LLC resonant converter with wide output voltage control ranges operating at a constant switching frequency

In this paper, an LLC resonant converter with a wide output voltage control range operating at a constant switching frequency is presented. The proposed converter provides a wide controllable output voltage (Vo~8Vo) with high efficiency over a wide load range. The LLC resonant converter's primary switching devices (Q1-Q4) are configured to operate in the half-bridge/full-bridge operating modes and the auxiliary switches (S
_a1
, S
_a2
) are turned on and off to meet the required voltage gain characteristic. The feasibility of the proposed converter is verified with experimental results of a 2kW prototype.