Abstract: At present, the technology maturity of air conditioning BLDC (Brushless Direct Current Motor) motors is relatively high, and there is serious homogenization in the industry. At the same time, customers have a demand for further cost reduction and miniaturization of motors has increased. Therefore, an external rotor topology motor is proposed and its optimization design is carried out based on Maxwell finite element simulation software. Firstly, from a performance perspective, a comparative analysis was conducted on different slot pole combinations; Then, with cost and performance as optimization objectives, optimization analysis was conducted on the aspect ratio of the motor, rotor yoke thickness, permanent magnet thickness, stator tooth width, yoke width, pole shoe thickness, and slot width, and optimization solutions were obtained; Finally, the optimization plan was validated through sample preparation. The results show that under the same output power, the optimized outer rotor scheme reduces electromagnetic costs by 19% and volume by 16% compared to the inner rotor scheme. At the same time, the measured data of the prototype is basically consistent with the simulation data, which verifies the accuracy of the simulation. Overall, for air conditioning BLDC motors, the outer rotor topology has lower cost and higher power density compared to existing inner rotor solutions.

Key words: Outer rotor, High torque density, Air conditioning fan