| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 105 === Full-bridge phase-shift converter has the merit of zero-voltage switching (ZVS) which can reduce the switching loss and the high frequency noise interference. However, there will be voltage spike induced on the secondary side synchronous rectification MOSEFTs. This thesis presents the study upon an active snubber circuit which is designed to reduce the spike. This active snubber is compared with the well-known RC and RCD passive snubbers. The stray energy on the secondary-side is restored to the snubber capacitors, then the snubber transfers the stored energy back to the primary-side. Due to the energy retrieval, the active snubber circuit surpasses the passive counterpart on energy efficiency. Besides, the voltage stress on the synchronous rectification MOSFETs is lowered benefited from the spike reduction; the MOSFET conduction resistance i.e. the conduction loss can also be reduced. That is, the power efficiency is further improved by the application of the active snubber.
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