Photovoltaic battery generates direct current,and inverter transforms direct current to alternating current by photovoltaic battery into electricity grid.Grid-connected inverter is a kind of interface device between photovoltaic battery and electricity grid,which plays a crucial role.As the developing of photovoltaic system,the grid inverter has got more and more attention.The technical requirements as starting point,the principle,topology structure and control policy of inverter were mainly illuminated,and...