高速永磁电机转子风摩耗对温升的影响

Influence of Wind Friction Loss of Rotor on Temperature Rise of High-Speed Permanent Magnet Motor

高速永磁电机(HSPMM)结构紧凑、功率密度高、散热困难,易使转子永磁体因温度过高而发生不可逆退磁。以一台额定转速为30000 r/min的HSPMM为例,基于计算流体力学和数值传热学的原理,从工程实际应用的角度,对不同通风量下的转子风摩耗及温升进行计算分析,并与电机温升试验进行对比。研究表明:HSPMM转子风摩耗占总风摩耗比重较大,且该比重随着流量的增加而增加;通风量达到一定值后,电机散热达到平衡,转子风摩耗随着流速的增加而急剧增加,使永磁体温度升高。增加机座水冷后,可以降低通风量,使电机达到理想温升水平。

The high-speed permanent magnet motor has compact structure,high power density and difficult heat dissipation,which would easily cause irreversible demagnetization of the rotor permanent magnet due to excessive temperature rise.Taking a high-speed permanent magnet motor with the rated speed of 30000 r/min as an example,based on the principles of computational fluid dynamics and numerical heat transfer,from the perspective of practical engineering applications,the wind friction loss of the rotor and temperature rise are calculated and analyzed under different ventilation rates,and compared with the motor temperature rise test results.The research shows that the wind friction loss of rotor accounts for a large proportion of total wind friction loss in the high-speed permanent magnet motor,and the proportion increases with the increase of flow rate.After the ventilation rate reaches a certain value,the heat dissipation of the motor reaches a balance,and the wind friction loss of the rotor increases sharply with the increase of flow rate,which causes the temperature of the permanent magnet to rise.After using water cooling for the motor base,the ventilation rate can be reduced,so that the motor can reach the ideal temperature rise level.