【作者】 江善林；

【导师】 梁维燕； 邹继斌；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2010， 博士

【摘要】 永磁同步电机效率高、结构简单、功率因数高、控制特性好,特别适合高速运行,已广泛应用于机械加工业、电动工具、飞轮储能、高速离心机、高速压缩机等领域。绕组交流损耗、定子铁心损耗以及转子涡流损耗的准确计算是高速永磁同步电机的关键问题,也是学术界研究的热点。本文针对高速永磁同步电机的高频损耗及温升问题进行了研究,包括:定子绕组高频铜耗、铁心损耗、转子涡流损耗的解析分析和数值计算以及相关的实验研究;驱动方式和转子位置检测误差对电机损耗的影响分析以及高速永磁同步电机三次谐波无位置传感器控制实验平台的构建;高速永磁同步电机电磁场-温度场的双向耦合计算。对高频电流引起的绕组趋肤效应、邻近效应进行了深入研究,分析了逆变器PWM谐波电流对高速永磁同步电机绕组交流损耗的影响,得出了电机绕组的交、直流损耗比随PWM载波比的变化规律。研究了绕组交流损耗随电机槽口宽度和槽口高度的变化规律,对槽内不同位置处的导体交流损耗进行了对比,指出离槽口最近的导体交流损耗最大。通过分析导体直径对导体交、直流损耗的影响,得出在电流频率和幅值一定时,导体总损耗随导体直径变化存在极小值的结论。对保持导体总面积相等,采用多股并绕减小高频交流损耗的方法进行了研究,指出保持导体总面积一定时,不同并绕根数的绕组有不同的临界频率。在临界频率以下,并绕时绕组的交流损耗小于不采用并绕的绕组;在临界频率以上,采用并绕方式的绕组交流损耗反而比不采用并绕的绕组交流损耗大。实验研究了逆变器PWM谐波以及多股并绕对绕组高频交流损耗的影响,证明了有限元计算结果的正确性。高速电机频率较高,传统的铁耗计算模型需要测量硅钢片的高频损耗曲线或者根据经验系数进行估算,已经不能满足高速电机铁耗计算的要求,由此提出一种综合考虑电机旋转磁化和高频趋肤效应的变系数正交分解高频铁心损耗计算模型。该模型只需根据硅钢片厂家提供的交变磁化方式下测得的低频损耗曲线即可拟合出相关的损耗系数,因此特别适合高速电机的铁心损耗计算。实验证明该计算模型在高、低频时都有较高的计算精度。采用该计算模型分析了逆变器PWM谐波电流、永磁体充磁方向、磁钢斜边角以及温度对高速永磁同步电机定子铁心损耗的影响。基于等效电流片原理建立了考虑气隙、保护套、涡流电枢反应以及电机有限长度影响的永磁同步电机转子涡流损耗的解析计算模型,采用该模型对定子谐波电流在转子中产生的涡流损耗进行了分析。采用时步有限元法研究了逆变器PWM谐波电流、定子槽口尺寸、气隙长度、保护套材料及厚度对电机转子涡流损耗的影响。通过损耗分离实验,证明了解析法和有限元法计算结果的正确性。永磁同步电机可分为方波驱动永磁同步电机和正弦波驱动永磁同步电机,两种驱动方式电机的电流波形不同,因此电机的性能和损耗也有所不同。采用有限元法对不同驱动方式下的电机损耗进行了数值分析和实验研究。分析结果表明,方波驱动方式下的电机损耗比正弦波驱动时大,而且随着转速的升高差值变大。研究了转子检测误差对高速永磁同步电机损耗的影响,指出转子位置检测误差对高速永磁同步电机的损耗影响较大。针对方波无位置传感器控制永磁同步电机在高速时电机损耗较大,正弦波无位置传感器控制起动困难和低速性能差的缺点,基于三次谐波法构建了方波和正弦波两种驱动方式相结合的新型高速永磁同步电机无位置传感器控制实验平台。对三次谐波法转子位置估算误差进行了理论分析和实验研究,并采用一阶保持法提高了转子位置估算精度,改善了系统的动、静态性能。对钕铁硼永磁材料的温度敏感性进行了研究,分析了恒电流控制和恒转矩控制两种控制策略下,温度对电机绕组交流损耗、定子铁心损耗以及转子涡流损耗的影响,指出实现电机电磁场-温度场双向耦合计算,对准确计算电机性能和各部件温升的必要性。建立了高速永磁同步电机三维暂态温度场计算模型,采用迭代的方法实现了电磁场-温度场的双向耦合计算,分析了恒转矩控制策略下的高速电机各部件温升。实验结果表明,采用迭代法的双向耦合计算结果要比传统的单向耦合计算结果更接近实测值。更多还原

【Abstract】 Permanent magnet synchronous motor (PMSM) is a good choice for high-speed operation due to the high efficiency, simple structure, high power factor and excellent control performance. PMSM is used widely in many applications such as mechanical process, tooling machines, flywheel applications, high-speed centrifuges, high-speed compressors, and so on. Accurately calculate the winding AC loss, stator core loss and rotor eddy current loss are key problems of high-speed PMSM and hot topics of academe. The research mainly focuses on high frequency loss and thermal problem which contains: analytical and numerical calculation of high frequency winding copper loss, core loss, rotor eddy current loss and related experiments; analysis of the influence of drive mode and the rotor position detection error on PMSM loss and construction of high-speed PMSM third-harmonic sensorless control experiment platform; electromagnetic field and temperature field two-way coupled calculation of high-speed PMSM.This dissertation analyses winding skin effect and proximity effect caused by high frequency current deeply. The effects on high-speed PMSM winding AC loss due to inverter PWM current harmonic are studied and the curve of AC/DC loss ratio with PWM carrier ratio is described. The change rule of winding AC loss with motor slot width and slot height variation is analyzed. Through the analysis of influence on AC and DC loss by conductor diameter, get conclusion that there is a minimum value of conductor total loss which changed with diameter in certain current frequency and amplitude. The method adopts multi-strands to reduce the high frequency AC loss in conditions of maintain total area of the conductor constant is researched. Keeping the conductor total area equal, different strands number winding has different critical frequency, multi-strands winding AC loss is smaller than single conductor winding AC loss when below the critical frequency, but above the critical frequency multi-strands winding AC loss is larger. The experiments about the impact of PWM harmonic current and multi-strands on the winding high frequency AC loss are studied and the results proved the correctness of finite element method.Focus on high frequency for high-speed motor and the traditional core loss model which need to measure high frequency loss curves or just estimates loss coefficient by experience, proposes a variable loss coefficient orthogonal decomposition core loss model which comprehensive consideration of motor rotation magnetization and high frequency skin effect. The model can be fitted correlation loss coefficient just through silicon steel loss curves measured on low frequency alternating magnetizing mode by factory and particularly suitable for high-speed motor core loss calculation. Experiments show that the proposed model has a high accuracy both in low frequencies and high frequencies. The improved model is employed to analyze the effects of current harmonic due to PWM chopping, magnetizing direction, the beveling angle of magnets and temperature on stator core loss of high-speed PMSM.A PMSM rotor eddy current loss analytical calculation model which considers the effects of motor airgap, retaining sleeve, eddy current armature reaction field and limited length is established based on the equivalent current sheet. The rotor eddy current loss that caused by stator harmonic current is analyzed through the proposed analytical calculation model. The rotor eddy current loss are also studied by time-stepping FEM and the effects of inverter harmonic current, stator slot-opening, airgap length, retaining sleeve material and thickness on the rotor eddy current loss is researched in depth. The loss separation experiment proves that the analytical method and FEM results are correct.PMSM can be divided into square wave drive PMSM (BLDCM) and sine wave drive PMSM (BLACM). The current waveforms of BLDCM and BLACM are different, so the motor performance and loss are also different. The loss of BLDCM and BLACM is comparative studied by Finite element method and experimental method. The results show that the BLDCM loss is larger than BLACM loss, and the difference become greater with the speed increasing. The influences of rotor position detection error on the high-speed PMSM loss are analyzed in detail and Points out that rotor position detection error impact on high-speed PMSM loss greatly. For the disadvantages that larger loss on sensorless BLDC mode and difficult to start and poor low speed performance on sensorless BLAC mode, a novel third harmonic sensorless PMSM drive system which combined BLDC mode and BLAC mode is proposed. Rotor position detection error of third harmonic sensorless method is studied by theory and experiment. The first-order hold method is used to extend the accuracy of rotor position estimation and improve the system dynamic and static performance.Through the study on NdFeB material temperature sensitivity and the impact of temperature on winding copper loss, stator core loss and rotor eddy current loss under constant current control and constant torque control, points out that it is necessary to realize electromagnetic field and temperature field two-way coupled calculation for accurate calculation of PMSM performance and the temperature rise of parts. A high-speed PMSM 3D transient temperature field model is established. Iterative method is used to achieve electromagnetic field and temperature field two-way coupling and components temperature rise of high-speed PMSM under constant torque control is calculated. The experiments show that the iterative two-way coupling method results closer to experimental values than the traditional one-way coupling results.更多还原