A Back EMF Optimization of Double Layered Large-Scale BLDC Motor by Using Hybrid Optimization Method

This paper presents an optimization method of the back EMF for the double layered (double air gap) large-scale BLDC motor by using a Latin-hypercube sampling strategy. In order to drive the large-scale BLDC motors in parallel and multiphases, the back EMF of inner stator is equal to the back EMF of the outer. A new configuration of the double layered BLDC motor is also proposed for the compactness and high efficiency of the system. By the optimization, it is concluded that the skew angle and the thickness difference between the outer and inner magnets have important roles in synchronization and same magnitude of the back EMF, respectively.