改进扰动观察法的最大功率点跟踪简

针对传统的扰动观察法在光伏电池最大功率点难以兼顾响应速度和稳态性能的问题,文章提出一种改进的扰动观察法。该方法的特点是,当光伏阵列的输出电压UK与前一时刻测得的最大功率点电压Um之差的绝对值大于电压的修正值△U时,将此时的输出电压UK替换为Um值,再进入下一循环,直至符合条件,重新采用传统扰动观察法进行检测。这样能够缩短最大功率跟踪时间,并能提高系统在最大功率点附近的稳定性。在Matlab环境下,建立了光伏电池和最大功率点跟踪（MPPT）算法的仿真模型,分析了温度及光照度对光伏电池输出特性的影响;对光伏电池控制系统进行仿真,对比了传统的和改进的扰动观察法的最大功率点跟踪曲线。结果表明,采用改进的扰动观察法时,光伏电池能更快地到达最大功率点,并且获得了更好的稳定性。

Maximum Power Point Tracking Based on Improved Perturbation and Observation Method

For the conventional perturbation and observation method is difficult to take into account both the response speed and steady state performance at the maximum power point of photovoltaic cells, an improved perturbation and observation method is proposed in this paper. In this method, when the absolute value of the difference between the output voltage UK of PV arrays and the maximum power point voltage Um measured at the previous moment is greater than the voltage of the revised AU, the output voltage UK is replaced with U, and then enters the next cycle, until is qualified for conventional perturbation and observation method for testing. This can shorten the time of the maximum power point tracking and improve the stability of the system near the maximum power point. Simulation models of PV cells and MPPT were established in Matlab; the influence of temperature and strength of illumination on the characteristic of PV cells were analyzed. Through simulating PV cells control system, the simulation curve of the maximum power point tracking was compared based on the conventional and improved methods. The results show that the improved method can make the PV cells faster reach the maximum power point, and has a better stability.