The output power of single-phase PV inverter is AC and the input power is DC，so there exists fluctuations in the power transmission. Generally, the fluctuations can be removed by using coupling capacitors. However, the voltage fluctuations of coupling capacitors will result in corresponding input power fluctuations, and will affect the maximum power tracking of the system. In this paper, the power transfer process is analysised, and a theoretical derivation to voltage fluctuations of the generatrix capacitor and the impact on the input currents is designed.The corresponding correction control algorithm of subdivision control is developed according to its characteristics. The feasibility of the solution is verified by the 3KW experimental prototype.