Minimization of Cogging Torque in Axial-Flux Permanent-Magnet Machines: Design Concepts

Various techniques exist for reducing the cogging torque in radial-flux permanent-magnet (RFPM) machines. However, although some of these can be applied to axial-flux PM (AFPM) machines, the additional manufacturing complexity and cost may be prohibitive. Therefore, alternative low-cost techniques are desirable for use in AFPM machines. In this paper, the utility of employing cogging torque minimization techniques that have been developed principally for use in RFPM machines is examined by 3-D finite-element analysis, and several alternative cogging torque minimization techniques for AFPM machines are proposed.