An Efficient Fault Tolerant Cascaded Step-Up Step-Down Converter for Solar PV Modules

Renewable energy sources become an increasing alternative power source. Among the available energy sources, Photovoltaic (PV) has a remarkable growth and a significant penetration in many applications. PV-based power supplies are managed by switching power converters and the connected activities will halt when power supply fails. In this paper, we propose an original fault tolerant cascaded step-up step-down converter circuit, under transistor fault. Both open-circuit fault (OCF) and short-circuit fault (SCF) of transistors are considered. The fault tolerant operation of the proposed circuit is based on the following elements: fault tolerant cascaded step-up step-down circuit, transistor fault diagnosis and suitable reconfigurable control. The originality of the proposed fault tolerant circuit lays on implementing a global reconfiguration for the two-cascaded stages, based on a single synchronous redundant transistor. Moreover, the fault detection is based on the waveforms of the inductance currents. An efficient reconfigurable control with fast post-fault management is also proposed. Some selected simulation results are provided to validate the effectiveness of the fault tolerant operation.