基于全局比较的光伏电池MPPT实验研究

Experimental study of photovoltaic cell MPPT based on global comparison

当光伏电池被阴影遮挡时,最大功率对应电压会出现偏移,导致传统算法追踪过程显得繁复,为解决传统最大功率点追踪(maximum power point tracking,MPPT)算法在进行功率判断时所存在的判断速度以及准确性方面的问题,提出在扰动观察法基础上加入全局比较算法(global comparison algorithm,GCA),该算法通过检测光伏电池短时间内由开路至短路过程的功率变化来进行最大功率点追踪。根据光伏电池的伏安特性设计四种不同光照强度及阴影遮挡的环境,采用光伏实验平台以及DC-DC升压电路对算法可靠性进行实验研究。结果表明:全局比较算法的加入可以有效提升扰动观察法在不同程度阴影及不同光照强度条件下追踪最大功率的时效性及可靠性,且在一个遮挡周期内,发电效率可提升5%以上。

When the photovoltaic cell is shaded,the maximum power corresponding voltage will shift,which leads to the complicated tracking process of the traditional algorithm.In order to solve the speed and correctness problems of the power judgment of the traditional maximum power point tracking(MPPT)algorithm,the global comparison algorithm(GCA)was added based on the perturbation and observation method.The algorithm performed maximum power point tracking by detecting the power change of the photovoltaic cells from the open circuit to short circuit in a short time.According to the volt-ampere characteristics of photovoltaic cells,four different illumination intensity and shadow shading environments were designed,and the algorithm reliability was verified by photovoltaic experimental platform and the boost circuit of DC-DC converter.The results show that the global comparison algorithm can improve the effectiveness and reliability of the maximum power tracking under different shading and illumination intensity,and the power generation efficiency can increase by more than 5%in one shading period.