Torque Quality Improvement of Radial Flux Permanent Magnet Brushless DC Motor

Abstract

With the constant rise in energy demand, there’s a rising concern about environmental pollution and the wastage of energy. A progressive step in this direction is the utilization of machines that operate at higher efficiency. There are many advantages of PMBLDC motors like higher efficiency, high energy density, better control, wide speed range, and higher power-to-weight ratio. Despite of many advantages that it has, it also suffers from problems. One significant problem is cogging torque. The cogging torque is an undesirable effect on the PMBLDC motor, causing vibration and audible noise. It is more predominant during low speed operation or when the rotor is stationary. It arises from the rotor’s permanent magnet interacting with the steel teeth on the stator. To improve the torque quality, the cogging torque should be minimized at the design stage itself. Initially, the PMBLDC motor was designed. The cogging torque of this initially designed PMBLDC motor was computed. The cogging torque of this initially designed PMBLDC motor was reduced by various cogging torque reduction techniques and the design of the motor has been improved. The effect of cogging torque on the torque quality of the PMBLDC motor was analyzed after applying different techniques. Finite Element Analysis was carried out to validate improved designs.