【作者】 韩则胤；

【导师】 陈阳生；

【作者基本信息】 浙江大学 ， 电机与电器， 2010， 硕士

【摘要】 在车载电动空调系统中,压缩机驱动系统通常使用电动机提供动力。永磁无刷直流电机(Permanent Magnet Brushless DC Motor)以其小体积、高功率密度、结构简单等特点,适合于车载工作环境。本文研究了一种永磁无刷直流电机驱动系统,用于车载空调压缩机的驱动。无刷直流电机的控制中,检测转子位置是一个至关重要的问题。在压缩机驱动系统中,电机与压缩机往往会密封在同一个空间里,工作环境恶劣,位置传感器等的使用受到很大限制。本文研究了一种基于反电势过零检测的无位置传感器控制方法,检测转子位置。与传统反电势过零检测方法相比,本文所使用的检测方法无需引出电机中性线,也不需要通过复杂的电路拟合电机反电势,电路结构简单,可靠性提高。对于反电势过零检测中,可能出现的过零点检测失误的问题,本文研究了一种过零点位置的修正方法,对每一个过零点的准确性进行评估。对于过零点位置检测错误和丢失等问题,采取错误甄别和丢失位置补偿的修正方法,提高系统运行的稳定性。通过对车载空调系统运行特点的研究,对于车载系统中一般使用的12V、24V等供电电源,设计了相应的低电压大电流无刷直流电机驱动器。对于电动汽车等应用领域高电压等级的要求,在低压驱动器基础上又进行了144V、288V等高电压等级驱动器的设计。对于这两类驱动器硬件电路,本文进行了比较研究,并对其稳定性和可靠性进行了实验验证。实验结果表明,本文所设计的驱动器能够很好的满足车用空调系统的控制要求,驱动器结构紧凑、工作可靠。针对无刷直流电机在空调系统应用中的高转速化和大功率化要求,电机本体的优化设计将成为整个系统设计的一个重要组成部分。基于此,本文研究了电磁和结构两方面的优化设计。电磁方面集中研究了隔磁桥等转子关键部分对电磁设计的影响。由于这些部分对转子的机械强度也有很大的影响,所以在结构优化中对这些方面也进行了研究。本文首先使用有限元分析软件建立电机的电磁模型,对“一”型、“V”型和“U”型三种磁钢结构的IPM电机进行电磁性能分析,同时计算转子冲片和磁钢受到的电磁力。然后,分别建立了三种电机的结构模型,并将电磁力导入,对转子进行结构分析。本文对比了几种磁钢结构的转子模型分析结果。隔磁桥、极靴等对电磁和结构性能的影响都比较严重,本文进行了对比研究。对于转子的优化设计,本文也进行了讨论。最后,对“一”型磁钢结构电机进行了实验分析。仿真和实验分析表明,考虑电磁力的影响时,隔磁桥上的应力会有一定程度的减低。相比“一”型磁钢结构,“U”型和“V”型磁钢结构不仅能够增加电机的磁通量,也能使电机承受更大的转速,但是生产成本会更高。更多还原

【Abstract】 In the automotive electrical air-conditioning, the compressor system is usually powered by motors. The permanent magnet brushless DC (BLDC) motor is small, high power density and simple. So it is very suitable for the automotive working conditions. In this paper, a permanent magnet BLDC motor sensorless drive has been studied for air-conditioning compressor.It is important for BLDC motor to detect the rotor positions. In an integrated compressor motor system, the motor is assembled and sealed within the compressor, where the conditions are harsh and the sensor method is not suitable. A sensorless method based on zero crosspoints of back-EMF was studied in this paper. In this method, there is no need to draw out the motor neutral line or rebuild the back-EMF. So it is much simple and stable, compared with the traditional back-EMF detecting solutions.The noise and occasional miss of zero crosspoints are common in zero crosspoints detection. Hence, a correction method was investigated in this paper to check the accuracy of zero crosspoints. For the mistake and miss in the zero crosspoints detection, the mistake screening and missed point compensation method were implemented to enhance the stability of system.Based on the preliminary study of automotive air-conditioning, a low voltage BLDC motor drive for 12V, 24V power supply was designed. For the high voltage areas such as the electric vehicles, 144V and 288V BLDC motor drive were developed. The comparison of the hardware has been investigated, and the stability and reliability of the two drives has been verified experimentally. The experimental results have shown that the design can meet the requirements of the air-conditioning in vehicles and the two drives are compact and reliability.For the requirements of high-speed and high power in the BLDC motor in air-conditioning, the optimization of motor was important in optimizing the whole system. Hence, the optimization in both electromagnetic and structural design was considered in this paper. Electromagnetic analysis focused on the effects of bridge on electromagnetic performance. In the structural analysis, these parts also had serve influence on mechnical stresses. So it is the important part in structural optimization too.The electromagnetic model was created by finite element method first. Three types of IPM rotors were analyzed. They were radial shape, V shape and U shape. The electromagnetic forces were calculated from electromagnetic model. And then those forces were transferred to a structural model for deformation and stresses analysis.Results of the three type rotors have been compared in this paper. The bridge and segment area have great influence on both electromagnetic and structural performance. Hence, more attention has been taken to them. Additionally, methods to optimize the rotor were investigated in this paper. Finally, experiments of radial shape rotor were taken to verify the simulation results. The experimental and simulation results have shown that the effect of electromagnetic forces are benifical to relief the stresses on bridges partly. The V shape and U shape rotor can not only increase the flux but also withstand severer stresses. However, the cost will be high.更多还原