基于二分法的变步长扰动观测MPPT算法

P&O MPPT algorithm with variable step size based on dichotomy

在光伏系统中基于扰动观测(P&O)的最大功率点追踪(MPPT)算法存在一些内在的问题,包括:在最大功率点附近存在振荡,较大的扰动步长以增加振荡的代价来加快跟踪速度,较小的扰动步长以增加跟踪时间为代价来减少振荡,光照缓慢变化时候跟踪效率低。针对以上问题,提出了一种基于二分法的变步长扰动观测算法,该算法初始时设置一个较大的扰动步长,随后步长多次减半直到追踪到最大功率点为止。使用仿真对提出的算法进行了验证,并与多种MPPT算法进行了对比。结果表明,提出的算法具有效率高、速度快、振荡少的优点,并且在光照缓慢变化时能够快速跟踪到最大功率点。

The perturbation and observation(P&O)algorithm is one of the most commonly used maximum power point tracking(MPPT)methods for photovoltaic(PV)system.However,it has some inner problems,such as oscillation near the maximum power point,increasing speed with larger disturbance step size at the cost of more oscillation,decreasing oscillation with small step size at the cost of increasing searching period,not suitable for slowly changing irradiation.In order to solve those problems,a variable step size P&O MPPT algorithm based on dichotomy was proposed,beginning with large perturbation step size and frequently decreasing the step size to half until tracking the MPP.In order to prove the better performance,the proposed algorithm was compared with different MPPT algorithms.The simulation results show that the proposed algorithm has the advantages of high efficiency,high speed and less oscillation and performs well when the solar irradiation slowly changes.