Short-Circuit Fault-Tolerant Topology for Multiport Cascaded DC/DC Converter in Photovoltaic Power Generation System

Abstract

A multiport dc/dc converter with cascaded submodules (SMs) can be employed in a photovoltaic (PV) power generation system for its high step-up ratio. Consisting of multiple low-voltage (LV) input ports and one high-voltage (HV) output port, the multiport converter is more likely to suffer short-circuit faults than a two-port converter. To ensure reliable operation of the converter, its short-circuit fault-tolerant capability should be necessarily considered. In this article, a short-circuit fault-tolerant topology for multiport cascaded dc/dc converter in the PV power generation system is proposed to satisfy the requirements of fault tolerance ability. When one or more short-circuit faults occur at LV ports, the proposed topology guarantees the normal operation of other fault-free SMs. When a short-circuit fault occurs at the HV port, the short-circuit fault current can be interrupted rapidly by the fault-tolerant topology, which protects the converter from a large current surge. The fault-tolerant ability of the proposed topology is verified by both simulation and experimental results.