Fault-tolerant topology of a grid-connected PV inverter coupled by a Scott transformer

A grid-connected photovoltaic(PV) power plant is mainly based on power electronics equipments which are considered as the most vulnerable parts in a PV system. In order to increase the reliability of modular grid-connected PV panel, a solution by using a Scott transformer is presented to reduce the number of switches and to continuously operate the PV system in case of switch-failures of the power converter. The three-phase type PV inverter is analyzed in the normal and fault-operation. The simulation has shown that fault tolerance can be achieved with the proposed system configuration to give a redundancy of power switches in an Integrated power electronic module. Index Terms-Power converter, Scott transformer, redundant components, fault-tolerant, grid-connected inverter, grid-tie, reference frame, Clarke transformation.