电推进用高效轻质永磁同步电机的设计方法

Design Method of High Efficiency Lightweight Permanent Magnet Synchronous Motor for Electric Propulsion

平流层飞行器夜间只能依靠蓄电池获得能量,因此,要求其推进电机兼具高效率和高转矩密度的特点。为满足该要求,提出一种电推进用高效轻质永磁同步电机的设计方法。根据电机的螺旋桨负载,建立外转子表贴式永磁同步电机(External rotor surface-mounted permanent magnet synchronous motor,ERSPMSM)轻量化结构的强度和刚度解析模型;基于等效磁网络,建立考虑高频电流谐波影响的ERSPMSM电磁模型,并与轻量化结构的解析模型相结合,进而得到ERSPMSM电磁—结构解析模型;基于该模型,对电机效率和整机质量进行多目标优化,并利用差分进化算法得到帕累托前沿,分析设计参数与优化目标之间的相关性;在帕累托前沿上选择一个解作为电机方案,并通过有限元分析和样机试验,验证了所提出的设计方法的有效性,所设计的10 kW样机重25.7 kg,转矩密度10 N·m/kg,额定效率94%。

Stratospheric aircraft can only rely on batteries to obtain energy at night,so its propulsion motor is required to have the characteristics of high efficiency and high torque density.To meet this requirement,a design method of high efficiency lightweight permanent magnet synchronous motor for electric propulsion is proposed.According to the propeller load of the motor,the strength and stiffness analytical model of lightweight structure for external rotor surface-mounted permanent magnet synchronous motor(ERSPMSM)is established.Based on the equivalent magnetic network,the electromagnetic model of ERSPMSM considering the influence of high-frequency current harmonics is established,and combined with the analytical model of lightweight structure,the electromagnetic-structural analytical model of ERSPMSM is obtained.Based on the model,the multi-objective optimization of motor efficiency and overall mass is carried out and the differential evolution algorithm is used to obtain the Pareto front.The correlations between design parameters and optimization objectives are analyzed.A solution in the Pareto front is selected as the motor scheme,and the validity of the proposed design method is verified by finite element analysis and prototype experiment.The designed 10kW prototype has a mass of 25.7 kg,a torque density of 10N·m/kg and a rated efficiency of 94%.