一种改进型扰动观察法在最大功率点跟踪中的应用

摘要

In order to improve the output efficiency of PV generation system, an effective maximum power point tracking method of PV array is necessary.And the perturbation and observation (P & O) method is most widely used due to its simplicity and ease of implementation.But there is oscillation around the maximum power point caused by P & O, so this paper proposes an improved variable step size perturbation and observation (P & O) method.The method introduced power P in step change trigger conditions and step form.Variable step regional changed little when the external environment occurred a substantial change, so MPPT can keep the good dynamic and steady state accuracy under different external conditions.It improved the problem that traditional variable step size P & O method can't take into account dynamic and steady state accuracy when the external environment occurs a substantial change.Compared before and after the improvement of the two methods in the simulation and experiment, the results show that the improved variable step size P & O method is correct and effective.%光伏发电系统中,为了提高发电效率,必须采用最大功率点跟踪方法,其中扰动观察法因其算法简单、容易实现,对参数检测精度要求不高等优点,而被广泛应用.但是传统扰动观察法在最大功率点处存在功率波动,针对这一问题,提出一种改进型变步长扰动观察法.该方法在步长的选择方式和步长形式中引入功率P,在外界环境变化较大时,变步长区域变化小,在不同外界条件下都可以保持较好的最大功率点动态跟踪特性和稳态精度,改善了传统的变步长扰动观察法在外界环境变化较大时,动态特性和稳态精度不能兼顾的问题.通过仿真和实验对比了改进前后两种方法的动、静态特性,验证了该方法的正确性和有效性.