Electromagnetic-Thermal Coupled Design of Halbach-Array Axial-Flux PM Machine for Direct-Drive Automated Guided Vehicle

This article focuses on the electromagnetic-thermal coupled design and optimization of a yokeless and segmented armature (YASA) Halbach-array axial flux permanent magnet (AFPM) machine for direct-drive automated guided vehicles (AGVs). According to the application condition, extra high torque density is required with the constraints of natural cooling and compact machine size. The machine topology with Halbach-array permanent magnets (PMs) and segmented stator is first introduced, and different slot/pole combinations are compared. Then, a comprehensive sensitivity analysis is carried out, and the electromagnetic-thermal coupled design optimization consisting of rough and refined processes is carried out based on a newly established thermal network model. Subsequently, the electromagnetic performance of the optimized machine is evaluated and compared with that of an optimized surface-mounted PM YASA (SPM-YASA) benchmark with the same envelop dimension by 3-D finite-element (FE) method. The mechanical structure of the investigated machine with a specially designed heat-transmission mechanism is introduced, and the mechanical strength analysis is carried out. Finally, a machine prototype is manufactured and tested to validate the FE analyses.