并联型NPC三电平有源电力滤波器关键技术研究

发布时间：2018-02-08 17:19

本文关键词： 有源电力滤波器 SVPWM调制策略 NPC三电平电流跟踪技术谐波　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

【摘要】：随着我国经济的快速发展和人民生活水平的日益提高,人们对于电能质量的要求越来越高,低压配电网的谐波污染问题也日益受到关注。有源电力滤波器(Active Power Filter,APF)作为一种高性能的谐波治理装置,能够快速、有效地抑制谐波和净化电网,为电力系统的安全运行和居民用电质量的提高提供了强有力的保障。中点箝位型(Neutral-Point Clamped,NPC)三电平APF因为其输出电流纹波小、直流母线电压利用率高、等效开关频率高等特点日益受到关注。本文以并联型NPC三电平APF为研究对象,针对三相三线制和三相四线制有源电力滤波器的调制策略、中点电位平衡算法、电流跟踪技术等关键技术展开了深入研究,取得了一定的研究成果。针对NPC三电平APF提出了一种简化的SVPWM(Space Vector Pulse Width Modulation)调制算法。与传统SVPWM调制算法相比,该简化算法无需进行复杂的扇区判断或者坐标平移,仅利用相参考电压瞬时值,通过端口电压伏秒平衡快速求取三相开关作用时间通解,进而获得PWM脉冲。为了达成线性调制下的调制度扩展、窄脉冲消除等目标,直接在通解的基础上求取特解,以满足不同的控制目标需求。该算法在拥有和传统SVPWM算法相同的直流母线电压利用率的同时,计算量大幅下降。针对三相三线制APF的中点电位不平衡问题,本文通过分析流过直流侧中点的电流与三相输出电流、上下母线电压偏差和三相作用时间的关系,提出了一种新颖的中点电位控制策略。该策略不用考虑正、反小矢量的选择问题,直接通过修正三相作用时间即可有效地抑制中点电位的偏移。而对于三相四线制APF,由于中线的存在,其中点电位偏移的机理与三相三线制APF存在较大差异。本文通过对中点电位偏移与各相电流大小、方向以及各器件开关状态关系的分析,引入了中点平衡因子的概念。通过分析三相开关状态P、O和N对于中点电位的影响,提出了一种新颖的中点电位控制方法。该方法结合中点平衡因子,将O状态作用时间拆分成P和N状态,增强了中点电位控制能力,从而实现了抑制中点电位偏移的目的。电流控制技术是APF的关键技术之一,决定了APF的补偿能力和补偿精度。本文在分析了多种电流控制技术的基础上,提出了一种新颖的电流控制技术。该技术引入有限控制集模型预测控制(Finite-Control-Set Model Predictive Control,FCS-MPC)策略中提出的价值函数(Cost Function)的思想,并与简化SVPWM调制算法相结合,通过优化价值函数从而实现快速、精确地跟踪谐波参考电流的控制目标。为了验证所提出的调制策略和控制方法,本文设计了一套APF实验平台。该实验平台采用NPC三电平拓扑结构,主控部分采用DSP+FPGA架构。最后,针对不同的谐波负载进行了相关实验。各种实验结果证明了本文所提出的调制算法和控制方法的正确性和有效性。
[Abstract]:With the rapid development of our economy and the improvement of living standards, people for higher power quality requirements more and harmonic pollution problems of low-voltage distribution network is also increasingly concerned. Active power filter (Active Power, Filter, APF) as a kind of harmonic control device, high performance can quickly and effectively suppress harmonic and clean power, provides a strong guarantee for the safe operation of power system and residents electricity quality. Neutral point clamped (Neutral-Point Clamped, NPC) APF three level because the output current ripple DC voltage utilization rate is high, the characteristics of higher equivalent switching frequency is getting more and more attention. Based on parallel NPC three level APF as the research object, aiming at the modulation strategy of three-phase three wire and three-phase four wire active power filter, neutral point potential balancing algorithm, the key technology of current tracking technology Carried out in-depth study, some achievements have been obtained. According to the three level NPC APF proposed a simplified SVPWM (Space Vector Pulse Width Modulation) modulation algorithm. Compared with the traditional SVPWM algorithm, the simplified algorithm requires no complicated sector judgment or coordinate translation, only by using the phase reference voltage instantaneous value, fast calculate the three-phase switching time solution through the port voltage second balance, so as to obtain a PWM pulse. In order to achieve linear modulation modulation, narrow pulse elimination, seeking solutions in directly based on general solutions, in order to meet the needs of different control objectives. At the same time the algorithm with the DC bus voltage and the traditional SVPWM algorithm has the same utilization rate, calculate the volume dropped significantly. The midpoint potential of three-phase three wire APF imbalance, through the analysis of current and three-phase DC side through the midpoint of the On the relationship between output current and bus voltage deviation and phase time, proposes a novel neutral point potential control strategy. This strategy is not considered, choice of anti phaselet, offset directly and effectively inhibit the midpoint by modifying the three-phase action time can be. But for the three-phase four wire APF, because the center line of the existence, the mechanism of point potential shift and three-phase three wire APF, there is a big difference. Based on the midpoint potential offset and the phase current size, the direction of the relationship and the analysis of state switching, introduces the concept of midpoint balance factor. Through the analysis of three-phase switching state of P, O and N for the point effect the potential of a novel neutral point potential control method. Combined with the method of neutral point balance factor, the O time split into P and N, enhanced the neutral point potential control ability, so as to realize the The inhibition of the deviation of neutral point voltage. The current control technology is one of the key technologies of APF, determine the compensation ability of the APF and compensation accuracy. Based on the analysis of the various current control technology, this paper presents a novel current control technology. The technology introduction of the finite control set of model predictive control (Finite-Control-Set Model Predictive Control FCS-MPC), the value function strategy proposed (Cost Function) theory, and combined with the simplified SVPWM modulation algorithm, by optimizing the value function so as to realize the rapid and accurate track control target harmonic reference current modulation strategy and control. In order to validate the proposed method, this paper designed a APF experiment platform. The experiment platform adopts NPC three level topology, the main control part adopts DSP+FPGA architecture. Finally, according to the different harmonic load experiments are conducted. The experimental The results show the correctness and effectiveness of the modulation and control methods proposed in this paper.

【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM761

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