A high-pole-number integral slot hub motor design: Configuration, optimization, and validation

The hub motor is an attractive propulsion source with many advantages; however, it increases the unsprung mass of vehicles, deteriorating handling performance and comfort during rides. Therefore, the mass torque density of the hub motor requires considerable improvement. In this study, a high-pole-number integral slot hub motor adopting continuous flat wire winding is designed. The design parameters are optimized by an automated design-optimization method based on a surrogate model, which can reduce the computing time. The method involves analyzing the main effect through one-factor-at-a-time (OFTA) experiments to determine the number of levels of different parameters. Subsequently, an asymmetrical design is employed for the training data to achieve a relatively high fitting accuracy with the surrogate model. Finally, the performance of the prototype machine is tested, and the rated mass torque density of the entire machine reaches 18.5 Nm/kg.