【作者】 刘冉冉；

【导师】 郑萍；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2010， 博士

【摘要】 在混合动力系统中,采用行星齿轮和两台电机的混联式驱动系统是目前最为先进和成功的电驱动系统,提供了高性能的电控无级变速驱动功能。而省去行星齿轮、将两台电机集成在一起的方案(我们称之为复合结构电机系统)可以实现相同的功能,同时具有结构紧凑、成本低廉、控制灵活等优势,是当前混合动力领域新的发展方向。本文对该类复合结构电机中的一种,即径向-径向磁通复合结构永磁同步电机(Compound-Structure Permanet-Magnet Synchronous Machine, CS-PMSM)进行了深入的研究,所做的工作主要包括以下几个部分:首先,对径向-径向磁通CS-PMSM由于结构的特殊性而产生的特殊电磁问题——磁耦合问题进行了研究,提出了实现磁解耦的设计原则,并提出了在保证磁解耦的前提下使外转子轭部厚度最小化来提高功率密度的设计方法。依照所提出的设计方法设计了一台20kW的CS-PMSM,通过有限元计算对磁场干涉程度进行了评估,验证了设计方法的正确性。另外,基于磁解耦的可行性,建立了全面反映CS-PMSM的电磁、机电关系并且能够考虑交叉磁化现象影响的统一数学模型,为CS-PMSM的精确控制奠定了基础。其次,对CS-PMSM的性能进行了有限元计算与验证,对电感参数进行了精确计算并对磁场特性进行了分析。采用多截面二维有限元法对电机的性能进行了计算,该方法可以利用二维求解结果解决斜槽电机三维有限元计算带来的计算机硬件要求高、计算时间长、计算精度有限等问题,计算结果表明CS-PMSM具有良好的工作性能。另外,给出了能够考虑电机饱和和交叉磁化现象求解电机的直、交轴自感和交叉磁化电感的方法和步骤,采用该方法对双转子电机和定子电机的电感参数进行了计算,并根据计算结果给出了两台电机的参数特点,为电机的精确控制提供依据。再次,建立了二维有限元热模型,对CS-PMSM的温度场分布进行了计算,给出了电机的局部过热点。采用了水冷和受迫风冷对CS-PMSM进行冷却,通过有限元计算对两种冷却方式的影响区域和冷却效力进行了分析,并提出了冷却流体参数对冷却效力的影响规律,该规律可以为合理地选择流体参数,反推冷却系统原动力的设计指标,优化地设计冷却系统,提高系统效率提供理论支撑。最后,研制了一台径向-径向磁通CS-PMSM的样机,并对样机进行了实验测试和功能性验证。实验测试结果验证了本文提出的设计方法和计算方法的正确性和可行性,并根据测试结果进一步提出了样机优化的建议。另外,对CS-PMSM系统应用于混合动力车中的特点和基本运行模式进行了分析,并在搭建的实验平台上模拟混合动力系统的运行模式进行测试,测试结果验证了CS-PMSM作启动机、发电机和无级变速器进行转速转矩调节的功能,为下一步CS-PMSM系统在混合动力车中的实际应用开发提供了重要借鉴。更多还原

【Abstract】 The power-split hybrid drive system which employs the plenetary gear and two electric machines is the most advanced and successfuel electric drive system among hybrid systems at present. It provides the function of the high-performance electronic continuously variable transmission (E-CVT). Another power-split hybrid system which gets rid of the plenetary gear and integrates two electric machines (we call it compound-structure electric machine system in this thesis) could realize the same function as E-CVT and also gain the advantages of compact structure, low cost and flexible control stategies. It has become a new development direction in the field of hybrid systems. This thesis makes an intensive study of a radial-radial flux compound-structure permanent-magnet synchronous machine (CS-PMSM), which belongs to one kind of the compound-structure electric machines, and the main research work is as follows.First of all, the issue of magnetic coupling caused by special structure of the radial-radial flux CS-PMSM is investigated. The design principle to realize magnetic decoupling is proposed, and the design method to mimimum the yoke thichness of the outer rotor and to improve power desity as well as to ensure magnetic decoupling is further investigated. A 20kW prototype machines is designed based on the proposed method, and the degree of the magnetic-field interference is evaluated by finite-element-method (FEM) calculations, which validates the proposed design method. Based on the feasibility of the magnetic decoupling, the mathematical model according with the electromagnetic and electromechanical relations of the CS-PMSM and considering the effect of the cross-magnetization phenemenon is established, which lays the foundation of controlling the CS-PMSM accurately.Secondly, the performance of the CS-PMSM is calculated and validated with FEM, as well as the inductance parameter is accurately calculated and the magnetic-field characteristic is analyzed. The performance is calculated with the method of multi-slice two dimentional (2D) FEM, which makes use of 2D FEM calculations to avoid problems of the harsh requirement for computer hardware, time consuming, limited calculation accuracy caused by three dimentional (3D) FEM calculations. The results show good working performance of the CS-PMSM. Furthermore, the method and step to calculate the d- and q-axis self and mutual inductances which could consider the saturation and cross-magnetization phenomenon are presented. The inductance parameter of the stator machine (SM) and double-rotor machine (DRM) is calculated, and the magnetic-field characteristic of the two machines is further investigated based on the calculated results, which provides a reference for accurate control.Thirdly, the 2D FEM thermal model is established and the temperature distribution is calculated, which show the hot spot of the CS-PMSM. The water and forced-air cooling are employed to cool the machine, and the effect of the two cooling method on different regions and their effectiveness are analyzed. Moreover, the discipline of the cooling-fluid parameter’s effect on the cooling effectiveness is investigated, which provides a theoretical reference for properly chosing the fluid parameter, reversely deducing the design index of the cooling system, optimizing the cooling-system design and improving the system effeciency.Lastly, a prototype machine of the radial-radial flux CS-PMSM was manufactured, and the experimental test and its functional validation was performed. The tested results validate the proposed design and calculation methods, and further optimization of the prototype machine was suggusted. Moreover, the features and operation modes of the CS-PMSM system used in hybrid electric vehicles (HEVs) are analyzed, and the operation modes of the hybrid system were simulated and tested on the test bench. The tested results validate the fuctions of the CS-PMSM as the starter motor, generator, and continuously variable transmission used to adjust speed and torque, which provides an important reference for the practical application of the CS-PMSM system used in HEVs.更多还原