Effects of Parasitics on An Active Clamp Assisted Phase Shifted Full Bridge Converter Operation

Mahapatra, M and Pal, A and Basu, K (2021) Effects of Parasitics on An Active Clamp Assisted Phase Shifted Full Bridge Converter Operation. In: 13th IEEE Energy Conversion Congress and Exposition, 10-14 Oct 2021, Virtual, Online, pp. 2162-2167.

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Abstract

The phase-shifted full bridge (PSFB) converter is widely used for isolated DC-DC applications due to simple control and zero voltage switching (ZVS) capability. The ZVS is achieved with the help of primary bridge device capacitances and transformer leakage inductance. The secondary diode parasitic capacitances cause high voltage stress and affect the converter voltage gain. In literature, several snubber circuits are presented to clamp the voltage overshoot, but the change in voltage gain due to secondary diode capacitances is ignored. In this paper the operation of PSFB with an active clamp is analysed considering all circuit parasitics including transformer leakage inductance, primary device and secondary diode capacitances. A closed form expression of the voltage gain is analytically derived. It is observed that the voltage gain is independent of snubber clamp voltage. Other than the known duty cycle loss due to leakage inductance, the output voltage has a duty cycle gain due to secondary diode capacitance. The paper also presents an estimation technique of key parasitics through experiment. These findings are essential for the design of a PSFB particularly for high-step-up application. A prototype of 1.5kW with input 400V and output 1.25kV is built and tested. Key experimental results are shown to verify the presented analysis of PSFB considering all parasitics. © 2021 IEEE.

Item Type:	Conference Paper
Publication:	2021 IEEE Energy Conversion Congress and Exposition, ECCE 2021 - Proceedings
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to Institute of Electrical and Electronics Engineers Inc.
Department/Centre:	Division of Electrical Sciences > Electrical Engineering
Date Deposited:	07 Feb 2022 12:20
Last Modified:	07 Feb 2022 12:20
URI:	http://eprints.iisc.ac.in/id/eprint/71278

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