【作者】 周柯；

【导师】 罗安；

【作者基本信息】 湖南大学 ， 电气工程， 2007， 博士

【摘要】 谐波的危害已得到了人们越来越多的认识和重视。在电网谐波污染越来越严重、用户对电能质量要求越来越高的背景下,利用有源电力滤波器(APF)这种先进的动态补偿装置对谐波污染严重的厂矿企业配电网进行电能质量的综合治理必将会带来显著的经济效益和社会效益。本论文围绕厂矿企业变电站的谐波抑制和大容量无功补偿混合治理问题进行了深入的研究。以江西某铜箔厂110kV变电站10kV配网的谐波治理和无功补偿问题为依托,提出了一种新型的大功率并联混合注入式有源电力滤波器HSHIAPF,着重讨论了其拓扑结构、工作原理、滤波性能、谐波检测、电流跟踪控制和综合设计等问题,并在理论研究基础上提出了基于HSHIAPF的谐波分析与治理一体化系统实现方案,最后在现场进行了HSHIAPF装置的投运,形成了较为完善的厂矿企业变电站谐波治理理论和技术方案,取得了令人满意的效果,为企业创造了良好的经济与社会效益。基于厂矿企业变电站的谐波治理背景,在HSHIAPF的设计过程中,将HSHIAPF的有源部分与基波串联谐振支路并联,再与注入支路串联形成一个整体,最后与单调谐无源滤波支路并联接入电网。由于基波串联谐振支路和注入支路的作用,有源部分承受的基波电压非常小,也几乎没有基波电流流入,其容量可以大大降低,适合于高压大容量系统的应用,初期投资也较小,其无源部分还可以承担一定的无功补偿任务。本论文同时还建立了HSHIAPF的控制原理方程,并选择了根据负载谐波电流来控制逆变器输出电压的控制策略。通过对HSHIAPF在负载谐波电流波动、电源谐波电压波动、电网阻抗波动以及电网频率波动这四种因素作用下的补偿特性和谐振抑制能力进行详细分析,证明了HSHIAPF具有很好的补偿性能。综合HSHIAPF对于谐波电流参考信号获取过程实时性、准确性的要求以及控制器部分需要谐波电流检测算法容易实现、计算量小的特点,本论文提出了一种基于离散傅立叶变换(DFT)的滑窗迭代电流检测算法。该算法利用将DFT看作一种FIR带通滤波器的思想,根据基波和谐波分次检测的需要,将FIR带通滤波器的中心频率设为相应的基波或谐波频率,采用长度为周期采样次数的滑动窗去迭代计算该带通滤波器的各项系数,不仅在基波电流和谐波电流突变的情况下能迅速、准确的求出其中的待检测成分,而且还能应用于单次谐波的快速分频检测。同时,该算法的软件实现十分方便,计算量很小,适用范围也较广,利用DSP和高速接口器件可以获得很高的检测精度,从而实现检测精度和动态响应速度的一致性。针对HSHIAPF的控制问题,本论文首先建立了HSHIAPF的系统模型。由于HSHIAPF的电压型逆变器在本质上是一个天然的变结构系统,因此在HSHIAPF的控制中应用滑模变结构控制有着非常明显的优势。同时,针对控制参考信号为周期量这一特征,采用递推积分PI控制算法可以实现对周期信号的无差跟踪。所以,结合传统滑模变结构控制算法快速性好和递推积分PI控制算法无稳态误差的优点,本论文提出了一种基于递推积分PI的离散滑模变结构控制算法,将递推积分PI控制算法计算出来的控制量作为滑模变结构控制率中的等效控制,使得控制器具有切换边带两侧以及边带内部的三种变化状态,既克服了滑模变结构控制有差调节、电流开关毛刺较大等不足,也避免了递推积分PI控制稳态到达时间较长的缺点,从而兼顾了动态性能和控制精度的统一,而且逆变器开关毛刺也易于被输出滤波器抑制。本论文从HSHIAPF的最佳滤波效果和最小经济成本两个角度出发,从主电路各组成部分的参数设计、设备选取、工程应用等方面对采用注入式结构的HSHIAPF进行了综合研究,构建了一整套完善的HSHIAPF优化设计方法,并以计算机仿真实验为基础,证明了HSHIAPF优化设计结果对于现场工况的可行性和有效性。为了更好的实现HSHIAPF的工程应用,本论文还提出了基于HSHIAPF的谐波分析与治理一体化系统的技术与实现方案,使得整个一体化系统不仅具有很强的动态谐波治理能力和大容量的无功静补能力,逆变器容量小,性价比高;同时还具备齐全的谐波分析、人机交互以及谐波信息集成和共享功能,能够为厂矿企业电力系统的运行、管理提供必要的、可靠的信息来源,也能为上级电力部门提供真实的电能质量数据,非常适合厂矿企业变电站谐波治理工程的应用需要。本论文最后研制了HSHIAPF工业应用装置,完成了整个一体化系统软、硬件和网络设备的调试,并在实地进行了投运,取得了良好的应用效果,在根本上实现了一个基于分层分布式结构的电网谐波监测、分析与治理综合系统,为推进大功率APF在我国的实用化进程提供了有益的参考和借鉴。更多还原

【Abstract】 Nowadays, people pay more attention to the harm of harmonic. However, the harmonic pollution in power grid is getting worse, and power quality requirement is becoming stricter by users. The advanced dynamic compensation device, APF(Active Power Filter), may reduce harmonic and synthetically control power quality in industrial enterprises, which will bring the remarkable economic and social benefit.This dissertation focused on the research of harmonic suppression and large-capacity reactive power compensation in industrial substations. According to the harmonic elimination project at the 10kV side of a 110kV substation in a JiangXi copper-foil enterprise, a novel HSHIAPF (High-capacity Shunt Hybrid Injection Type Active Power Filter) was proposed, and some key problems of HSHIAPF were emphatically discussed, such as topology structure, work principle, filter performance, harmonic detection algorithm, current tracking control algorithm and so on. Based on HSHIAPF, an integrated harmonic analysis and elimination scheme was realized. Finally, HSHIAPF was operated and obtained good results in the industrial field, which produced great economic and social benefit for the copper-foil enterprise.In the HSHIAPF structure, active part was firstly connected with a FSRC (Fundamental Series Resonant Circuit) in parallel, and then linked in series with an injection circuit, finally connected in parallel with passive power filters and injected into power grid directly. Because of the functions of FSRC and injection circuit, the active part’s fundamental-wave voltage and fundamental-wave current were very small, and even close to zero. Therefore, the topology structure of HSHIAPF was very suitable for harmonic suppression in high voltage and large capacity situations, and the initial investment was also small. Moreover, the passive part of HSHIAPF could also provide much reactive power. Meanwhile, the control equation of HSHIAPF was established in this dissertation. According to the theory, that the output of voltage source inverter would be determined by load harmonic current, a kind of basic control strategies was chose for HSHIAPF. Both theoretical analysis and simulation research have been done under the situations of load harmonic current fluctuation, power source harmonic voltage fluctuation, power grid impedance fluctuation, and power grid frequency fluctuation. All the results have shown that HSHIAPF can get perfect harmonic elimination effect.To satisfy the demands of the real-time detection and high precision of harmonic current reference signal, and the characters of easy realization and less calculation of harmonic current detection algorithm, a sliding-window and iterative harmonic current detection algorithm was proposed based on DFT (Discrete Fourier Transform). Regarding DFT as a type of FIR band-pass filters, the proposed algorithm set the corresponding fundamental-wave frequency or harmonic frequency as the FIR filter’s center frequency to meet the demands of current frequency-division detection. A sliding window was used to iteratively compute the FIR filter’s coefficients and the sliding window’s width equaled the sampling times in one power-grid cycle. Simulation results have proved that good detection effect can be obtained by the algorithm even under the abrupt changes of fundamental-wave current or harmonic current. In addition, each order of harmonic current could be detected quickly by extending the algorithm. The algorithm could not only decrease the detection calculation greatly, but also be directly applied in three-phase three-wire, three-phase four-wire and single-phase systems. Moreover, the algorithm was fit for software programming and could ensure the consistency of good detection precision and perfect response speed with DSP (Digital Signal Processor) and some high speed devices.The mathematical model of HSHIAPF was built in this dissertation. On the one hand, because the voltage source inverter of HSHIAPF was a natural variable structure system, it would bring extremely obvious advantages in fast control with discrete sliding-mode variable structure control algorithm. On the other hand, because control reference signal was a periodic parameter, it could eliminate system steady error well with recursive integral PI control algorithm. Combining the merits of above two algorithms, a novel compound control algorithm was proposed. In the proposed algorithm, the output of recursive integral PI control algorithm was introduced as an equivalent control of sliding-mode variable structure control algorithm. In this manner, there were three alterable controller conditions with three corresponding switching modes—inside a limit band and either outside of the limit band. Sliding-mode control law would be put into use when the tracking error of reference current was out of the limit band. In this way, the tracking error would be reduced rapidly. When the tracking error entered into the limit band, it would be diminished to zero by recursive integral PI control algorithm. Consequently, this novel controller could provide fast respond and high accuracy. In addition, the switching harmonic could be eliminated easily by the output filter.In order to obtain better filter performance and less investment, a whole set of optimal design methods has been established including the design of some important parameters in main circuit, the choice of some key components, application experience and so on. Based on these proposed design methods and simulation results, HSHIAPF had been testified its feasibility and validity for industrial applications. Furthermore, an advanced integrated system based on HSHIAPF was proposed to realize harmonic analysis and suppression better in the industrial field. The integrated system had forceful dynamic harmonic suppression abilities and large-capacity reactive power compensation abilities, however, the inverter’s capacity could be limited to a small range and the cost was also less. Besides, the integrated system had excellent harmonic analysis abilities, friendly human-machine interfaces and reliable harmonic-data share abilities. Therefore, it could not only provide enterprise managers with necessary information of industrial power-grid, but also send actual power quality data to some upper power departments. Finally, all the developing and debugging tasks have been finished, and the integrated system has been put into use in the industrial field. In essential, the integrated system was equivalent to a layered distributed system which gathered many functions together, such as harmonic watch, data analysis, harmonic suppression, and so on. Furthermore, these proposed design methods, software, hardware and network design ideas, and engineering experience of HSHIAPF would be very useful for large-capacity active power filters’ research and applications in china.更多还原