一种开路电压和短路电流相结合的MPPT算法研究

摘要

In order to effectively improve the max output power of photovoltaic power generation system, according to the output characteristics of PV and mathematical model, this paper proposes a new MPPT algorithm combining open circuit voltage and short circuit current, which uses open voltage, short circuit current and the S-function for MPPT. As the external environment constant changes will disturb frequently the PV system that introduces the algorithm, and the algorithm uses a lot of estimation algorithms in the process of theoretical derivation, thus threshold current and micro perturbation variable step length method are introduced in the algorithm. Current threshold reduces the disturbance of the system and energy losses. Micro perturbation variable step length method further corrects maximum power point of the system and solves the error problem brought by theory estimation. Experiments show that the open circuit voltage and short circuit current combined method after introducing the threshold current and micro step perturbation method can quickly and accurately track the maximum power point and improve the conversion efficiency.%为了能够有效地提高光伏发电系统的最大输出功率，根据光伏电池的输出特性和数学模型，提出了一种新型MPPT算法，即开路电压和短路电流相结合的MPPT算法。利用开路电压、短路电流和S-function函数快速解得最大功率点。针对不断变化的外界环境会给引入该算法的光伏系统带来频繁扰动，以及该算法在理论推导过程中采用了大量的估算算法，因此在该算法中引入阈值电流∆I和微变步长扰动法。阈值电流∆I降低了系统的扰动，减少能量的损失，微变步长扰动法进一步的修正了系统的最大功率点，解决了因理论估算而带来的误差问题。实验证明，引入了阈值电流和微变步长扰动法的开路电压和短路电流相结合的MPPT算法能快速、准确的跟踪最大功率点，提高转换效率。