APF的无谐波检测改进控制研究

发布时间：2018-04-29 00:37

本文选题：无谐波检测控制 + 级联延迟信号对消　；参考：《太原理工大学》2017年硕士论文

【摘要】：本文研究内容是山西省煤基重点科技攻关项目“大规模间歇式新能源并网技术开发”(MD2014-06)中的子课题,针对的是新能源微电网中的电能质量问题。有源电力滤波器(active power filter,APF)是电能质量治理的重要装置,其控制方法有谐波检测法和无谐波检测法两大类。其中无谐波检测法的控制系统结构简单、计算量小,因此有更好的实时性,便于工程实现。但在实际工况运行中发现,在现有的无谐波检测控制法下,APF直流侧电压随负载变化波动严重,这不仅减小了直流电压利用率而且会降低APF运行的稳定性,严重影响了APF的补偿效果。为此,本文通过分析在无谐波检测控制法下APF的功率转换过程及控制模型和算法,提出了应用于APF系统的静止坐标系下网侧有功正序电流前馈控制策略,依次通过仿真和实验对所提出的控制策略及算法进行了验证。功率流动机理和数学模型的建立是控制系统设计的基础。本文首先从APF状态空间方程的小信号模型出发,对传统无谐波检测控制法的功率变换关系进行了分析,对APF直流电压波动的产生机理和交直流功率变换的原理进行了详细的解释。基于对电压-电流双环控制机理的分析结果,认为控制中应将APF视为负载的一部分,以网侧电能质量为控制目标,在传统无谐波检测法的基础上加入网侧电流前馈算法,以减小APF的动态损耗,加快调整过程。在前馈信号产生环节的设计中,首先分析了前馈信号的特点和需求,据此设计了级联延迟信号对消(cascaded delayed signal cancellation,CDSC)滤波器和电流逼近算法:一方面,基于有限长单位冲激响应(finite impulse response,FIR)滤波器设计原理和延迟信号对消(DSC)滤波器设计思想,再结合对CDSC滤波效果的分析,指出CDSC在应用于非对称负载的情况下存在的设计问题,并通过CDSC的频谱特性分析提出了解决方案;另一方面,结合无谐波检测法下APF控制的网侧电流的功率因数变化特点,提出以一种新的逼近算法代替瞬时无功的计算,不仅简化了计算过程,同时也加快动态调整过程。本文提出的网侧电流前馈控制算法可以降低APF系统的损耗,提高直流电压的稳定性,并优化了负荷动态波动过程中的补偿效果,减小了APF补偿后的不平衡度。合理的电流环参数是整个APF补偿优化和系统稳定运行的先决条件。本文在传统电压-电流双环控制基础上,针对比例谐振控制器的特点和实际离散算法的要求,设计了准比例谐振控制在静止坐标系下的简化实现方法,实现了APF的精确补偿和系统快速响应。然后结合电压环、电流环的动态性能及电流矢量变化过程,分析了CDSC滤波和网侧电流逼近算法对动态调整过程的影响。最后分析了改进算法在三相四线制系统的应用。仿真和实验结果均表明,本文提出的改进的无谐波检测控制方案提高了APF的动态响应特性,有效抑制了直流电压的波动,明显改善了APF系统的运行稳定性和补偿效果。
[Abstract]:The research content is a sub topic of the key scientific and technological research project of Shanxi Province, "large-scale intermittent new energy grid technology development" (MD2014-06), aiming at the power quality problem in the new energy micro grid. Active power filter (active power filter, APF) is an important device for the power quality control, and its control method is harmonic. There are two kinds of wave detection method and non harmonic detection method, of which the control system without harmonic detection is simple in structure and small in calculation. Therefore, it has better real-time performance and is convenient for engineering implementation. But it is found in the actual operating conditions that under the existing non harmonic detection and control method, the APF DC side voltage fluctuates seriously with the load, which not only reduces the DC voltage. The voltage utilization can reduce the stability of APF operation and seriously affect the compensation effect of APF. By analyzing the power conversion process and the control model and algorithm of APF under the non harmonic detection and control method, this paper proposes a positive sequence current feedforward control strategy for the network side under the stationary coordinate system of the APF system, which is in turn through simulation. The power flow mechanism and the mathematical model are the basis of the control system design. Starting from the small signal model of the APF state space equation, the power transformation relationship of the traditional non harmonic detection control method is analyzed, and the generation of the APF DC voltage fluctuation is produced. The mechanism and the principle of AC and DC power conversion are explained in detail. Based on the analysis of the mechanism of voltage and current double loop control, it is considered that the APF should be regarded as a part of the load, and the network side electric energy quality is the control target, and the network side current feedforward algorithm is added to the traditional non harmonic detection method to reduce the dynamics of the APF. In the design of the feedforward signal production link, the characteristics and requirements of the feedforward signal are analyzed first, and the cascaded delay signal cancellation (cascaded delayed signal cancellation, CDSC) filter and the current approximation algorithm are designed, on the one hand, based on the finite unit impulse response (finite impulse response, FIR) The design principle of filter design and the design idea of delayed signal cancellation (DSC) filter and the analysis of the effect of CDSC filter, point out the design problem of CDSC in the case of asymmetric load, and propose a solution through the spectrum characteristic analysis of CDSC; on the other hand, the network side current under the APF control under the non harmonic detection method is combined with the non harmonic detection method. A new approximation algorithm is proposed to replace the instantaneous reactive power calculation, which not only simplifies the calculation process, but also speeds up the dynamic adjustment process. The network side current feedforward control algorithm proposed in this paper can reduce the loss of the APF system, improve the stability of the DC voltage, and optimize the dynamic load fluctuation process. The compensation effect reduces the imbalance degree after APF compensation. Reasonable current loop parameters are the prerequisite for the whole APF compensation optimization and the system stable operation. Based on the traditional voltage and current double loop control, this paper designed the quasi proportional resonance control in static sitting in view of the characteristics of the proportional resonant controller and the requirement of the actual discrete algorithm. The simplified realization method under the standard system realizes the precise compensation of APF and the rapid response of the system. Then the dynamic performance and current vector change process of the voltage loop, the current loop are combined, and the influence of the CDSC filtering and the network side current approximation algorithm on the dynamic adjustment process is analyzed. Finally, the application of the modified algorithm in the three-phase four wire system is analyzed. The experimental results show that the improved non harmonic detection and control scheme proposed in this paper improves the dynamic response characteristic of APF, effectively restraining the fluctuation of DC voltage, and obviously improving the operation stability and compensation effect of the APF system.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM761;TM935

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