一种轴向风冷结构对高速永磁电机转子温升的抑制研究

在变频器驱动方式下，高速永磁电机具有较大的转子涡流损耗，由于其转子的散热能力较差，易使永磁体温升较高，而发生不可逆失磁现象。采用机壳水冷结构可以有效地带走电机定子侧的热量，但是对于高速永磁电机的转子部位，水冷结构的冷却效果有限。以一台15 kW、30 000 r/min的高速永磁电机为例，设计了一种风、水混合冷却结构，基于流固耦合的计算方法分析了水速、风向以及不同风道截面积对电机永磁体部位温升的影响，并得出了相对的最优值。与仅采用水冷结构相比，增加该风冷结构可使永磁体温升降低了18.1 K，该结构可对大功率高速永磁电机的冷却系统设计提供一定的参考。

Study on Suppression of Rotor Temperature Rise of High Speed Permanent Magnet Motor by an Axial Air Cooling Structure

Under the power supply mode of frequency converter, high speed permanent magnet motor has large rotor eddy current loss. Due to the poor heat dissipation capacity of the rotor, it is easy to cause high temperature rise of permanent magnet and irreversible demagnetization. The shell water cooling structure can effectively remove the heat from the stator side of the motor, but the cooling effect of the water cooling structure is limited for the rotor of high speed permanent magnet motor. Taking a 15 kW, 30 000 r/min high speed permanent magnet motor as an example, an air-water hybrid cooling structure is designed. Based on the fluid structure coupling calculation method, the effects of water velocity, wind direction and different cross-sectional area of air duct on the temperature rise of motor permanent magnet are analyzed, and the relative optimal values are obtained. Compared with the water cooling structure only, the air-water hybrid cooling structure can reduce the temperature rise of permanent magnet by 18.1 K. This structure can provide a certain reference for the cooling system design of high power high speed permanent magnet motor.