一种光伏发电系统变步长MPPT控制策略研究

Research on Variable Step MPPT Strategy for Photovoltaic System

为了提高光伏器件的发电效率,提出一种变扰动步长的最大功率点跟踪算法,根据光伏组件输出P-U特性曲线上各点斜率的绝对值确定最大功率点跟踪的扰动步长,使搜索的快速性和稳定性同时增强。Matlab仿真验证结果表明:该算法能够实时对光伏组件输出功率进行跟踪调节,大大提高光伏系统跟踪最大输出功率速度的同时,有效降低系统输出功率在最大功率点处的振荡现象,减小光伏组件的能量损耗。系统实现简单,易于推广应用。

For improving the efficiency on power generation of photovoltaic（PV） device,a variable perturb step method was proposed which uses the absolute value of P-U characteristic curve′s points slope of PV device output to determine the variable perturb step and can enhance the search speed and stability at the same time.The Matlab simulation results show that this method can be effective to adjust PV output power in real time.It can greatly improve the tracking speed and reduce the oscillation around the maximum power point（MPP） to lower the engery lost of PV device.This system is simple and easy to promote and use.