GaN Based 1MHz Phase Shifted Full Bridge Converter

• Main Author: HIEU PHU PHAM
• Other Authors: Huang-Jen Chiu
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/rba7t8

博士 === 國立臺灣科技大學 === 電子工程系 === 106 === The Power Supply Unit (PSU) for data center and telecommunication application typically handles from few hundreds Watt to few kilo Watts, that is composed of Power Factor Corrector (PFC) stage and frond-end DC-DC stage. For application such as telecommunication, the output voltage range is typically regulated at 48-60V from the 360- 400V input voltage source of PFC circuit. For high power application, the full bridge topologies, i.e. phase shifted full bridge (PSFB) converters are mostly used due to ability of carrying high current. The conventional PSFB converters have the drawbacks of narrow zero voltage switching (ZVS) operating range and high voltage stresses on the output rectifiers, which limit the operating of converter in MHertz switching frequencies. In this dissertation, the Tr-lead type PSFB converter employing two clamping diodes to overcome abovementioned issues is presented. The parasitic capacitor and reverse recovery characteristics of the output rectifiers that severely effect the performance of converter in high switching frequencies are discussed, together with the detailed analysis of both conventional and proposed converter. The solution of using enhanced mode Gallium Nitride wide band gap devices is introduced in order to overcome the drawback of Silicon based devices. Finally, a 480W 1MHz switching frequency prototype is built up and tested in laboratory. The experimental results show the ZVS achievement of switches in the wide range of load conditions, featuring the capability of operating in MHertz frequencies of this converter. The achieved peak efficiency of converter is up to 93% at full load condition