Cogging torque reduction by utilizing the unequal rotor slot arc method for FSPM Machines

• Cogging torque is one of the problems for permanent magnet machines. • Magnetic permeance distribution is one of the components of the cogging torque. • Unequal rotor slot arc (URSA) angles help to manipulate the magnetic permeance distribution. • URSA method has promising outcomes to mitigate the cogging torque. Cogging torque is a crucial and offending problem for electric machines that consist permanent magnets. Flux switching permanent magnet (FSPM) machines have magnets embedded inside the stator coils. Due to the interaction between the stator magnetic flux and the rotor steel, cogging torque occurs. To express this interaction, Magnetic Permeance Distribution Model is implemented in this study. To minimize the cogging torque, unequal rotor slot arc (URSA) technique is developed and cogging torque is calculated by using finite element method. An optimization study is performed to get the minimum value of the cogging torque under reasonable output torque. Results prove that, the proposed URSA method have promising outcomes for cogging torque reduction.