一种改进的光伏阵列最大功率点跟踪方法

针对光伏阵列最大功率点跟踪常用的控制方法即恒压法、扰动观察法、增加电导法存在的问题,提出了一种将恒压法和扰动观察法相结合的快速最大功率点跟踪控制方法。该方法采用恒压法获取光伏阵列最大功率点处的近似电压,然后根据光伏阵列的输出电压与该近似电压的差值确定扰动步长:如果差值较大,则表明光伏阵列工作点离最大功率点比较远,应采用较大的步长;如果差值较小,应采用较小的步长,从而减小功率振荡。仿真和实验结果表明,该方法不仅可快速跟踪光伏阵列的最大功率点,而且可有效减小功率振荡。

An Improved Method of MPPT of Photovoltaic Array

In view of problems existed in common control methods of constant voltage(method,) disturbance observation method and conductance adding method in MPPT of photovoltaic array,the paper proposed a fast MPPT control method which combines constant voltage method with disturbance observation method.The method uses constant voltage method to obtain approximate voltage of maximum power point of photovoltaic array,then according to difference between output voltage of photovoltaic array and the approximate voltage to determine disturbance step: if the difference is big,it indicates that working point of photovoltaic array is far from maximum power point,the bigger disturbance step need to be used;if the difference is small,the smaller disturbance step need to be used,so as to reduce power oscillation.The results of simulation and experiment showed that the method not only can track maximum power point of photovoltaic array rapidly,but also can reduce power oscillation effectively.