短路电流法与变步长扰动观察法结合的MPPT算法研究

摘要

针对小型家用光伏系统的特点,设计了一种有效的改进型最大功率点跟踪(MPPT)控制方法.当外界环境突变时,采用改进的短路电流法进行初步跟踪,调整光伏阵列的工作点到最大功率点附近.在此基础上再使用双阶段变步长扰动观察法,使得工作点进一步调节到最大功率点,并有效减少了光伏阵列输出功率在最大功率点的振荡.对该结合方法及相关的常用MPPT算法分别仿真,结果表明,该方法可以在外界环境剧烈变化下快速、有效、准确地跟踪最大功率点,同时有效减少在光伏阵列最大功率点附近振荡所带来的能量损失,提高了光伏发电系统的效率.%According to the characteristics of small home PV system,an effective improved MPPT method is presented.When the external environment rapidly changes,in order to regulate the PV array operating point near the maximum-power point quickly,the improved short-current method to track MPP is utilized at first,and then the two-level variable step P&O is adopted to adjust the PV array operating point to be at the maximum-power point.The simulation of the improved method and common methods show that,contrast to the latter,the former can trace the maximum-power point more quickly,efficiently and accurately,and also can reduce the energy loss caused by the oscillation of the operating point about the maximum-power point,thus enhancing the PV system efficiency.