三相四线制三电平APF的控制算法研究

发布时间：2018-04-09 02:32

本文选题：有源电力滤波器　切入点：三相四线制NPC型三电平　出处：《电子科技大学》2014年硕士论文

【摘要】：随着大量非线性负载的使用,向电网注入了大量的谐波,三相四线制公用电网的谐波污染问题越来越不可忽视。三相四线制三电平有源电力滤波器(Active Power Filter,APF)具有响应速度快、实时性高等优点,能够有效地补偿负载产生的谐波电流,是理想的电网谐波治理方案。本文以三相四线制中点箝位(Neutral-Point Clamped,NPC)型三电平三桥臂结构为拓扑,针对三相四线制三电平APF的控制算法开展了以下几个方面的研究:1.对NPC型三电平三桥臂拓扑的工作原理进行分析,以单个桥臂为例分析NPC型三电平三桥臂APF的各种开关状态和中线电流对直流侧电容电压的影响,并推导了三相四线制NPC型三电平三桥臂APF的数学模型。2.对APF电流控制策略进行了研究。首先分析了基于PI调节器的电流控制环跟踪补偿谐波电流指令能力不足的问题。然后,在电流控制环中引入了重复控制器,构建了以重复控制器为外环、PI调节器为内环的双环电流控制系统。详细地给出了重复控制器的设计方法,理论分析了双环电流控制系统在稳态方面表现出的优越性。3.对APF直流侧电容的总电压和电压差进行了分析,设计了高效的稳压和均压控制方法以满足负载切换时直流侧电容电压的稳定。并对提升直流母线电压的方法进行了分析和研究,设计了一种简单实用的直流母线电压软启动方法以保证设备在启动过程中直流电容电压可以平稳地上升到预值,且整个过程中无过压、过流现象。4.分析了APF功率损耗与直流母线电压、APF补偿效果与调制比的关系。通过分析得到电网电压的波动和负载谐波的变化都可以由三相最大调制比来反映,提出了一种通过三相最大调制比来计算直流母线电压给定值的方法,以达到APF补偿效果和功率损耗的综合优化。
[Abstract]:With the use of a large number of nonlinear loads, a large number of harmonics have been injected into the power network, and the problem of harmonic pollution in the three-phase four-wire public power network can not be ignored more and more.Three-phase four-wire three-level active Power filter (APF) has the advantages of fast response speed and high real-time performance. It can effectively compensate the harmonic current generated by the load.In this paper, the three-level three-level three-level APF with three-phase four-wire neutral-point clamp is used as the topology. The following aspects of the control algorithm of three-phase four-wire three-level APF are studied as follows: 1.The working principle of NPC three-level three-level three-leg topology is analyzed. Taking a single bridge arm as an example, the influence of various switching states and neutral current on DC capacitive voltage of NPC three-level three-level three-level bridge arm is analyzed.The mathematical model of three-level three-level three-level APF with three-phase four-wire NPC is deduced.The current control strategy of APF is studied.Firstly, the problem of current control loop tracking and compensating harmonic current command based on Pi regulator is analyzed.Then, the repetitive controller is introduced into the current control loop, and a double loop current control system with the repetitive controller as the outer loop and Pi regulator as the inner loop is constructed.The design method of repetitive controller is given in detail, and the superiority of double loop current control system in steady state is analyzed theoretically.The total voltage and voltage difference of DC side capacitors of APF are analyzed, and an efficient voltage stabilizing and voltage equalizing control method is designed to meet the voltage stability of DC side capacitors under load switching.The method of raising DC bus voltage is analyzed and studied. A simple and practical soft starting method of DC bus voltage is designed to ensure that the DC capacitor voltage can rise smoothly to the pre-value during the start-up process.And the whole process has no overpressure, overcurrent phenomenon. 4.The relationship between APF power loss and DC bus voltage compensation and modulation ratio is analyzed.It is concluded that the fluctuation of voltage and the variation of load harmonics can be reflected by the maximum modulation ratio of three phases. A method of calculating the given value of DC bus voltage by the maximum modulation ratio of three phase is proposed.In order to achieve the APF compensation effect and power loss optimization.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN713.8;TM761

【参考文献】