【作者】 吴芳；

【导师】 黄声华； 万山明；

【作者基本信息】 华中科技大学 ， 电力电子与电力传动， 2011， 博士

【摘要】 永磁同步电动机广泛应用于工业和民用等多个领域。它的优点包括功率密度高、功率因数高、效率高、可靠性高等。由于转子上没有电刷,它维护起来也比较方便。由于转子采用了永磁体,因此永磁同步电动机在高温下有退磁的风险,这是它的一个缺点。另外在控制时需要对转子的位置进行检测,而高精度的位置传感器价格也较高,因此成本等原因也妨碍了永磁同步电动机在一些领域的进一步应用。无位置传感器控制技术不仅可以降低系统成本,还由于简化了设计而提高了系统的可靠性。特别是在某些场合,如高速、微型、水下等,有时无法安装位置传感器。因此永磁同步电动机的无位置传感器控制(以下简称无传感器控制)具有重要意义。永磁同步电动机按转子的结构分永磁体内置式和永磁体表贴式同步电动机。表贴式永磁同步电动机成本更低些,因此应用得更广泛些。但由于表贴式永磁同步电动机弱凸极性,因此其无传感器控制难度更大些。本文主要研究表贴式永磁同步电动机的无传感器控制技术,但研究结论其实完全可以适用于内置式永磁同步电动机。首先,在大量阅读国内外相关参考文献的基础上,对永磁同步电动机的无传感器控制技术进行了综述。主要包括该技术的研究进展和目前的国内外研究现状；另外阐述了表贴式永磁同步电动机的无传感器控制技术的优点,在工业等一些相关领域的应用前景等；对适用于零速、低速、高速的永磁同步电动机的无传感器控制技术进行了分类和比较。第二章首先全面推导了永磁同步电动机的数学模型,在此基础上研究了一种转子静止状态下的初始位置辨识方法。转子初始位置的辨识在很多场合具有重要意义。该方法分两个步骤：第一步先向静止坐标轴注入静止的幅值正弦变化电压矢量,并根据离线测试的数据通过查表得出转子的初始位置；第二步向转子d轴注入静止的幅值正弦变化电压矢量,通过正负半周电流的大小来判断转子d轴的正方向。该方法的辨识精度较高。第三章研究了一种低速下转子位置的辨识方法。该方法向三相坐标系注入三相高频旋转的电压矢量,并通过对采样到的三相高频电流幅值进行分析,得出转子位置。该方法成立的前提是认为转子位置不同时各相电流响应的幅值也不相同,因为各相磁路的饱和程度会相应发生改变。本章的特色在于提出了一种新的高频电压注入方法：基于载波信号的高频注入方法,也就是利用三相高频PWM载波信号互差120度(而不是常用的0度)从而自动得到频率为开关频率的高频相电压矢量。该方法只适用于低速,因为在高速下基波电压不断变大,注入的高频电压的幅值将相应衰减,使高频电流幅值不断衰减,衰减到一定程度就无法从中辨识出位置信息了。第四章研究了一种高速下位置跟踪的无传感器控制技术。其原理为认为定子电压的d轴分量在稳态下应该为0。设计了一个锁相环,锁相环的输入为代表位置信息的角度,输出为转速,转速的积分为位置,这样构成了一个闭环辨识回路。另外,同时研究了一种单位功率因数的控制方法,即令输出的电压矢量与电流矢量同相位,其优点在于避免了对电机参数的信息要求,简化了编程过程。第五章研究了超高速下永磁同步电动机的弱磁控制方法及其在无传感器控制系统中的应用。在转速超过额定点以后,由于反电动势大于逆变器所能提供的最大电压,因此需要向负d轴注入一个励磁电流,即进行弱磁控制,从而使转速能够进一步上升。研究了SVPWM过调制技术以及提供负励磁电流的依据-零矢量作用时间。研究了弱磁算法在无传感器控制方法下的适用性。最后介绍了实验平台,包括以TMS320F28335为核心的硬件控制平台和软件平台。该控制系统是全数字化控制系统,所有环节包括速度环、位置环、以及位置辨识算法均由软件完成。给出了一些软件编程的思路和框图。本文对以上各种位置辨识方法在实验平台上进行了试验验证,证明了本文所提出的算法均是有效的。更多还原

【Abstract】 Permanent Magnet (PM) machine is widely used in both industrial and civilian applications because of the advantages which it inherits, such as high power density, high power factor, high efficiency and high reliability. Also, the maintaining of PM machine is convenient due to the brushless rotor structure. But the risk of irreversible demagnetizing of PM under high temperature is a tough problem. What’s more, the expensive position sensor hinders the application of PM machine in some areas. Position senseless control is important for industrial applications because it can reduce price and enhance reliability of the system, especially suitable for the occasions which the position sensors can not be installed, i.e. very high-speed machine, micro machine and under-water machine. Based on the rotor PM structures, the PM machine can be classified to Surface Mounted (SM) machine and Interior Permanent Magnet (IPM) machine. The SM machine has relative wide used because it is cheaper. But the low saliency ratio brings more difficulty in senseless control than IPM machine. In this paper, the senseless control strategy is developed on SM machine, but the method can also be applied to IPM machine.In Chapter 1, the review of PM machine senseless control strategy has been done. Mainly includes the research state of this strategy both at home and abroad; the advantage of senseless control method in SM machine and its prospects in industrial applications. Then, the senseless control technologies of PM machine at zero speed, low speed and high speed has been categorized and compared.In Chapter 2, the mathematic model of PM machine has been derived in detail, based on it, one of the initial position identification methods has been studied. This method includes two steps:firstly, inject immobile sine wave voltage to standstill coordinate, the rotor initial position can be get from an off line look up table; second step is injecting the same voltage to d axis, the positive direction of d axis is obtained by judging the amplitude of current of both positive and negative cycles. This method has high precision which is meaningful in many applications.Chapter 3 introduced a kind of rotor position identification algorithm at low speed. In this method, three-phase high frequency voltage vector has been injected into coordinate; the rotor position is identified by analyzing three-phase current amplitude. This method is based on the presupposition that the current response will change while the rotor position changes because of the variation of flux saturation of three phases. The novelty of this part is a kind of new method of high frequency voltage injection has been proposed. This technology is called carrier wave based high frequency voltage injection. The high frequency voltage vector is got by using 120 degree delayed (not the usual one with 0 degree) three-phase PWM carrier wave. But because of the voltage fundamental wave component is increasing with the rising of speed, the high frequency voltage signal will be hard to detect, so this method is only suitable for low speed operation.In Chapter 4, the technology of senseless control at high speed has been developed. Assuming the d axis voltage component is zero at steady state. A closed loop of position is designed by using a phase-locked loop (PLL) with the input and output are position and speed respectively. On the other hand, a kind of unit power factor control strategy has been studied. This method needs no machine parameters, so the programming can be simplified.In Chapter 5, the PM machine field weakening control method at ultra high speed and its applications in senseless control system has been studied. For getting higher speed than rated speed, the negative d axis current should be applied to PM machine for the controllable terminal voltage based on the inverter. The SVPWM over modulation method has been developed; the needed negative excitation current is analyzed based on the operation time of zero vector. Also, the applicability of proposed field weakening strategy in senseless control is discussed.At last, the experimental platform is introduced. This full digital control system is based on TI TMS320F28335, all of the speed control loop, position loop and position identification algorithm are implemented by software. The programming flow chart is given. The results prove the proposed control strategy can be come to pass by commercial DSP chip.更多还原