A Natural Current Sharing in LLC Resonant Converter and Analysis of the Current Sharing Error

Abstract

Input-parallel and output-parallel (IPOP) converters are commonly used to share the high output current. However, unbalanced current occurs because they have a voltage gain difference due to the tolerance of the components. Therefore, IPOP converters require expensive current sensors and complex controls for current sharing. To improve these drawbacks, this paper proposes a novel LLC resonant converter capable of natural current sharing. The proposed converter can achieve current sharing without expensive current sensors and complex controls. In addition, it can have small current sharing errors. Furthermore, the structure of proposed converter is implemented simply through the secondary-side point connection without additional components. Finally, the feasibility of the proposed converter is verified by the experimental results with a 100 V/20 A 2000 W lab prototype converter.