【作者】 郭鸣星；

【导师】 孙云莲；

【作者基本信息】 武汉大学 ， 电力电子与电力传动， 2004， 硕士

【摘要】 在工业、农业、交通运输、国防军事装备、科研设备和人民的日常生活中，都广泛地应用着各式各样的依靠电力传动的机械—电气传动系统。从小功率家用电器到大功率工业生产的电力驱动，异步电动机发挥着不可或缺的作用。目前，缺电是我国绝大部分地区普遍存在的问题。有资料表明，如果电力供应充分，我国某些地区的工业产值将有较大百分比的提高。而电力部门的负荷资料又表明，电动机负荷占整个负荷的80％以上，我国目前在役的电动机中，尚有4亿KW的高能耗电动机，这些电动机的损耗占额定出力的10％～23％，具有极大的节能降耗潜力。因此，为提高国民经济产值，对电动机进行节电研究，是一件具有很大经济效益和社会效益的事。 本文的研究对象是经常处于轻载或空载状态下运行的变频调速异步电动机。在这种情况下，电动机成为一个接近于纯电感的负载，造成电力系统无功功率消耗的增加，引起不必要的有功功率损耗，运行效率下降。因此，本文的研究目标是：对于这种状态下的电动机，寻找合适的磁通，使其在最优磁通下运行，使其在能安全带动负载的前提下，自身损耗尽可能的小，即提高异步电动机轻载或空载时运行的效率。 为此，本文分析了变频调速异步电动机轻载或空载时的运行特性，利用最优控制规律，得出了其轻载或空载时的调节磁通节能规律，并对最优磁通下变频调速异步电动机提出了节能算法。为了解决电动机受到扰动后在定子频率改变的情况下对电机参数的影响问题，本文又以异步电动机频率改变下电机参数作为可调模型，利用自适应控制规律，提出了异步电动机的参考模型自适应控制方案，得出了其自适应控制规律的求解方程，并在实际装置上对该方案进行了检验。为了避免一般电力电子调压装置的谐波损耗和污染问题，本文将空间矢量脉宽调制(SVPWM)技术用于三相交流电机的变频调速节能控制。 为了实现对变频调速异步电动机节能时的实时控制，本文设计了调压／频比(即调磁通)节能装置和以大功率电力电子器件IPM为开关组件的三相交流控制电路，解决了IPM的过流、过压保护问题。控制装置是基于双CPU的TMS320LF2407和AT89C51，其主要功能是实现变频调速异步电机的节能控制及运行状态显示功能。更多还原

【Abstract】 In China, asynchronous motors are widely used in many aspects and they play an essential role in modern society. Now there is a great shortage of electrical power in most areas of China. References of electrical power department show that the load caused by the use of asynchronous motors takes eighty percent of the whole. So, it is both necessary and beneficial to study how to reduce the loss and improve the efficiency of asynchronous motors.The VVVF asynchronous motors studied in this paper often run under the circumstances of low load or no load. Under these conditions, they can be nearly considered as a pure inductance that cause the increase of reactive power and more unnecessary losses of active power. And all of these will result in the decrease of their efficiency. So what this paper is going to achieve is, to those asynchronous motors with low load or no load, to seek for a proper ratio of voltage to frequency and when the motors run with it, their active power loss will be decreased as much as possible while they can burden their load safely. That is to say, this paper is going to find the way to improve the efficiency of VVVF asynchronous motors with low load or no load.To achieve the goal, this paper analyses the VVVF asynchronous motors’ characteristics which run with low load or no load. Firstly we find that the active power losses in motors can be lowered when both the input voltage and the frequency is adgusted and then we get the optimal principle about the value of the ratio of the voltage to frequency relative to various loads. Then we realize that the optimal principle doesn’t fit the disturbed motors in real operation very well. So another adaptive method is put forward in this paper and we conclude a principle of adaptive by means of adjuestion of parameter of motor. To eliminate the harmonic comes out when both the voltage ang frequency is adjusted by the PWM modulation, we apply the SVPWM wave that is able to efface specific harmonic which should disappear.To make these theory realizations, we design a device which can supervise the running of motors and adjust ratio of the voltage to frequency offered to them. The Computer is the DSP that is used to control motor. In addition, we design a circuit whose main components are IPM. It is this circuit that is used to adjust ratio of the voltage to frequency by using the SVPWM wave.更多还原