基于变步长电导增量法的光伏MPPT控制研究

Research on Photovoltaic MPPT Control Based on Variable Step Conductance Increment Method

光伏电池在不同的光照强度和环境温度下具有多个峰值状态,为保证光伏电池在外界环境条件发生变化时输出最大功率,利用其P-U特性曲线,对电导增量算法进行步长优化,并利用与电流相关的系数对动态步长进行修正。采用P-U特性曲线的斜率作为动态步长,在远离最大功率点处其斜率较大,利用较大步长实现快速跟踪;在靠近最大功率点处其斜率较小,利用较小步长减小系统的稳态振荡。为验证改进的变步长电导增量法的有效性,在Matlab/Simulink中搭建仿真模型,并与传统的控制算法进行对比,结果表明,该算法能够快速准确地追踪到光伏电池的最大功率点,并且降低系统在最大功率点处的振荡幅度。

Photovoltaic cells have multiple peak states under different light intensity and ambient temperature.In order to ensure that the photovoltaic cells output the maximum power when the external environmental conditions change,the P-U characteristic curve is used to optimize the step size of the conductance increment algorithm,and the dynamic step size is modified by using the current-related coefficients.The slope of the P-U characteristic curve is adopted as the dynamic step size.The slope of the P-U curve is larger far away from the maximum power point,so that the fast tracking can be achieved with a larger step length.The slope of the P-U curve is smaller near the maximum power point,so that the steady-state oscillation of the system can be reduced with a smaller length.In order to verify the effectiveness of the improved variable step conductance increment method,a simulation model is built in Matlab/Simulink and compared with the traditional control algorithm.The results show that the algorithm can quickly and accurately track to the maximum power point of the photovoltaic cell and reduce the oscillation amplitude of the system at the maximum power point.