改进的光伏MPPT算法及含光伏电源的综合负荷建模

发布时间：2018-04-15 05:13

本文选题：分布式电源 + 光伏电池　；参考：《郑州大学》2017年硕士论文

【摘要】：电力系统仿真计算是分析电力系统行为的基本依据和主要方法,而电力负荷的数学模型是搭建仿真的基础。随着分布式电源在电力系统配电网中的不断渗入,其对电力系统的影响也越来越严重,使得传统配电网的结构更加复杂,也给配电网综合负荷建模提出新的问题以及挑战。分布式发电因能量来源的不同包含光伏、风力、燃料电池发电等多种类型,将其大量接入配电网时,因不同类型分布式电源发电机理和特性的不同,对负荷模型的影响也各有差异。其中,光伏发电能源来自太阳光,是目前最具潜力的可再生能源产业之一,本文在分析电力系统传统负荷模型的基础上,描述光伏电池发电原理,构建光伏电池数学模型。其输出特性表明在外部环境条件一定时,光伏电池输出功率有一个唯一的最大值,为了使光伏电池的输出功率达到最大化并保持,就需要对其最大功率点进行跟踪。本文通过分析光伏电池输出功率和PWM控制中占空比之间的关系,提出一种基于PWM控制的牛顿插值最大功率点跟踪(MPPT)算法,明确输出功率的变化是基于占空比的改变而产生的,用占空比扰动替换传统的电压扰动,以达到跟踪最大功率点的目标。通过在MATLAB/Simulink中的仿真验证,并与传统扰动观测法仿真结果对比,证明改进算法可以最大限度地避免传统MPPT算法因在最大功率点周围振荡而产生能量损耗的问题,且能够快速地实现跟踪目标,可作为光伏并网系统的MPPT控制模块。为研究含光伏电源的配电网广义综合负荷模型,本文在光伏电池模型结构基础上搭建其并网仿真模型,并将其接入四节点配电网系统。因该系统的综合负荷包含感应电动机、光伏电源和静态负荷三种类型,其机理过程各不相同,故选择二阶差分方程的非机理模型结构作为综合负荷的初始模型结构,并分别用最小二乘法和粒子群算法辨识模型参数,且后者的辨识结果优于前者。将其结果与MATLAB系统辨识工具箱的辨识结果相比,虽然拟合误差略高,但也能够有效地描述含光伏电源的配电网综合负荷,且其模型结构简单易于表达与辨识,更适用于系统仿真分析。
[Abstract]:Power system simulation is the basis for the analysis of power system behavior and main method, and the mathematical model of power load is established. The simulation with the penetration of distributed power in the power system in the distribution network, and its impact on power system is more and more serious, which makes the structure of the traditional distribution network is more complex, also put forward a new the problems and challenges to the distribution network comprehensive load modeling. Because of the different distributed generation energy sources include photovoltaic, wind power generation, fuel cell and other types, the large number of access to distribution network, because of the different type of distributed power generation mechanism and the different characteristics had different influence on the different load model. Among them, PV energy from the sun, is currently the most potential renewable energy industries, based on the analysis of the traditional load model of power system, the photovoltaic cell The generation principle, construct the mathematic model of photovoltaic cell. Its output characteristics show that in certain external environment condition, the output power of photovoltaic cells has a maximum value only, in order to make the output power of the photovoltaic cells to maximize and maintain, you need to track the maximum power point. Through the analysis of the relationship between accounting duty ratio. The output power of photovoltaic cells and PWM control, proposed a Newton interpolation of maximum power point tracking based on PWM control (MPPT) algorithm, a clear change of output power is generated based on the change of the duty cycle, with duty cycle perturbation to replace the traditional voltage disturbance, in order to achieve the maximum power point tracking by target. The simulation in MATLAB/Simulink, and the disturbance observation method and traditional simulation results, proves that the improved algorithm can avoid the maximum of traditional MPPT algorithm for maximum power point around oscillation The energy loss problem, and can quickly achieve the target tracking, can be used as the grid connected photovoltaic system MPPT control module for distribution network generalized composite load model of photovoltaic power, based on the structural basis of photovoltaic cell model and built the simulation model of grid connection, and access to the four node distribution network system. Because of the comprehensive load the system includes induction motor, photovoltaic power and static load of three types, the mechanism of the process is different, so the choice of non mechanism model structure two order differential equation as the initial structure of the comprehensive load model, and respectively using the least squares method and particle swarm algorithm to identify the model parameters, and the identification results are better than the former. The results of identification and system identification toolbox in MATLAB and compared with the results, although the fitting error is slightly higher in the distribution network but also can effectively describe with photovoltaic power and load, And its model structure is simple and easy to express and identify, and it is more suitable for system simulation analysis.

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM615;TM743

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