Naturally Commutated Bidirectional Half-Bridge High Efficient DC/DC Converter for Biomedical Imaging Systems

Deepak Kumar Nayak¹, R. Murugan¹, K. Selvakumarasamy¹, S. Rama Reddy¹, S. Sheik Aalam²  

¹Department of ECE, Aalim Muhammed Salegh College of Engineering, Muthapudupet, Avadi, IAF, Chennai-600055, India. ²Department of EEE, Jerusalem college of Engineering, Centre for collaborative research with Anna University, Pallikaranai, Chennai-600100, India.

Abstract: DC/DC Converters play a vital role in biomedical imaging systems such as x-ray, ultra sound and Magnetic Resonance Imaging systems. These applications require low ripple voltage waveforms, low voltage spikes and variable output voltages. This paper presents a naturally clamped bidirectional secondary modulation based zero current switching (ZCS) current fed half-bridge DC/DC converter for biomedical imaging systems. The proposed bidirectional converter achieves zero current switching (ZCS) of the main switches at the primary side and zero voltage switching (ZVS) of the rectifier switches at the secondary side. In the proposed converter, the secondary modulation clamps the voltage across the main switches in the primary side naturally, so that voltage spike at the switch turn-off is not seen. The operation of the proposed converter is explained, analyzed, and the performance of the converter is implemented in MATLAB for a model of 20 kHz switching frequency and 20 W output power.

Keywords: Voltage fed inverter; current fed inverter; zero voltage switching (ZVS); zero current switching (ZCS); bidirectional converter  

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