基于切换系统理论的有源电力滤波器控制策略研究

发布时间：2018-12-15 14:10

【摘要】：随着电力电子器件的发展和广泛应用,谐波污染成为威胁电能质量的重要因素,而有源电力滤波器可有效抑制谐波、改善供电质量,因此有源电力滤波器在生活和工业中的应用越来越广泛。此外,一次能源的过度开采,使环境受到严重污染,并且人们对供电可靠性的要求越来越高,传统供电方式已经不能满足现实需要,因此微电网越来越受到人们的关注。微电网逆变器和有源电力滤波器主电路十分相似,为了节约投资,可将微电网与有源电力滤波器共用一套逆变器设备,但是目前微电网逆变器与有源电力滤波器属于两套不同的设备,资源浪费严重。为了解决上述问题,本文研究基于切换系统理论的有源电力滤波器控制策略,可有效滤除系统谐波并可以保持直流侧电容电压稳定在较高值,并且为微电网与有源电力滤波器共用一套逆变器设备提供坚实可行的理论基础,对提高供电质量、降低损耗、节约投资等具有十分重要的意义。本文首先介绍了切换系统,它由一系列子系统和描述它们之间联系的切换规则组成。切换系统的稳定性取决于所选择的切换规则,即使它的子系统是稳定的,如果切换规则不当,有可能导致整个系统不稳定。反之,即使它的子系统是不稳定的,在适当的切换规则下,可使整个系统稳定运行。切换规则的设计是研究切换系统稳定性的关键性问题,本文基于李雅普诺夫稳定性定理设计出了可使系统渐进稳定的切换控制策略。建立单相有源电力滤波器与切换系统基本形式相符合的误差数学模型,并将单相有源电力滤波器分为两个子系统,根据李雅普诺夫定理分析子系统稳定性并确定使子系统渐进稳定的李雅普诺夫函数,然后设计出使单相有源电力滤波器稳定运行的切换序列,并以此控制单相有源电力滤波器主电路功率开关通断,使系统运行在最佳补偿状态。提出了基于切换系统理论的三相有源电力滤波器谐波电流控制策略,以三相有源滤波器的两相谐波补偿电流和直流侧电容电压为变量建立系统误差数学模型,根据李雅普诺夫稳定性定理设计出最佳切换序列,使其谐波补偿电流、直流侧电容电压与参考值之间的误差逐渐减小,保证系统运行在最佳补偿状态。分别搭建单相、三相有源电力滤波器仿真模型对本文方法进行了验证,并利用设计出的切换序列控制有源电力滤波器主电路功率开关通断,通过仿真结果证明了此方法是正确的、可行的。
[Abstract]:With the development and wide application of power electronic devices, harmonic pollution has become an important factor threatening power quality. Active power filter can effectively suppress harmonics and improve the quality of power supply. Therefore, active power filter is more and more widely used in life and industry. In addition, the over-exploitation of primary energy causes the environment to be seriously polluted, and the demand for reliability of power supply is more and more high. The traditional power supply method can not meet the actual needs, so people pay more and more attention to micro-grid. The main circuit of microgrid inverter and active power filter is very similar. In order to save investment, microgrid and active power filter can be shared a set of inverter equipment. However, microgrid inverter and active power filter belong to two different sets of equipment, which is a serious waste of resources. In order to solve the above problems, the active power filter control strategy based on switching system theory is studied in this paper, which can effectively filter the harmonic of the system and keep the DC side capacitance voltage stable at a higher value. It also provides a solid theoretical basis for sharing a set of inverter equipment between microgrid and active power filter. It is of great significance to improve the quality of power supply, reduce losses and save investment. In this paper, we first introduce a switching system, which consists of a series of subsystems and switching rules describing the relationship between them. The stability of switched systems depends on the selected switching rules, even if its subsystems are stable, if the switching rules are not appropriate, it may lead to the instability of the whole system. On the other hand, even if its subsystem is unstable, it can make the whole system run stably under proper switching rules. The design of switching rules is the key problem to study the stability of switched systems. Based on Lyapunov stability theorem, a switching control strategy is designed to make the system asymptotically stable. The error mathematical model of single-phase active power filter and switching system is established, and the single-phase active power filter is divided into two subsystems. According to Lyapunov theorem, the stability of the subsystem is analyzed and the Lyapunov function that makes the subsystem asymptotically stable is determined. Then a switching sequence is designed to make the single-phase active power filter run stably. The power switch of the main circuit of the single-phase active power filter is controlled to make the system run in the optimal state of compensation. The harmonic current control strategy of three-phase active power filter based on switching system theory is proposed. The mathematical model of system error is established by taking the two-phase harmonic compensation current and DC capacitor voltage of three-phase active power filter as variables. According to Lyapunov stability theorem, the optimal switching sequence is designed to reduce the error between the harmonic compensation current, the DC capacitor voltage and the reference value, so as to ensure the system to run in the optimal compensation state. The simulation model of single-phase and three-phase active power filter is built to verify the method, and the switching sequence is used to control the power switch on and off of the main circuit of the active power filter. The simulation results show that this method is correct and feasible.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM761;TN713.8

【相似文献】