The Analysis of Current Sharing and Parameter Sensitivity for Paralleled LLC Resonant DC/DC Converter

With the development of medium-voltage direct current (MVDC) collection for photovoltaics, high-power isolated resonant DC/DC converter with multi-module input-parallel output-parallel (IPOP) structure has become a focus due to its advantages of high efficiency and redundant design. However, the IPOP-type converters suffer from parameter deviations, which lead to current sharing unbalance among power modules, causing additional losses and device damage. In order to predict the current sharing unbalance of the IPOP-type converters, this paper derives a quantified model through differential equations. Based on the model, critical parameters are identified, and the impact of the different levels of parameter variation on the current sharing is evaluated. Meanwhile, the impact of the positions of the resonant components is also studied. Modeling and analysis are verified by means of simulation and experiment.