Maximum torque control for optimal design to reduce cogging torque in spoke type interior permanent magnet synchronous motor

This paper proposes the optimal design process to effectively reduce the cogging torque considering the torque and efficiency in constant torque region and constant power region by maximum torque control in spoke type interior permanent magnet synchronous motor (IPMSM). For an increase in torque and efficiency in constant power region, the saliency ratio is increased more than initial model. The two points, 2000 rpm (rated speed) in the constant torque region and 4000 rpm (double rated speed) in the constant power region, are chosen for comparing the torque and efficiency with the initial model. The maximum torque control is composed of maximum torque per ampere (MTPA) control in constant torque region and flux weakening (FW) control in constant power region. In the optimal design process, the d- and q- axis inductances at each current angle are extracted by finite element method (FEM) for MTPA and FW control. The FEM is used to calculate the cogging torque. And then, radial basis function (RBF) and genetic algorithm (GA) are used. The results showed an increase in the efficiency and torque compare to the initial model, and also the cogging torque is decreased more than initial model.