一种适用于单峰光伏曲线的MPPT方法

摘要

针对传统单峰光伏曲线MPPT方法跟踪速度慢,寻优精度不高的问题,提出了一种基于抛物线预测的功率闭环最大功率跟踪(MPPT)方法.该方法通过用光伏特性曲线上的3个点来拟合一个二次函数,用函数驻点的实际功率值来迭代地预测和修正最大功率点(MPP)的位置,最终使得光伏系统工作在最大功率点.此外,针对光伏系统采用合理的初始点选取策略,提升了MPPT的速度.给出了光伏系统的MPPT控制框图,搭建了基于Buck-Boost电路的直流光伏系统硬件平台.使用抛物线预测法进行了光伏电池组件的最大功率跟踪,与变步长扰动观察法MPPT结果进行了比较,验证了该方法的可行性和实用性.研究结果表明:这种基于抛物线预测的单峰值MPPT方法具有跟踪速度快,稳态无振荡的优良性能.%Aiming at the problem that traditional single-peak PV curve MPPT method has low tracking speed and low precision, a para-curve predictive power close-loop maximum power point tracking ( MPPT) method was proposed. By quadratic fitting, the actual power value at the stationary point of the fitting function was considered to predict and revise the position of maximum power point, making PV system work on the maximum power point. Initial points were chosen reasonably to speed up MPPT. Schematics of photovoltaic control system with MPPT were presented, and the hardware platform of DC photovoltaic system based on Buck-Boost circuit was built. The algorithm proposed was im-plemented in experimental prototype and compared with variable-step perturbation and observation method, which proved the feasibility and effectiveness of the scheme. The results indicate that the single-peak MPPT scheme proposed has good performance with high tracking speed and favorable stability.