一种VWP分段模糊控制的光伏系统MPPT方法

当天气情况快速变化时,如何同时优化光伏(photovoltaic,PV)系统在最大功率跟踪(maximum power point tracking,MPPT)控制中的快速性、准确性和平稳性目前仍是一个难题.针对这一问题,提出了一种可变天气参数(variable weather parameter,VWP)分段模糊MPPT方法.该方法采用两条VWP直线将输出功率曲线分为三个跟踪区域,每个区域采用一个模糊控制器进行控制,其总体控制决策为:在控制量远离理想最大功率点(maximum power point,MPP)时采用大步长以确保跟踪的快速性,在控制量接近MPP时采用小步长以确保跟踪的准确性和平稳性.仿真实验证明,该控制方法比传统扰动观察法具有更好的快速性、准确性和平稳性.

A VWP-Section Fuzzy MPPT Method for PV Systems

It is difficult to simultaneously optimize the maximum power point tracking (MPPT) of the photovoltaic (PV) systems under the criteria of rapidity， accuracy and placidity， when the weather varies quickly. Aimed at solving this problem， a fuzzy MPPT method combined with variable weather parameters (VWP) is proposed. In this method， the power curve of the output signal is divided into three sections by the two VWP straight lines and each section has one fuzzy controller for tracking control. The overall control strategy is that a big tracking step-size is selected to ensure the MPPT rapidity when the control signal is far from its ideal value at maximum power point (MPP)， while a small tracking step-size is used to ensure the MPPT accuracy and placidity. Simulation experiments verify that the method proposed outperforms the conventional perturbation and observasion (P & O) method in rapidity， accuracy and placidity.