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A GaN 500 kHz High Current Active Clamp Phase-Shifted Full-Bridge Converter with Zero-Voltage Switching over the Entire Line and Load Range
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| Author(s) |
Martin HEINTZE |
| Abstract |
A GaN Active Clamp Phase-Shifted Full-bridge (PSFB) is introduced which enables zero-voltageswitching (ZVS) over entire load and voltage range without any additional auxiliary circuit elements.For high load operation ZVS is achieved through a small leakage inductance as in conventional PSFBconverters. To expand the ZVS range to zero load conditions the ripple current of the current doublerinductor in conjunction with an increased magnetizing current of the main transformer is used toobtain ZVS in every operating point. A secondary active clamp circuit limits the over-voltage of thecurrent doubler rectifier. The ZVS mechanism is discussed in detail and some design tradeoffs arehighlighted.The ability of the proposed circuit is demonstrated using a 1.5 kW, 400 V to 12 V DC/DC converterfor automotive application with a wide voltage and power range. The small leakage inductancetogether with the ability to realize soft switching even under low load conditions enables a significantincrease of the switching frequency up to 500 kHz and thus a remarkable increase of power densitywith very high efficiency. |
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| Filename: | 0436-epe2018-full-17053958.pdf |
| Filesize: | 1.997 MB |
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| Type |
Members Only |
| Date |
Last modified 2019-05-05 by System |
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