double layer magnet design technique for cogging torque reduction of dual rotor single stator axial flux brushless dc motor

Cogging torque is the major limitation of axial flux permanent magnet motors. the reduction of cogging torque during the design process is highly desirable to enhance the overall performance of axial flux permanent magnet motors. this paper presents a doublelayer magnet design technique for cogging torque reduction of axial flux permanent magnet motor. initially, 250 w, 150 rpm axial flux brushless dc (bldc) motor is designed for electric vehicle application. initially designed reference axial flux bldc motor is designed considering 48 stator slots and 16 rotor poles of ndfeb type single layer permanent magnet. threedimensional finite element modeling and analysis have been performed to obtain cogging torque profile of reference motor. additional layer of the permanent magnet is created keeping usage of permanent magnet same with an objective of cogging torque reduction. threedimensional finite element modeling and analysis have been performed to obtain cogging torque profile of improved axial flux bldc motor with double layer permanent magnet design. it is analyzed that doublelayer magnet design is an effective technique to reduce the cogging torque of axial flux bldc motor.