基于NARX模型的光伏并网逆变器非线性模型辨识方法

A Nonlinear Model Identification Method of Photovoltaic Grid-Connected Inverters Based on the NARX Model

摘要: 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。

Abstract: The system identification method of single-phase photovoltaic grid-connected inverter NARX model was proposed. For the black box feature of commercial photovoltaic grid-tied inverters, as well as the strongly nonlinear problem of the inverter which cannot be solved by existing linear modeling approach, in this method, the inverter was considered as a black box, wherein it was not necessary to know the topology and the parameters of the inverter internal circuits and power switching devices, as well as the type and logical relations of the control system. It only used the input-output external measurement data of the inverter, based on the NARX model nonlinear system identification techniques, to create an accurate mathematical model. The model can accurately imitate the behavior of the commercial inverter, and has simple structure and a small amount of computation. It takes a good balance between the complexity of the model and the model accuracy. It is suitable for power system with the grid-connected photovoltaic system scheduling, joint operation and coordinated control, and stochastic simulation research areas, in which the fast modeling and simple model structure are required.