光伏最大功率点跟踪变步长电导增量法的算法优化

根据光伏(photovoltaic,PV)系统输出电压-功率(U-P)曲线在最大功率点(maximum power point,MPP)两侧斜率变化的规律有所不同,MPP左侧曲线变化舒缓,右侧相对陡直的特点,在光伏最大功率点跟踪(maximum power point tracking,MPPT)控制方法的研究基础之上,结合现有一些变步长电导增量法,提出了一种在MPP左侧利用指数函数来调整跟踪电压步长;在MPP右侧利用对数函数来调整跟踪电压步长的分段式变步长电导增量优化算法。仿真实验结果表明该方法良好地实现了对光伏系统最大功率点的跟踪,有效地降低了跟踪过程中MPP附近由步长振荡引起的功率损耗,提高了PV系统的功率输出效率。

Algorithm Optimization of Variable Step-size Incremmental Conductance Method for Photovoltaic Maximum Power Point Tracking

According to the photovoltaic system output voltage curve in the change rule of the maximum power point on both sides of the different slope, the left slope of MPP changing smoothly, right relatively steeply, on the basis of maximum power point tracking control method research, and combined with the existing variable step-size incremental conductance method, this paper presents a optimization algorithm of the piecewise variable step-size incremental conductance method that a exponential function is used to adjust the tracking voltage step on the left side of the MPP, and a logarithmic function is used to adjust the tracking voltage step on the right side of the MPP. Simulation results show that this method is good for photovoltaic system maximum power point tracking, effectively reducing the power loss near the MPP caused by the oscillation of step-size in the tracking process, and improve the power output efficiency of PV system.