并联型三电平有源电力滤波器设计与控制研究

发布时间：2018-07-01 12:09

本文选题：有源电力滤波器 + 二阶广义积分器　；参考：《西安科技大学》2017年硕士论文

【摘要】：电力电子装置等非线性负载在电力系统中的普遍应用,引起大量的谐波电流进入公用电力系统,造成严重危害,如增加线路损耗,影响设备寿命,引起串并联谐振等问题。有源电力滤波器是解决该谐波污染问题的有效装置。本文主要针对并联型有源电力滤波器的锁相环、有源阻尼建模及电流跟踪控制算法进行研究。首先,有源电力滤波器运行需要实时监测电网频率及相位,并要求锁相环能稳定准确运行于不平衡、畸变电网环境。针对该目标,本文在传统SRF-PLL的基础上利用二阶广义积分器和对称分量法进行改进。与传统的SRF-PLL锁相环相比,它不仅能消除电网电压谐波的干扰,且能稳定跟踪电网正序分量,抵抗电网电压不平衡影响。通过仿真和理论推导验证了该方法的可靠性和优越性。其次,有源阻尼型LCL输出滤波的系统建模是有源电力滤波器的关键技术。针对LCL型滤波器的谐振尖峰问题,本文采用电容电流比例反馈的方法进行有源阻尼,介绍了有源阻尼LCL的基本特性。并在abc坐标系下推导建立了电流环的传递函数及控制模型。针对数字控制存在采样延时和调制延时,本文分析了数字延时的产生机理,分析了数字延时对系统控制环路的影响,并建立了考虑数字延时的精确的系统模型,为电流环控制器设计提供设计依据。最后还分析了数字延迟下的LCL有源阻尼特性。再次,本文还针对输出电流跟踪控制进行了频域的分析和设计。具体来说,本文设计了多比例谐振控制器配合比例积分控制器完成输出电流跟踪,该方法可提高谐波频率处的开环增益,提高补偿效果。应用对数稳定性判据和Nyquist稳定性判据保证了设计的控制器的稳定性和可靠性。控制效果利用PSIM仿真软件完成了验证。最后,本课题搭建了一台10kVA的三相三电平APF实验样机,分别对本文设计的软件锁相环和电流环环路建模及控制进行了实验验证,实验结果验证了本文设计的锁相环、建模及控制器设计是有效的。
[Abstract]:The widespread application of nonlinear loads such as power electronic devices in power systems causes a large number of harmonic currents to enter public power systems, causing serious harm, such as increasing line losses, affecting equipment life, causing series-parallel resonance and so on. Active power filter is an effective device to solve the problem of harmonic pollution. In this paper, phase locked loop (PLL), active damping modeling and current tracking control algorithm of shunt active power filter (APF) are studied. First, the active power filter needs to monitor the frequency and phase of the power network in real time, and the PLL can run stably and accurately in the unbalanced and distorted power network environment. Based on the traditional SRF-PLL, the second order generalized integrator and symmetric component method are used to improve the target. Compared with the traditional SRF-PLL PLL, it can not only eliminate the interference of voltage harmonics, but also stably track the positive sequence components and resist the influence of voltage imbalance. The reliability and superiority of the method are verified by simulation and theoretical derivation. Secondly, the system modeling of active damping LCL output filter is the key technology of active power filter. In order to solve the problem of resonant spike of LCL filter, this paper introduces the basic characteristics of active damping LCL by the method of proportional feedback of capacitive current. The transfer function and control model of the current loop are derived in abc coordinate system. In view of the existence of sampling delay and modulation delay in digital control, this paper analyzes the mechanism of digital delay, analyzes the influence of digital delay on the control loop of the system, and establishes an accurate system model considering digital delay. It provides the basis for the design of current loop controller. Finally, the active damping characteristics of LCL with digital delay are analyzed. Thirdly, the output current tracking control is analyzed and designed in frequency domain. Specifically, the multi-proportional resonance controller and the proportional integral controller are designed to track the output current. This method can improve the open-loop gain at the harmonic frequency and improve the compensation effect. The logarithmic stability criterion and Nyquist stability criterion are applied to ensure the stability and reliability of the designed controller. The control effect is verified by PSIM simulation software. Finally, a 10kVA three-phase three-level APF experimental prototype is built, and the software phase-locked loop and the current loop are modeled and controlled, respectively. The experimental results verify the design of the phase-locked loop. Modeling and controller design are effective.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM761

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