有限转角旋转电枢式永磁同步电动机设计

Design of Limited Angle Rotational Armature Permanent Magnet Synchronous Motor

为降低运行噪声,提升仿生鱼腰关节驱动用电动机(简称腰电机)无故障工作时间,降低维护成本,腰电机采用直驱方式,且还应轻质高效.根据仿生鱼鱼体尺寸、鱼体结构及鱼尾的拍动模式,结合流体力学理论,对仿生鱼尾鳍部分进行了力学分析.根据腰电机的安装位置、旋转角速度及尾鳍受力,计算得腰电机的输出转矩和输出功率要求.由于电机转矩与气隙处直径的平方成正比,故针对腰电机低速大扭矩设计要求,选择外转子电机结构形式;但是,考虑到安装空间的限制,以及腰电机运行角度有限的特点,提出了一种有限转角旋转电枢式永磁同步电动机用作腰电机,即通过变换传统外转子永磁同步电动机拓扑结构,将传统的永磁外转子变换为定子,将传统的定子电枢改为在有限转角内旋转的转子电枢,在克服安装空间受限的同时增大了电机单位体积的输出转矩.运用有限元方法对一台54槽60极有限转角旋转电枢式永磁同步电动机进行了电磁设计,通过选取合适的齿宽达到腰电机轻质高效的设计目的.根据实际运行工况,分析了腰电机在仿生鱼尾部拍动频率为0.35 Hz时的运行效率为75.5%,满足不低于75%的设计要求.最后,对腰电机样机进行了寿命试验.结果表明:该电机满足仿生鱼腰关节驱动设计要求,且运行效率较高.

To minimize operating noise,increase the mean time between failures of biomimetic fish,and save maintenance costs,the electric motor for driving biomimetic fish waist joint(waist motor)was adopted in a direct-drive mode,which should be light weight and efficient.First,mechanical analysis of biomimetic fish caudal fin was conducted in combination with the hydrodynamics theory based on the fish body size and structure and caudal fin flapping pattern.The waist motor output torque and power were acquired through its installation position,rotational angular velocity,and force on the caudal fin.Because the torque was proportional to the square of the air gap diameter,the external rotor structure was selected to meet the low-speed and high-torque demands.The limited angle rotational armature permanent magnet synchronous motor(PMSM)used as the waist motor was proposed to consider the space constraint of the installation and the restricted operating angle of the waist motor.By changing the external rotor motor topology structure,the traditional permanent magnet external rotor was fixed to use as a stator,and the traditional stator armature was transformed to be rotor armature with a limited rotational angle.Thus,the installation space limitation problem was solved while increasing the output torque per unit volume.Using finite element analysis,a 54-slot 60-pole limited angle rotational armature PMSM was designed.Meanwhile,an appropriate tooth width was selected to achieve the design goal of light weight and high efficiency.Through analysis,motor operation efficiency reached 75.5%when the caudal fin flapping frequency was 0.35 Hz,which met the requirement of not less than 75%.Finally,the life test of the prototype was conducted.Results show that the motor with this structure can meet the requirement of waist joint drive and possesses high operation efficiency.