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Title: Analysis of Diode Reverse Recovery Effect on ZVS Condition for GaN-Based LLC Resonant Converter

Journal Article · · IEEE Transactions on Power Electronics

LLC resonant converter can achieve zero voltage switching (ZVS) for primary-side devices and zero current switching (ZCS) for secondary-side rectifiers. However, the reverse recovery and junction capacitance (C j ) of secondary-side diode critically affect the ZVS condition of primary-side switches. The effect of C j has been discussed in literature, but not the reverse recovery. In this paper, the reverse recovery charge (Q rr ) is converted to an equivalent capacitance (C rr_eq ) for the study of primary-side ZVS performance. An accurate model during deadtime is derived and further applied to characterize ZVS performance with different reverse recovery charges in different regions. The concept of establishing parameter C total to consider both C j and C rr_eq is proposed to evaluate the effect of the secondary-side rectifiers. This concept provides the guideline for diode and synchronous rectification MOSFET selection to ensure ZVS condition for LLC converters. To verify the concept and the derived model,a 200/400 V 400 W LLC resonant converter prototype operating from 200 to 700 kHz is built and its ZVS performances with different diodes are compared. Two issues caused by Q rr effect, including V ds reverse charging and asymmetrical waveform during deadtime, are explained thoroughly as well.

Research Organization:
Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
Sponsoring Organization:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Grant/Contract Number:
AR0000843
OSTI ID:
1803991
Journal Information:
IEEE Transactions on Power Electronics, Vol. 34, Issue 12; ISSN 0885-8993
Publisher:
IEEECopyright Statement
Country of Publication:
United States
Language:
English