Active power decoupling topology with fault tolerant ability for a single phase grid connected inverter

Bulk electrolytic capacitors are used in single phase inverters to reduce the ripple in dc link voltage which is due to the pulsating nature of the instantaneous power. The reliability of an inverter is limited by the lower lifetime of these capacitors. In addition, the switching devices also deteriorate the reliability, due to their significant failure rate. In order to improve the overall reliability of the inverter, a novel active power decoupling topology is proposed with fault tolerant ability. The proposed topology eliminates the need of bulk electrolytic capacitors by using an auxiliary circuit for active power decoupling. It ensures redundancy in achieving the active power decoupling in case of a switch failure. It is observed that the proposed topology can deliver 50% of the rated power along with ripple power compensation under fault tolerant operation. The operation and modulation strategy of the proposed topology are explained under normal and fault tolerant operations. Simulation studies validate the claims of the proposed topology.