【作者】 刘平；

【导师】 刘和平；

【作者基本信息】 重庆大学 ， 电气工程， 2008， 硕士

【摘要】 无刷直流电机以电子控制线路代替机械电刷和换向器实现直流电机的换相,集有刷直流电机和交流电机的优点于一体,是当今最高效率的调速电机。采用无位置传感器控制技术,不但可以克服位置传感器的诸多弊端,而且能进一步拓宽无刷直流电机的应用领域。目前,无刷直流电机无位置传感器控制已成为无刷直流电机控制技术的发展方向。近二三十年来众多的院校、科研机构对无刷直流电机控制的研究大多集中在“无位置传感器的转子位置检测”、“起动”、“转矩脉动”等几个方面。但是在无位置传感器控制技术仍然有许多待解决的问题。而且现有的各种位置传感器检测及无位置传感器的位置检测方法都不可避免地存在转子位置检测误差,这个误差就会使电机偏离正常换相点,发生换相超前或滞后,导致电机运行不平稳,震动和噪声加大,效率降低,电机电流过冲,严重时会导致换相失败,使得电机失步或使驱动模块发生故障保护等致使电机产生振荡及停转。本论文首先介绍了多种主流的无位置传感器的位置检测方法。在分析了它们的优缺点的基础上,选用反电动势过零检测法,详细叙述了这种方法的检测原理,定性地分析了转子位置检测误差产生的原因。其次对无刷直流电机工作在三相星型六状态模式下的换相进行了深入分析,并在此基础上对驱动系统的三种换相情况:换相正常、超前和滞后进行了详细讨论,并从理论上定性地分析了基于转子位置检测误差的三种换相情况下相电流的解析表达式,为研究在线抑制换相不正常时的大电流、提出暂态电流的最优控制算法奠定基础。本论文设计了控制系统的总体方案,并介绍了其中的几个关键环节。在Saber环境下建立了基于反电动势过零检测法的无刷直流电机控制系统模型。在所建立的控制系统模型中对电流闭环控制系统运行和几种换相情况进行了仿真分析。采用DSP TMS320LF2407A控制芯片和智能功率模块构建了无位置传感器控制系统平台。论文详细介绍了硬件控制电路和与之对应的系统软件的设计。最后进行了无刷直流电机系统运行和换相的相关实验研究,得到了与理论和仿真分析一致的结论。更多还原

【Abstract】 The brushless DC motor(BLDC), with the electrical circuit to replace the mechanical brush and the commutator, is one of the most high effective motor currently for combining the advantages of both AC motor and DC motor. The introduction of sensorless control technology not only surmounts the deficiency of sensor’s precision and installation but also impulses the application realm of BLDC. Nowadays, sensorless control technology has been the major direction of BLDC control strategies.In recent decades, most institutes focuses on the issues– detection of rotor position without position sensor, the problems on motor starting, the ripple of torque etc. However, the sensorless control technology has many problems, and the very important one is the leading or delaying commutation caused by unavoidable errors in both sensor and sensorless control strategies. These errors may cause the vibration, noise, and low efficiency, high current impulse even lead to failure commutation and out of step. By introducing and comparing the mainstream sensorless control methods, the zero cross detection of Back Electromotive Force is adopted and presented specifically in the paper. And also the paper gives the qualitative analysis of the rotor position detection error.Then the paper deeply analyzes the BLDC commutation with three-phase Y-connected windings in six-state operate mode, and discusses specifically on the three situation: commutation correcting, leading and delaying. The phase current analytical expressions in three situations are deduced. It can lay a foundation of the online transient current optimized control when the motor works at commutation failure. The paper focuses on some key points and proposes the corresponding control scheme.The simulation model of BLDC sensorless system based on the zero cross detection of Back Electromotive Force is established in the Saber simulation platform. Based on the model, the operation of the current close-loop control system and under the different commutations are analyzed specifically.Then the paper presents the experiment platform which is based on the DSP TMS320LF2407A and the Intelligent Power Modules and presents the hardware and software design.Finally, based on the experiment platform, the issues on BLDC operation and commutation are discussed. The paper obtains the coherent results with theory simulation and analysis.更多还原