光伏并网逆变器辨识建模方法及应用

发布时间：2018-01-06 08:39

本文关键词：光伏并网逆变器辨识建模方法及应用　出处：《重庆大学》2014年博士论文　论文类型：学位论文

更多相关文章：光伏 逆变器 系统辨识 NARX Wiener

【摘要】：能源危机和气候变化是当今全球面临的主要挑战之一。作为人类应对这些挑战的努力，太阳能光伏产业应运而生。光伏并网逆变器作为太阳能光伏电池阵列与公共电网的接口装置，是光伏并网发电系统中的核心部件，在新能源的开发利用中起到了至关重要的作用，对其进行研究具有重要意义。建立光伏并网逆变器的数学模型，，是一切研究工作的基础。目前由逆变器供应商提供的数学模型都是基于机理建模法，通过大量简化假设而得到的，使用方难以判断其准确性，要通过逐个产品的验证测试来修正其模型，这对于设备使用方来说具有极大的难度，制约了分布式电源接入电力系统的建模、仿真、控制方法、电能质量等方面的研究与设计，因此迫切需要提出新的分布式电源逆变器建模方法来满足新能源并网系统的理论分析与建设需求。针对光伏并网逆变器的建模问题，基于非线性系统辨识建模方法，较为深入地研究了不同光伏并网逆变器的建模问题，包括单相、三相光伏并网逆变器的辨识建模方法及三相光伏逆变器模型的系统仿真研究。论文提出了单相光伏并网逆变器NARX模型的系统辨识方法。针对商用光伏并网逆变器的“黑箱”特征，以及现有的线性化建模方法无法解决逆变器的强非线性问题，将单相光伏并网逆变器视为“黑箱”，无需逆变器内部电路、功率开关器件等拓扑结构和参数及其控制系统的类型和逻辑关系，仅仅利用逆变器输入-输出两侧的外部测量数据，基于NARX模型非线性系统辨识技术，可建立较为准确的数学模型，实现对商用光伏并网逆变器准确描述其动态特性的可能。辨识所得单相光伏并网逆变器NARX模型结构简单，运算量小，在模型的复杂性和模型的精确性方面取了很好的平衡，适用于电力系统对并网光伏发电系统的调度、联合运行与协调控制、随机模拟等需要快速建模与简单模型结构的研究领域。针对进一步提高辨识模型精度的问题，论文提出了基于Wiener模型的单相光伏并网逆变器模型辨识方法。方法基于非线性理论和离散时间方法，仍然将单相光伏并网逆变器视为“黑箱”，采集多时间阶段、不同典型光照条件下单相光伏并网逆变器的输入-输出信息，辨识出与“黑箱”特性等价的单相光伏并网逆变器Wiener模型。最后在相同实验条件下，对比分析了单相光伏并网逆变器Wiener模型与Hammerstein-Wiener模型以及本文第二章提出的NARX模型。结果表明，单相光伏并网逆变器Wiener模型及其辨识建模方法，能更好的反映实际单相光伏并网逆变器在不同天气条件下的动态行为，具有更高的精确度与适应性，但模型相对复杂，运算量较大。适用于需要精确使用光伏并网逆变器模型的场合。光伏并网模式有单相模式和三相模式。辨识建模方法用于三相逆变器时，输入、输出变量多，模型复杂，模型参数难以辨识。在单相光伏并网逆变器辨识建模方法的基础上，提出了适用于三相光伏并网逆变器的非线性系统辨识建模方法。为了简化三相逆变器的建模，对三相系统进行了简化处理。在输入端，选取输入电压电流作为输入量；在输出端，借鉴对称三相电路的分析方法，任选一相有功无功输出用于辨识，然后根据三相对称关系进行重建。将辨识模型简化为双输入双输出系统，降低了辨识难度，对三相系统简化后分别应用NARX模型和Wiener模型构建了三相光伏逆变器的建模方法。为了分析比较不同建模方法的优劣，建立了双级三相光伏并网发电仿真系统，在系统中对各种三相光伏并网逆变器模型(详细模型、NARX模型、Wiener模型)进行了仿真研究，优选了基于NARX模型的非线性系统辨识建模方法。所得模型结构简单、运算量小、模型精度较高，可作为三相光伏并网逆变器的辨识建模方法。
[Abstract]:The energy crisis and climate change is one of the major challenges facing the world today. As human efforts to address these challenges, the solar photovoltaic industry emerged. Photovoltaic inverter is an interface device of photovoltaic arrays and public power grid, is a core component of photovoltaic power generation system, the development and utilization of new energy has played a crucial role of research to have the important meaning. The establishment of mathematical model of grid connected photovoltaic inverters, is the foundation of all research work. The mathematical model of the inverter is provided by the supplier are based on the mechanism modeling method, and through a large number of simplifying assumptions, the use is difficult to determine its accuracy, to modify the model by one product this test, it is difficult for the equipment to use, restricting the DG power system construction The research and design of mode, simulation, control method, power quality and so on. Therefore, it is urgent to put forward a new distributed power inverter modeling method to meet the theoretical analysis and construction needs of the new energy grid connected system.
Aiming at the modeling problem of photovoltaic grid connected inverter, nonlinear system identification modeling method based on thoroughly study the modeling problem of different photovoltaic inverter including single-phase, research on system simulation modeling methods of the three-phase grid connected photovoltaic inverter and three-phase PV inverter model.
This paper presents the system identification method of single phase photovoltaic grid connected inverter. The NARX model for commercial photovoltaic inverter "black box" features, as well as the existing linear modeling method to solve nonlinear problem of inverter, the single-phase photovoltaic inverter as a "black box", without the internal circuit of the inverter, the type and logic relation of power switch devices such as topology and parameters and its control system, only the use of external data input - output inverter on both sides of the NARX model, nonlinear system identification technique based on the established mathematical model is quasi accurate, accurately describe the dynamic characteristics of the commercial photovoltaic inverter. The identification of the single-phase photovoltaic grid connected inverter NARX model has the advantages of simple structure and a small amount of computation, take a good balance in the accuracy of the model complexity and model, which is suitable for power system The research field of fast modeling and simple model structure is needed for the scheduling, joint operation and coordinated control, random simulation of the grid connected PV power generation system.
In order to improve the identification accuracy of the model, the proposed model identification method of single phase photovoltaic grid connected inverter based on the Wiener model. Based on the method of nonlinear theory and discrete time method, will still be single-phase photovoltaic inverter as a "black box", for a long time between the acquisition stage, different typical light input - output under the condition of single phase photovoltaic grid connected inverter information, identify the Wiener single-phase photovoltaic grid connected inverter model and the characteristics of the "black box" equivalent. Finally, under the same experimental conditions, comparative analysis of the model of single phase photovoltaic grid connected inverter NARX Wiener model and Hammerstein-Wiener model and puts forward the second chapter of this paper. The results show that the single-phase photovoltaic grid connected inverter Wiener model and its modeling methods can be better reflect the actual single-phase photovoltaic grid connected inverter in different weather conditions, the dynamic behavior, has higher Accuracy and adaptability, but the model is relatively complex and the amount of operation is large. It is suitable for the situation where the model of photovoltaic grid connected inverter needs to be used accurately.
A single-phase photovoltaic grid connected mode mode and three-phase model. Modeling methods for three-phase inverter, the input, output variables, complex model, model parameters are difficult to identify. Based on the inverter identification method of single phase photovoltaic grid connected on the proposed nonlinear system identification modeling method for three-phase PV grid connected inverter. In order to simplify the modeling of three-phase inverter the three-phase system was simplified. At the end of the input, select the input voltage and current as inputs; at the output reference analysis method of symmetrical three-phase circuit, choose a phase of active power and reactive power output for identification, then reconstructed based on the three-phase symmetrical relationship. The identification model is simplified as a double input and double output system, reduce the the identification difficulty of three-phase simplified system respectively using NARX model and Wiener model to construct the modeling method of PV inverter.
In order to compare the different methods of modeling and analysis of advantages and disadvantages, established a two-stage three-phase photovoltaic grid connected power generation simulation system, in the system of three-phase grid connected photovoltaic inverter model (with model, NARX model, Wiener model) simulation, optimization of nonlinear system identification modeling method based on NARX model. The model has the advantages of simple structure, operation small, the model is of high precision, can be used as the identification method of the three-phase grid connected photovoltaic inverter.

【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM464;TM615

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