The photovoltaic (PV) DC boosting collection system with input-independent output-series (IIOS) type is prone to short-circuit fault on the DC side

which will seriously affect the stable operation of the collection system. In extreme cases

a large number of switching devices in the system may be damaged. In order to solve this problem

this paper proposes a new short-circuit fault-tolerant topology

which can ensure the normal operation of the collection system during low-voltage side short-circuit fault

and can quickly remove the fault current during medium-voltage side short-circuit fault. Compared with the existing schemes

the proposed topology significantly reduces the number of switching devices

reduces device stress

improve the fault tolerance of low-voltage side short-circuit fault

realizes the soft switching of some semiconductor devices

and effectively improves the operation efficiency and reliability of the collection system. In this paper

the working principle and control strategy of the proposed topology are analyzed in detail

and its effectiveness is verified by simulation and experiment.