Abstract: In a photovoltaic DC collection system, the application of parallel large-capacity electrolytic capacitors is able to suppress the low-frequency voltage ripples on the DC bus voltage. However, when a short circuit occurs on the DC bus, large-capacity DC bus capacitors dramatically discharge, which will introduce a large short circuit current, exposing the control and protection of the system in a extreme case. In order to reduce the electrolytic capacitors on the DC bus side and limit the short-circuit current under inter-pole short-circuit conditions, this paper proposes that the switched-capacitor topology is applied in a photovoltaic DC collection system based on a Buck-Boost circuit. A flexible adjustable control strategy has also been designed for the equivalent capacitance value based on this topology. The research results show that this topology and control method can be employed to effectively suppress voltage ripples, reduce the use of electrolytic capacitors, and realize electroless capacitance of the system. Under the short circuit condition, this scheme can be adopted effectively reduce the short circuit current and improve the control and protection characteristics of the system. Finally, the effectiveness of the proposed topology and control strategy is verified by the MATLAB/Simulink simulation model.