Optimizing cogging torque reduction in slot opening shift method for BLDC motor by RSM

The main target of this paper is optimizing the slot-opening shift for cogging torque reduction in BLDC motors. In a slot-opening shift method there is no skew, therefore the known drawbacks of the skewing is prevented. In the first part of the paper the slot-opening shift method for a BLDC motor is discussed. In this case, it is desired to find a method for cogging torque reduction without deteriorating the trapezoidal shape of back- EMF. In the second part optimization of this method is discussed. In this case, it´s tried to optimize the amount of shifts in slot opening for maximum reduction in cogging torque. Response surface Method (RSM) which is a branch or Design of Experiments (DOE) is used as optimization Method. The simulation result by finite element shows a considerable reduction in the cogging torque of the optimized motor. Moreover the simulation verifies the quality of back-EMF shape in each case.