电流时间谐波对转子带护套伺服永磁同步电动机温度场的影响

针对转子带护套伺服永磁同步电机运行过程中永磁体温升较高的问题,本文以一台2 000r/min、12.5kW的伺服永磁同步电动机为研究对象,对变频驱动时永磁电机的温升问题进行了研究.测试了样机额定负载下变频器供电时的相电流,通过傅里叶分解计算出电流各次谐波值.建立了永磁电机二维瞬态电磁场方程,计算出不同电流谐波在护套内产生的涡流损耗.并建立了三维温度场模型,对电机各部分的温度分布进行求解.经计算分析可知绕组内谐波次数位于控制电路载波比附近的电流时间谐波,将导致电机永磁体温升明显变大.将计算所得的电机温度分布与实测结果进行对比,验证了计算结果的正确性.

Effect of the temperature field of permanent magnet synchronous servo motor with rotor sheath caused by current harmonics

To solve the problem that the temperature rise of the permanent magnet of synchronous servo motor with rotor sheath are heavy,a 2000 r/min,12.5 kW permanent magnet servo motor is taken as the research object,temperature rise of permanent magnet motor caused by frequency conversion driving is studied.Rated phase current of prototype driving by inverter is tested firstly.Value of current harmonics is calculated through Fourier decomposition.Secondly,transient electromagnetic field equations of permanent magnet motor are established,eddy current losses of sheath caused by different current harmonics is calculated.On this basis,a permanent magnet servo motor domain-dimensional finite element model of temperature field is established;temperature distribution of the motor is solved.After analysis,a conclusion that higher harmonic of winding current,the number of which is closed to the carrier wave ratio of control circuit,would cause obvious temperature rises in permanent magnet is proposed.Finally,the calculation of the temperature field of motor and the measured results are compared,the correctness of the calculation results is verified.