A New SEPIC-Based Step-Up DC-DC Converter With Wide Conversion Ratio for Fuel Cell Vehicles: Analysis and Design

In this article, a new single-ended primary-inductor converter (SEPIC)-based step-up dc-dc converter which integrates discontinuous-current quasi-Z-source (qZS) and switched-capacitor networks is proposed. The proposed converter has a low input current ripple, wide voltage gain range, low voltage stress on the semiconductor devices, and a constant potential difference between the grounds of its input and output ports. These features make the proposed converter an excellent interface between the fuel cell and the dc-link bus inside the electric vehicle. The analysis of the proposed converter for steady-state operations in continuous conduction mode and discontinuous conduction mode are given. Finally, a 3-kW/800-V scaled-down prototype was built using a gallium nitride power switch and silicon carbide diodes to validate the feasibility of the proposed converter and its theoretical analysis.

Automated summary

A new single-ended primary-inductor converter (SEPIC)-based step-up dc-dc converter is proposed, which integrates discontinuous-current quasi-Z-source (qZS) and switched-capacitor networks. The converter has low input current ripple, wide voltage gain range, and a constant potential difference between the grounds of its input and output ports, making it suitable for interface between fuel cells and DC-link buses in electric vehicles. Analysis for steady-state operations and a scaled-down prototype were conducted to validate the feasibility of the converter.