A High Step Up Multi-Input DC/DC SEPIC-Based Converter with Coupled Inductor for Renewable Applications

Abstract

To overcome low output voltage of renewable energy sources such as photovoltaic arrays and fuel cells, a high step up SEPIC-based multi-input converter with dual coupled inductor is proposed. A new structure is presented in this paper, as an improved structure. This converter is based on combination of modified quadratic buck-boost converter, Dickson switched capacitor (DSC), and voltage multiplier modules (VMM). The high voltage gain can be achieved by adjusting the duty cycle and turn ratio of coupled inductor of VMM. This structure inherits all the advantages of the SEPIC converter such as step-up/down capability without inverting the polarity of regulated output voltage and using a bidirectional input port (in which an energy storage system (ESS) can be connected), and several unidirectional input ports. The load power can be flexibly divided among various power sources. Due to the buck-boost characteristics of the presented converter, it is suitable to charge-discharge the ESS. A coupled inductor (CI) is used to couple energy from input to the output equipped with the VMM. The usage of the DSC technique also enables the converter to obtain an additional double voltage gain while reducing the voltage stress on switches. Simulation results verify the performance of the proposed converter and feasibility of the control strategy.