Authors

Abstract

In order to enhance the utilization of solar energy in photo-voltaic greenhouse, this paper takes the optimization strategy of photo-voltaic array's maximum power point tracking algorithm as research object. According to the changing rule of the slope of photo-voltaic array's output P-U curve, this paper proposes a new variable-step conductance increment method to track the maximum power point. When the working point is located on the left side of maximum power point, the logarithmic function value of curve’s slope is adopted as the voltage step to adjust the position of working point. When the working point is located on the right side of maximum power point, the exponential function value of curve’s slope is adopted as the voltage step to adjust the position of working point. Through the MPPT modeling and simulation in MATLAB/Simulink and the corresponding circuit test, the result shows that comparing with the traditional variable-step conductance increment method, the proposed algorithm can find the maximum power point faster, and it can effectively reduce the power loss caused by step oscillation in the searching process, which achieves the goal of enhancing conversion efficiency of photo-voltaic power generation.

Abstract in English

为了提高光伏农业大棚对太阳能的利用率，本文对光伏阵列最大功率点跟踪算法的优化策略进行了深入研究。根据光伏阵列输出P-U曲线斜率的变化规律，文章提出一种新型的变步长电导增量法对MPP点进行追踪，当工作点位于MPP点左侧时，采用曲线斜率的对数函数值作为电压步长调整工作点的位置，当工作点位于MPP点右侧时，采用曲线斜率的指数函数值作为电压步长调整工作点的位置。通过在MATLAB/Simulink中进行MPPT建模与仿真，并对相应的电路进行测试，结果表明该算法相较于传统的变步长电导增量法，能够更快地寻找到MPP点，且有效降低了寻找过程中由步长振荡造成的功率损失，提高了光伏发电转换效率。