Analysis of light and no‐load operation of a 300 kW resonant single active bridge based on 3.3 kV SiC‐devices
Résumé
The resonant single active bridge topology (R-SAB) operated in the half-cycle discon-tinuous current mode (HC-DCM) is a very attractive solution due to its high efficiency,low complexity and fixed voltage transfer ratio (DCX). However, as expected for aseries-resonant converter (SRC), its DCX operation depends on the resonant tank circuit-parameters, parasitic capacitive elements and output load. Specially, at light and no-loadoperation, when the system is extremely underdamped, it may present a large output over-voltage due to resonance interactions. This is of prime importance for converters usingmedium voltage (MV) SiC-MOSFETs, which feature significant output capacitances thatcan lead to voltage breakdown of the rectifier semiconductors. Therefore, the supposedfixed-voltage transfer ratio is not entirely valid and deserves a proper understanding dueits criticality. This paper reviews the subject, clarifying its root cause and its multifactorialdependencies. Moreover, it provides a simple solution based on a variable dead-time withfixed magnetizing current experimentally verified with a 300kW/1.8kV R-SAB prototypeimplemented with MV SiC-devices.
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Licence : CC BY NC ND - Paternité - Pas d'utilisation commerciale - Pas de modification
Licence : CC BY NC ND - Paternité - Pas d'utilisation commerciale - Pas de modification