Design and analysis of soft-switching isolated step-up/down DC–DC converter for fuel cell vehicles and EV battery charging applications

ABSTRACT

With the increasing adoption of non-conventional energy sources, there is a significant demand for DC energy conversion systems as they play a crucial role in integrating power sources and loads that operate at different voltage levels. In this paper, a novel DC–DC converter topology is presented, which can efficiently perform Buck-boost operation with minimal duty cycle operation, making it an attractive option for DC energy conversion applications. Furthermore, its switching voltage stress is less than the voltage present at the output, allowing the use of low power rated devices. Additionally, the topology contains isolation between the load and source, which prevents circulating currents and protects the source from load harmonics. The proposed converter has the ability to achieve soft switching without using any extra circuitry. Moreover, the presented converter is evaluated against recently developed topologies in terms of active/passive components, gain, efficiency, and switching stress. Closed-loop analysis is done for the proposed converter using small-signal modeling. The converter is tested by subjecting it to a sudden step change at the input voltage from 20 V to 40 V in boost condition while maintaining a constant output voltage of 240 V. Additionally, load disturbances are introduced to assess the system’s robustness in closed-loop operation. In the laboratory, A 100-W prototype of the presented converter is built, which gives an efficiency of 95% at the rated load condition.

KEYWORDS:

• DC–DC converters
• soft switching
• stability analysis
• non-conventional energy sources
• duty cycle

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Sai Harsha Naidu Marrapu

Sai Harsha Naidu Marrapu earned a Bachelor of Technology from Acharya Nagarjuna University, Guntur, in 2019 and a Master of Technology from the National Institute of Technology, Raipur, in 2021. He is pursuing a PhD in the Department of Electrical and Electronics Engineering at the National Institute of Technology Tiruchirappalli. His research interests include Power Electronic Converters, Electric Vehicle Charging Stations, Active Power Decoupling, and PFC Converters.

Josephine Rathinadurai Louis

Josephine Rathinadurai Louis was born in Coimbatore, India, in 1984. She earned her Bachelor of Engineering degree from Anna University, Chennai, followed by a Master of Technology in Power Electronics from the National Institute of Technology, Trichy. She then completed her PhD in Electrical and Electronics Engineering at the Coimbatore Institute of Technology (CIT), affiliated with Anna University, Chennai. Previously, she worked in the Department of Instrumentation and Control Engineering at PSG College of Technology, Coimbatore. She is currently a faculty member in the Department of Electrical and Electronics Engineering at the National Institute of Technology, Trichy. Her research interests include Power Electronics and Drives, Electric Vehicles and Charging Stations, and Power Electronic Applications in Renewable Energy Systems. She has published extensively in both international and national journals and has presented at numerous international and national conferences.