基于变步长扰动观察法的MPPT仿真研究

MPPT Simulation Study Based on Variable Step Perturbation Observation Method

本文在Matlab/Simulink中搭建了MPPT的仿真模型并分析了最大功率跟踪的意义和方法。本文基于扰动观察法,针对步长选择难的问题提出了一种自动变步长的改进型扰动观察法。此方法结合固定大步长和小步长的优点,在外部条件变化时为大步长可以进行对最大功率的快速跟踪,接近最大功率点后自动变为小步长,可以减小震荡损耗。其中,由于功率变化率和本文希望的步长大小成正相关,所以本文采用实时功率的变化率的绝对值|d P/dt|作为自动变步长的参考参量。且为了减小线路中杂波对系统的影响,防止功率出现"尖峰",本文仿真的功率采样中增加了平均计算模块。最后将改进后的扰动观察算法封装成了模块形式,通过仿真验证了该方法在提高光伏发电效率方面具有可行性和有效性。

This paper set up the simulation model of MPPT in Matlab/Simulink and analyzed the significance and method of the maximum power tracking.Based on the perturbation observation method,it presented an improved perturbation observation method for step length selection.This method took the advantages of both long and small steps,which can quickly track the maximum power points when the external condition changed to long step,and automatically converted to small step to reduce the shaking loss when power point got very close to the maximum power points.Moreover,due to the positive correlation between the rate of power change and the step size,it used the absolute value of the current power|dP/dt|as the reference amount of the variable step length.In order to reduce the influence of clutter on the system and prevent the"sharp peak"of power,the average calculation module was added in the power sampling of the simulation.Finally,the improved perturbation observation algorithm was encapsulated into a modular form,which proved the feasibility and effectiveness of this method in improving the efficiency of photovoltaic power generation.