改进的光伏发电系统最大功率点跟踪方法

光伏发电系统可采用最大功率点跟踪控制技术来提高输出功率,但常规变步长扰动观察法存在功率-电压特性曲线的低压区变步长跟踪效果差、步长灵敏度受光照强度影响大等缺点。从变步长算法和控制系统结构两方面提出了改进措施,并在利用MATLAB/Simulink工具建立的最大功率点跟踪系统仿真平台上与常规变步长扰动观察法进行了对比试验。试验结果表明,跟踪时间和跟踪步数分别减少了50%和75%,同时PID控制环节使光照强度快速变化时的跟踪电压偏差从48.3%降低到13.8%,明显地提高了系统的动态性能。

Improved Maximum Power Point Tracking Techniques in PV System

Maximum power point tracking(MPPT) techniques are employed in photovoltaic(PV) systems to maximize the PV array output power.Among all the MPPT strategies,the P&O maximum power point tracking algorithm is mostly used,due to its simplicity,less requirements in hardware,higher efficiency and so on.However,the step size can’t change in the left of the maximum power point(MPP) and its sensitivity is influenced greatly by light intensity using conventional variable step P&O algorithm.Two modified measures are proposed in algorithm and the system’s structure.And the modified measures were compared with the conventional in the simulation platform which is built by MATLAB/Simulink tool.The experimental results show that tracking time and tracking steps are reduced 50% and 75%,and the tracking voltage deviation is reduced from 48.3% to 13.8% when the illumination rapidly changed for the PID control,so the system’s dynamic performance is improved obviously.