Extendable Multi-Input High Step-up DC–DC Converter for Multi-Source Energy Systems

Abstract

Boosting the output voltage of the energy sources in a multi-energy system is often a key factor in ensuring energy source compatibility, improving transmission efficiency, enabling effective power conversion, supporting energy storage, and meeting grid or system standards. This paper proposes a multi-input, high step-up DC-DC converter capable of providing a regulated DC link while using different energy sources. Based on a specialized structure that employs coupled inductors and voltage multiplier cells, the converter offers an adjustable high voltage gain. A key advantage of the converter is its scalability, which allows for the integration of multiple inputs. The soft-switching operation enhances efficiency, thereby making it suitable for a wide range of applications. The current-fed structure ensures low input current ripple, making it particularly well-suited for renewable energy applications. Additionally, reduced current spikes on the switches extend their lifespan and allow for the use of more cost-effective components. The resonant operation of the primary sides of the coupled inductors mitigates reverse recovery issues in the output diode. The operating principle of the proposed converter is analyzed in detail, and losses in different components are studied. Design considerations for the components are provided, and the proposed converter is compared with similar designs to assess its advantages and disadvantages. The proposed multi-port converter is modeled, and its control system is designed. Finally, a 550 W prototype is implemented, and experimental results are presented.