Open AccessMagnetic flux density analysis of series resonant converter operating in discontinuous conduction mode for high‐voltage high‐power applications
Author(s) -
Ning Guangfu,
Chen Wu,
Ling Yanbo,
Su Mei,
Xu Guo
Publication year - 2020
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2020.0086
Subject(s) - transformer , voltage , capacitor , physics , pulse width modulation , materials science , power density , electrical engineering , power (physics) , engineering , quantum mechanics
Due to its zero‐current switching characteristic, the series resonant converter operating in discontinuous conduction mode (DCM‐SRC) is suitable for high‐voltage high‐power applications. To meet the requirement of a wide output voltage range, the pulse frequency modulation with constant on‐time can be adopted for DCM‐SRC. By comparing the resonant capacitor voltage with input voltage, it is first discovered that there are two different operation cases with different magnetic flux density (MFD) values for the transformer core. The boundary conditions for the two cases are revealed, and the exact maximum MFD (MMFD) expression of each case is derived. According to the obtained expressions, the MMFD has the smallest value under the lowest switching frequency and increases with the increase of switching frequency for both cases, indicating that the high‐power transformer can be designed at the highest switching frequency. The fundamental cause of higher MMFD case is derived according to the in‐depth analysis of resonant capacitor voltage. Moreover, a transformer turns ratio design guideline can be easily obtained to reduce the MMFD. Both the simulation model and laboratory prototype are established for verification, and the results show that the theoretical analysis is convincing.