double layer winding layout is observed in it. This paper presents a novel direct approach for the conversion of the existing 3–phase BLDC Hub motor to a six–phase BLDC Hub motor. Using this proposed approach, a six-phase winding layout is designed and developed for the existing 48 slots stator of the BLDC Hub motor. This approach reduces the number of iterations to determine the proper phase sequence and phase offset among the phase windings compared to regular Cros’ method. In this work, first the existing 3–phase BLDC Hub motor is dismantled, and its stator is rewound with the six – phase winding layout, which is determined by author’s presented direct approach. The winding was designed in such a way to keep the stator slot fill factor in practical limits. Six hall-sensors placed in the stator slots to identify the position of the rotor. Secondly, a new controller is designed to run the developed six-phase BLDC Hub motor. Six-phase and 3–phase BLDC Hub motors are loaded at common load conditions, for performance comparison, and experimental results of both the motors presented. The results show that the six-phase BLDC Hub motor performs better than the existing 3–phase BLDC Hub motor. Hence, this work proves that the conversion of existing 3–phase BLDC Hub motor to a six–phase BLDC Hub motor is viable and can be adopted commercially.