【作者】 王爱元；

【导师】 凌志浩；

【作者基本信息】 华东理工大学 ， 控制科学与工程， 2010， 博士

【摘要】 感应电动机的变频调速是随着风机、泵类负载的调速节能以及生产工艺、伺服控制的需要发展起来的,现有工程中广泛应用的感应电机变频控制方法具有算法简单、动态特性好的优点,但未顾及电机轻载运行时的高效运行。随着全球环保和能源短缺问题的日益突出,人们开始更多的关注节能问题。感应电机作为主要的用电设备,对其节能进行研究有重要的现实意义。在此背景下本文开展了变频器供电的感应电机高效节能控制及其相关技术的研究,解决电机轻载低效率运行问题。通过分析感应电机的数学模型和四种基本的调速控制技术即电压-频率协调控制、转差频率控制、矢量控制和直接转矩控制,表明这些控制方法导致电机轻载运行时效率下降的原因在于忽略了铁耗,并采用额定恒磁通控制。在此基础上提出了感应电机考虑铁耗的矢量控制系统,通过控制气隙电流的转矩分量和励磁分量实现转矩和磁链的矢量解偶控制,并由此间接控制定子电流,研究表明系统的动态性能有了明显的提高。针对于调速控制和节能控制中所需参数的时变性、非线性的特点,论文对感应电机参数的两类辨识方法既离线辨识和在线辨识进行了研究,提出了考虑铁耗的离线辨识和转子电阻自校正的在线辨识方法。本文对转速控制器进行了三项研究：一是对传统的PI转速控制器进行了改进,由运行工况选择调节参数,提高了动静态性能；二是对滑模控制器、神经网络控制器根据其运行特性进行改进设计,滑模控制器采用非线性的光滑连续函数取代滑模面上的符号函数消除了高频抖动,神经网络控制器的权值具有自适应能力；三是提出一种感应电机的扰动观测器和基于转差频率控制的抗干扰控制,这种扰动观测器采用跟踪微分器对各种负载扰动进行观测,再根据转差频率控制原理对扰动转矩进行补偿,可以有效解决感应电机转差频率控制中动态响应差、控制精度低的缺点。变频器供电的感应电机节能运行控制是本文研究的重点,通过对电机系统的损耗分析和运行效率分析,确定出电机系统效率优化的方向是电机本体的节能运行,并且主要针对中小型电机的节能运行控制,效率优化通过调节定子供电电压、频率、压频比或励磁磁通实现,并由此得出以下感应电机实现节能控制的若干方法：(1)根据感应电机的稳态模型提出了一种标量控制的节能运行方案,这种方案根据转速调节电源频率实现电机的节能运行、通过调节电源电压满足一定转速下负载转矩的要求；(2)根据电机的不同运行工况,提出了压频比调节的模糊节能控制,提高了电机的效率并保持了一定的动态响应特性；(3)提出了基于损耗模型的矢量控制方案,矢量控制和节能控制中均考虑了铁耗,并对额定转速以上和额定转速以下的矢量节能控制分别进行了探讨,控制方案兼顾系统的优良动态性能、宽调速范围和节能运行。更多还原

【Abstract】 With the requirement of speed-regulated energy saving for fan and water pump, manufacturing technique and servo control, frequency control of induction motor has developed. The techniques for motor control in engineering have the advantages of simple algorithm and good dynamic performance. However, they are not considered high efficiency for light load. As the increasing prominence of global environmental protection and energy shortage, people have to pay more attention on energy saving. The induction motor is the main power consumption equipment. Thus, the research for its energy saving has great practical significance. In this case, the paper adheres to energy saving for induction motor supplied by converter to solve the low efficiency for the motor with light load.The main control techniques for speed regulation are coordinated control for voltage to frequency, slip frequency control, vector control and direct torque control. By analyzing these techniques and the mathematical model of induction motor, we find that the low efficiency for the motor with light load result from neglecting core loss and constant rated flux. On that basis, we present vector control considering core loss. It realizes decoupling control of torque and flux by controlling components of gap current, which indirectly command stator currents to achieve vector control. The research indicates the distinct improvement of the proposed control in dynamic performance.For the motor parameters used for speed control and energy-saving control have time variant and nonlinear characteristics, the paper investigates the offline technique and the online technique for parameter identification. It further proposes offline technique and online auto-tuning rotor resistance identification considering core loss.The paper has presented three items research for speed controller. The first is the improvement for PI speed controller. Its parameters adapt operating condition. Thus, the dynamic and static performances improve. The second is the improvement for sliding mode controller and neural network controller. A nonlinear smooth and continuous function takes the place of sign function on sliding surface and eliminates the high dither of sliding mode controller. The weight for neural network controller can be adjusted adaptively. The third is to present an novel zero-order disturbance observer and disturbance rejection control based on slip regulation. The disturbance observer uses tracking differentiator to observer all disturbance. Then, the disturbance torque is compensated based on slip control. It can overcome the disadvantages of poor dynamic response and lower control precision in slip regulation. The energy-saving control of induction motor fed by converter is the key research in the paper. By analyzing the losses and operating efficiency of the motor system, we find that the orientation of efficiency optimum is the energy saving of the motor self. And it stress on medium and small-sized motors. The optimum efficiency can be realized by adjusting stator voltage, frequency, ratio of voltage to frequency, or flux. From this, we get the following methods of energy saving control.(1) By the steady model, we propose a novel energy-saving realization of scale-controlled induction motor. The proposition adjusts the supply frequency by the speed, and adjusts supply voltage to meet the required load torque.(2) According to the different operating condition, we present fuzzy energy-saving control of induction motor by adjusting ratio of voltage to frequency. By the way, the motor runs at high efficiency and keeps good dynamic response.(3) We present vector-energy-saving control. We consider the core loss both in vector control and in energy-saving control. Also, we discuss the vector-energy-saving control for the motor operated below the rated speed and up the rated speed. The proposition gives consideration to better dynamic performance, large scope speed regulation, and energy saving.更多还原