【作者】 汪万伟；

【导师】 管霖；

【作者基本信息】 华南理工大学 ， 电力系统及其自动化， 2011， 博士

【摘要】 由PWM整流器和PWM逆变器构成的双PWM调速系统因具有可实现单位功率因数、能量双向流动等特点，而被越来越广泛地应用于海运、铁路、风力发电、钢铁加工等行业。在这种场合，往往有多个双PWM系统连接在同一母线上，构成开放式的双PWM动态负荷群，具有集群化的特点，这就使得双PWM系统之间容易相互影响，严重时，甚至可能导致整个负荷群难以正常工作。本文为了解决以上问题，从以下两个方面做了大量的研究工作：一是如何提高双PWM系统的控制性能和抗干扰能力；二是如何进行负荷群的协调控制，将各负荷间的相互影响限定在可接受的范围内，避免重大事故的发生。具体包括以下内容：首先，研究了三相VSR的工作原理、直接电流控制策略，以及直接功率控制策略。通过对直接电流控制策略的研究，提出了一套三相VSR的系统参数整定方案，有效地提高了控制系统的抗扰动能力。此外，还提出了将滑模变结构控制理论运用于三相VSR的直接功率控制系统，增强了系统的鲁棒性。其次，研究了由PWM逆变器驱动的异步电机的矢量控制系统及其控制系统参数的理论设计方法，并借鉴三相VSR的参数整定方法，来对理论设计的参数进行修正，弥补了理论设计的不足。第三，研究了双PWM的协调控制算法，采用主-从协同控制方案，使任一时刻网侧整流器的无功为0，而传送的有功则近似等于电机侧逆变器吸收（或回馈）的有功，从而有效地抑制直流侧电容充放电产生的泵升电压，提高双PWM控制系统的动态响应和抗干扰能力。最后，研究了双PWM负荷群的协调控制策略。在建立双PWM负荷群的数学模型的基础上，分析了各负荷相互影响的原因；研究了负荷群协调控制的关键问题—负荷工况的辨识。具体做法是，由三相VSR的输入电压推算出母线电压之后，运用信号处理工具—短时傅里叶变换（STFT），提取母线电压基频的初相位和幅值的变化曲线，从而得到负荷群的工况，并在此基础上提出可行的负荷群协调控制算法。本文的研究工作得到了国家自然科学基金（50777022）的资助。更多还原

【Abstract】 The dual-PWM speed regulation system is composed of a PWM rectifier and a PWMinverter. Due to its ability of bi-directional energy flow and high power factor, it has beenwidely used in many applications such as shipping, railway, wind power generation, and ironand steel processing machinery. In these applications, there are many dual-PWM systemsconnected to the same bus line to form an opening dual-PWM dymanic load group. Thegrouping and dynamic feature makes it difficult for the load groupto avoid mutual influencebetween different dual-PWM systems, and in some serious cases, it is even possible for thewhole load group to fall in failure.In order to solve the above-mentioned problems, a lot of research focused on thefollowing two aspects has been done in this paper: one is how to improve the controlperformance and anti-interference ability of the dual-PWM system; and the other is how tocontrol the dynamic load group coordinately so that the interaction between each load can belimited within an acceptable range, and avoid the occurrence of serious accidents. The detailsare as follows:Firstly, the principle of three-phase voltage source rectifier (VSR), the direct currentcontrol strategy and the direct power control strategy are studied. Based on the research of thedirect current control strategy, a simple and feasible parameter setting method which canimprove the anti-interference ability is proposed for three-phase VSR control system. In orderto enhance the robustness of the three-phase VSR control system, a control scheme combinedthe sliding-mode variable structure control and the direct power control (DPC) is proposed.Secondly, induction motor’s vector control system and its theoretical parameter designmethod are studied. On the consideration of the defects of the theoretical design method, anapproach to tune the theoretical design parameters by referring to the parameter settingmethod of three-phase VSR is proposed.Thirdly, coordinating control algorithm of dual-PWM system is studied and amaster-slave control method is proposed. The proprosed control strategy will control the PWM rectifier’s reactive power equal to0and the active power equal to the active power usedor regenerated by the PWM inverter, so that the pump voltage caused by the capacitance’scharge-discharge can be restrained effectively, and the dynamic response and anti-interferenceability of the dual-PWM system can be improved effectively.Lastly, the coordination control of the dual-PWM dynamic load group is studied. Basedon the mathematical model of dual-PWM dynamic load group, the mutual influence betweendifferent dual-PWM systems are anaylzed and the key problem of coordinatingcontrol—identification of the operation states of the dynamic load group is studied. A newapproach to solve this key problem is proposed, which employs the Short Time FourierTransform (STFT) to detect the amplitude and phase of the voltage of the bus line so that theexact load situation of the load group can be identified. Then based on the load identificationmodel, a coordination control algorithm for dual-PWM dynamic load group is proposed.This paper is sponsored by National Natural Science Foundation (50777022).更多还原