Quadratic flying-capacitor Boost Converter and comparative evaluation

The photovoltaic (PV) grid-connected power system in the residential applications is becoming a fast growing segment due to the shortage of the fossil fuel energy and the great environmental pollution. A new research trend in the residential generation system is to employ the PV parallel connected configuration rather than the series-connected configuration to satisfy the safety requirements and to make full use of the PV generated power. This paper mainly investigates and compares four dc-dc converters i.e. Conventional Boost Converter (CBC), Quadratic Boost Converter (QBC), Flying Capacitor Boost Converter (FCBC) and a new high step-up dc-dc converter in wide range power conversion from the aspects of silicon devices, passive components requirements, efficiency and cost. In the proposed topology a high voltage gain is achieved at relatively low duty ratio. Moreover, the stress on the power switches and the inductor size is reduced, which means the cost and the losses is minimized.