The Design And Research Of The Countercurrent Preventing Device

With the continuous improvement of photovoltaic technology, solar photovoltaic system to form a complete set of electrical components with higher requirements are put forward. When the photovoltaic power generation system (especially non countercurrent photovoltaic grid connected power system) generated electric energy into the public grid, easy to cause the impact on the public power grid, and even lead to a serious decline in the quality of public power.So according to the national standard Q/GDW480-2010 for this kind of photovoltaic power generation system must be matched with anti reflux facilities, to prevent the "upstream" into the public grid. Therefore, the use of Backflow prevention device and intelligent design become more important.Based on the analysis of non reflux photovoltaic grid connected power system characteristics, this paper analyzed and compared the characteristics of many kinds of AC sampling algorithm, considering the needs of intelligent photovoltaic countercurrent preventing device, select the FFT algorithm as the sampling algorithm. The chip of LPC1114 is taken as the CPU of the controller, and countercurrent preventing device mainly comprises a current and voltage sampling circuit, Module power circuit, Remote signal input circuit, Remote control output circuit, clock circuit, keyboard and display circuit etc.. The device realizes the monitoring, protection of inverse power phenomenon of photovoltaic power generation system.This paper for the countercurrent preventing device hardware design and the key to the comparative analysis of AC sampling algorithm finally through a lot of experiments,to verify the feasibility of the device.