Open AccessHigh‐efficiency design method of LLC resonant converter for PHEV battery chargers (based on time‐domain model)
Author(s) -
Shen Chaochao,
Xiao Qianghui,
Zhang Yang
Publication year - 2020
Publication title -
iet electrical systems in transportation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.588
H-Index - 26
eISSN - 2042-9746
pISSN - 2042-9738
DOI - 10.1049/iet-est.2019.0092
Subject(s) - inductance , voltage , resonant converter , transformer , electrical impedance , engineering , electronic engineering , electrical engineering , inductor
High efficiency, high power density and wide output voltage are required for on‐board charger (OBC) applications. LLC resonant converter has the advantage of achieving zero‐voltage switching for variable frequency and different load conditions. Compared with conventional fundamental harmonic approximation method, operation‐mode analysis based on the time domain model provides an accurate description of resonant current, voltage and DC gain. In this study, the efficiency‐oriented modified method is proposed based on the operation‐mode analysis. The converter inductance ratio, characteristic impedance and transformer turns ratio are optimised and both‐side soft switching can be achieved in the high output voltage region. Conduction loss can be minimised by optimising resonant parameters. Finally, a high‐efficiency design method is proposed and validated through experiments on a 3.3kW prototype applied in OBC. The prototype of the LLC resonant converter has been tested for dynamic charging voltage (230–430V) with a peak efficiency value of 98.5%.