Optimizing Current Sharing in Interleaved LLC Converters via Variable Magnetizing Inductance

With the increasing power demands of server supplies, multiphase LLC converters have become widely adopted due to their excellent characteristics. However, slight variations in resonant parameters among phases can lead to significant current imbalances, resulting in various operational issues. This paper proposes a method based on variable magnetizing inductance to address these challenges. Through control of an auxiliary winding current, which generates an orthogonal magnetic flux, the magnetizing inductance of the transformer is varied. Therefore, the gain of the LLC converter could be adjusted to be the same with same load. Hence, all the LLC converters’ currents are equally shared. To validate the effectiveness of this approach, the paper analyzes its impact on system performance, specifically examining phase voltage gain as a metric. Simulation results confirm the viability and correctness of the proposed method.