车用螺旋型水道永磁同步电机温升特性

Temperature Rise Characteristics of Helical Channel Permanent Magnet Synchronous Motor for Vehicles

为了解决车用单向螺旋型水道永磁同步电机局部温度过高,提出一种对流双水道冷却模型。基于传热学和流体力学,采用磁热耦合法对某额定功率为38 kW的单水道水冷永磁同步电机进行电磁场与温度场的仿真计算,得到了电机各位置温升分布情况;再将仿真计算结果与台架温升试验测试结果对比分析,相对误差为3%,验证了仿真计算方法的准确性;最后,在原有样机模型基础上建立对流双水道与单水道模型,将2种模型的温升仿真对比分析。结果表明:对流双水道电机模型在38 kW、4000 r/min运转时绕组端部最高温度降低5.3%,在74 kW、10000 r/min运转时间增加6.6%。

The conventional single spiral water channel motor coolant only flows in one direction,which may cause the temperature of the components in the direction of the water outlet to be higher than the temperature in the direction of the water inlet.To solve the problem of uneven axial temperature distribution of the unidirectional spiral waterway permanent magnet synchronous motor,this paper creatively proposes a spiral dual-channel convective cooling model.Based on the basic theoretical knowledge of electromagnetics,heat transfer,and fluid mechanics,a simulation analysis of the coupling of the electromagnetic field and temperature field was carried out on a water-cooled permanent magnet synchronous motor with a rated power of 38 kW.First,the two-dimensional electromagnetic simulation of the motor was carried out using Maxwell,and the main loss values of each part of the motor were accurately obtained.At the same time,the overall three-dimensional model of the motor was reasonably simplified,and the correct boundary conditions were set in the CFX software.The loss value obtained by electromagnetic simulation was used as the heat source required for temperature field simulation,the temperature field simulation was carried out,and the temperature rise characteristics of the motor and the temperature rise distribution law of various parts of the motor were obtained.Then,the transient simulation results of the motor under rated operating condition were compared and analyzed with the test results of the bench temperature rise test,and the maximum value of the simulated winding end temperature was stable at 87.5℃,the test temperature was 90℃,and their relative error was only 3%.This result verifies the accuracy of the simulation model and method.Finally,based on the prototype model,a comparison model of the convective double channel and the single-channel was established.The axial temperatures of the windings and rotors of the two different models under rated operating conditionwere compared and analyzed,as well as the time for the maximum temperature of the two models to reach 150℃when operating under peak operating condition.When running under rated operating condition,comparing the axial temperature of the motor winding under different water channel models,the maximum temperature of the convective dual-channel model was 88.3℃,and the maximum temperature of the single spiral channel was 4.9℃higher than the former,which was 93.2℃.Compare the temperature of the motor rotor under different models,the maximum temperature of the convection dual-channel model was 61.5℃,and the maximum temperature of the single spiral channel was 1.6℃higher than the former,which was 63.1℃.Since the convective dual-channel model has a more uniform motor axial temperature and smaller temperature difference than the single spiral channel model,the maximum temperature was lowered,but comparing the average temperature of the two water channel models,it was found that the average axial temperature of the convective dual-channel model was higher than that of the single spiral channel.When running under peak operating condition,comparing the time to reach 150℃under different models,the time for the single spiral channel model was 61 s,and the time for the convective dual-channel model was increased by 6.6%,65 s.It shows that the spiral double-channel motor has a lower maximum temperature and can increase the running time of the motor under peak operating condition.